Between us here on the Forum, I suspect we have enough knowledge to help anyone who finds themselves with Puredrive batteries which are no longer manufactured.

After all, they are fairly standard LiFePO4 cells within the outer case.
They can still operate satisfactorily for years to come, and the existing capacity can be extended using the same chemistry.

The BMS doesn't matter as much as might be supposed.

Over the last 20-months I've been using LiFePO4 batteries in parallel with a mix of BMS units from Daly, JK (Jikong) and JBD (Jiabaida).
Yes, each manufacturer's BMS would have its own App to monitor or configure it.
But, honestly, how often would you want to revisit the App once the system is operating within the parameters you've set?

@transparent Hi, I am new to this, and have been searching for some answers and came across this post, I'm  hoping someone can help or advise, I had a solis hybrid inverter installed in 2022, with a puredrive gen 1 5kw battery, at the end of last year I wanted an additional battery installed, and purchased a Dura5+ as I was told by my installer that these were compatible. I have has issues with the SOC jumping erratically, eventually discovering from puredrive that they are not compatible, and my puredrive battery would not work with anything but another puredrive gen1 battery. Is this right or is there anything I can do, this was a big investment for me  and it now seems as though my 3 year old battery, which should have a 10 year warranty is of no use. Hope that makes sense and Thanks

@scmilne 

If the manufacturer says they are not compatible, it seems the best option may be to return it. The installer should have checked it before advising you. Section 75 is probably the best route if you paid some of it with a credit card.

When an inverter is using a bank of batteries, it essentially only connects to one, and that one acts as the master. That one needs to be able to talk to the other(s). It could be that the most recent battery could act as the master, but again the manufacturer would have probably mentioned it. The communication is happening between BMS boards that every battery has. If they are the same type, it could be that the latest version is able to manage the older. 

Sometimes it is just a matter of ensuring the bms's are using the same version of the firmware, by updating it. But I assume the manufacturer would have told you if that is possible.

Without knowing the capacities and what your goal is, it is difficult to comment further, but getting a gen1 battery may be the simplest upgrade path. You may be lucky to find someone that had to sell because they wanted to upgrade. 

I believe puredrive have their own configuration on the Solis, but sometimes the BMS is able to use a more common protocol like pylontech. This may be another option. To be sure, it may be also worth to confirm if these are configurations supported by the manufacturers. 

Hope that helps, let us know how it goes.