Why everyone is talking about it now
Dynamic and time-of-use tariffs have gone mainstream in Europe. In Germany every supplier has had to offer a dynamic tariff since 1 January 2025 (you need a smart meter). In the UK, Octopus Agile sets a new price every half hour. Spain's regulated PVPC tariff changes every hour, the Netherlands are preparing for the end of net metering, planned for 1 January 2027, and Tibber, aWATTar, Frank Energie and others sell hourly prices in several countries. Since the European day-ahead market moved to 15-minute steps in October 2025, some offers even change four times an hour.
The pattern is the same everywhere: cheap at night and around midday on sunny days, expensive at the evening peak. A battery that is already on the wall is the obvious way to move energy from one to the other.
Does it pay off? The honest sum
Three numbers decide it:
- The spread between the price you charge at and the price you avoid.
- The round trip. Grid to battery and back to your sockets typically returns 85 to 90 % of the energy. To use 1 kWh in the evening you buy about 1.15 kWh at night.
- The wear. Every kWh that goes through the battery uses a little of its life. A simple estimate is purchase price ÷ (capacity × rated cycles). Pylontech rates its current US modules at around 6,000 cycles; for example, a 4.8 kWh module bought at €1,000 costs roughly 3.5 cents per kWh cycled.
| Cheap hour | Expensive hour | Gain per kWh used (example) |
|---|---|---|
| 10 c | 30 c | 30 − 11.5 − 3.5 = about 15 c: worth it |
| 20 c | 30 c | 30 − 23 − 3.5 = about 3.5 c: marginal |
| 25 c | 30 c | a loss |
With a typical stack shifting 5 to 10 kWh a night through the winter, a good spread is worth a few tens of euros a month; a small one is not worth the cycles.
What to set, and where
Nothing changes on the Pylontech. Grid charging is an inverter setting, and the BMS keeps protecting the cells through its charge current and voltage limits on the CAN or RS485 link (how that link works). The usual options:
- Fixed off-peak window (French heures creuses, Italian F3 band, a cheap night rate): a "time of use" or "AC charge" slot in the inverter, with a target state of charge. Deye, Sunsynk, Growatt, Solis, SolaX, Fox ESS and others all have one.
- Dynamic hourly prices: Victron's Dynamic ESS in VRM plans charging from the day-ahead prices; on other brands, Home Assistant or evcc combine a price integration (Tibber, Octopus Energy, Nord Pool, ENTSO-E) with an integration that can write your inverter's charge settings.
Three rules keep it sensible. Charge only what tonight needs: if the house uses 6 kWh between the evening peak and the next cheap window, a target of 100 % every night just adds cycles (our runtime calculator gives the figure). Leave room for the sun in spring and autumn, when a morning of solar can fill the rest. Keep the grid-charge current moderate: a few hours at night are enough, and the BMS will reduce it in the cold anyway (winter guide).
A free bonus: winter full charges
In winter many Pylontech stacks go weeks without reaching 100 %, which is exactly when the state of charge drifts and the cells drift apart (why). If you charge from the grid anyway, let one cheap night a month go to 100 % and stay there about two hours: that is a full balancing session at off-peak price. Pylon-Monitor's Force Balance gives you the exact settings for your inverter and a before/after report, cell by cell.
Where Pylon-Monitor fits
An automation is only as good as the numbers it reads. Pylon-Monitor reads the state of charge, voltage, current and temperature of every battery, and every cell, straight from the BMS on the Console port, and publishes them to Home Assistant through MQTT auto-discovery or a local JSON API (integration guide). Your automation can stop the grid charge at the right level, skip it when a module is too cold, or warn you when one battery lags behind. It does not drive the inverter itself; it gives the thing that does an accurate picture. On the free online dashboard you see the energy in and out day by day, the number of cycles and the state of health of each battery over three years, so you can check that the savings are not quietly costing you capacity (what those numbers mean).
Frequently asked questions
- Can I charge a Pylontech battery from the grid?
- Yes. Grid charging is an inverter setting (time-of-use or AC charge slot, or a dynamic scheduler such as Victron Dynamic ESS). The Pylontech BMS keeps its own charge current and voltage limits.
- Is a dynamic tariff worth it with a battery?
- When the spread between cheap and expensive hours is around 10 cents per kWh or more. Below that, conversion losses (10 to 15 %) and battery wear eat most of the gain.
- Does charging from the grid wear out a Pylontech faster?
- Every extra cycle uses a little of the battery’s life. Pylontech rates its current US modules at around 6,000 cycles. Charging only what the night needs keeps the extra cycles low.
- Should I charge to 100 % every night?
- No. Charge what the evening and night need, and leave room for solar in spring and autumn. One full charge held for about two hours each month is useful for balancing.
- Can Pylon-Monitor control my inverter?
- No. It reads every battery and cell from the BMS and publishes the data to Home Assistant (MQTT or JSON), where your automation or scheduler controls the inverter.
Feed your automations accurate state of charge, temperatures and cell data for every Pylontech battery, and follow cycles and health over three years on the free online dashboard.
Order now — €59 One-off purchase, €59 all in. No VAT, no subscription.