Bongo Fury

Hi all. Anybody is welcome to reply, but it is mostly aimed at my solar guru, Geoff!
Firstly a bit about my set up:
150w solar with MPPT controller
180ah sealed LB
Noco Genius 10a smart charger
VSR split charge relay (works both ways)

My question is:
If I am on EHU and have my smart charger on, topping up the LB as I'm using it. The split charge relay, due to working both ways, is also topping up my SB at the same time. Will my SB just keep charging regardless of it being full or not? Or will the smart charger and/or relay switch to stop adding power to SB when it's no longer needed. I have put an isolator switch between the LB and relay, so am able to isolate the SB if needed.
My starter battery does have a slight power drain, so it is useful to be able to top up on a few sources (alternator, solar, smart charger), but I don't want to risk overcharging.
Thanks in advance and sorry for the lengthy post!

The Split Charge Relay is pretty dumb it merely operates once either battery voltage exceeds 13.8 volts approximately, at that point both batteries are in parallel. Once the voltage drops back below 13.8 volts then the relay drops out and isolates the two batteries from each other. As to continuing to charge that depends on the "smart" charger which is usually pretty dumb as they don't know what the capacity of the batteries are!

g8dhe wrote: Sat Jan 14, 2023 12:57 pm The Split Charge Relay is pretty dumb it merely operates once either battery voltage exceeds 13.8 volts approximately, at that point both batteries are in parallel. Once the voltage drops back below 13.8 volts then the relay drops out and isolates the two batteries from each other. As to continuing to charge that depends on the "smart" charger which is usually pretty dumb as they don't know what the capacity of the batteries are!

Thanks Geoff. Sound advice as always.
Think I'll give it a boost as and when needed on hook up, then open relay with isolator switch to avoid overcharging. I can also isolate to stop cranking the engine from LB when relay is closed due to solar voltage.

Bear in mind that flooded lead acid are designed to withstand overcharging, the alternator simply pushes out the required voltage/current at all times. It can be a bit different for modern battery designs where they have minimised spacing/lead content/waste collection area at the bottom of the cells, all to reduce costs ..... so its unlikely that your SB will ever suffer!