Hi. I have had my solar+battery running since August and the battery reserve was set at 4% but I noticed that the battery was being drained to 0%. I then set it to 20% reserve and it still drains to 0%. I thought the reserve would be the figure it would stop discharging at. Have I got this wrong or is my system not working correctly.
steveroberts1 the battery should stop draining at the target soc, usually 4%.
Try a reset to defaults on the portal but it does sound like something is wrong. Maybe the battery needs recalibrating
My reserve is set to 4% but it stops draining at 5 or 6%. Never seen it go to 4.
nophead mine is pretty consistent at stopping at 4%, but then I said that but both batteries stopped at 3% last night
Bear in mind the % is just an estimate by the inverter. The inverter can only measure voltages and temperature of the battery, from which it derives the % state of charge. So it’s a guess really and if it stops at 5% it’s not really an issue
There's actually two settings -
1) Battery Power Reserve - this is apparently meant for EPS reserve and is the value (4% is the default) you see in the app;
2) Battery Power Cutoff - this is the level at which the battery should stop outputting power. You can't see this in the app or on the portal except on the inverter remote control panel. Obviously its visible in givTCP as well. Default is 4%.
So in the app if you set the "reserve" higher then I don't believe it actually tells the battery to stop outputting power at the new value as the "cutoff" will still be 4%.
If you want the battery to stop discharging at a higher SoC then try using the Battery Power Cutoff - its called Battery Cutoff % Limit on the remote control panel in "My Inverter" on the portal. Obviously if the system has miscalculated the SoC then all bets are off anyway 🙂
Vestas that's interesting, thank you, didn't know about the power cut-off %.
Also worth mentioning that there are two soc's, one from the inverter and one from the battery.
GivTcp<inverterid>soc
GivTcp<batteryid>battery_soc
I use the inverter soc in my calculations and dashboards but from looking at the battery behaviour it looks like the battery soc is used when deciding whether to charge to reserve soc or not.
And in my case the two soc's are not always the same, the inverter soc being sometimes 1 or 2% above the battery soc
(only one battery per inverter BTW)
geoffreycoan If you look at the app and drill all the way down into the battery info you'll find they're never the same except when the battery is at 100% for extended periods. The SoC reported by the inverter is always 2% above that reported by the battery IME.
Re the reserve/cutoff figures - they don't make any logical sense to me.
Cutoff seems to act as battery "protection" in its default configuration so you don't end up with totally depleted lithium ion cells (very bad news, requires special charging equipment to recover etc). You can't reduce it below 4%.
So why is the "reserve" being set at 4% as default and can't be reduced? Surely that means no reserve as cutoff is at 4% too? Default value only makes sense if there's no EPS - as all the documentation suggests that's what its intended for.
I don't have EPS connected so I don't know whether that influences how the "reserve" level works but cutoff worked better for me when I ran some tests a couple of months ago.
Not sure that helps with the confusion 🙂
geoffreycoan Many thanks I will try this. I presume it's the one in the settings for my inverter. I can't find a reset to defaults for the battery.
steveroberts1 yes there’s only the reset to defaults for the inverter, but it’s the inverter that’s controlling what’s being put into the battery and apparently ignoring the 4% reserve. So resetting the inverter settings might get it working right
geoffreycoan Many thanks
I tried the reset but it didn't solve the problem. I phoned GE and they emailed me a software fix but I have to take out the USB dongle and delete the data on it and then load the fix on it. This to me shouldn't be done by the user and was surprised what they want me to do. I looked at the battery data from a few days ago and the battery voltage dropped to 47.1 V when %was zero. Does this look low?
Yes my battery stops discharging at 6% and that is about 50V. Fully charged is about 56V.
steveroberts1 it sounds like they are wanting you to reload the battery management software which is on the usb stick.
I agree this isn't something that end users really should be doing.
I had a BMS issue and called my installer out to fix it. It turns out to have been a cable that had come loose but during the call from him to @Givenergy they were wanting him to do the same and he wasn't at all keen either.
The next option would have been to get a givenergy engineer out but they are in short supply and waits of 4-8 weeks are apparently not uncommon. I'd suggest you try to get your installer to look at the issue
geoffreycoan Cheers. Yes it's a firmware fix or bodge. I should of read the email properly. Looking at other threads I think I have the battery dropping to zero problem which seems to have been going on for over a year.
steveroberts1 If you don't want to do it yourself then it's one for your installer.
Personally, I don't have an issue doing it myself - but then I am pretty comfortable around this stuff as I work with electric at work as well as various controllers.
Only two issues.
Dropping the screws.
Dropping the allen key.
Oh and a potential third, which is if the USB stick is glued in - the later ones are from the factory as they found many installers not fitting them when they were installed (Mine included) and had to buy one as I didn't have one small enough that wasn't a sandisk.