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Posted by: dcpac Jan 11 2018, 11:15 AM

I need to replace the lead acid batteries that came with my Hallmark truck camper. I want to use AGM. Can anyone provide a recommendation. I have solar on the camper if that matters.

Thanks!

Posted by: RV_Tech Jan 11 2018, 04:13 PM

I picked up two AGMs at Sam's Club for my Hallmark last year. No problems. Solar is not an issue as i am sure you have a controller between your panels and the batteries. Makes life much simpler with no need to periodically add water to the cells.

Posted by: Freespool Jan 14 2018, 09:10 PM

Take a look at Mikes site, Truck Camper Adventure. Scroll down to the bottom for an excellent article on care and maintenance of AGM battery's.

Posted by: SidecarFlip Jan 15 2018, 06:32 PM

Actually, if your converter is working properly, the maintenance on a flooded cell (I have 2, Group 31's, is not much more than a twice yearly water check. and insuring the cableing is tight.

The only advantage to a sealed agm is no venting required but my battery box was already vented. Draw down is the same (no less than 50% total charge and charge rates are the same as well. Only advantage is no venting and no water checks, both of which are easy for me.

If I was to go to a different battery, it would be a Lithium or Lithium/Iron Oxide battery. Half the weight of any conventional battery, ability to install anywhere, even up side down and the ability to discharge to almost no capacity remaining without damage.

Problem is, they are very expensive, typically around 800 bucks for a Group 31 equal.

If you have the wallet, a Lithium or Lithium/Iron oxide is the way to fly.

If I was flush, I'd have a pair.

Posted by: fishinfool145 Feb 4 2018, 05:20 PM

AGM is a good idea. I use them in both my RVs and in my bass boat. However, most people end up with the Optima. Their deep-cycle is low on capacity and high on price.

I use the AGM from Cabelas or Bass pro. Both seem to be equal quality and I never have a problem with either. Both are available in large electrical capacity. The price is in the range of the Optima.

On the wet cell side, the Trojan SC225 is the best for a deep cycle.

Lithium... Never looked at them, probably can't afford them. I wonder if my chargers would work with them. Sidecar?

Posted by: SidecarFlip Feb 5 2018, 07:46 PM

No and no. One, expensive and 2, requiire a specialized charger. Best Converter has the chargers but they are pricey too.

Big advantage is weight (a group 31 equivalent weighs about 20 pounds versus 60 for a conventional) and you can put them anywhere, even up side down as there are no vents at all and discharge to 10% or even less without damage. Your typical AGM/flooded cell is no less than 50% or you risk plate damage.

Downside is cost of the battery and the charger. Batteries are around 800 bucks each (Group 31). I never priced the charger, the battery alone scared me off.

I can go through a bunch of 31 flooded cell batteries and not come close to 800 bucks.

I too have been down the Optima road and I to have found it to be bumpy. I feel Optima batteries are over priced and under performing as well.

I run a pair of Crown's now but will probably go to Trojans when these expire. Not sure when that will be. 3 years now and just fine.

No solar with me. Just a small inverter and shore power when home.

Posted by: fishinfool145 Feb 5 2018, 11:06 PM

I don't know where you are buying your AGM batteries, but Cabelas size 30 (pretty much the same as 31) is currently $250, and they are often on sale. I didn't check bass pro. Mine were $190 last time I purchased. Weight is no advantage, these dudes are 65lbs. Only advantage that I can see is longevity, no gas venting and zero maintenance.

You have a valid point about the charger, and one should check to ensure that their charger supports AGM. Both my RVs and boat do and I've been using AGM for so long, I forgot to consider that others may not.

In both my boat and my RVs, the batteries are placed where it is very difficult to maintain the water level properly on a wet cell and I would destroy 4 wet cells for every one AGM I purchase.

Posted by: SidecarFlip Feb 11 2018, 05:23 PM

I get my AGM's at battery warehouse. The only reason a flooded cell uses water is it's being overcharged or rapid rate discharge.

My Crown's are flooded cell and they use very little distilled water. They have to be topped off maybe 2 times a year.... maybe.

The Crown's came from Battery Warehouse as well.

Lithium Iron Phosphate batteries are insanely expensive no matter where you get them. Far as I know, there are only 3 manufacturers (builders) in the US. All the cells come from China (cheaper ones) and Japan (better ones) and are assembled here in arrays that equal the amp hour ratings of the batteries.

Posted by: daveren Jun 1 2023, 10:17 PM

I payed the big-bucks for Lithium and am pretty happy. I figure it cost me about an extra $500 CDN going from 2 big heavy Trojans to one light Lithium at half the rated capacity and a updated solar charger. Because the Lithium rides at a higher voltage (and stays there) and charges quicker, it has worked out just as well having the lower capacity. The $500 is about 5 fuel fills for me to put things in perspective ..... its worth it.