Am familiar with that brand, spoke to their tech support last year. They recommended me to use either a lifepo4 compatible alternator (not possible in our boats) or use a dc dc converter. Their current charging instructions publication still seems to reflect that. If you have more recent or different technical info from them I'd love to hear it. I'd love to have smaller batteries which would give me better storage in that compartment.
When I spoke to the supervisor of ReLion’s tech support he stated that with PMG / PMA ( permanent magnet generators/ alternators) charging systems there would not be a problem.
The main reason is that our charging systems/alternators are always at full output, the rectifier / regulator shunts the unwanted energy to ground, these are the same type of systems found in other power sports equipment like dirt bikes, snow mobiles, side by sides etc. So the electron hungry LiFePO4 batteries will just absorb what would otherwise just be shunted to ground. Our systems peak charging voltage is 14.4-14.5 which is the sweet spot for LiFePO4 batteries. The same is true with Battle Born batteries and other brands.
Automotive style alternators regulate the output by changing the magnetic field density on the rotor, or changing the excitation voltage. Automotive alternators can put out a tremendous amount of charge current for their size especially when compared to the oldest automotive PMG type of generator. LiFePO4 batteries have very little resistance when compared to lead acid batteries, and can take all of that current for a very long time while they charge, whereas a lead acid battery and its higher resistance will back down on the amount of current that can be delivered to the battery. This high output is what damaged many auto type alternators in the past.
I quizzed both BB and ReLion extensively about the application in my boat, and the MinnKota MK 330 charger which does hot have lithium specific profile, but it does have an AGM profile which is 14.4 volts, with a 13.6 volt float for 12 hours, the only difference I can see in charging profiles in the new series of Minnkota chargers like mine is that the lithium setting does not have a float voltage after the bulk cycle.
I did have one problem with the BEP Marine DVSR that came stock on my boat with the change over to a 100ah LiFePO4 battery in that the DVSR is looking for 13.4 volts from either the start or house battery which is a charging level voltage as far as the DVSR is concerned. Well the BB LiFePO4 batteries resting voltage of 13.6 is above that threshold so the DVSR closes in the stock / OEM configuration. I put in an Interstate AGM dual purpose start battery over the winter, and when the DVSR closes, the LiFePO4 battery starts transferring power to the AGM battery. So, I had to cut the red wire on the back of the DVSR and connected it to a spare ckt rocker switch. After the engines are started and the voltage on the AGM battery comes up to or greater than the LiFePO4 battery I energize the ckt to the DVSR and the relay closes 10 seconds later paralleling the start and house battery.
In the near future I’ll be using an ignition hot to energize the DVSR through a 300 second time delay relay to give the start battery voltage time to come up before the DVSR closes. It is important that the AGM and the LiFePO4 batteries are not left in parallel while floating … so when the ignition is turned off the DVSR control voltage drops and the relay opens breaking parallel.
If anyone is interested I started a thread about this subject some time back….
https://jetboaters.net/threads/conversion-to-lifepo-batteries.35834/page-4#post-599247
