Lithium Battery Upgrade from AGMs for RV house battery bank


New Member
Decisions, Decisions, Decisions… (AGM replacement vs. Lithium upgrade)

Well, it is time to replace the house batteries on our 2009 Magna as the six LifeLine AGMs are dying off and only work maybe 5hrs overnight with just refrigerator running before generator attempts to auto-start. Our coach is full-electric (no propane) with six 8D AGM house batteries, and also has the 400w solar package add-on. The current batteries are 6+ years old.

I am doing my research to possibly upgrade our system in steps: 1st – lithium batteries, 2nd – hybrid converter(s), 3rd – solar system upgrade.

As a conversation starter, I am looking into initially switching over to lithium batteries and adding the necessary components to do this first step. BTW, we rarely ‘boondock’ longer than 1-2 days and we also plan to have this coach 10+ years. Just looking for a nice balanced dependable system, not a full blown ‘off-grid’ system. I don’t mind running the generator on occasion, just would like dependable overnight battery use of refrigerator (plus furnace if necessary) and refer plus heat or one A/C during day.

LifeLine GPL-8DL are about $750ea. They are rated 255ah, so our original six (6) house battery bank had 1530ah. We have only had the coach about a year, and therefore never got to experience new-condition AGMs. Research states AGMs are only about 50% efficient overall, so even at best when new have about 765ah of true usable capacity out of six 8Ds. (replacing 6 AGMs approx. $4500)

BattleBorn BB8D are $2259 each currently. They are rated 270ah each, have same dimensions as AGMs, and are stated to be 80% overall efficient and last 10+ years. So my initial thoughts would be to start with three (3) BB8D for 810ah in the house battery bank. Their stated 80% efficiency would yield 648ah usable capacity out of three batteries. (cost of 3 BB8Ds approx. $6800)

Yes, I am aware there are less expensive lithium battery options; but right now Battle Born gets my vote as their customer service has been the most helpful of any contacted. They have guided me to setting a ‘Custom’ charging profile on our existing dual Xantrex RS3000 inverters so I can use our existing inverter / charger until upgrading to recommended Hybrid unit(s) in the future. They also instructed me that I would have to replace our existing charge solenoid with a Lithium Battery Isolation Manager (Li-BIM) or a DC-DC charger to protect alternator from being overworked / damaged from lithium battery draw. Our alternator in the coach is rated at 320amps.

Sounds like I could also use our original equipment HelioTrope solar controller for a while, but would benefit from replacing with a modern MPPT unit.

So my initial question to this group is… have any of you with a similar coach to ours switched over to lithium batteries for your house bank? Pros / Cons?

Any advice or input would be appreciated as I’m just beginning my research. Dr Jerry


Solar Addict
Well, IF you had the budget to go to BattleBorns and IF you get the right charger thingy to not fry the coach and IF you're comfortable reprogramming your controllers and inverter then it's a good option.

Having said that, paying over $2,200 per battery HURTS just thinking about.

Reprogramming a dozen tewaking options into the rest of your system to not kill anything scares the hell out of me. What's the point of a drop-in replacement if you can't just drop it in, maybe changing the SEALED to LiFePo4 option in the controller and walking away?

My gut tells me that you could find other LiFePo4's in the same rating for cheap enough that you could upgrade your existing controller to one that's LiFe ready, replace your DC-DC charger AND still afford sandwiches.

Now, I'm not saying to go for the bargain basement ChingDongWang batteries from AliExpress, but there are many other reputable battery companies out there selling comparable batteries for about half the price as the BattleBorn's.

But that's just my $0.02


Solar Enthusiast
the HelioTrope solar controller will need to be changed to a lithium profile

i would say no question, change to lithium, there are other benefits, not just capacity i.e. steady 13.2V throughout it's useful capacity, less weight
as long as the IF's in the previous reply are met