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Anyone got these?
Mine seem to be discharging very rapidly without load. So system shuts down with around 10pct state of charge as darkness falls. Then voltage and soc plummet, with around 1% Soc lost every hour.
2400 as in 2.4kwh ....
It'll deplete quickly because that's not very much power in storage.
Your 10% is 240watts.
It’s not under load.
It gets to 10 percent and then switches back to the grid. But then overnight drops about 1 percent an hour without any load.
At some point (when it hits 0 i think, it then decides to charge from the grid back to 10pct)
I have two in parallel so 4.8kwh not the biggest storage but surely the size of the battery shouldn’t impact how it is discharging under no load.
What's driving your inverter ?
I don’t know. It’s grid tie so goes to eps if no grid. Could be the battery I guess. 40w seems quite high standby draw?
The battery powers the inverter. Our house baseload is 150w, but with the inverter running, it's 250w. Without the battery, the inverter would shutdown when the solar generation is insufficient to power the inverter. With the battery connected that additional power is provided by the battery. It does kind of bug me that I need 2.4kWh a day to keep the solar array running, but really, it's only a notable issue in the winter where there are more night hours. For 9 months of the year, it's going to be just noise.
@daffy what about when the inverter is on standby as mine is overnight and the battery has hit the minimum safe level (10pct) - is the consumption still that high?
Does it draw standby current from the battery and so kill it or take it from the grid?
Okay - your battery is 2.4kWh with a usable 2.2kWh of power. This is very small.
Your battery usage should be governed by the either the BMS or the inverter. The battery should be able to deplete normally to 20% SOC remaining capacity and then will pretty much only power the inverter. At 10% SOC remaining, it should, if enabled, charge itself from the grid back to 20% to maintain battery health.
Remember - at 20% SOC, you only have 0.2kW of usable power remaining in the battery. Powering my 5kW inverter is 0.1kW/h, which would mean you'd get 2 hours until fully depleted or an hour of discharge before it's supposed to again charge.
It sounds to me like even in standby, it's consuming enough power to deplete the pack and as it's in standby, doesn't allow triggering the battery to charge from the grid at 10% SOC.
Our Skybox consumes 30W/h on standby...perhaps the inverter is the same/similar.
It sounds to me like even in standby, it’s consuming enough power to deplete the pack and as it’s in standby, doesn’t allow triggering the battery to charge from the grid at 10% SOC
Surely that's a setting in there that is wrong. It should force charge before it goes below 10%
I have two batteries as you say useable is 2.2kw in each and both deplete so 4.4kwh or at 10pct 440wh so if it’s using 40w then overnight it could drain as you say. So sounds like the problem is with the inverter, which is a lux one, not the battery.
I agree, it should but, it depends on how the software is written. Is the standby based on time, solar gain, what? Does the standby have the function to wake on a signal from the battery to charge itself, like a wake-on-LAN function? Without the inverter and setup information we can only infer that the system doesn't wake from a battery signal and that the standby is consuming sufficient power to quickly kill the battery.
I'd get your installer out to sort it before the deep discharging damages the battery.
How many deep discharges damage a battery?
There’s been a weeks worth already!
I am on to the installer but I don’t think they really understand it. The sub contracted electricians certainly didn’t when they set it up.
These are the options I have.
https://ibb.co/nQ8FVXG
https://ibb.co/t2W0JnR
Seems like the battery isn’t calling for charge when it should so goes to 0. Then inverter goes hang on I need power, turns it self back on and calls grid at which point it realises battery too low and charges. Don’t get how the inverter turns on at the point the battery is 0 though!
Is there nothing in the settings that state what happens at certain charge states? Mine has a setting which limits power at a set value and forces charge at a set value (%).
No that’s all I have. I do notice in the front info screen of the app that the bms charge and discharge limits do change from time to time, presumably based on state of charge. It’s not a variable I can change in the inverter settings as far as I am aware.
I guess I could set ac charge on, the level to 10 percent and then the time to cover the whole day? No idea on the other parameters and what their values should be though!
It’s pretty normal. I have LFP batteries and they discharge at about 1% per hour even with no load. Just checked mine for last night and I lost 8% between midnight and 4am (when the house runs on Octopus Go cheap rate), even though the measured discharge power was 0W.
I'd try just enabling AC charge and seeing if the BMS handles what should happen.
@flaperon Are you not concerned that your batteries are being deep discharged and going to be turned to paper weights?
Was thinking about getting a few more batteries but now thinking maybe I should go pylontech rather than uhome, guessing it’s a no no to expect uhome and pylon to talk to each other so would have to ditch the uhome ones
Not particularly. They’ll only discharge down to 10%.