Hi,
My 5.2kWh battery seems to be topping out, saying it’s 100% full when it’s only taken 3.2kWh. It’s about three years old and hasn’t shown any gradual decline, the system just suddenly seems to think it’s smaller than it is.
Here are some screenshots from the app showing that the battery thinks it’s full but only 3.2kWh has gone in.
Any ideas?
Thanks,
J.
When did you last run a calibration?
Errrrr… never. 🫢
How do you do that, how often, and what should it do?
I assume it’s the full calibration mentioned here -> https://givenergy.com/resource-hub/customer-guides/how-to-calibrate-your-givenergy-battery/
JeremyGooch On the second picture, battery seems to stop discharging around 1am (at the large spike in consumption), but the SoC seems to continue to decline until around 6am. Do you intentionally stop discharge, or did it reach reserve ? How low did SoC get by 6am before it started recharging ?
When battery is idle for a time, it seems to get a chance to evaluate SoC more accurately - mine tends to drift up, but perhaps yours does the opposite ?
I bet that spike was the dishwasher. I can’t think of anything else running at that time.
At 6am, it got down to 3%.
We’ve got no charge or discharge schedules active. And here’s the battery config as shown in the app. 👇
Basically the battery state of charge can drift over time as there is not all that large a range between a fully charged cell and one discharged as low as it will safely go. On older firmwares in particular if you don't regularly fully charge and discharge the battery then it can lose track of where the limits are, resulting in lower capacity.
The calibration will stop the solar, fully discharge the battery down to zero (below the usual limits and reserves), then switch the solar back on and use that and the grid to charge to completely full. These points will then be used to establish the State Of Charge (SOC) of the system going forward.
Newer firmwares are supposed to keep better track of the State Of Charge and self calibrate around the top and bottom end.
Newer firmware also better protects the cells during cold weather charging.
It is possible that calibrating the battery will restore some of your missing capacity, especially if you do so during milder/warmer weather.
It is also possible that you have one or more bad/damaged cells and without GivEnergy to repair or replace that is now your capacity until you replace the system.
Assuming that your battery was 80% Depth of Discharge/usable storage that would mean you have lost about 1kWh of capacity.
Thank you. I’ll run a calibration and report back.