SIMULATED - no board is connected and nothing is being written. This view only exists on preview builds.
MultiBMSPRO
Put your battery bank online.
Flash a common ESP32 board right here, then finish setup in the app. No account needed.
Open this page in Chrome or Edge (or Firefox 151+) on a Mac or PC. Phones, iPads and Safari cannot flash.
Step 1 · on this computer
0%
Ready when you are
Plug the board into this computer with a USB data cable.
Technical log
Step 2 · keep this
Keep this — you need it to set up your gateway
This QR is the key to your gateway and it is shown only now. Save it to this computer or print it, then stick the label on the board.
Print this label and stick it on the board. Then open MultiBMS, tap Scan gateway code and point the camera at the QR. Nothing to type. The code is in the QR only; it is never sent to a server. Anyone holding the card or label can claim this gateway, so keep it private.
Lost it? Reflash the board over USB, or read the code from the serial console, and make a new card. A lost card does not expose your Wi-Fi: Wi-Fi details are sealed between your phone and the gateway and are never on the card.
Bluetooth setup not working? Set Wi-Fi over USB instead
Why Pro
Your BMS has no Wi-Fi. Now it does.
Most Bluetooth battery monitors only talk to a phone standing next to them. Put a common ESP32 board near your batteries, flash it above, and MultiBMS shows you those packs from anywhere: the batteries need Wi-Fi, Starlink or a hotspot, and you need service. Every cell, every pack, charging or discharging, live.
1
Up close: Bluetooth, like always
Standing next to the pack, your phone connects straight to the BMS. No subscription, no account, nothing to buy. Everything on the home page works exactly as it does today.
2
Far away: the gateway holds the link
The board sits with your batteries and keeps the Bluetooth connection open, then hands the readings to your phone over your home Wi-Fi for free, or over the internet with Pro.
Where people put one
One at the house. One on the boat. See both.
A gateway goes wherever the batteries live. Add as many as you have places, and they all show up in the same app, alongside whatever you are connected to over Bluetooth right now.
Off-grid house
Watch the house bank from town
Solar in, loads out, state of charge overnight. Group the packs and read the whole bank as one number, from anywhere the house has Wi-Fi.
Boat at the marina
Check in without driving down
Marina Wi-Fi or Starlink on the boat is all it needs. Know the house bank is charged before you get there, and that the bilge pump has not been running all week.
Two places at once
House and boat in one screen
Put a gateway at each. Both banks sit in the same app, each with its own name, and you flip between them or see them together.
On the ride
Bluetooth up close, remote for the rest
Out on the e-bike or the golf cart, your phone connects to that pack over Bluetooth like always. The house bank is still there in the same app, coming in over the gateway.
Projects on a hotspot
Anything with a hotspot or Starlink
A trailer, a camper, an EV conversion, a fast RC build with a phone tethered to it. If the battery has a way onto the internet, you can watch it.
The shop
Carts, forklifts, loaners
Every pack in the building on one screen from the office, with the free home-Wi-Fi tier. No subscription needed inside your own walls.
What you see
Everything the BMS knows, not a summary.
The gateway forwards the raw readings and the app decodes them exactly as it does over Bluetooth, so the remote view is the same view.
Every cell voltageMin, max and spread, the same cell grid you get up close.
Pack voltage, current and powerCharging or discharging, right now.
Temperatures and BMS stateWhatever your BMS reports, the app shows.
Groups and banksCombine packs into one bank total, remote or local, mixed together.
History, recorded on the gatewayIt keeps logging while the app is closed; charts fill in when you open it.
Alerts for low and highIn the app today while it is open or on your home Wi-Fi. Push alerts while you are away are next.Coming
Works with
Growing every week. Tell us what you have.
Through the gateway today: JiKong (JK) and JBD / Xiaoxiang packs, the two families we run on our own banks. Every other BMS the app supports still works over Bluetooth up close, and we are adding gateway support for more protocols and more ESP32 boards all the time. Do not see yours? Say so and we will try to get you going as fast as we can.
Use the gateway from anywhere on the same home Wi-Fi. No account, and nothing leaves your house.
Unlimited gateways
No account, no sign-up
Dashboard, alerts and history stay local
Pro · $1.99/month per gateway
Anywhere, through our relay
Open your batteries from anywhere. It costs money because we run the relay servers. Cancel any time; the app and your home gateway stay free.
Live readings on cellular or any Wi-Fi
7-day free trial, cancel any time
Share a read-only link with a family member
Pro pricing
$1.99/month
per gateway, billed through Apple or Google
7-day free trial Cancel any time The app and your home gateway stay free
Works with your setup
Built to play nice.
Works with Home Assistant
Point the gateway at your own MQTT broker and readings show up in Home Assistant. It is read-only and free, and the readings go straight to your broker, not through us.
Read-only, by design
The gateway reads your batteries and cannot send commands to them. Like the app, it is a monitor, not a replacement for a properly configured BMS.
Privacy
What data goes where.
Nothing sent to us
Bluetooth and home Wi-Fi
Your phone talks to your batteries or your own gateway directly.
Pro only
Remote access
Your gateway sends readings to our relay, and the relay sends them to your phone. It stores only the latest reading per pack. TLS in transit, not end-to-end encrypted.
Sealed, no accounts
Setup and Wi-Fi details
Sealed between your phone and the gateway and never sent through the relay.
ESP32-WROOM-32 DevKitC (generic 38 / 30 pin) ESP32 (classic) · 4MB · holds 2 packs In testing 
ESP32-S3-DevKitC-1 (N8R8; also N8, N8R2) ESP32-S3 · 8MB · holds 4 packs In testing