Li-Ion Drop in Battery Upgrade

[MSR]

I changed out my OEM 6V AGMs for a pair of 12V, 100A BattleBorn LiFePO4 GC2 Deep Cycle batteries with built in BMS. Everything fitted well in the bank with some minor adjustments!


I haven’t changed the solar or inverters. Hopefully, this will work for me! I don’t do dry docking. Usually there is power or I run the generator when I need something extra. I plan to keep the RV plugged in when parked at home!

[autostaretx]

If you're planning long down-times, Lithiums don't like to be fully charged when not in use.
50 to 80% seems better. (if i recall correctly).

Dig through the lithium threads.

--dick

[irvingj]

I believe you're right, Dick, it's the same for RC stuff: for storage, NOT fully charged is best for LI batteries. Some LI battery chargers even have a setting for that!

[msmolow]

MSR, if you are always on shore power or generator was there a reason you elected for the significantly more expensive Lithium batteries?

[MSR]

there was an occasional overnight stay when I would not have shore power, the OEM batteries would just go down to 11v always!!! Hopefully, this is going to be better. I have to my charging modules thought. I am too green with that stuff to figure it out. I hate taking the RV to a shop. Such a chore and who’s around where we live army any good !!

[cooltravelers]

What kind of coach? Will these fit Unity 24MB?

[MSR]

It’s a 2018 Unity. They fit in the bay but you have to remove a couple of guides they install to secure the OEM batteries. Also, these are in parallel configuration. So you 2 similar battery connecting cables, 2 feet length.

[Klipstr]

So you have the factory solar system? I think I would replace at least the charge controller with a Victron 100/30 so you can setup the charging profile to fit your new batteries. Your alternator/generator charging won't be quite correct but the BMS within the batteries seems to do a reasonable job. Anecdotally based on Scarecrow's system (he has the Victron stuff and the Battleborn batteries) which seems to keep his batteries in tip top shape. The nice thing about the solar charging is when you roll into camp in the afternoon and turn the engine off the solar kicks in to finish the charging cycle no matter where it is at in that cycle. It turns out the late stages of the charging cycle are the most complicated and essential so it's good to have a very smart charge controller working the problem for you.

[MSR]

Wow. That’s very insightful Klipstr. Is this a DIY for electrical naïveté like me?

I presume you are talking about this unit on Amazon?

[TampaSteve]

I installed 2 12V Battleborns. I did put in the better Magnum remote control ME-RC50 so I could have more profile choices and a Victron 712 to monitor. So far the whole thing seems fine, with the caveat that solar, alternator, and the Magnum charger all are bit quirky on LiFePO4 and often don't charge the batteries the last 10%. That's not a huge deal but I think I will go ahead and install the SmartSolar MPPT 100/50 Charge Controller before next summer. The reason for going 50 amps is it's just a little bit more and who knows someday when the flex panels fail I may pile a lot more cells on the roof.

With a better solar charger the Magnum inverter and relay under the seat can wait probably a long time for an upgrade like when they fail.

There are other reasons besides more juice for upgrading to LiFePO4. Lower weight, super long warranty, no gassing or acid, and the built in BMS means if I do something stupid like leave the van unplugged for a few weeks with the switch on I don't return to ruined batteries.