Lifep04

kordo

I'm thinking of replacing my 2 house batteries with 2 lifep04 batteries.  I would program my pronautic 1250 charger to bulk charge at 14v and float charge at 13v.  I would lose some charging efficiency, but this would allow me to keep my 2 sealed flooded lead acid start batteries.  I know it is not recommended to mix battery types but since each bank will be of a consistent type (2 banks of lead acid starting batteries and a house bank of 2 deep cycle lifep04s), I think this will work.  My question is what happens if the battery management system (bms) on the house bank shuts them down while the engines are running.  Will this be a problem for my alternators which are not externally regulated.  I have a promariner 2 70 3 battery isolator.  Thanks.  

YYZRC

I think you would want to run a setup like @Squatch68 put together using a DC-DC smart charger.  Check out this post:

https://rinkerboats.vanillacommunities.com/discussion/comment/174193#Comment_174193

kordo

Thanks YYZRC.  Read the thread but it looked like he was using straight lithium batteries instead of lifep04s which are safer and include bsm's.  I'm looking for a drop in solution.  I have seen a youtube on the subject and the "expert" said that a battery isolator would prevent the alternator from being damaged so looking for confirmation.  I'll keep looking around for more info.  I guess it's early days for drop in lifep04 batteries on boats.  

YYZRC

I'm running a single Victron LiFePO4 200ah for my inverter setup. I haven't changed anything with my house (still AGM).  When the AGMs crap out I will likely do the same as you.

Two Victron Lithium 200ah with the BMS 12/200 and the ARGO FET isolator would probably work great for you. I would leave the ProMariner to do only the starter batteries and add a Victron 120v charger for the Lithium.

I am really happy with the Victron stuff; it's not cheap but it all works well together.