3rd Party Low-Voltage Battery Support?

As GivEnergy has entered administration and warranties are now unlikely to be fulfilled, I have a few questions regarding 3rd-party battery options.

Can anyone here advise whether 3rd-party low-voltage batteries are supported unofficially?

I am fully aware of the potential risks involved in using batteries that are not officially supported by GivEnergy.

I already know that the inverters have a Battery Type setting for Lithium-ion or Lead-Acid, but I cannot see any parameters that allow you to configure the inverter for a Lead-Acid battery or a non-GivEnergy Lithium-ion battery.

I know there are some very knowledgeable people lurking on this forum, so I'm particularly interested in your thoughts and experiences.

The biggest issue I can foresee is the battery configuration. GivEnergy's official low-voltage batteries use a 16S cell configuration, whereas some 3rd-party low-voltage lithium batteries use a 15S configuration.

Would the inverter/BMS communication accommodate a 15S battery, or is the inverter expecting the voltage/SOC characteristics of a 16S GivEnergy battery?

Has anyone successfully used a 3rd-party low-voltage battery with a GivEnergy inverter, either with BMS communication or in some other configuration?

Please let me know your thoughts and, ideally, any practical experience.

Thanks in advance.

Yes I've done this. Been running fine for over 3 years now.
I think it's a quirk of the Gen 1 gear though (I upgraded one of my Gen 1s to the 'fast firmware' and it stopped being able to read them.

Everyone jumps to the 'oh your running them in lead acid mode' but I'm not. These are working natively and actively talking to the inverter (so for example GiVTCP will show the (valid) battery temperature, capacity in Ah and so on.) over RS485.

You need:
Battery Type: Lithium
Auto Judge Battery Type: Off
Auto Read BMS*: Off
If you want you can also set the battery AH capacity register (as this impacts power slider scaling) but if your BMS is talking properly then it should auto populate this one.)

And that's it. It seems happy enough with my batteries BMS talking in Pylontech but some other protocols seem to work (can't recall which ones)

I'd not go for 15S packs (actual Pylontech) as you'd have to force voltages down from the built in settings. Obviously it's be a very bad idea to mix 15 & 16S stuff together.

Other option is site a 3rd party 16S pack behind a real Giv one. You won't be able to see what they are doing in the apps but it would just float up and down with the real battery.

*I think this has been specifically named as such to throw people off in GivTCP as it's really a toggle between speaking 'other' BMS and Givenergy BMS's unique protocol.

I will suffix this with: I've not tried a Gen2 or Gen 3 to see if they work this way (the Gen 1 not working on Fast Firmware may be that they needed the code space for the fast firmware as it's an old STM32 chip with limited storage.)
I do have a G2 & 3 to try this on but never got around to it.
I've no idea about AC3 but seeing as they are the Gen 1 hybrids with the PV guts removed it MIGHT work on the old 500 series firmware (& probably not on the newer 200 series firmware which is the equivalent of the 'fast firmware' for gen 1)

I was not aware that anyone had successfully used 3rd-party batteries at all with any of the GivEnergy inverters.
Interestingly you mention Pylontech, as that is/was exactly my plan, using six US2000 (15S) batteries with a Giv-HY3.6 (Gen1) Inverter.
I am aware that can't mix and match 15S and 16S batteries on one inverter.
And as you already pointed out with a 15S configuration the min/max voltages would need to be adjusted to suit, but I don't know if this would even be possible.
I know as part of the RS485 BMS communication register Func 0x04, Byte offset 0, shows a value of 16 cells, so I don't know if you spoofed this to 15 if the inverter would readjust the voltages.

Often wondered if you could just put a 16S battery behind a GivEnergy battery with no comms connected, i.e just plugged in + to +, - to - from the Giv batt out connector,

Letting the new 16S battery just change and discharge with the main one.

MadProfessor2002 id probably not be too keen on the 15S spoofing (even less so of using actual 15S Pylontechs) - Pylons used pouch cells for theirs hence why they are relatively compact BUT their BMS is very poor at stopping over voltage (something a pouch cells is less resistant to than prismatic) so I'd imagine if you spoof fails for whatever reason and it reverts to 16S your going to end up with a lot of swollen packs.

I'd simply assume the Givenergy firmware to be flakey / obtuse and generally fight you at every opportunity - which I guess is a fairly good description of the company itself to be honest.

(Although I'm all for an experiment obviously so if you do go for it keep us informed how it goes - these days you can just use Ai to write you a script to force all those registers you need - point it at the givenergy-modbus GitHub library and it'll take it from there)