Add LiPo battery monitoring with ESP-NOW cache and dashboard API.

Slaves report pack voltages every 30s; the master caches them for fast
BATTERY_STATUS reads. goTool exposes REST/WebSocket and shows values in
the dashboard, with a nanopb fix so optional lipo submessages encode.

Co-authored-by: Cursor <cursoragent@cursor.com>

goTool/README.md

@@ -87,7 +87,7 @@ Polling runs only when at least one connection has `receive_accel: true` **and**
 **Hello** (on connect; accel is off until `set_stream`):
 
 ```json
-{"type":"hello","serial_port":"/dev/ttyUSB0","interval_ms":16,"commands":["set_stream","get_stream","set_accel_stream","get_accel_stream","set_led_ring"]}
+{"type":"hello","serial_port":"/dev/ttyUSB0","interval_ms":16,"commands":["set_stream","get_stream","set_accel_stream","get_accel_stream","set_led_ring","get_battery"]}
 ```
 
 **Receive accel on this connection** (optional `interval_ms`, default from `-accel-interval`):
@@ -167,7 +167,7 @@ The dashboard can configure nodes using the same UART commands as the CLI:
 | Alle Slaves | per-slave ESP-NOW (Master bleibt unverändert; CLI `-all` setzt auch den Master) |
 | Unicast test | `unicast-test -client ID` |
 
-HTTP API (used by the web UI): `GET/POST /api/deadzone`, `GET/PUT /api/clients/{id}/accel-stream`, `POST /api/accel-stream` (legacy / `all_clients`), `POST /api/led-ring`, `POST /api/unicast-test`, `POST /api/find-me`, `POST /api/restart`, `POST /api/ota` (multipart field `firmware`, max 2 MiB).
+HTTP API (used by the web UI): `GET/POST /api/deadzone`, `GET/PUT /api/clients/{id}/accel-stream`, `POST /api/accel-stream` (legacy / `all_clients`), `GET/POST /api/battery`, `POST /api/led-ring`, `POST /api/unicast-test`, `POST /api/find-me`, `POST /api/restart`, `POST /api/ota` (multipart field `firmware`, max 2 MiB).
 
 **LED ring** (`POST /api/led-ring` and WebSocket `set_led_ring` on `:8081`):
 
@@ -179,6 +179,16 @@ HTTP API (used by the web UI): `GET/POST /api/deadzone`, `GET/PUT /api/clients/{
 
 Modes: `clear`, `color` (full ring), `progress` (0–100), `digit` (0–10 symbols), `blink`, `find-me`. Use `client_id` (0 = master), or `all_clients` (+ optional `slaves_only`) for broadcast.
 
+**Battery** (`GET/POST /api/battery`, WebSocket `get_battery` on `:8081`):
+
+```json
+{"all_clients":true}
+{"client_id":0}
+{"client_id":16}
+```
+
+Response: `samples[]` with `client_id`, `lipo1`/`lipo2` (`valid`, `voltage_mv`, `percent`), `age_ms`. Slaves push to the master every **30 s**; UART reads the cache (fast). Dashboard polls with `all_clients`.
+
 **Accel stream per slave** (must be enabled before values appear; goTool polls only while at least one slave has stream on):
 
 ```http

goTool/api_battery.go

@@ -0,0 +1,60 @@
+package main
+
+import (
+	"encoding/json"
+	"net/http"
+	"strconv"
+)
+
+func mountBatteryAPI(mux *http.ServeMux, link *managedSerial) {
+	mux.HandleFunc("/api/battery", func(w http.ResponseWriter, r *http.Request) {
+		switch r.Method {
+		case http.MethodGet:
+			serveBatteryGet(w, r, link)
+		case http.MethodPost:
+			serveBatteryPost(w, r, link)
+		default:
+			http.Error(w, "method not allowed", http.StatusMethodNotAllowed)
+		}
+	})
+}
+
+func serveBatteryGet(w http.ResponseWriter, r *http.Request, link *managedSerial) {
+	req := batteryAPIRequest{}
+	if v := r.URL.Query().Get("all_clients"); v == "1" || v == "true" {
+		req.AllClients = true
+	}
+	if s := r.URL.Query().Get("client_id"); s != "" {
+		id, err := strconv.ParseUint(s, 10, 32)
+		if err != nil {
+			writeJSON(w, http.StatusBadRequest, batteryAPIResponse{Error: "invalid client_id"})
+			return
+		}
+		req.ClientID = uint32(id)
+	} else if !req.AllClients {
+		req.AllClients = true
+	}
+	out := applyBatteryStatus(link, req)
+	status := http.StatusOK
+	if out.Error != "" || !out.Success {
+		status = http.StatusServiceUnavailable
+	}
+	writeJSON(w, status, out)
+}
+
+func serveBatteryPost(w http.ResponseWriter, r *http.Request, link *managedSerial) {
+	var body batteryAPIRequest
+	if err := json.NewDecoder(r.Body).Decode(&body); err != nil {
+		writeJSON(w, http.StatusBadRequest, batteryAPIResponse{Error: "invalid JSON"})
+		return
+	}
+	if !body.AllClients && body.ClientID == 0 {
+		body.AllClients = true
+	}
+	out := applyBatteryStatus(link, body)
+	status := http.StatusOK
+	if out.Error != "" || !out.Success {
+		status = http.StatusServiceUnavailable
+	}
+	writeJSON(w, status, out)
+}

goTool/api_serve.go

@@ -70,6 +70,7 @@ type otaAPIResponse struct {
 func mountServeAPI(mux *http.ServeMux, link *managedSerial, hub *wsHub, streamCtl *accelStreamCtl) {
 	mountAccelStreamAPI(mux, link, hub, streamCtl)
 	mountLedRingAPI(mux, link)
+	mountBatteryAPI(mux, link)
 	mux.HandleFunc("/api/deadzone", func(w http.ResponseWriter, r *http.Request) {
 		switch r.Method {
 		case http.MethodGet:

goTool/api_stream.go

@@ -133,7 +133,8 @@ func (h *accelStreamHub) register(conn *websocket.Conn, portName string) *wsSubs
 		Serial:     portName,
 		IntervalMs: int(h.defaultInterval / time.Millisecond),
 		Commands: []string{
-			"set_stream", "get_stream", "set_accel_stream", "get_accel_stream", "set_led_ring",
+			"set_stream", "get_stream", "set_accel_stream", "get_accel_stream",
+			"set_led_ring", "get_battery",
 		},
 	}
 	if data, err := json.Marshal(hello); err == nil {
@@ -319,6 +320,15 @@ func writeStreamStatus(conn *websocket.Conn, msg StreamStatusMessage) {
 	_ = conn.WriteMessage(websocket.TextMessage, data)
 }
 
+func writeBatteryStatus(conn *websocket.Conn, out batteryAPIResponse) {
+	out.Type = "battery_status"
+	data, err := json.Marshal(out)
+	if err != nil {
+		return
+	}
+	_ = conn.WriteMessage(websocket.TextMessage, data)
+}
+
 func writeLedRingStatus(conn *websocket.Conn, out ledRingAPIResponse) {
 	out.Type = "led_ring_status"
 	data, err := json.Marshal(out)
@@ -416,10 +426,21 @@ func handleAccelWSCommand(conn *websocket.Conn, sub *wsSubscriber, data []byte,
 		}
 		writeLedRingStatus(conn, applyLedRing(link, body))
 
+	case "get_battery":
+		var body batteryAPIRequest
+		if err := json.Unmarshal(data, &body); err != nil {
+			writeBatteryStatus(conn, batteryAPIResponse{Error: "invalid JSON"})
+			return
+		}
+		if !body.AllClients && body.ClientID == 0 {
+			body.AllClients = true
+		}
+		writeBatteryStatus(conn, applyBatteryStatus(link, body))
+
 	default:
 		writeStreamStatus(conn, StreamStatusMessage{
 			Type: "stream_status",
-			Error: "unknown type (set_stream, get_stream, set_accel_stream, get_accel_stream, set_led_ring)",
+			Error: "unknown type (set_stream, get_stream, set_accel_stream, get_accel_stream, set_led_ring, get_battery)",
 		})
 	}
 }
@@ -478,6 +499,7 @@ func runAPIServer(portName string, link *managedSerial, addr string, defaultInte
 	mux := http.NewServeMux()
 	mountExternalAPI(mux, portName, defaultInterval, hub, link, dash, ctl)
 	mountLedRingAPI(mux, link)
+	mountBatteryAPI(mux, link)
 
 	srv := &http.Server{Addr: addr, Handler: mux}
 	go func() {

goTool/battery_api.go

@@ -0,0 +1,120 @@
+package main
+
+import (
+	"powerpod/gotool/pb"
+)
+
+const (
+	lipoMinMv = 3000
+	lipoMaxMv = 4200
+)
+
+type lipoReadingJSON struct {
+	Valid     bool   `json:"valid"`
+	VoltageMv uint32 `json:"voltage_mv"`
+	Percent   int    `json:"percent,omitempty"`
+}
+
+type batterySampleJSON struct {
+	ClientID uint32          `json:"client_id"`
+	Lipo1    lipoReadingJSON `json:"lipo1"`
+	Lipo2    lipoReadingJSON `json:"lipo2"`
+	AgeMs    uint32          `json:"age_ms,omitempty"`
+}
+
+type batteryAPIRequest struct {
+	ClientID   uint32 `json:"client_id"`
+	AllClients bool   `json:"all_clients"`
+}
+
+type batteryAPIResponse struct {
+	Type     string              `json:"type,omitempty"` // battery_status (WebSocket)
+	Success  bool                `json:"success"`
+	Samples  []batterySampleJSON `json:"samples,omitempty"`
+	Error    string              `json:"error,omitempty"`
+}
+
+func lipoPercent(mv uint32) int {
+	if mv <= lipoMinMv {
+		return 0
+	}
+	if mv >= lipoMaxMv {
+		return 100
+	}
+	return int((mv - lipoMinMv) * 100 / (lipoMaxMv - lipoMinMv))
+}
+
+func lipoFromPBMsg(l *pb.LipoReading) lipoReadingJSON {
+	if l == nil {
+		return lipoReadingJSON{}
+	}
+	return lipoFromPB(l.GetValid(), l.GetVoltageMv())
+}
+
+func lipoFromPB(valid bool, mv uint32) lipoReadingJSON {
+	out := lipoReadingJSON{Valid: valid, VoltageMv: mv}
+	if valid {
+		out.Percent = lipoPercent(mv)
+	}
+	return out
+}
+
+func batterySamplesFromPB(samples []*pb.BatterySample) []batterySampleJSON {
+	out := make([]batterySampleJSON, 0, len(samples))
+	for _, s := range samples {
+		out = append(out, batterySampleJSON{
+			ClientID: s.GetClientId(),
+			Lipo1:    lipoFromPBMsg(s.GetLipo1()),
+			Lipo2:    lipoFromPBMsg(s.GetLipo2()),
+			AgeMs:    s.GetAgeMs(),
+		})
+	}
+	return out
+}
+
+func applyBatteryStatus(link *managedSerial, in batteryAPIRequest) batteryAPIResponse {
+	resp, err := link.BatteryStatus(&pb.BatteryStatusRequest{
+		ClientId:   in.ClientID,
+		AllClients: in.AllClients,
+	})
+	if err != nil {
+		return batteryAPIResponse{Error: err.Error()}
+	}
+	samples := batterySamplesFromPB(resp.GetSamples())
+	out := batteryAPIResponse{
+		Success: resp.GetSuccess() || len(samples) > 0,
+		Samples: samples,
+	}
+	if len(samples) == 0 && out.Error == "" {
+		out.Error = "battery status unavailable"
+	}
+	return out
+}
+
+func findBatterySample(samples []batterySampleJSON, clientID uint32) (batterySampleJSON, bool) {
+	for _, s := range samples {
+		if s.ClientID == clientID {
+			return s, true
+		}
+	}
+	return batterySampleJSON{}, false
+}
+
+// applyBatterySamplesToState merges UART/REST battery samples into dashboard views.
+func applyBatterySamplesToState(st *DashboardState, samples []batterySampleJSON) {
+	if st == nil || len(samples) == 0 {
+		return
+	}
+	if m, ok := findBatterySample(samples, 0); ok {
+		st.Master.Lipo1 = m.Lipo1
+		st.Master.Lipo2 = m.Lipo2
+		st.Master.BatteryAgeMs = m.AgeMs
+	}
+	for i := range st.Clients {
+		if s, ok := findBatterySample(samples, st.Clients[i].ID); ok {
+			st.Clients[i].Lipo1 = s.Lipo1
+			st.Clients[i].Lipo2 = s.Lipo2
+			st.Clients[i].BatteryAgeMs = s.AgeMs
+		}
+	}
+}

goTool/client_api.go

@@ -59,6 +59,86 @@ func (m *managedSerial) readAccelSnapshotPoll(clientID uint32) (*pb.AccelSnapsho
 	return decodeAccelSnapshotPayload(respPayload)
 }
 
+func decodeBatteryStatusPayload(payload []byte) (*pb.BatteryStatusResponse, error) {
+	if len(payload) < 2 {
+		return nil, fmt.Errorf("short battery response")
+	}
+	if payload[0] != byte(pb.MessageType_BATTERY_STATUS) {
+		return nil, fmt.Errorf("unexpected command id 0x%02x (want 0x%02x)",
+			payload[0], byte(pb.MessageType_BATTERY_STATUS))
+	}
+	var msg pb.UartMessage
+	if err := proto.Unmarshal(payload[1:], &msg); err != nil {
+		return nil, fmt.Errorf("decode: %w", err)
+	}
+	if msg.GetType() != pb.MessageType_BATTERY_STATUS {
+		return nil, fmt.Errorf("unexpected type %v", msg.GetType())
+	}
+	r := msg.GetBatteryStatusResponse()
+	if r == nil {
+		return nil, fmt.Errorf("missing battery_status_response")
+	}
+	return r, nil
+}
+
+func (m *managedSerial) BatteryStatus(req *pb.BatteryStatusRequest) (*pb.BatteryStatusResponse, error) {
+	var resp *pb.BatteryStatusResponse
+	err := m.withPort(func(sp *serialPort) error {
+		var e error
+		resp, e = sp.batteryStatus(req)
+		return e
+	})
+	return resp, err
+}
+
+func (m *managedSerial) BatteryStatusPoll(req *pb.BatteryStatusRequest) (*pb.BatteryStatusResponse, error) {
+	msg := &pb.UartMessage{
+		Type: pb.MessageType_BATTERY_STATUS,
+		Payload: &pb.UartMessage_BatteryStatusRequest{
+			BatteryStatusRequest: req,
+		},
+	}
+	body, err := proto.Marshal(msg)
+	if err != nil {
+		return nil, fmt.Errorf("encode: %w", err)
+	}
+	payload := append([]byte{byte(pb.MessageType_BATTERY_STATUS)}, body...)
+	respPayload, err := m.batteryStatusPayloadPoll(payload)
+	if err != nil {
+		return nil, err
+	}
+	return decodeBatteryStatusPayload(respPayload)
+}
+
+func (m *managedSerial) batteryStatusPayloadPoll(payload []byte) ([]byte, error) {
+	var resp []byte
+	err := m.withPortPoll(func(sp *serialPort) error {
+		var e error
+		resp, e = sp.exchangePayloadForBattery(payload, "BATTERY_STATUS")
+		return e
+	})
+	return resp, err
+}
+
+func (s *serialPort) batteryStatus(req *pb.BatteryStatusRequest) (*pb.BatteryStatusResponse, error) {
+	msg := &pb.UartMessage{
+		Type: pb.MessageType_BATTERY_STATUS,
+		Payload: &pb.UartMessage_BatteryStatusRequest{
+			BatteryStatusRequest: req,
+		},
+	}
+	body, err := proto.Marshal(msg)
+	if err != nil {
+		return nil, fmt.Errorf("encode: %w", err)
+	}
+	payload := append([]byte{byte(pb.MessageType_BATTERY_STATUS)}, body...)
+	respPayload, err := s.exchangePayloadForBattery(payload, "BATTERY_STATUS")
+	if err != nil {
+		return nil, err
+	}
+	return decodeBatteryStatusPayload(respPayload)
+}
+
 func (m *managedSerial) AccelStream(req *pb.AccelStreamRequest) (*pb.AccelStreamResponse, error) {
 	return m.accelStreamVia(m.withPort, req)
 }

goTool/cmd_serve.go

@@ -41,6 +41,7 @@ func runServe(portName string, baud int, args []string) error {
 	stop := make(chan struct{})
 	defer close(stop)
 	go runPoller(link, portName, hub, streamCtl, *interval, stop)
+	go runBatteryPoller(link, hub, 5*time.Second, stop)
 	go runAccelDashboardPoller(link, hub, *accelInterval, stop)
 
 	var apiSrv *http.Server

goTool/dashboard.go

@@ -19,7 +19,10 @@ type MasterView struct {
 	GitHash           string `json:"git_hash"`
 	RunningPartition  string `json:"running_partition,omitempty"`
 	Deadzone          uint32 `json:"deadzone,omitempty"`
-	OK                bool   `json:"ok"`
+	Lipo1             lipoReadingJSON `json:"lipo1"`
+	Lipo2             lipoReadingJSON `json:"lipo2"`
+	BatteryAgeMs      uint32          `json:"battery_age_ms,omitempty"`
+	OK                bool            `json:"ok"`
 	Error             string `json:"error,omitempty"`
 }
 
@@ -37,7 +40,10 @@ type ClientView struct {
 	AccelY          int32  `json:"accel_y"`
 	AccelZ          int32  `json:"accel_z"`
 	AccelAgeMs      uint32 `json:"accel_age_ms"`
-	AccelStream     bool   `json:"accel_stream"`
+	AccelStream     bool            `json:"accel_stream"`
+	Lipo1           lipoReadingJSON `json:"lipo1"`
+	Lipo2           lipoReadingJSON `json:"lipo2"`
+	BatteryAgeMs    uint32          `json:"battery_age_ms,omitempty"`
 }
 
 type DashboardState struct {
@@ -62,8 +68,16 @@ func newWSHub() *wsHub {
 
 func (h *wsHub) setState(st DashboardState) {
 	h.mu.Lock()
-	prev := h.state.Clients
-	st.Clients = preserveClientAccel(st.Clients, prev)
+	prev := h.state
+	st.Clients = preserveClientAccel(st.Clients, prev.Clients)
+	st.Clients = preserveClientBattery(st.Clients, prev.Clients)
+	if !st.Master.Lipo1.Valid && !st.Master.Lipo2.Valid {
+		if prev.Master.Lipo1.Valid || prev.Master.Lipo2.Valid {
+			st.Master.Lipo1 = prev.Master.Lipo1
+			st.Master.Lipo2 = prev.Master.Lipo2
+			st.Master.BatteryAgeMs = prev.Master.BatteryAgeMs
+		}
+	}
 	h.state = st
 	conns := make([]*websocket.Conn, 0, len(h.clients))
 	for c := range h.clients {
@@ -156,6 +170,33 @@ func preserveClientAccel(newClients, oldClients []ClientView) []ClientView {
 	return out
 }
 
+func preserveClientBattery(newClients, oldClients []ClientView) []ClientView {
+	if len(oldClients) == 0 {
+		return newClients
+	}
+	oldByID := make(map[uint32]ClientView, len(oldClients))
+	for _, c := range oldClients {
+		oldByID[c.ID] = c
+	}
+	out := make([]ClientView, len(newClients))
+	for i, c := range newClients {
+		out[i] = c
+		if c.Lipo1.Valid || c.Lipo2.Valid {
+			continue
+		}
+		prev, ok := oldByID[c.ID]
+		if !ok {
+			continue
+		}
+		if prev.Lipo1.Valid || prev.Lipo2.Valid {
+			out[i].Lipo1 = prev.Lipo1
+			out[i].Lipo2 = prev.Lipo2
+			out[i].BatteryAgeMs = prev.BatteryAgeMs
+		}
+	}
+	return out
+}
+
 func anyClientAccelStream(clients []ClientView) bool {
 	for _, c := range clients {
 		if c.AccelStream {
@@ -294,6 +335,7 @@ func pollDashboard(link *managedSerial, portName string, last *DashboardState, s
 		}
 		st.Clients = append(st.Clients, cv)
 	}
+	applyBatteryToState(link, &st)
 	if anyClientAccelStream(st.Clients) {
 		for i := range st.Clients {
 			if !st.Clients[i].AccelStream {
@@ -319,6 +361,60 @@ func pollDashboard(link *managedSerial, portName string, last *DashboardState, s
 	return st
 }
 
+func applyBatteryToState(link *managedSerial, st *DashboardState) {
+	bat, err := link.BatteryStatusPoll(&pb.BatteryStatusRequest{AllClients: true})
+	if err != nil {
+		log.Printf("battery poll: %v", err)
+		return
+	}
+	applyBatterySamplesToState(st, batterySamplesFromPB(bat.GetSamples()))
+}
+
+func (h *wsHub) mergeBattery(samples []batterySampleJSON) {
+	if len(samples) == 0 {
+		return
+	}
+	h.mu.Lock()
+	st := h.state
+	applyBatterySamplesToState(&st, samples)
+	st.UpdatedAt = time.Now().Format(time.RFC3339)
+	h.state = st
+	conns := make([]*websocket.Conn, 0, len(h.clients))
+	for c := range h.clients {
+		conns = append(conns, c)
+	}
+	h.mu.Unlock()
+
+	data, err := json.Marshal(st)
+	if err != nil {
+		return
+	}
+	for _, c := range conns {
+		_ = c.WriteMessage(websocket.TextMessage, data)
+	}
+}
+
+func runBatteryPoller(link *managedSerial, hub *wsHub, interval time.Duration, stop <-chan struct{}) {
+	ticker := time.NewTicker(interval)
+	defer ticker.Stop()
+
+	for {
+		select {
+		case <-stop:
+			return
+		case <-ticker.C:
+			if hub.clientCount() == 0 {
+				continue
+			}
+			bat, err := link.BatteryStatusPoll(&pb.BatteryStatusRequest{AllClients: true})
+			if err != nil {
+				continue
+			}
+			hub.mergeBattery(batterySamplesFromPB(bat.GetSamples()))
+		}
+	}
+}
+
 func runAccelDashboardPoller(link *managedSerial, hub *wsHub, interval time.Duration, stop <-chan struct{}) {
 	ticker := time.NewTicker(interval)
 	defer ticker.Stop()

goTool/pb/uart_messages.pb.go

@@ -43,6 +43,7 @@ const (
 	MessageType_RESTART             MessageType = 23
 	MessageType_ACCEL_SNAPSHOT      MessageType = 24
 	MessageType_ACCEL_STREAM        MessageType = 25
+	MessageType_BATTERY_STATUS      MessageType = 26
 )
 
 // Enum value maps for MessageType.
@@ -67,6 +68,7 @@ var (
 		23: "RESTART",
 		24: "ACCEL_SNAPSHOT",
 		25: "ACCEL_STREAM",
+		26: "BATTERY_STATUS",
 	}
 	MessageType_value = map[string]int32{
 		"UNKNOWN":             0,
@@ -88,6 +90,7 @@ var (
 		"RESTART":             23,
 		"ACCEL_SNAPSHOT":      24,
 		"ACCEL_STREAM":        25,
+		"BATTERY_STATUS":      26,
 	}
 )
 
@@ -148,6 +151,8 @@ type UartMessage struct {
 	//	*UartMessage_AccelSnapshotResponse
 	//	*UartMessage_AccelStreamRequest
 	//	*UartMessage_AccelStreamResponse
+	//	*UartMessage_BatteryStatusRequest
+	//	*UartMessage_BatteryStatusResponse
 	Payload       isUartMessage_Payload `protobuf_oneof:"payload"`
 	unknownFields protoimpl.UnknownFields
 	sizeCache     protoimpl.SizeCache
@@ -422,6 +427,24 @@ func (x *UartMessage) GetAccelStreamResponse() *AccelStreamResponse {
 	return nil
 }
 
+func (x *UartMessage) GetBatteryStatusRequest() *BatteryStatusRequest {
+	if x != nil {
+		if x, ok := x.Payload.(*UartMessage_BatteryStatusRequest); ok {
+			return x.BatteryStatusRequest
+		}
+	}
+	return nil
+}
+
+func (x *UartMessage) GetBatteryStatusResponse() *BatteryStatusResponse {
+	if x != nil {
+		if x, ok := x.Payload.(*UartMessage_BatteryStatusResponse); ok {
+			return x.BatteryStatusResponse
+		}
+	}
+	return nil
+}
+
 type isUartMessage_Payload interface {
 	isUartMessage_Payload()
 }
@@ -526,6 +549,14 @@ type UartMessage_AccelStreamResponse struct {
 	AccelStreamResponse *AccelStreamResponse `protobuf:"bytes,26,opt,name=accel_stream_response,json=accelStreamResponse,proto3,oneof"`
 }
 
+type UartMessage_BatteryStatusRequest struct {
+	BatteryStatusRequest *BatteryStatusRequest `protobuf:"bytes,27,opt,name=battery_status_request,json=batteryStatusRequest,proto3,oneof"`
+}
+
+type UartMessage_BatteryStatusResponse struct {
+	BatteryStatusResponse *BatteryStatusResponse `protobuf:"bytes,28,opt,name=battery_status_response,json=batteryStatusResponse,proto3,oneof"`
+}
+
 func (*UartMessage_AckPayload) isUartMessage_Payload() {}
 
 func (*UartMessage_EchoPayload) isUartMessage_Payload() {}
@@ -576,6 +607,10 @@ func (*UartMessage_AccelStreamRequest) isUartMessage_Payload() {}
 
 func (*UartMessage_AccelStreamResponse) isUartMessage_Payload() {}
 
+func (*UartMessage_BatteryStatusRequest) isUartMessage_Payload() {}
+
+func (*UartMessage_BatteryStatusResponse) isUartMessage_Payload() {}
+
 type Ack struct {
 	state         protoimpl.MessageState `protogen:"open.v1"`
 	unknownFields protoimpl.UnknownFields
@@ -1251,6 +1286,235 @@ func (x *AccelStreamResponse) GetSlavesUpdated() uint32 {
 	return 0
 }
 
+// * Host → master: read LiPo ADC voltages (master local and/or slaves via ESP-NOW).
+type BatteryStatusRequest struct {
+	state protoimpl.MessageState `protogen:"open.v1"`
+	// * 0 = master only; >0 = one slave; ignored when all_clients
+	ClientId uint32 `protobuf:"varint,1,opt,name=client_id,json=clientId,proto3" json:"client_id,omitempty"`
+	// * Master (client_id 0) plus every registered slave
+	AllClients    bool `protobuf:"varint,2,opt,name=all_clients,json=allClients,proto3" json:"all_clients,omitempty"`
+	unknownFields protoimpl.UnknownFields
+	sizeCache     protoimpl.SizeCache
+}
+
+func (x *BatteryStatusRequest) Reset() {
+	*x = BatteryStatusRequest{}
+	mi := &file_uart_messages_proto_msgTypes[12]
+	ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
+	ms.StoreMessageInfo(mi)
+}
+
+func (x *BatteryStatusRequest) String() string {
+	return protoimpl.X.MessageStringOf(x)
+}
+
+func (*BatteryStatusRequest) ProtoMessage() {}
+
+func (x *BatteryStatusRequest) ProtoReflect() protoreflect.Message {
+	mi := &file_uart_messages_proto_msgTypes[12]
+	if x != nil {
+		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
+		if ms.LoadMessageInfo() == nil {
+			ms.StoreMessageInfo(mi)
+		}
+		return ms
+	}
+	return mi.MessageOf(x)
+}
+
+// Deprecated: Use BatteryStatusRequest.ProtoReflect.Descriptor instead.
+func (*BatteryStatusRequest) Descriptor() ([]byte, []int) {
+	return file_uart_messages_proto_rawDescGZIP(), []int{12}
+}
+
+func (x *BatteryStatusRequest) GetClientId() uint32 {
+	if x != nil {
+		return x.ClientId
+	}
+	return 0
+}
+
+func (x *BatteryStatusRequest) GetAllClients() bool {
+	if x != nil {
+		return x.AllClients
+	}
+	return false
+}
+
+type LipoReading struct {
+	state protoimpl.MessageState `protogen:"open.v1"`
+	Valid bool                   `protobuf:"varint,1,opt,name=valid,proto3" json:"valid,omitempty"`
+	// * Estimated pack voltage in millivolts from ADC
+	VoltageMv     uint32 `protobuf:"varint,2,opt,name=voltage_mv,json=voltageMv,proto3" json:"voltage_mv,omitempty"`
+	unknownFields protoimpl.UnknownFields
+	sizeCache     protoimpl.SizeCache
+}
+
+func (x *LipoReading) Reset() {
+	*x = LipoReading{}
+	mi := &file_uart_messages_proto_msgTypes[13]
+	ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
+	ms.StoreMessageInfo(mi)
+}
+
+func (x *LipoReading) String() string {
+	return protoimpl.X.MessageStringOf(x)
+}
+
+func (*LipoReading) ProtoMessage() {}
+
+func (x *LipoReading) ProtoReflect() protoreflect.Message {
+	mi := &file_uart_messages_proto_msgTypes[13]
+	if x != nil {
+		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
+		if ms.LoadMessageInfo() == nil {
+			ms.StoreMessageInfo(mi)
+		}
+		return ms
+	}
+	return mi.MessageOf(x)
+}
+
+// Deprecated: Use LipoReading.ProtoReflect.Descriptor instead.
+func (*LipoReading) Descriptor() ([]byte, []int) {
+	return file_uart_messages_proto_rawDescGZIP(), []int{13}
+}
+
+func (x *LipoReading) GetValid() bool {
+	if x != nil {
+		return x.Valid
+	}
+	return false
+}
+
+func (x *LipoReading) GetVoltageMv() uint32 {
+	if x != nil {
+		return x.VoltageMv
+	}
+	return 0
+}
+
+type BatterySample struct {
+	state    protoimpl.MessageState `protogen:"open.v1"`
+	ClientId uint32                 `protobuf:"varint,1,opt,name=client_id,json=clientId,proto3" json:"client_id,omitempty"`
+	Lipo1    *LipoReading           `protobuf:"bytes,2,opt,name=lipo1,proto3" json:"lipo1,omitempty"`
+	Lipo2    *LipoReading           `protobuf:"bytes,3,opt,name=lipo2,proto3" json:"lipo2,omitempty"`
+	// * Milliseconds since last ESP-NOW battery report from this pod.
+	AgeMs         uint32 `protobuf:"varint,4,opt,name=age_ms,json=ageMs,proto3" json:"age_ms,omitempty"`
+	unknownFields protoimpl.UnknownFields
+	sizeCache     protoimpl.SizeCache
+}
+
+func (x *BatterySample) Reset() {
+	*x = BatterySample{}
+	mi := &file_uart_messages_proto_msgTypes[14]
+	ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
+	ms.StoreMessageInfo(mi)
+}
+
+func (x *BatterySample) String() string {
+	return protoimpl.X.MessageStringOf(x)
+}
+
+func (*BatterySample) ProtoMessage() {}
+
+func (x *BatterySample) ProtoReflect() protoreflect.Message {
+	mi := &file_uart_messages_proto_msgTypes[14]
+	if x != nil {
+		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
+		if ms.LoadMessageInfo() == nil {
+			ms.StoreMessageInfo(mi)
+		}
+		return ms
+	}
+	return mi.MessageOf(x)
+}
+
+// Deprecated: Use BatterySample.ProtoReflect.Descriptor instead.
+func (*BatterySample) Descriptor() ([]byte, []int) {
+	return file_uart_messages_proto_rawDescGZIP(), []int{14}
+}
+
+func (x *BatterySample) GetClientId() uint32 {
+	if x != nil {
+		return x.ClientId
+	}
+	return 0
+}
+
+func (x *BatterySample) GetLipo1() *LipoReading {
+	if x != nil {
+		return x.Lipo1
+	}
+	return nil
+}
+
+func (x *BatterySample) GetLipo2() *LipoReading {
+	if x != nil {
+		return x.Lipo2
+	}
+	return nil
+}
+
+func (x *BatterySample) GetAgeMs() uint32 {
+	if x != nil {
+		return x.AgeMs
+	}
+	return 0
+}
+
+type BatteryStatusResponse struct {
+	state         protoimpl.MessageState `protogen:"open.v1"`
+	Success       bool                   `protobuf:"varint,1,opt,name=success,proto3" json:"success,omitempty"`
+	Samples       []*BatterySample       `protobuf:"bytes,2,rep,name=samples,proto3" json:"samples,omitempty"`
+	unknownFields protoimpl.UnknownFields
+	sizeCache     protoimpl.SizeCache
+}
+
+func (x *BatteryStatusResponse) Reset() {
+	*x = BatteryStatusResponse{}
+	mi := &file_uart_messages_proto_msgTypes[15]
+	ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
+	ms.StoreMessageInfo(mi)
+}
+
+func (x *BatteryStatusResponse) String() string {
+	return protoimpl.X.MessageStringOf(x)
+}
+
+func (*BatteryStatusResponse) ProtoMessage() {}
+
+func (x *BatteryStatusResponse) ProtoReflect() protoreflect.Message {
+	mi := &file_uart_messages_proto_msgTypes[15]
+	if x != nil {
+		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
+		if ms.LoadMessageInfo() == nil {
+			ms.StoreMessageInfo(mi)
+		}
+		return ms
+	}
+	return mi.MessageOf(x)
+}
+
+// Deprecated: Use BatteryStatusResponse.ProtoReflect.Descriptor instead.
+func (*BatteryStatusResponse) Descriptor() ([]byte, []int) {
+	return file_uart_messages_proto_rawDescGZIP(), []int{15}
+}
+
+func (x *BatteryStatusResponse) GetSuccess() bool {
+	if x != nil {
+		return x.Success
+	}
+	return false
+}
+
+func (x *BatteryStatusResponse) GetSamples() []*BatterySample {
+	if x != nil {
+		return x.Samples
+	}
+	return nil
+}
+
 // Host → master: read cached accel samples from slaves (only while stream enabled).
 // client_id 0 = all registered slaves; otherwise one slave.
 type AccelSnapshotRequest struct {
@@ -1262,7 +1526,7 @@ type AccelSnapshotRequest struct {
 
 func (x *AccelSnapshotRequest) Reset() {
 	*x = AccelSnapshotRequest{}
-	mi := &file_uart_messages_proto_msgTypes[12]
+	mi := &file_uart_messages_proto_msgTypes[16]
 	ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 	ms.StoreMessageInfo(mi)
 }
@@ -1274,7 +1538,7 @@ func (x *AccelSnapshotRequest) String() string {
 func (*AccelSnapshotRequest) ProtoMessage() {}
 
 func (x *AccelSnapshotRequest) ProtoReflect() protoreflect.Message {
-	mi := &file_uart_messages_proto_msgTypes[12]
+	mi := &file_uart_messages_proto_msgTypes[16]
 	if x != nil {
 		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 		if ms.LoadMessageInfo() == nil {
@@ -1287,7 +1551,7 @@ func (x *AccelSnapshotRequest) ProtoReflect() protoreflect.Message {
 
 // Deprecated: Use AccelSnapshotRequest.ProtoReflect.Descriptor instead.
 func (*AccelSnapshotRequest) Descriptor() ([]byte, []int) {
-	return file_uart_messages_proto_rawDescGZIP(), []int{12}
+	return file_uart_messages_proto_rawDescGZIP(), []int{16}
 }
 
 func (x *AccelSnapshotRequest) GetClientId() uint32 {
@@ -1312,7 +1576,7 @@ type AccelSample struct {
 
 func (x *AccelSample) Reset() {
 	*x = AccelSample{}
-	mi := &file_uart_messages_proto_msgTypes[13]
+	mi := &file_uart_messages_proto_msgTypes[17]
 	ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 	ms.StoreMessageInfo(mi)
 }
@@ -1324,7 +1588,7 @@ func (x *AccelSample) String() string {
 func (*AccelSample) ProtoMessage() {}
 
 func (x *AccelSample) ProtoReflect() protoreflect.Message {
-	mi := &file_uart_messages_proto_msgTypes[13]
+	mi := &file_uart_messages_proto_msgTypes[17]
 	if x != nil {
 		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 		if ms.LoadMessageInfo() == nil {
@@ -1337,7 +1601,7 @@ func (x *AccelSample) ProtoReflect() protoreflect.Message {
 
 // Deprecated: Use AccelSample.ProtoReflect.Descriptor instead.
 func (*AccelSample) Descriptor() ([]byte, []int) {
-	return file_uart_messages_proto_rawDescGZIP(), []int{13}
+	return file_uart_messages_proto_rawDescGZIP(), []int{17}
 }
 
 func (x *AccelSample) GetClientId() uint32 {
@@ -1391,7 +1655,7 @@ type AccelSnapshotResponse struct {
 
 func (x *AccelSnapshotResponse) Reset() {
 	*x = AccelSnapshotResponse{}
-	mi := &file_uart_messages_proto_msgTypes[14]
+	mi := &file_uart_messages_proto_msgTypes[18]
 	ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 	ms.StoreMessageInfo(mi)
 }
@@ -1403,7 +1667,7 @@ func (x *AccelSnapshotResponse) String() string {
 func (*AccelSnapshotResponse) ProtoMessage() {}
 
 func (x *AccelSnapshotResponse) ProtoReflect() protoreflect.Message {
-	mi := &file_uart_messages_proto_msgTypes[14]
+	mi := &file_uart_messages_proto_msgTypes[18]
 	if x != nil {
 		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 		if ms.LoadMessageInfo() == nil {
@@ -1416,7 +1680,7 @@ func (x *AccelSnapshotResponse) ProtoReflect() protoreflect.Message {
 
 // Deprecated: Use AccelSnapshotResponse.ProtoReflect.Descriptor instead.
 func (*AccelSnapshotResponse) Descriptor() ([]byte, []int) {
-	return file_uart_messages_proto_rawDescGZIP(), []int{14}
+	return file_uart_messages_proto_rawDescGZIP(), []int{18}
 }
 
 func (x *AccelSnapshotResponse) GetSamples() []*AccelSample {
@@ -1436,7 +1700,7 @@ type EspNowUnicastTestRequest struct {
 
 func (x *EspNowUnicastTestRequest) Reset() {
 	*x = EspNowUnicastTestRequest{}
-	mi := &file_uart_messages_proto_msgTypes[15]
+	mi := &file_uart_messages_proto_msgTypes[19]
 	ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 	ms.StoreMessageInfo(mi)
 }
@@ -1448,7 +1712,7 @@ func (x *EspNowUnicastTestRequest) String() string {
 func (*EspNowUnicastTestRequest) ProtoMessage() {}
 
 func (x *EspNowUnicastTestRequest) ProtoReflect() protoreflect.Message {
-	mi := &file_uart_messages_proto_msgTypes[15]
+	mi := &file_uart_messages_proto_msgTypes[19]
 	if x != nil {
 		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 		if ms.LoadMessageInfo() == nil {
@@ -1461,7 +1725,7 @@ func (x *EspNowUnicastTestRequest) ProtoReflect() protoreflect.Message {
 
 // Deprecated: Use EspNowUnicastTestRequest.ProtoReflect.Descriptor instead.
 func (*EspNowUnicastTestRequest) Descriptor() ([]byte, []int) {
-	return file_uart_messages_proto_rawDescGZIP(), []int{15}
+	return file_uart_messages_proto_rawDescGZIP(), []int{19}
 }
 
 func (x *EspNowUnicastTestRequest) GetClientId() uint32 {
@@ -1488,7 +1752,7 @@ type EspNowUnicastTestResponse struct {
 
 func (x *EspNowUnicastTestResponse) Reset() {
 	*x = EspNowUnicastTestResponse{}
-	mi := &file_uart_messages_proto_msgTypes[16]
+	mi := &file_uart_messages_proto_msgTypes[20]
 	ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 	ms.StoreMessageInfo(mi)
 }
@@ -1500,7 +1764,7 @@ func (x *EspNowUnicastTestResponse) String() string {
 func (*EspNowUnicastTestResponse) ProtoMessage() {}
 
 func (x *EspNowUnicastTestResponse) ProtoReflect() protoreflect.Message {
-	mi := &file_uart_messages_proto_msgTypes[16]
+	mi := &file_uart_messages_proto_msgTypes[20]
 	if x != nil {
 		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 		if ms.LoadMessageInfo() == nil {
@@ -1513,7 +1777,7 @@ func (x *EspNowUnicastTestResponse) ProtoReflect() protoreflect.Message {
 
 // Deprecated: Use EspNowUnicastTestResponse.ProtoReflect.Descriptor instead.
 func (*EspNowUnicastTestResponse) Descriptor() ([]byte, []int) {
-	return file_uart_messages_proto_rawDescGZIP(), []int{16}
+	return file_uart_messages_proto_rawDescGZIP(), []int{20}
 }
 
 func (x *EspNowUnicastTestResponse) GetSuccess() bool {
@@ -1560,7 +1824,7 @@ type LedRingProgressRequest struct {
 
 func (x *LedRingProgressRequest) Reset() {
 	*x = LedRingProgressRequest{}
-	mi := &file_uart_messages_proto_msgTypes[17]
+	mi := &file_uart_messages_proto_msgTypes[21]
 	ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 	ms.StoreMessageInfo(mi)
 }
@@ -1572,7 +1836,7 @@ func (x *LedRingProgressRequest) String() string {
 func (*LedRingProgressRequest) ProtoMessage() {}
 
 func (x *LedRingProgressRequest) ProtoReflect() protoreflect.Message {
-	mi := &file_uart_messages_proto_msgTypes[17]
+	mi := &file_uart_messages_proto_msgTypes[21]
 	if x != nil {
 		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 		if ms.LoadMessageInfo() == nil {
@@ -1585,7 +1849,7 @@ func (x *LedRingProgressRequest) ProtoReflect() protoreflect.Message {
 
 // Deprecated: Use LedRingProgressRequest.ProtoReflect.Descriptor instead.
 func (*LedRingProgressRequest) Descriptor() ([]byte, []int) {
-	return file_uart_messages_proto_rawDescGZIP(), []int{17}
+	return file_uart_messages_proto_rawDescGZIP(), []int{21}
 }
 
 func (x *LedRingProgressRequest) GetMode() uint32 {
@@ -1686,7 +1950,7 @@ type LedRingProgressResponse struct {
 
 func (x *LedRingProgressResponse) Reset() {
 	*x = LedRingProgressResponse{}
-	mi := &file_uart_messages_proto_msgTypes[18]
+	mi := &file_uart_messages_proto_msgTypes[22]
 	ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 	ms.StoreMessageInfo(mi)
 }
@@ -1698,7 +1962,7 @@ func (x *LedRingProgressResponse) String() string {
 func (*LedRingProgressResponse) ProtoMessage() {}
 
 func (x *LedRingProgressResponse) ProtoReflect() protoreflect.Message {
-	mi := &file_uart_messages_proto_msgTypes[18]
+	mi := &file_uart_messages_proto_msgTypes[22]
 	if x != nil {
 		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 		if ms.LoadMessageInfo() == nil {
@@ -1711,7 +1975,7 @@ func (x *LedRingProgressResponse) ProtoReflect() protoreflect.Message {
 
 // Deprecated: Use LedRingProgressResponse.ProtoReflect.Descriptor instead.
 func (*LedRingProgressResponse) Descriptor() ([]byte, []int) {
-	return file_uart_messages_proto_rawDescGZIP(), []int{18}
+	return file_uart_messages_proto_rawDescGZIP(), []int{22}
 }
 
 func (x *LedRingProgressResponse) GetSuccess() bool {
@@ -1766,7 +2030,7 @@ type EspNowFindMeRequest struct {
 
 func (x *EspNowFindMeRequest) Reset() {
 	*x = EspNowFindMeRequest{}
-	mi := &file_uart_messages_proto_msgTypes[19]
+	mi := &file_uart_messages_proto_msgTypes[23]
 	ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 	ms.StoreMessageInfo(mi)
 }
@@ -1778,7 +2042,7 @@ func (x *EspNowFindMeRequest) String() string {
 func (*EspNowFindMeRequest) ProtoMessage() {}
 
 func (x *EspNowFindMeRequest) ProtoReflect() protoreflect.Message {
-	mi := &file_uart_messages_proto_msgTypes[19]
+	mi := &file_uart_messages_proto_msgTypes[23]
 	if x != nil {
 		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 		if ms.LoadMessageInfo() == nil {
@@ -1791,7 +2055,7 @@ func (x *EspNowFindMeRequest) ProtoReflect() protoreflect.Message {
 
 // Deprecated: Use EspNowFindMeRequest.ProtoReflect.Descriptor instead.
 func (*EspNowFindMeRequest) Descriptor() ([]byte, []int) {
-	return file_uart_messages_proto_rawDescGZIP(), []int{19}
+	return file_uart_messages_proto_rawDescGZIP(), []int{23}
 }
 
 func (x *EspNowFindMeRequest) GetClientId() uint32 {
@@ -1811,7 +2075,7 @@ type EspNowFindMeResponse struct {
 
 func (x *EspNowFindMeResponse) Reset() {
 	*x = EspNowFindMeResponse{}
-	mi := &file_uart_messages_proto_msgTypes[20]
+	mi := &file_uart_messages_proto_msgTypes[24]
 	ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 	ms.StoreMessageInfo(mi)
 }
@@ -1823,7 +2087,7 @@ func (x *EspNowFindMeResponse) String() string {
 func (*EspNowFindMeResponse) ProtoMessage() {}
 
 func (x *EspNowFindMeResponse) ProtoReflect() protoreflect.Message {
-	mi := &file_uart_messages_proto_msgTypes[20]
+	mi := &file_uart_messages_proto_msgTypes[24]
 	if x != nil {
 		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 		if ms.LoadMessageInfo() == nil {
@@ -1836,7 +2100,7 @@ func (x *EspNowFindMeResponse) ProtoReflect() protoreflect.Message {
 
 // Deprecated: Use EspNowFindMeResponse.ProtoReflect.Descriptor instead.
 func (*EspNowFindMeResponse) Descriptor() ([]byte, []int) {
-	return file_uart_messages_proto_rawDescGZIP(), []int{20}
+	return file_uart_messages_proto_rawDescGZIP(), []int{24}
 }
 
 func (x *EspNowFindMeResponse) GetSuccess() bool {
@@ -1863,7 +2127,7 @@ type RestartRequest struct {
 
 func (x *RestartRequest) Reset() {
 	*x = RestartRequest{}
-	mi := &file_uart_messages_proto_msgTypes[21]
+	mi := &file_uart_messages_proto_msgTypes[25]
 	ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 	ms.StoreMessageInfo(mi)
 }
@@ -1875,7 +2139,7 @@ func (x *RestartRequest) String() string {
 func (*RestartRequest) ProtoMessage() {}
 
 func (x *RestartRequest) ProtoReflect() protoreflect.Message {
-	mi := &file_uart_messages_proto_msgTypes[21]
+	mi := &file_uart_messages_proto_msgTypes[25]
 	if x != nil {
 		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 		if ms.LoadMessageInfo() == nil {
@@ -1888,7 +2152,7 @@ func (x *RestartRequest) ProtoReflect() protoreflect.Message {
 
 // Deprecated: Use RestartRequest.ProtoReflect.Descriptor instead.
 func (*RestartRequest) Descriptor() ([]byte, []int) {
-	return file_uart_messages_proto_rawDescGZIP(), []int{21}
+	return file_uart_messages_proto_rawDescGZIP(), []int{25}
 }
 
 func (x *RestartRequest) GetClientId() uint32 {
@@ -1908,7 +2172,7 @@ type RestartResponse struct {
 
 func (x *RestartResponse) Reset() {
 	*x = RestartResponse{}
-	mi := &file_uart_messages_proto_msgTypes[22]
+	mi := &file_uart_messages_proto_msgTypes[26]
 	ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 	ms.StoreMessageInfo(mi)
 }
@@ -1920,7 +2184,7 @@ func (x *RestartResponse) String() string {
 func (*RestartResponse) ProtoMessage() {}
 
 func (x *RestartResponse) ProtoReflect() protoreflect.Message {
-	mi := &file_uart_messages_proto_msgTypes[22]
+	mi := &file_uart_messages_proto_msgTypes[26]
 	if x != nil {
 		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 		if ms.LoadMessageInfo() == nil {
@@ -1933,7 +2197,7 @@ func (x *RestartResponse) ProtoReflect() protoreflect.Message {
 
 // Deprecated: Use RestartResponse.ProtoReflect.Descriptor instead.
 func (*RestartResponse) Descriptor() ([]byte, []int) {
-	return file_uart_messages_proto_rawDescGZIP(), []int{22}
+	return file_uart_messages_proto_rawDescGZIP(), []int{26}
 }
 
 func (x *RestartResponse) GetSuccess() bool {
@@ -1960,7 +2224,7 @@ type OtaStartPayload struct {
 
 func (x *OtaStartPayload) Reset() {
 	*x = OtaStartPayload{}
-	mi := &file_uart_messages_proto_msgTypes[23]
+	mi := &file_uart_messages_proto_msgTypes[27]
 	ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 	ms.StoreMessageInfo(mi)
 }
@@ -1972,7 +2236,7 @@ func (x *OtaStartPayload) String() string {
 func (*OtaStartPayload) ProtoMessage() {}
 
 func (x *OtaStartPayload) ProtoReflect() protoreflect.Message {
-	mi := &file_uart_messages_proto_msgTypes[23]
+	mi := &file_uart_messages_proto_msgTypes[27]
 	if x != nil {
 		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 		if ms.LoadMessageInfo() == nil {
@@ -1985,7 +2249,7 @@ func (x *OtaStartPayload) ProtoReflect() protoreflect.Message {
 
 // Deprecated: Use OtaStartPayload.ProtoReflect.Descriptor instead.
 func (*OtaStartPayload) Descriptor() ([]byte, []int) {
-	return file_uart_messages_proto_rawDescGZIP(), []int{23}
+	return file_uart_messages_proto_rawDescGZIP(), []int{27}
 }
 
 func (x *OtaStartPayload) GetTotalSize() uint32 {
@@ -2006,7 +2270,7 @@ type OtaPayload struct {
 
 func (x *OtaPayload) Reset() {
 	*x = OtaPayload{}
-	mi := &file_uart_messages_proto_msgTypes[24]
+	mi := &file_uart_messages_proto_msgTypes[28]
 	ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 	ms.StoreMessageInfo(mi)
 }
@@ -2018,7 +2282,7 @@ func (x *OtaPayload) String() string {
 func (*OtaPayload) ProtoMessage() {}
 
 func (x *OtaPayload) ProtoReflect() protoreflect.Message {
-	mi := &file_uart_messages_proto_msgTypes[24]
+	mi := &file_uart_messages_proto_msgTypes[28]
 	if x != nil {
 		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 		if ms.LoadMessageInfo() == nil {
@@ -2031,7 +2295,7 @@ func (x *OtaPayload) ProtoReflect() protoreflect.Message {
 
 // Deprecated: Use OtaPayload.ProtoReflect.Descriptor instead.
 func (*OtaPayload) Descriptor() ([]byte, []int) {
-	return file_uart_messages_proto_rawDescGZIP(), []int{24}
+	return file_uart_messages_proto_rawDescGZIP(), []int{28}
 }
 
 func (x *OtaPayload) GetSeq() uint32 {
@@ -2057,7 +2321,7 @@ type OtaEndPayload struct {
 
 func (x *OtaEndPayload) Reset() {
 	*x = OtaEndPayload{}
-	mi := &file_uart_messages_proto_msgTypes[25]
+	mi := &file_uart_messages_proto_msgTypes[29]
 	ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 	ms.StoreMessageInfo(mi)
 }
@@ -2069,7 +2333,7 @@ func (x *OtaEndPayload) String() string {
 func (*OtaEndPayload) ProtoMessage() {}
 
 func (x *OtaEndPayload) ProtoReflect() protoreflect.Message {
-	mi := &file_uart_messages_proto_msgTypes[25]
+	mi := &file_uart_messages_proto_msgTypes[29]
 	if x != nil {
 		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 		if ms.LoadMessageInfo() == nil {
@@ -2082,7 +2346,7 @@ func (x *OtaEndPayload) ProtoReflect() protoreflect.Message {
 
 // Deprecated: Use OtaEndPayload.ProtoReflect.Descriptor instead.
 func (*OtaEndPayload) Descriptor() ([]byte, []int) {
-	return file_uart_messages_proto_rawDescGZIP(), []int{25}
+	return file_uart_messages_proto_rawDescGZIP(), []int{29}
 }
 
 // Device → host status (also used as ACK after each 4 KiB written).
@@ -2099,7 +2363,7 @@ type OtaStatusPayload struct {
 
 func (x *OtaStatusPayload) Reset() {
 	*x = OtaStatusPayload{}
-	mi := &file_uart_messages_proto_msgTypes[26]
+	mi := &file_uart_messages_proto_msgTypes[30]
 	ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 	ms.StoreMessageInfo(mi)
 }
@@ -2111,7 +2375,7 @@ func (x *OtaStatusPayload) String() string {
 func (*OtaStatusPayload) ProtoMessage() {}
 
 func (x *OtaStatusPayload) ProtoReflect() protoreflect.Message {
-	mi := &file_uart_messages_proto_msgTypes[26]
+	mi := &file_uart_messages_proto_msgTypes[30]
 	if x != nil {
 		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 		if ms.LoadMessageInfo() == nil {
@@ -2124,7 +2388,7 @@ func (x *OtaStatusPayload) ProtoReflect() protoreflect.Message {
 
 // Deprecated: Use OtaStatusPayload.ProtoReflect.Descriptor instead.
 func (*OtaStatusPayload) Descriptor() ([]byte, []int) {
-	return file_uart_messages_proto_rawDescGZIP(), []int{26}
+	return file_uart_messages_proto_rawDescGZIP(), []int{30}
 }
 
 func (x *OtaStatusPayload) GetStatus() uint32 {
@@ -2165,7 +2429,7 @@ type OtaSlaveProgressRequest struct {
 
 func (x *OtaSlaveProgressRequest) Reset() {
 	*x = OtaSlaveProgressRequest{}
-	mi := &file_uart_messages_proto_msgTypes[27]
+	mi := &file_uart_messages_proto_msgTypes[31]
 	ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 	ms.StoreMessageInfo(mi)
 }
@@ -2177,7 +2441,7 @@ func (x *OtaSlaveProgressRequest) String() string {
 func (*OtaSlaveProgressRequest) ProtoMessage() {}
 
 func (x *OtaSlaveProgressRequest) ProtoReflect() protoreflect.Message {
-	mi := &file_uart_messages_proto_msgTypes[27]
+	mi := &file_uart_messages_proto_msgTypes[31]
 	if x != nil {
 		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 		if ms.LoadMessageInfo() == nil {
@@ -2190,7 +2454,7 @@ func (x *OtaSlaveProgressRequest) ProtoReflect() protoreflect.Message {
 
 // Deprecated: Use OtaSlaveProgressRequest.ProtoReflect.Descriptor instead.
 func (*OtaSlaveProgressRequest) Descriptor() ([]byte, []int) {
-	return file_uart_messages_proto_rawDescGZIP(), []int{27}
+	return file_uart_messages_proto_rawDescGZIP(), []int{31}
 }
 
 func (x *OtaSlaveProgressRequest) GetClientId() uint32 {
@@ -2214,7 +2478,7 @@ type OtaSlaveProgressEntry struct {
 
 func (x *OtaSlaveProgressEntry) Reset() {
 	*x = OtaSlaveProgressEntry{}
-	mi := &file_uart_messages_proto_msgTypes[28]
+	mi := &file_uart_messages_proto_msgTypes[32]
 	ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 	ms.StoreMessageInfo(mi)
 }
@@ -2226,7 +2490,7 @@ func (x *OtaSlaveProgressEntry) String() string {
 func (*OtaSlaveProgressEntry) ProtoMessage() {}
 
 func (x *OtaSlaveProgressEntry) ProtoReflect() protoreflect.Message {
-	mi := &file_uart_messages_proto_msgTypes[28]
+	mi := &file_uart_messages_proto_msgTypes[32]
 	if x != nil {
 		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 		if ms.LoadMessageInfo() == nil {
@@ -2239,7 +2503,7 @@ func (x *OtaSlaveProgressEntry) ProtoReflect() protoreflect.Message {
 
 // Deprecated: Use OtaSlaveProgressEntry.ProtoReflect.Descriptor instead.
 func (*OtaSlaveProgressEntry) Descriptor() ([]byte, []int) {
-	return file_uart_messages_proto_rawDescGZIP(), []int{28}
+	return file_uart_messages_proto_rawDescGZIP(), []int{32}
 }
 
 func (x *OtaSlaveProgressEntry) GetClientId() uint32 {
@@ -2290,7 +2554,7 @@ type OtaSlaveProgressResponse struct {
 
 func (x *OtaSlaveProgressResponse) Reset() {
 	*x = OtaSlaveProgressResponse{}
-	mi := &file_uart_messages_proto_msgTypes[29]
+	mi := &file_uart_messages_proto_msgTypes[33]
 	ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 	ms.StoreMessageInfo(mi)
 }
@@ -2302,7 +2566,7 @@ func (x *OtaSlaveProgressResponse) String() string {
 func (*OtaSlaveProgressResponse) ProtoMessage() {}
 
 func (x *OtaSlaveProgressResponse) ProtoReflect() protoreflect.Message {
-	mi := &file_uart_messages_proto_msgTypes[29]
+	mi := &file_uart_messages_proto_msgTypes[33]
 	if x != nil {
 		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 		if ms.LoadMessageInfo() == nil {
@@ -2315,7 +2579,7 @@ func (x *OtaSlaveProgressResponse) ProtoReflect() protoreflect.Message {
 
 // Deprecated: Use OtaSlaveProgressResponse.ProtoReflect.Descriptor instead.
 func (*OtaSlaveProgressResponse) Descriptor() ([]byte, []int) {
-	return file_uart_messages_proto_rawDescGZIP(), []int{29}
+	return file_uart_messages_proto_rawDescGZIP(), []int{33}
 }
 
 func (x *OtaSlaveProgressResponse) GetActive() bool {
@@ -2357,7 +2621,7 @@ var File_uart_messages_proto protoreflect.FileDescriptor
 
 const file_uart_messages_proto_rawDesc = "" +
 	"\n" +
-	"\x13uart_messages.proto\x12\x04alox\x1a\fnanopb.proto\"\xba\x0f\n" +
+	"\x13uart_messages.proto\x12\x04alox\x1a\fnanopb.proto\"\xe5\x10\n" +
 	"\vUartMessage\x12%\n" +
 	"\x04type\x18\x01 \x01(\x0e2\x11.alox.MessageTypeR\x04type\x12,\n" +
 	"\vack_payload\x18\x02 \x01(\v2\t.alox.AckH\x00R\n" +
@@ -2388,7 +2652,9 @@ const file_uart_messages_proto_rawDesc = "" +
 	"\x16accel_snapshot_request\x18\x17 \x01(\v2\x1a.alox.AccelSnapshotRequestH\x00R\x14accelSnapshotRequest\x12U\n" +
 	"\x17accel_snapshot_response\x18\x18 \x01(\v2\x1b.alox.AccelSnapshotResponseH\x00R\x15accelSnapshotResponse\x12L\n" +
 	"\x14accel_stream_request\x18\x19 \x01(\v2\x18.alox.AccelStreamRequestH\x00R\x12accelStreamRequest\x12O\n" +
-	"\x15accel_stream_response\x18\x1a \x01(\v2\x19.alox.AccelStreamResponseH\x00R\x13accelStreamResponseB\t\n" +
+	"\x15accel_stream_response\x18\x1a \x01(\v2\x19.alox.AccelStreamResponseH\x00R\x13accelStreamResponse\x12R\n" +
+	"\x16battery_status_request\x18\x1b \x01(\v2\x1a.alox.BatteryStatusRequestH\x00R\x14batteryStatusRequest\x12U\n" +
+	"\x17battery_status_response\x18\x1c \x01(\v2\x1b.alox.BatteryStatusResponseH\x00R\x15batteryStatusResponseB\t\n" +
 	"\apayload\"\x05\n" +
 	"\x03Ack\"!\n" +
 	"\vEchoPayload\x12\x12\n" +
@@ -2437,7 +2703,23 @@ const file_uart_messages_proto_rawDesc = "" +
 	"\aenabled\x18\x01 \x01(\bR\aenabled\x12\x1b\n" +
 	"\tclient_id\x18\x02 \x01(\rR\bclientId\x12\x18\n" +
 	"\asuccess\x18\x03 \x01(\bR\asuccess\x12%\n" +
-	"\x0eslaves_updated\x18\x04 \x01(\rR\rslavesUpdated\"3\n" +
+	"\x0eslaves_updated\x18\x04 \x01(\rR\rslavesUpdated\"T\n" +
+	"\x14BatteryStatusRequest\x12\x1b\n" +
+	"\tclient_id\x18\x01 \x01(\rR\bclientId\x12\x1f\n" +
+	"\vall_clients\x18\x02 \x01(\bR\n" +
+	"allClients\"B\n" +
+	"\vLipoReading\x12\x14\n" +
+	"\x05valid\x18\x01 \x01(\bR\x05valid\x12\x1d\n" +
+	"\n" +
+	"voltage_mv\x18\x02 \x01(\rR\tvoltageMv\"\x95\x01\n" +
+	"\rBatterySample\x12\x1b\n" +
+	"\tclient_id\x18\x01 \x01(\rR\bclientId\x12'\n" +
+	"\x05lipo1\x18\x02 \x01(\v2\x11.alox.LipoReadingR\x05lipo1\x12'\n" +
+	"\x05lipo2\x18\x03 \x01(\v2\x11.alox.LipoReadingR\x05lipo2\x12\x15\n" +
+	"\x06age_ms\x18\x04 \x01(\rR\x05ageMs\"g\n" +
+	"\x15BatteryStatusResponse\x12\x18\n" +
+	"\asuccess\x18\x01 \x01(\bR\asuccess\x124\n" +
+	"\asamples\x18\x02 \x03(\v2\x13.alox.BatterySampleB\x05\x92?\x02\x10\x11R\asamples\"3\n" +
 	"\x14AccelSnapshotRequest\x12\x1b\n" +
 	"\tclient_id\x18\x01 \x01(\rR\bclientId\"\x81\x01\n" +
 	"\vAccelSample\x12\x1b\n" +
@@ -2519,7 +2801,7 @@ const file_uart_messages_proto_rawDesc = "" +
 	"\x0faggregate_bytes\x18\x03 \x01(\rR\x0eaggregateBytes\x12\x1f\n" +
 	"\vslave_count\x18\x04 \x01(\rR\n" +
 	"slaveCount\x12:\n" +
-	"\x06slaves\x18\x05 \x03(\v2\x1b.alox.OtaSlaveProgressEntryB\x05\x92?\x02\x10\x10R\x06slaves*\xc3\x02\n" +
+	"\x06slaves\x18\x05 \x03(\v2\x1b.alox.OtaSlaveProgressEntryB\x05\x92?\x02\x10\x10R\x06slaves*\xd7\x02\n" +
 	"\vMessageType\x12\v\n" +
 	"\aUNKNOWN\x10\x00\x12\a\n" +
 	"\x03ACK\x10\x01\x12\b\n" +
@@ -2540,7 +2822,8 @@ const file_uart_messages_proto_rawDesc = "" +
 	"\aFIND_ME\x10\x16\x12\v\n" +
 	"\aRESTART\x10\x17\x12\x12\n" +
 	"\x0eACCEL_SNAPSHOT\x10\x18\x12\x10\n" +
-	"\fACCEL_STREAM\x10\x19b\x06proto3"
+	"\fACCEL_STREAM\x10\x19\x12\x12\n" +
+	"\x0eBATTERY_STATUS\x10\x1ab\x06proto3"
 
 var (
 	file_uart_messages_proto_rawDescOnce sync.Once
@@ -2555,7 +2838,7 @@ func file_uart_messages_proto_rawDescGZIP() []byte {
 }
 
 var file_uart_messages_proto_enumTypes = make([]protoimpl.EnumInfo, 1)
-var file_uart_messages_proto_msgTypes = make([]protoimpl.MessageInfo, 30)
+var file_uart_messages_proto_msgTypes = make([]protoimpl.MessageInfo, 34)
 var file_uart_messages_proto_goTypes = []any{
 	(MessageType)(0),                  // 0: alox.MessageType
 	(*UartMessage)(nil),               // 1: alox.UartMessage
@@ -2570,24 +2853,28 @@ var file_uart_messages_proto_goTypes = []any{
 	(*AccelDeadzoneResponse)(nil),     // 10: alox.AccelDeadzoneResponse
 	(*AccelStreamRequest)(nil),        // 11: alox.AccelStreamRequest
 	(*AccelStreamResponse)(nil),       // 12: alox.AccelStreamResponse
-	(*AccelSnapshotRequest)(nil),      // 13: alox.AccelSnapshotRequest
-	(*AccelSample)(nil),               // 14: alox.AccelSample
-	(*AccelSnapshotResponse)(nil),     // 15: alox.AccelSnapshotResponse
-	(*EspNowUnicastTestRequest)(nil),  // 16: alox.EspNowUnicastTestRequest
-	(*EspNowUnicastTestResponse)(nil), // 17: alox.EspNowUnicastTestResponse
-	(*LedRingProgressRequest)(nil),    // 18: alox.LedRingProgressRequest
-	(*LedRingProgressResponse)(nil),   // 19: alox.LedRingProgressResponse
-	(*EspNowFindMeRequest)(nil),       // 20: alox.EspNowFindMeRequest
-	(*EspNowFindMeResponse)(nil),      // 21: alox.EspNowFindMeResponse
-	(*RestartRequest)(nil),            // 22: alox.RestartRequest
-	(*RestartResponse)(nil),           // 23: alox.RestartResponse
-	(*OtaStartPayload)(nil),           // 24: alox.OtaStartPayload
-	(*OtaPayload)(nil),                // 25: alox.OtaPayload
-	(*OtaEndPayload)(nil),             // 26: alox.OtaEndPayload
-	(*OtaStatusPayload)(nil),          // 27: alox.OtaStatusPayload
-	(*OtaSlaveProgressRequest)(nil),   // 28: alox.OtaSlaveProgressRequest
-	(*OtaSlaveProgressEntry)(nil),     // 29: alox.OtaSlaveProgressEntry
-	(*OtaSlaveProgressResponse)(nil),  // 30: alox.OtaSlaveProgressResponse
+	(*BatteryStatusRequest)(nil),      // 13: alox.BatteryStatusRequest
+	(*LipoReading)(nil),               // 14: alox.LipoReading
+	(*BatterySample)(nil),             // 15: alox.BatterySample
+	(*BatteryStatusResponse)(nil),     // 16: alox.BatteryStatusResponse
+	(*AccelSnapshotRequest)(nil),      // 17: alox.AccelSnapshotRequest
+	(*AccelSample)(nil),               // 18: alox.AccelSample
+	(*AccelSnapshotResponse)(nil),     // 19: alox.AccelSnapshotResponse
+	(*EspNowUnicastTestRequest)(nil),  // 20: alox.EspNowUnicastTestRequest
+	(*EspNowUnicastTestResponse)(nil), // 21: alox.EspNowUnicastTestResponse
+	(*LedRingProgressRequest)(nil),    // 22: alox.LedRingProgressRequest
+	(*LedRingProgressResponse)(nil),   // 23: alox.LedRingProgressResponse
+	(*EspNowFindMeRequest)(nil),       // 24: alox.EspNowFindMeRequest
+	(*EspNowFindMeResponse)(nil),      // 25: alox.EspNowFindMeResponse
+	(*RestartRequest)(nil),            // 26: alox.RestartRequest
+	(*RestartResponse)(nil),           // 27: alox.RestartResponse
+	(*OtaStartPayload)(nil),           // 28: alox.OtaStartPayload
+	(*OtaPayload)(nil),                // 29: alox.OtaPayload
+	(*OtaEndPayload)(nil),             // 30: alox.OtaEndPayload
+	(*OtaStatusPayload)(nil),          // 31: alox.OtaStatusPayload
+	(*OtaSlaveProgressRequest)(nil),   // 32: alox.OtaSlaveProgressRequest
+	(*OtaSlaveProgressEntry)(nil),     // 33: alox.OtaSlaveProgressEntry
+	(*OtaSlaveProgressResponse)(nil),  // 34: alox.OtaSlaveProgressResponse
 }
 var file_uart_messages_proto_depIdxs = []int32{
 	0,  // 0: alox.UartMessage.type:type_name -> alox.MessageType
@@ -2596,35 +2883,40 @@ var file_uart_messages_proto_depIdxs = []int32{
 	4,  // 3: alox.UartMessage.version_response:type_name -> alox.VersionResponse
 	6,  // 4: alox.UartMessage.client_info_response:type_name -> alox.ClientInfoResponse
 	8,  // 5: alox.UartMessage.client_input_response:type_name -> alox.ClientInputResponse
-	24, // 6: alox.UartMessage.ota_start:type_name -> alox.OtaStartPayload
-	25, // 7: alox.UartMessage.ota_payload:type_name -> alox.OtaPayload
-	26, // 8: alox.UartMessage.ota_end:type_name -> alox.OtaEndPayload
-	27, // 9: alox.UartMessage.ota_status:type_name -> alox.OtaStatusPayload
+	28, // 6: alox.UartMessage.ota_start:type_name -> alox.OtaStartPayload
+	29, // 7: alox.UartMessage.ota_payload:type_name -> alox.OtaPayload
+	30, // 8: alox.UartMessage.ota_end:type_name -> alox.OtaEndPayload
+	31, // 9: alox.UartMessage.ota_status:type_name -> alox.OtaStatusPayload
 	9,  // 10: alox.UartMessage.accel_deadzone_request:type_name -> alox.AccelDeadzoneRequest
 	10, // 11: alox.UartMessage.accel_deadzone_response:type_name -> alox.AccelDeadzoneResponse
-	16, // 12: alox.UartMessage.espnow_unicast_test_request:type_name -> alox.EspNowUnicastTestRequest
-	17, // 13: alox.UartMessage.espnow_unicast_test_response:type_name -> alox.EspNowUnicastTestResponse
-	28, // 14: alox.UartMessage.ota_slave_progress_request:type_name -> alox.OtaSlaveProgressRequest
-	30, // 15: alox.UartMessage.ota_slave_progress_response:type_name -> alox.OtaSlaveProgressResponse
-	18, // 16: alox.UartMessage.led_ring_progress_request:type_name -> alox.LedRingProgressRequest
-	19, // 17: alox.UartMessage.led_ring_progress_response:type_name -> alox.LedRingProgressResponse
-	20, // 18: alox.UartMessage.espnow_find_me_request:type_name -> alox.EspNowFindMeRequest
-	21, // 19: alox.UartMessage.espnow_find_me_response:type_name -> alox.EspNowFindMeResponse
-	22, // 20: alox.UartMessage.restart_request:type_name -> alox.RestartRequest
-	23, // 21: alox.UartMessage.restart_response:type_name -> alox.RestartResponse
-	13, // 22: alox.UartMessage.accel_snapshot_request:type_name -> alox.AccelSnapshotRequest
-	15, // 23: alox.UartMessage.accel_snapshot_response:type_name -> alox.AccelSnapshotResponse
+	20, // 12: alox.UartMessage.espnow_unicast_test_request:type_name -> alox.EspNowUnicastTestRequest
+	21, // 13: alox.UartMessage.espnow_unicast_test_response:type_name -> alox.EspNowUnicastTestResponse
+	32, // 14: alox.UartMessage.ota_slave_progress_request:type_name -> alox.OtaSlaveProgressRequest
+	34, // 15: alox.UartMessage.ota_slave_progress_response:type_name -> alox.OtaSlaveProgressResponse
+	22, // 16: alox.UartMessage.led_ring_progress_request:type_name -> alox.LedRingProgressRequest
+	23, // 17: alox.UartMessage.led_ring_progress_response:type_name -> alox.LedRingProgressResponse
+	24, // 18: alox.UartMessage.espnow_find_me_request:type_name -> alox.EspNowFindMeRequest
+	25, // 19: alox.UartMessage.espnow_find_me_response:type_name -> alox.EspNowFindMeResponse
+	26, // 20: alox.UartMessage.restart_request:type_name -> alox.RestartRequest
+	27, // 21: alox.UartMessage.restart_response:type_name -> alox.RestartResponse
+	17, // 22: alox.UartMessage.accel_snapshot_request:type_name -> alox.AccelSnapshotRequest
+	19, // 23: alox.UartMessage.accel_snapshot_response:type_name -> alox.AccelSnapshotResponse
 	11, // 24: alox.UartMessage.accel_stream_request:type_name -> alox.AccelStreamRequest
 	12, // 25: alox.UartMessage.accel_stream_response:type_name -> alox.AccelStreamResponse
-	5,  // 26: alox.ClientInfoResponse.clients:type_name -> alox.ClientInfo
-	7,  // 27: alox.ClientInputResponse.clients:type_name -> alox.ClientInput
-	14, // 28: alox.AccelSnapshotResponse.samples:type_name -> alox.AccelSample
-	29, // 29: alox.OtaSlaveProgressResponse.slaves:type_name -> alox.OtaSlaveProgressEntry
-	30, // [30:30] is the sub-list for method output_type
-	30, // [30:30] is the sub-list for method input_type
-	30, // [30:30] is the sub-list for extension type_name
-	30, // [30:30] is the sub-list for extension extendee
-	0,  // [0:30] is the sub-list for field type_name
+	13, // 26: alox.UartMessage.battery_status_request:type_name -> alox.BatteryStatusRequest
+	16, // 27: alox.UartMessage.battery_status_response:type_name -> alox.BatteryStatusResponse
+	5,  // 28: alox.ClientInfoResponse.clients:type_name -> alox.ClientInfo
+	7,  // 29: alox.ClientInputResponse.clients:type_name -> alox.ClientInput
+	14, // 30: alox.BatterySample.lipo1:type_name -> alox.LipoReading
+	14, // 31: alox.BatterySample.lipo2:type_name -> alox.LipoReading
+	15, // 32: alox.BatteryStatusResponse.samples:type_name -> alox.BatterySample
+	18, // 33: alox.AccelSnapshotResponse.samples:type_name -> alox.AccelSample
+	33, // 34: alox.OtaSlaveProgressResponse.slaves:type_name -> alox.OtaSlaveProgressEntry
+	35, // [35:35] is the sub-list for method output_type
+	35, // [35:35] is the sub-list for method input_type
+	35, // [35:35] is the sub-list for extension type_name
+	35, // [35:35] is the sub-list for extension extendee
+	0,  // [0:35] is the sub-list for field type_name
 }
 
 func init() { file_uart_messages_proto_init() }
@@ -2658,6 +2950,8 @@ func file_uart_messages_proto_init() {
 		(*UartMessage_AccelSnapshotResponse)(nil),
 		(*UartMessage_AccelStreamRequest)(nil),
 		(*UartMessage_AccelStreamResponse)(nil),
+		(*UartMessage_BatteryStatusRequest)(nil),
+		(*UartMessage_BatteryStatusResponse)(nil),
 	}
 	type x struct{}
 	out := protoimpl.TypeBuilder{
@@ -2665,7 +2959,7 @@ func file_uart_messages_proto_init() {
 			GoPackagePath: reflect.TypeOf(x{}).PkgPath(),
 			RawDescriptor: unsafe.Slice(unsafe.StringData(file_uart_messages_proto_rawDesc), len(file_uart_messages_proto_rawDesc)),
 			NumEnums:      1,
-			NumMessages:   30,
+			NumMessages:   34,
 			NumExtensions: 0,
 			NumServices:   0,
 		},

goTool/serial_link.go

@@ -119,7 +119,7 @@ func (m *managedSerial) exchangePayloadVia(
 	var resp []byte
 	err := portFn(func(sp *serialPort) error {
 		var e error
-		resp, e = sp.exchangePayloadLocked(payload, cmdName)
+		resp, e = sp.exchangePayloadLocked(payload, cmdName, readTimeout)
 		return e
 	})
 	return resp, err

goTool/serialport.go

@@ -12,6 +12,9 @@ import (
 
 const readTimeout = 3 * time.Second
 
+// batteryReadTimeout: master may query each slave over ESP-NOW (~400 ms each).
+const batteryReadTimeout = 12 * time.Second
+
 type serialPort struct {
 	port  serial.Port
 	mu    sync.Mutex
@@ -44,10 +47,16 @@ func (s *serialPort) Close() error {
 func (s *serialPort) exchangePayload(payload []byte, cmdName string) ([]byte, error) {
 	s.mu.Lock()
 	defer s.mu.Unlock()
-	return s.exchangePayloadLocked(payload, cmdName)
+	return s.exchangePayloadLocked(payload, cmdName, readTimeout)
 }
 
-func (s *serialPort) exchangePayloadLocked(payload []byte, cmdName string) ([]byte, error) {
+func (s *serialPort) exchangePayloadForBattery(payload []byte, cmdName string) ([]byte, error) {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	return s.exchangePayloadLocked(payload, cmdName, batteryReadTimeout)
+}
+
+func (s *serialPort) exchangePayloadLocked(payload []byte, cmdName string, timeout time.Duration) ([]byte, error) {
 	if len(payload) == 0 {
 		return nil, fmt.Errorf("empty payload")
 	}
@@ -63,6 +72,14 @@ func (s *serialPort) exchangePayloadLocked(payload []byte, cmdName string) ([]by
 		return nil, fmt.Errorf("write: %w", err)
 	}
 
+	if timeout <= 0 {
+		timeout = readTimeout
+	}
+	if err := s.port.SetReadTimeout(timeout); err != nil {
+		return nil, fmt.Errorf("set read timeout: %w", err)
+	}
+	defer func() { _ = s.port.SetReadTimeout(readTimeout) }()
+
 	respPayload, err := uartframe.ReadFrame(s.port, nil)
 	if err != nil {
 		return nil, fmt.Errorf("read response: %w", err)

goTool/webui/index.html

@@ -200,6 +200,10 @@
                 <dd class="col-7" x-text="state.master.running_partition || '—'"></dd>
                 <dt class="col-5 text-muted">Deadzone</dt>
                 <dd class="col-7" x-text="state.master.deadzone != null ? state.master.deadzone + ' LSB' : '—'"></dd>
+                <dt class="col-5 text-muted">LiPo 1</dt>
+                <dd class="col-7" x-text="formatLipo(state.master?.lipo1)"></dd>
+                <dt class="col-5 text-muted">LiPo 2</dt>
+                <dd class="col-7" x-text="formatLipo(state.master?.lipo2)"></dd>
               </dl>
             </template>
             <template x-if="state.master && !state.master.ok">
@@ -280,13 +284,14 @@
                     <th>Status</th>
                     <th>Deadzone</th>
                     <th>Accel (LSB)</th>
+                    <th>Akku</th>
                     <th>Stream</th>
                     <th>Aktion</th>
                   </tr>
                 </thead>
                 <tbody>
                   <template x-if="!(state.clients || []).length">
-                    <tr><td colspan="8" class="text-muted text-center py-4">No clients</td></tr>
+                    <tr><td colspan="9" class="text-muted text-center py-4">No clients</td></tr>
                   </template>
                   <template x-for="c in (state.clients || [])" :key="c.id + c.mac">
                     <tr>
@@ -305,6 +310,7 @@
                               x-text="formatAccel(c)"
                               :title="accelTitle(c)"></span>
                       </td>
+                      <td class="small" x-text="formatLipoPair(c)" :title="lipoTitle(c)"></td>
                       <td>
                         <button type="button"
                                 class="btn btn-sm"
@@ -576,9 +582,14 @@
         connect() {
           const proto = location.protocol === 'https:' ? 'wss:' : 'ws:';
           const url = proto + '//' + location.host + '/ws';
+          if (this._batteryTimer) clearInterval(this._batteryTimer);
+          this._batteryTimer = setInterval(() => this.refreshBattery(), 5000);
           const connect = () => {
             this.ws = new WebSocket(url);
-            this.ws.onopen = () => { this.wsConnected = true; };
+            this.ws.onopen = () => {
+              this.wsConnected = true;
+              this.refreshBattery();
+            };
             this.ws.onclose = () => {
               this.wsConnected = false;
               setTimeout(connect, 2000);
@@ -590,7 +601,13 @@
                   this.applyOTAProgress(msg);
                   return;
                 }
+                if (msg.type === 'battery_status') {
+                  if (msg.samples?.length) this.applyBatterySamples(msg.samples);
+                  return;
+                }
+                const prev = this.state;
                 this.state = msg;
+                this.preserveBatteryInState(prev, this.state);
                 if (msg.master?.deadzone != null) {
                   this.masterDz = msg.master.deadzone;
                 }
@@ -604,10 +621,87 @@
           };
           connect();
         },
+        preserveBatteryInState(prev, next) {
+          if (!prev || !next) return;
+          const keepLipo = (oldL, newL) => {
+            if (newL?.valid) return newL;
+            if (oldL?.valid) return oldL;
+            return newL ?? oldL;
+          };
+          const keepAge = (oldAge, newAge, hasValid) => {
+            if (hasValid && newAge != null) return newAge;
+            if (oldAge != null && !hasValid) return oldAge;
+            return newAge ?? oldAge;
+          };
+          if (next.master) {
+            const pm = prev.master || {};
+            const l1 = keepLipo(pm.lipo1, next.master.lipo1);
+            const l2 = keepLipo(pm.lipo2, next.master.lipo2);
+            next.master.lipo1 = l1;
+            next.master.lipo2 = l2;
+            next.master.battery_age_ms = keepAge(
+              pm.battery_age_ms, next.master.battery_age_ms, !!(l1?.valid || l2?.valid));
+          }
+          if (!Array.isArray(next.clients)) return;
+          const prevById = Object.fromEntries((prev.clients || []).map((c) => [c.id, c]));
+          next.clients = next.clients.map((c) => {
+            const p = prevById[c.id];
+            if (!p) return c;
+            const l1 = keepLipo(p.lipo1, c.lipo1);
+            const l2 = keepLipo(p.lipo2, c.lipo2);
+            return {
+              ...c,
+              lipo1: l1,
+              lipo2: l2,
+              battery_age_ms: keepAge(p.battery_age_ms, c.battery_age_ms, !!(l1?.valid || l2?.valid))
+            };
+          });
+        },
+        applyBatterySamples(samples) {
+          if (!samples?.length) return;
+          for (const s of samples) {
+            if (s.client_id === 0) {
+              if (!this.state.master) this.state.master = {};
+              this.state.master.lipo1 = s.lipo1;
+              this.state.master.lipo2 = s.lipo2;
+              this.state.master.battery_age_ms = s.age_ms;
+              continue;
+            }
+            const c = (this.state.clients || []).find((x) => x.id === s.client_id);
+            if (c) {
+              c.lipo1 = s.lipo1;
+              c.lipo2 = s.lipo2;
+              c.battery_age_ms = s.age_ms;
+            }
+          }
+        },
+        async refreshBattery() {
+          if (!this.state?.uart_connected) return;
+          try {
+            const r = await fetch('/api/battery?all_clients=1');
+            if (!r.ok) return;
+            const data = await r.json();
+            if (data.samples?.length) this.applyBatterySamples(data.samples);
+          } catch (_) {}
+        },
         formatMac(hex) {
           if (!hex || hex.length !== 12) return hex || '';
           return hex.match(/.{2}/g).join(':');
         },
+        formatLipo(l) {
+          if (!l?.valid) return '—';
+          const v = (l.voltage_mv / 1000).toFixed(2);
+          return l.percent != null ? `${v} V (${l.percent}%)` : `${v} V`;
+        },
+        formatLipoPair(c) {
+          return `1: ${this.formatLipo(c?.lipo1)} · 2: ${this.formatLipo(c?.lipo2)}`;
+        },
+        lipoTitle(c) {
+          if (!c?.lipo1?.valid && !c?.lipo2?.valid) return 'Keine ADC-Daten (Cache ~30 s)';
+          let t = `LiPo1 ${c.lipo1?.voltage_mv ?? '—'} mV, LiPo2 ${c.lipo2?.voltage_mv ?? '—'} mV`;
+          if (c.battery_age_ms != null) t += `, Alter ${c.battery_age_ms} ms`;
+          return t;
+        },
         formatAccel(c) {
           if (!c?.accel_stream) return '—';
           if (!c?.accel_valid) return '…';