Originally Posted by Scott keling
Yeah I wasn’t really wanting a lithium battery for the starting battery. Seen a complete boat setup on one of the lithium battery sites and it had a 12v lithium starting battery and one 36v TM battery and a power pole charge for 5k. Wasn’t going to go to that. But was wondering about how it all works in conjunction with the engine alternator
With that set-up,the engine's alternator sends amps to main battery,then the PP charge can send amps to the aux battery if desired.
What I think is with the LifePO4 batteries,is when they are fully charged there is no headroom.That could be causing the spikes?A flooded/AGM battery really doesn't reach 100%,so there is headroom to absorb those spikes?When I first installed mine,they were charged 100%,and I noticed that voltage on locator would fluctuate even up to 16.7V.Did not harm anything,and that was back in late June.But that's my theory.
But since then,batteries have may spent around 3 hours on AC plug.After every trip,I just plug it in to read battery SOC.And most times they read 83%/95%.
It's a good set-up that weighs less than the single 31 AGM I removed,and have room for only 2 batteries.So went with a 24V 75AH single.