B2B and Battery Master

[oldiesontour]

I have an Ablemail which is a battery master type device, though can be configured to only transfer power if your preset volyage conditions of the two batteries are met.
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They don't all do this, but the Renogy 50A combined B2B and MPPT controller that I fitted will send spare solar generated power to the starter battery if the leisure battery is full. It uses the same connection for this that it uses to take power from the starter battery/alternator in B2B mode when the engine is running.

As a matter of interest does the power flow to the starter battery show on the app screen....I have the 50a B2B with mppt works superbly except it only occasionally/very rarely shows the SB being charged...but I have a built in voltmeter on the dash and as soon as the lb if full the voltage of the SB rises but no charge is shown in the app

 

[Snelly]

I have a different set up to yours as when I started the process I wasn't fully conversant with the different parts needed. So I have an ePever 100ah LifePo battery. An ePever mppt duo racer controller which has adjustable output for the leisure battery to accommodate a lithium battery, and a standard output for the vehicle battery. I also fitted a Victron mains charger to replace the built in BCA charger/psThe b2b is is a Renogy 40A - it's the grey one but can't see any other model marking. I fitted a a battery master which is non adjustable but the normal one marketed by VanBitz. I can only monitor the battery through a Bluetooth link.

 

[oldiesontour]

I actually sat and watched mine on the Renogy,KH shunt and 2 320ah bms's and dash volt meter this afternoon .When the fridge cut out the KH said 99% 619.85ah the solar brought it back to 100% 640ah nothing showed on either BMS the dash volt meter was around 12.6v this started to rise the KH showed around 1.5a leaving the leisure batteries the Renogy showed nothing the BMS showed similar to the KH the volt meter rose within a minute to 14.8vthe KH and BMS showed zero and the volt meter returned to 12.8v,then the solar kiks in and returns the lipo's to 100%.Meaning the starter only gets a charge when the lb is at 100%.The 30amp Renogy I swopped for the 50a used to charge both at the same time and show it in the ..but both were la.so maybe la starter and lipo mix confuses it or maybe a software error..but it does it's job just doesn't tell you what it's doing ! Also for it to work in the winter means storing lipo's at 100%.Ive got round this with a second mppt installed for a 200w folding panel and switching that ollows it's output to go to either battery