[RedDevil]

I'd like to add that I have had no IMA errors during my last month of PHEV usage.

Those, it seems, are mainly caused by having a load on the terminals on key-on.
Making sure the (relayed) harness is switched off when I start the engine is enough to prevent it. And of course, the relay lamp shunt allows for a 10 Ampere feed maximum.

One tiny problem is that the number 2 cell in my number 2 pack is lagging a bit.
When I charge the batteries that cell trips the BMS because it is full earlier than the rest.
The BMS will top balance it in line, but that is a very slow process.
Then, it is not a lot off. If I drain the overcharge at about 300 milliAmp a few minutes is all it takes to make it match the others (all cells at about 3.65 Volt on charger cutoff).

It could be the cell or the BMS.
Next time after balancing I'll swap the no.1 and 2 cells on that battery, and see whether the problem swaps position too. I hope it is the cell, much cheaper to replace than the BMS!