Set up and control a Marstek Venus storage from your browser, over Bluetooth. No app, no account, no cloud.
English · Deutsch
👉 Use it right now, nothing to install: https://sphings-dev.de/marstek/control/
A Marstek Venus battery normally expects you to go through the Marstek app and the Marstek cloud to change anything about it. Marstek BLE Control takes that detour out: it is a single static web page that talks to the battery directly over Bluetooth Low Energy using the browser's Web Bluetooth API.
Open the page, hit connect, pick your storage — you are talking to the device. Nothing is installed, no account exists, and no data is sent anywhere: the page is served as static files and every command goes straight from your browser to the battery.
This is a fork and continued development of Hypfer/venuscontrol, which targets the Venus A. All credit for the original tool and the reverse-engineering groundwork goes to Hypfer. This fork adds Venus D and Venus E 3.0 support, OTA firmware updates and a number of extra controls.
Unofficial project. Not affiliated with, endorsed by, or supported by Marstek. "Marstek" and "Venus" are trademarks of their respective owner and are used here only to describe which hardware this tool talks to.
The interesting part is what is not in that picture. Running a Venus cloud-free needs three things, and none of them is a Marstek service:
- A way to configure the battery — that is Marstek BLE Control, over Bluetooth.
- A grid power source — the battery wants a Shelly Pro 3EM. It is happy with anything on your LAN that answers its UDP broadcast (see the Shelly trick below).
- A way to monitor it — Modbus TCP into Home Assistant or anything else that speaks Modbus.
- ✅ Marstek Venus D support — tested on real hardware
- ✅ Marstek Venus E 3.0 support (
MST_VNSE3_*) — own dashboard without PV/MPPT, without the multi-module battery view and without surplus feed-in, since its firmware implements none of them. Confirmed working on real hardware by a user (state, control, CT and OTA). - 🔄 OTA firmware updates over Bluetooth — for Venus A, D and E 3.0; Control/EMS, BMS, MPPT and Micro-Inverter modules (EMS, BMS and VNS/Micro flashes confirmed working on a Venus D and a Venus E 3.0; MPPT is unverified only because no MPPT image is in the firmware archive yet). The firmware's own validation logic was verified to be identical across all three models.
- 🛡️ Model detection for firmware files — warns before flashing another model's image, based on
the
VNSA/VNSD/VNSEtag embedded in every image; verified against all 27 Venus images in the firmware archive - 🌍 English and German — the whole interface, picked from your browser and switchable at any time
- ⚡ Device Power Class selection — the values each model's firmware actually accepts (Venus A 800 / 1200 / 1500 W, Venus D 800 / 2200 / 2500 W, Venus E 3.0 600 / 800 / 2500 W)
- 📉 Peak Shaving — cap grid draw at a configurable threshold
- 🎚️ Self-Consumption Power Offset — bias the controller to target a grid power other than 0 W
- 🔌 Local API toggle — enable the on-device UDP JSON-RPC API
- 🕐 Set Time on the device
- 🐛 Reliability fixes — correct BLE command IDs, and robust reassembly of fragmented BLE responses so Device Info and Work Mode load dependably
- 📜 Changelog — the full release history
This is an illustration of the panel, not a photograph of a running instance.
The firmware image is inspected before anything is sent: the model and the target component are read out of the file and checked against the device you are connected to. A file for the wrong model, or an MPPT image about to be sent as if it were Control/EMS firmware, is flagged rather than flashed.
⚠️ Firmware updates carry risk. An interrupted or wrong flash can leave a module unusable. Keep the browser tab open and the device close by for the duration of the transfer.
The whole panel on a desktop
| Device | BLE name | Status |
|---|---|---|
| Marstek Venus A | MST_VNSA_xxxx |
Supported (from upstream), plus OTA and the extra controls |
| Marstek Venus D | MST_VNSD_xxxx |
Supported — the focus of this fork, confirmed on real hardware |
| Marstek Venus E 3.0 | MST_VNSE3_xxxx |
Supported, but not yet tested on real hardware |
Other Venus models fall back to a generic device view, which shows what can be read but does not offer the model-specific controls.
Web Bluetooth is a browser feature, and not every browser ships it.
| Platform | Use |
|---|---|
| Desktop (Windows, macOS, Linux) | Chrome or Edge |
| Android | Chrome |
| iOS / iPadOS | Bluefy – Web BLE Browser (free) |
Safari and Chrome on iOS do not support Web Bluetooth — that is a restriction of iOS itself, not of this tool. Bluefy brings its own engine and works. Open https://sphings-dev.de/marstek/control/ inside it.
Everything needed to run a storage cloud-free with an (emulated) Shelly Pro 3EM smart meter, plus monitoring over Modbus TCP:
- State — state of charge, remaining energy, battery / grid / AC power, backup load, PV inputs, and energy history for today, this month and lifetime
- Work mode — including schedules with start/end time and charge/discharge power
- Power limits and Device Power Class (800 / 2200 / 2500 W)
- Depth of discharge
- Peak shaving with a configurable threshold
- Self-consumption power offset
- CT / meter settings
- Local API toggle (UDP JSON-RPC on the device)
- Set time, device info, battery module state, factory reset
- OTA firmware updates
Cloud features such as dynamic grid-price arbitrage are deliberately out of scope — those need the vendor's service, which is exactly what this tool exists to avoid.
You do not need uni-meter or anything comparable. All this battery wants from a Shelly Pro 3EM is something on the subnet broadcast address listening on UDP port 1010 that answers its inquiries.
You do not even need to speak the Shelly protocol properly. During testing the firmware's JSON parser turned out not to be a JSON parser at all, but roughly "find string offset, read int 2 bytes later". So responding with this works:
a_act_power==${l1},b_act_power==${l2},c_act_power==${l3},total_act_power==${total}
You could also send it some prose:
Dearest Marstek,
I hope this UDP packet finds you well.
Today, the a_act_poweris${pA}watts.
However, the b_act_poweris${pB}watts, which is interesting.
And look at c_act_poweris${pC}watts!
In conclusion, the total_act_poweris${total}watts.
Sincerely,
The Shelly Emulator.
You probably shouldn't, but you could.
- The page is static — HTML, CSS and JavaScript, no backend, no API calls to anything.
- Bluetooth traffic goes browser → battery directly. It does not pass through a server.
- No account, no login, no telemetry, no analytics.
- Hosting it yourself is a matter of serving the built files from any web server; the hosted copy at sphings-dev.de is provided purely for convenience.
Web Bluetooth requires a secure context, so the page must be served over HTTPS (or from
localhost) — this is a browser rule, not a choice made here.
npm install
npm run dev # development server
npm run build # static files in dist/The contents of dist/ are the whole application. Drop them on any static web host that serves
HTTPS.
Do I have to give up the Marstek app? No. Marstek BLE Control changes settings on the device; the app keeps working. The point is that you no longer need the app or its cloud for the settings covered here.
Does my battery have to be online for this? No — quite the opposite. Bluetooth is a direct radio link between your phone or laptop and the battery. It works with the battery's WiFi disabled entirely.
Why Bluetooth and not the local API? The on-device API has to be switched on first, and there is no way to do that except over Bluetooth or via the cloud app. Marstek BLE Control has a toggle for it.
Can I brick my battery with the OTA function? A failed firmware flash can leave a module in a bad state, as with any firmware update. The tool checks the image against the connected device before it starts, but you carry the risk. Only flash images you trust, and do not interrupt a running transfer.
Is Venus E supported? Not specifically. Venus E v1/v2 runs on a different firmware base, so it falls back to the generic device view.
- 📡 Out of Bluetooth range? sphings79/marstek-ble-bridge — an ESP32 that relays the storage's Bluetooth link over your network and serves this app from its own flash. Flash it in your browser.
- 🌐 More projects and tools: sphings-dev.de
- 📦 Firmware archive for Marstek Venus devices: sphings79/marstek-firmware-archiv
- 🛡️ Firmware backup / checker tool: marstek-fw-checker — grab a copy of a firmware image and contribute it to the archive. Note: firmware can only be backed up while it is still pending, i.e. before it has been installed — once flashed, it can no longer be extracted.
- 🔬 Venus firmware reverse engineering: sphings79/Marstek-Venus-Firmware-Reverse-Engineering
- 🏠 Home Assistant integration over Modbus: sphings79/marstek-modbus-suite
- Original tool: Hypfer/venuscontrol
- Firmware archive and reverse-engineering references: rweijnen/marstek-firmware-archive · rweijnen/marstek-venus-monitor
If this helped you get your storage off the cloud, a star on the repository is genuinely appreciated — it helps other Venus owners find it. Thanks!
These tools are built and maintained in my free time, and they stay free, open and cloud-free. If one of them saved you an afternoon, you can buy me a coffee.
Apache License 2.0 — see LICENSE.