What "cheap" monitoring should still give you
A low price is only a bargain if the essentials are there. Whatever you buy, check that it does all of this — most cheap options quietly skip two or three:
- Every battery, individually — not one averaged "virtual battery" for the whole stack.
- Every cell voltage — the cell spread is the earliest sign of a problem.
- State of health (SOH), cycles and temperatures per module.
- History — health and cell drift only mean something as a curve over months.
- An alert when something goes wrong, including when the monitor itself goes quiet.
- No subscription. A €5/month plan costs more than the hardware within a year.
- Read-only access — a monitor has no business writing to your battery's BMS.
Every way to monitor a Pylontech battery — and what it really costs
| Option | Up-front cost | What you get | The catch |
|---|---|---|---|
| Your inverter's app | Free | Charge and power of the whole stack | Reads the CAN/RS485 link: no per-battery or per-cell data (why) |
| PYLON Console / BatteryView on a laptop | Free software + a USB-to-serial cable | Everything, in detail | A session, not monitoring: no history, no alerts, a laptop by the battery every time (details) |
| DIY (ESP32 or Raspberry Pi + open-source code) | Low parts cost | Whatever you manage to build | Evenings of work, level shifting, no warranty, no support when it breaks |
| Solar Assistant | Paid licence + a small computer | Excellent inverter-centred monitoring | Built around the inverter; more than you need if the battery is what you want to watch |
| PylonCheck | About €200 | Cloud-based battery monitoring | Around five times the price, cloud-first (full comparison) |
| Pylon-Monitor Lite | €39, once | Every battery, every cell, history, alerts, Home Assistant | No screen on the box — you read it on your phone |
What €39 actually buys
- A finished, tested device and both cables (RJ45 console + USB). Plug into the Console port, power it from any USB charger, pick your WiFi — about two minutes.
- A live web dashboard on your phone or PC: charge, voltage, current, power, health, cycles, temperatures and every cell — up to 16 batteries, mixed models.
- The free online dashboard: your battery from anywhere, 3 years of history, kWh in and out per day, an email if the device goes quiet.
- Home Assistant (MQTT auto-discovery or REST), Node-RED, Jeedom, and a JSON API for anything else.
- Free firmware updates for life, a 2-year warranty, and a real person answering your emails.
Why it can cost this little
Three reasons, none of them a corner cut. The device does one job — read a Pylontech console — on a small board designed for exactly that, instead of a general-purpose computer. The firmware is our own, so there is no licence to pay per unit. And it is sold directly, with no distributor margin in between. The optional cloud is light enough to run for free, so it is included rather than rented back to you.
Lite or V2 with a screen?
Same firmware, same data, same dashboard, same Home Assistant support. The only difference is the 1.8″ screen on the V2, which shows the battery at a glance without a phone. If your batteries sit in a garage or a technical room nobody looks at, the Lite at €39 is the sensible choice; if you walk past them every day and like a glance, the V2 is €49.
What you do not give up by paying less
- Your warranty. The Pylon-Monitor is read-only: its firmware contains no write command at all.
- Your privacy. Everything works locally; the cloud is off until you switch it on.
- Your inverter setup. The Console port is separate from the CAN/RS485 link your inverter uses — nothing changes on that side.
Before buying any monitor, run through the eight readings worth checking: a cheap tool that cannot show them is not cheap, it is incomplete.
Frequently asked questions
- What is the cheapest way to monitor a Pylontech battery?
- For free, your inverter's app shows the stack's charge but no per-battery or per-cell data, and PYLON Console on a laptop shows everything but only while you sit there. The cheapest complete option — every battery, every cell, history and alerts — is the Pylon-Monitor Lite at €39, once, with no subscription.
- Is there a cheap Pylontech diagnostic tool?
- Yes. The Pylon-Monitor Lite (€39) reads the same Console port as Pylontech's own diagnostic software: state of health, cycles, temperatures, alarms and every cell voltage, per battery — but continuously, from your phone, instead of one laptop session at a time.
- Does a cheap Pylontech monitor show individual cell voltages?
- Only if it reads the Console (RS-232) port. Monitors that use the inverter's CAN or RS485 link cannot see cells or individual batteries. The Pylon-Monitor reads the Console port, so it shows every cell of every battery.
- Is there a subscription?
- No. The device is a one-time purchase, and the online dashboard with 3 years of history, the email alerts and firmware updates are free.
- Will a cheap monitor void my Pylontech warranty?
- Not the Pylon-Monitor: it is read-only and sends only standard diagnostic queries on the Console port, the interface Pylontech provides for monitoring. It cannot change any battery setting.
Pylon-Monitor Lite: every battery, every cell, 3 years of free history and Home Assistant — for €39, once. No subscription, ever.
Order the Lite — €39 One-time purchase · free updates for life · 2-year warranty