question

Your mppts are switching to ESS mode, and that shouldn't be happening. There was a (very) brief discussion just yesterday re this and a relationship to DVCC. Try turning DVCC off.

Ok, so I think I have figured out what is happening here.

I turned of DVCC then waited until all three controllers were in FLOAT. I then told them to EQUALISE - they responded obediently by flashing the orange and blue LED's. For one hour, the voltage remained around 58.4v - so I re-read the smart solar manual. I also turned DVCC back on because as @Boekel pointed out ESS= DVCC in VRM.

Now I think the issue where the battery fails to reach the EQUALISE voltage is that the 25% of BULK current limit is stopping the battery terminal voltage from rising to the EQUALISE voltage. This seems to be because that 25% limit is NOT battery charge current but controller output. So, in the case of my 150/100 controller, it is enforcing a limit of 25amps from the controller - if my loads are using 20amps, that leaves just 5amps to charge the battery bank and force the terminal voltage up to the EQUALISE setting. Simply just not enough.

This is quite sad as one of the reasons that I decided to use Victron gear was because I thought that the Venus GX would resolve issues like this (as it can see/calculate the real battery current) by bringing all known data together to make truly system wide intelligent decisions.

I can only hope that the vision for the Venus GX going forward is to resolve issues like this and perhaps even have true multi controller synchronised charging. Seems far more important to me than getting something as obscure (but very interesting) like Node Red working on the Venus GX. I, for one, would much prefer to be able to correctly charge and equalise my battery bank!

I'm now considering the possibility that I will have to change the absorption voltage every month to actually perform an equalise.

Anybody got any better ideas?