I had a new PV installation commissioned yesterday with a 9.5kWh battery and 3kW inverter.
The battery calibration yesterday didn’t work properly (capacity was low) and GE recalibrated today. They did it at a slower charge rate (850w) and it took about 9 hours to empty and charge.
Looking at the mobile app it says the discharge was 3.88 kWh and charge was 6.7 kWh.
Does that sound about right? I’m a complete newbie so any advice would be appreciated.
Rich31k No. The batteries are shipped with about 50% State of Charge (SoC). 3.88kWh discharge could be right, but 6.7kWh charge just isn't. The Batt9.5 is actually 12kWh under the hood and I would expect it to take about that much from actual empty to the brim. The useable energy is 15% off the bottom and 5% off the top, leaving an operational capacity of 9.5kWh. Give the support people at Givenergy a call tomorrow and ask what's going on?
Tim Thank you. It's good to know it’s not right - it’ll give me more confidence speaking to support tomorrow morning.
The discharge from the battery seems to be limited to 1kW at the moment too.
After calibrating, the older firmware (3012) it will charge to 50%, the latest will charge it to 80%
6.7 kWh is 70% which is close to the 80%. At 850w charging rate:
(watts x hrs) / 1000 = kWh
(850 * 9) / 1000 = 7.65
The inverters have a charge efficiency around 85-92% that gives you somewhere between
(total / 100) * percentage = percentage of total
(7.65 / 100) * 85 = 6.5 kWh
(7.65 / 100) * 85 = 7.038 kWh
For the discharge issue, you can try reset the settings on https://givenergy.cloud/dashboard
Go to My Inverter -> Settings -> Reset to default. Should now be discharging at full rate, unless Givenergy need to unlock something on their side.
Thank you for the detailed explanation. After a reset the inverter is still only at 1kW, so I’ll call in a bit.
I still don’t feel it’s working properly. Overnight the app shows the battery discharging from 100% down to 30%. It has only discharged 2.3 kWh in that time. Please correct me if I’m wrong, but that doesn’t seem correct.
I’ll speak to GE when the support line opens.
Spoke to GE this morning and they are going to do a forced charge of the battery to see if that fixes it. The inverter is back to full 3kW.
There is an odd pattern from the calibration and regular charging.
In the first calibration it dropped from 46% to 0% over 5 mins, then jumped from 47% to 100% over 5 minutes during calibration charging. On the first regular charge it went from 46% to 100% over 5 mins, and then on the second calibration it dropped from 52% to 0% over five minutes. That doesn’t feel right, but it fits with the capacity of the battery (9.5 kWh) working at about half the advertised capacity.
The installer is going to have a look at the cells later too.
Yeah that doesn't sound right at all. Mine is a slow recharge and slow discharge.
Mine took 3-4 hours to discharge and recharge during the first calibration, and since it has been steady... for reference:
Thank you for the reference photo.
These are the last three days showing the sharp drop to 0% and rise to 100%. It's just done it again - jumping from 59% to 100% over a five minute period. I'm on the latest firmware (3013), which was installed as part of the commissioning on Monday.
That seems very weird with your PV Power and Export also... it looks like the export is exceeding the generation which only usually occurs in "blips" but yours appears more consistent... Perhaps even the inverter is faulty or the way it was installed?
Rich31k That does look odd, could you add the battery voltage to the chart and repost it? Specifically for the 22nd where the calibration took place. It should take longer than 6 hours to fill a 9.5kWh battery at 850W, I'm wondering if the battery didn't hit top and bottom properly, or maybe there is a dodgy cell within it which is causing an incorrect top/bottom.
Thinking about it the voltage on today's graph would be good too given you have a jump to 100%