Replacing OEM Batteries

[Kendorado]

If it works, don't fix it

[f14av8r]

Originally Posted by pmoroney

I have the original batteries that came with the coach, just wondering if I should replace them with the new AGM?
I don't want to wait until they start causing problems.

Thoughts ?


Thanks,
Patrick

2018 32sa

Skip the half-measure AGM step and replace them with Lithium. The batteries are much better, require no maintenance, and provide dependable power all the way down to near complete discharge. And, fully discharging lithium cells will not damage them.

[pmoroney]

Originally Posted by f14av8r

Skip the half-measure AGM step and replace them with Lithium. The batteries are much better, require no maintenance, and provide dependable power all the way down to near complete discharge. And, fully discharging lithium cells will not damage them.

are the AGM batteries more $$ or the Lithium ?

[f14av8r]

Originally Posted by pmoroney

are the AGM batteries more $$ or the Lithium ?

Lithium are the most expensive. And, you should evaluate them on their life cycle costs, not just purchase price.

[cmillet77]

Lithium is most expensive.. two 12V 205AH batteries giving you about 80% usable capacity = 328AH will cost you about $2000 (Renogy sells them for $999 ea right now, free shipping). Pros: You can charge them at 100% rate to full vs the three stage bulk/absorb/float that takes longer for lead acid and AGM. Great for boondocking if you have solar or want to minimize how much generator time you need to get them back to full. Full voltage all the time.
Consider multiple chargers to cut the time even further. Cons: you cannot charge them in below freezing weather although you can just install head pads or pay about 20% more for the new batteries that have built in heaters (if you even plan on using in cold weather that frequently).

6x6V 230AH FLA will run about $1k and at 50% usable capacity (to prolong life) you get about 300AH. Pros: least expensive Cons: longer charge times to full, maintenance, increased weight.

Because Lithium has come down so much in price, AGM is about 90% of the cost of Lithium.. not sure why you would go AGM when you can go Lithium for a little more $.

On my 2014 Phaeton, I can install 3 of the 205AH Lithium batteries I quoted above and get 615AH (492AH usable at 80% discharge).. fits in the same footprint as the 6x6V in the battery tray I currently have. $3k but you get at least 40% more battery capacity than the equivalent FLA, faster charges, etc all mentioned above.

Within a couple more years, probably get near price parity on Lithium and it will become the new standard.

Edit: as far as cycles, the lithium batteries I mentioned are good for 2000 cycles. I looked up a FLA 6v 2XXAH battery and if you go to 50% SoC you'll get about 1200 cycles out of it. So Lithium wins there and makes it easier to swallow the higher price if you plan on using these batteries for 5-10 years regularly (i.e. full timing).

[gdhugh]

Originally Posted by pmoroney

I have the original batteries that came with the coach, just wondering if I should replace them with the new AGM?
I don't want to wait until they start causing problems.

Thoughts ?


Thanks,
Patrick

2018 32sa

AGM offer very little benefit over flooded except not water to keep an eye on. Just a matter of worth to you personally.

[Globeflyer2]

The trouble with Lithium (LiFePo) is cost. Not only the cost of the batteries but also the cost of replacing the charger (which may be the inverter) if it does not have lithium charging mode/profile. Then adding some sort of protection for the engine alternator. Discharged lithiums can take a lot of power very fast and look like nearly a dead short to the charging system.

I agree with the others who pointed out that lead-acids require periodic maintenance but if cared for will last a very long time. When mine eventually die, I'll revisit the cost to convert but not until then.

[Mark_K5LXP]

if you go to 50% SoC you'll get about 1200 cycles out of it.

Cycles don't run things, Ah's do. Shallower DOD results in less Ah, which is less time or less stuff that runs. What benefit does "more" cycles provide if in the normal course of operation you never use them? 1200 cycles is a cycle *every day* for almost four years. No one in an RV does that, even full time. If you can't use up all the cycles a battery offers before it expires for any one of a dozen other reasons, then economizing for cycle life has no benefit, and actually increases the net cost per delivered Ah. Part of the cost/benefit analysis would be to realistically determine required Ah and cycle life based on actual numbers and not make lead acid look artificially "bad" and lithium "good" by using arbitrary or specious operating parameters.

Mark B.
Albuquerque, NM

[2Yung2 Quit]

Originally Posted by cmillet77

Lithium is most expensive.. two 12V 205AH batteries giving you about 80% usable capacity = 328AH will cost you about $2000 (Renogy sells them for $999 ea right now, free shipping). Pros: You can charge them at 100% rate to full vs the three stage bulk/absorb/float that takes longer for lead acid and AGM. Great for boondocking if you have solar or want to minimize how much generator time you need to get them back to full. Full voltage all the time.
Consider multiple chargers to cut the time even further. Cons: you cannot charge them in below freezing weather although you can just install head pads or pay about 20% more for the new batteries that have built in heaters (if you even plan on using in cold weather that frequently).

6x6V 230AH FLA will run about $1k and at 50% usable capacity (to prolong life) you get about 300AH. Pros: least expensive Cons: longer charge times to full, maintenance, increased weight.

Because Lithium has come down so much in price, AGM is about 90% of the cost of Lithium.. not sure why you would go AGM when you can go Lithium for a little more $.

On my 2014 Phaeton, I can install 3 of the 205AH Lithium batteries I quoted above and get 615AH (492AH usable at 80% discharge).. fits in the same footprint as the 6x6V in the battery tray I currently have. $3k but you get at least 40% more battery capacity than the equivalent FLA, faster charges, etc all mentioned above.

Within a couple more years, probably get near price parity on Lithium and it will become the new standard.

Edit: as far as cycles, the lithium batteries I mentioned are good for 2000 cycles. I looked up a FLA 6v 2XXAH battery and if you go to 50% SoC you'll get about 1200 cycles out of it. So Lithium wins there and makes it easier to swallow the higher price if you plan on using these batteries for 5-10 years regularly (i.e. full timing).

The charger on your 2014 coach has lithium charging capability? Or did you have to upgrade it?

[PLColman]

I replaced my house batteries with AGM cells in September 2021. I found the replacement cells at a local Interstate Batteries dealer and they were about $250 each. They're not Interstate (made in China) but Interstate warranties them. Love 'em! No more checking water levels or densities (which ruined a few jeans) and they work fine. Currently boondocking, and a couple of hours of generator run twice a day keeps them happy (12V or more).

[tomkatprop]

Have a 2018 37ba red have 6 6volt AGM lot cleaner no mess

[B52Rnav]

Originally Posted by Arch Hoagland

Sam's: Club has them for $189.

I have been casually shopping for batteries over last 3 months.

My observations: no Sam's that I have been to had GC2 AGM in stock. If you check online it says not available in store, not available on line.

I was in Costco yesterday. It looks like all of their batteries are now Interstate. Costco did have GC2 FLA in stock. I talked to service manager and he said they no longer stock GC2 AGM and CANNOT order them.

[B52Rnav]

Just for reference current prices for GC2 AGM;
NAPA. $349. to $390 at another source.

[bneumann]

As suggested in previous post, understand one's need & requirements .... we replaced ours with OEM Duracell 6V "like for like", batteries from Batteries Plus.

Replacement can be done carefully by oneself .... take photos before, turn off ALL connections, label EVERY battery & cable, each side connection. You can wrap / attach painter's tape, inscribe both connection sides same. The toughest part was lifting the batteries in & out.

Double check.