Can the victron bluesolar mppt be used with two battery banks using a ACR?
So when the first bank is full, the relay diverts the charge to other battery.
Wouldn't this cause the controller confusion? As I read that the controller should be first connected to the battery before any solar is.
thanks
Hi Jman. Victron call their solution 'Battery Combiners'. They don't switch totally from one batt to another, just divert the spare power as needed/available.
https://www.victronenergy.com/battery-isolators-and-combiners
It is required to connect the MPPT to the battery first so that the auto battery voltage detection (12v/24v/48v) can work properly. With the current firmware this is now a 'once off' operation upon initial connection and then stored (unless fully reset to factory defaults).
If you setup a relay to divert the MPPT charge to another battery bank after an initial charge cycle is completed - you may face issues with getting the MPPT to start a new 2nd charge cycle and also with the absorption phase length.
To start a 2nd charge cycle the battery voltage on the 2nd battery will need to be low enough to be under the 'Re-bulk' voltage trigger - otherwise the MPPT will remain in float phase.
Also with the current firmware - if you use the timer to end the absorption phase and the full time has already been utilised with the 1st charge cycle/battery, then it will not reset the timer during the 2nd charge cycle and should go directly from bulk to float phase.
However, if you used 'tail current' as the only trigger to end absortion phase, then you might be able to get it to work better. Tail current is configurable in FW v1.42, but the Victron Connect app with the updates to configure it is not yet officially released.
It's also probably not great for the MPPT to be instantly switching between batteries, particularly if ever switched while under high loads. So your proposed usage would not be something tested or supported by Victron.
