Questions about single AC inverter/multiple battery installation.

Trying to get my head around how systems with multiple batteries linked to a single AC inverter work. Is someone with such a system (or someone from GivEnergy) able to shed any light?

1. Are the batteries charged/discharged consecutively or simultaneously ?

2. Will the system still operate on the remaining batteries if one battery develops a fault or is intentionally switched off?

3. Do all batteries need a USB installed to perform a battery update or just the master?

4. On the beta portal do you see separate information for each battery or is it displayed/controlled as if there is just one big battery or maybe a bit of both?

5. Where different sized batteries are connected why does the master battery have to be the biggest one?

6. Does the system require recommissioning and/or recalibrating each time you add (or switch off/remove) a battery?

   Grateful for any experiences of single AC inverter/multiple battery installations you may have.

Woodstock I have one inverter and 2x 5.2kWh

1. They charge simultaneously - or seem to based on the charge status lights of each one (similarly discharge) - they stay in sync. It appears to treat both as one large battery
2. No - speaking from experience. I've got a fault currently with one of the batteries (I think - GivEnergy visiting soon to hopefully fix) - the other slave battery isn't available. Whether you could re-wire so only one battery is in use, and that would allow continued operation, don't know.
3. Not sure
4. On the beta portal the % figure is just the over-all figure, ditto the inverter battery data. The old portal used to show the battery pack breakdown for both batteries separately, but that's gone.
5. Not sure
6. I would imagine it would need recalibrating, as the inverter needs to understand the capacity available, and calculate charging profile accordingly etc.

GrahamRead isnt there a caroselle on the header for the battery to scroll between them now. I recall that being added
You may need to move your mouse there to see the arrows ( if on a desktop ) or swipe if on touch device ) same as changing the header from grpahs tp numbers, just inside the battery part of the header )

GrahamRead Thank you for your reply. I hope your battery is fixed soon. I was thinking that multiple batteries would introduce a level of redundancy to the system (making it more resistant to total failure) but it sounds as though this might not be the case. Now wondering if adding more batteries (the failure of any one of which shuts down the lot) would actually make the system less reliable!

Woodstock resilience is better if you have more inverters too as a single inveter or battery failure would not disable the whole system, but that adds significantly to the cost.

I think the next question is "what is the resonse time for installers and GE to fix an issue"? If its a day or two then what is the real problem you are mitigating.
If its a month.....

Maybe thats a question for your installer. If the answer is its fixed qicky the idea of stacking multiple batteries on a single inverter is fine.

Another factor in the equation is the failure rate. If they don't break often is that a risk you need to mitigate? I dont know how failure rates can be surfaced to inform that decsion

3) Yes.
5) I initially had my 5.2 as master, then added a 8.2 as a slave. About 2 months later while adding another inverter, support said the batteries were the wrong way around. Apparently the bigger the battery the more charge it gives relative to the smaller battery, so the bigger battery should be first. Much like on a house hold consumer unit the heaviest trip switch should be closest to the main switch.... More current draw, so give it the shortest route.

Seye I have added a second inverter, and a second set of batteries. They are connected up as a 'plant' - so work as one. Main advantage is that the occasional spike requiring mains ( boiling kettle for example ) no longer goes to mains. Two inverters with double batteries provide spike of 7kw...

anabanet Oh, also is something fails you have backup, but fingers crossed nothing has gone wrong...

anabanet Sounds like the resilient way I was suggesting, aslo gives quicker charging and higher max power output.

I know management of plant isnt great at present. It works but isnt the best experience. I believe GE are planning to improve that.

When that is avaialble I may add an AC inverter to my current hybrid system, but thats some way off

anabanet I am guessing that the GE inverters in the plant have to be the same type so you can't mix and match say 3kW AC coupled inverter and 3.6kW Hybrid?

Kryten I dont know - I would think they should work the same - but I have two identical 3.0

1. They are charged simultaneously
2. If the main battery develops a fault, they will not as this one controls the charging/discharging of the 2nd, if the 2nd was to develop a fault yes it will still work.
3. All batteries need a USB, the batteries have no onboard memory and the USB is simply there to provide memory to write the firmware.
4. You will have the ability to see both batteries yes, as we can from support however it's been taken down temporarily.
5. The bigger one has to be installed first so as to balance the packs accordingly so they dont fall out of sync with their state of charges.
6. It will need recalibrating, it's not a commission we just need to ensure that it's reading right, and on the same firmware, balanced out between 1V and then yes, run a calibration.

Hmm - my two 5.2kWh batteries charge at the same time from the single 3.0 inverter?

My bad - long week! (edited original message)

Adam-Reynolds Thank you for your comprehensive answers; just what I was looking for.

Adam-Reynolds Phew, for a moment there I worried that my system wasn't working correctly! 😃