Got solar and battery installed this week, so we haven't got the MCS certificate yet, so can't get paid for exports. A couple of days when the battery charged to 100% it then started discharging to the grid down to about 95%.
Why does it do this instead of just sitting with the battery at 100% until we need it? It is annoying because we can't get paid for exports yet so we are giving 5% away.
You are not alone. I have the same issue
Are you on a gen 2 inverter? And what firmware is it running? This was a big that has now been fixed.
We have GivEnergy Hybrid 5.0 Gen 3 5.000kW of Inverter Power
Software Version D0.393-A0.393
The firmware version listed in the knowledge base for gen 3 is 305, are you on a beta version to have 393?
I don't think so. It was just an normal install. The electrician said GE would have to update the firmware when it was connected and they did. No mention of beta.
Seems to have a much more complex behaviour than is suggested for ECO mode. It is supposed to prioritise powering the house, any left over should charge the battery and when full it should export. Instead it does all sorts of weird things.
I realise the maximum charge into the battery is limited to about 2.5kW but I have seen it split the excess between the battery and export, giving 1.8kW to each.
Also when it starts to get near 100% charge it seems to throttle back and export the rest.
When at 100% I used some down to 95% but it then wouldn't charge again until it got down to 90%. I don't know if it is just buggy or there is some complex logic or battery temperature is changing its decisions.
In the night it might stop discharging when it drops to 6% and run from the grid for an hour, then decide it has 7% so runs from the battery for an hour and then it drops to 6% and repeats the cycle. Again I can only think temperature must affect its idea of what the charge state is.
The reserve is set to 4% but it might stop at 6 or 5%. Then when dawn breaks and the panels are generating a few tens of watts the percentage rises and it suddenly has some more charge to supply.
All very random looking from the outside.
Today is is very sunny and I can see it charges up to 100%, the last 5% at a reduced rate, then it slowly discharges to 95% dumping to the grid and then the cycle repeats. Why does it not just leave it at 100% and export the rest? Seems like more wear and tear on the battery needlessly cycling it.
Presumably this means when the sun goes down instead of being at 100% it will be at a random charge between 95 and 100.
I don't think 100% is really 100% full because it is a 5.2kWh battery but you can only use about 4kWh, so I presume 100% is more like 80% to be kind to the battery.
This is a typical plot:
As you can see once it gets to 100% it slowly discharges to 95% and then rapidly charges to 100% repeatedly. During this time we are generating more then we use and exporting, so there is no reason for the battery to add to the export.
Do other people see this behaviour or is out system faulty?
I raised this as an issue with our installation company (SunSave) and they said they haven't see it before and forwarded my email to GivEnergy asking them to look into it.
nophead I have a gen 1 hybrid inverter with a 5.2 battery (and a second with a 9.5) and I don’t see any of these behaviours. It charges to 100% and holds there, and when discharging it pretty much always goes down to 4%. Occasionally 5% or 3% but mostly 4%.
The only similar behaviour I’ve seen is throttling back as it gets towards 100%, but it’s never been anything I’ve been concerned over, it just gradually throttles back.
So maybe a gen 3 bug/feature ? Definitely raise with GivEnergy support
Yes I have seen other peoples plots without this behaviour but @"Edwards40" said he has the same issue.
It is very consistent. I.e. it always does it when it gets to 100%, with solar, and sometimes even charging from the grid in the early morning. It doesn't have time to drop all the way to 95% in the morning because the charge period ends first and it doesn't go to the grid, it partially powers the house, so actually slightly beneficial although it means at 5 AM I might have only 98% instead of 100%.
The battery does seem to have quite complex behaviour. It throttles when the charge is below 20% or above 95%. It also seems to throttle if it gets to 28C.
When it runs down it seems to stop of 6% or 5% even though the reserve is set to 4%. Also it can get to 5% and start running from the grid. An hour later it can decide the charge is 7% and run the house for about an hour dropping back to 5% and that can repeat 2 or 3 times. I.e. the apparent charge increases without any charge being put in. Free energy!
GE have told me I need to upgrade the inverter firmware from 393 to 303, which apparently is newer despite being a lower number and lower than 305, which @Phil_H said was the latest. Are the version numbers just random?
nophead they may have removed 305 if there were problems. (battery version 3013 was removed and only 3012 is available now).
the numbering generally goes up as the firmware gets newer, the exception is beta firmwares which have a much higher number than standard releases.
I don't know how I managed to get a beta because the installer just did a normal firmware update on 20th September as far as I can see.