No Maintenance Coach Barttery

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Sealed slosh battery is junk for cycling

AGM will do just fine

AGM batteries do require a slightly lower charge voltage. Check your charger documentation to see if it is adjustable. If it is not, you would risk damaging the expensive AGM battery.

So far, Sealed (slosh) battery is out, not good for deep cycling.
AGM, 1. it will do fine, 1. it will be damaged, but I'll try to find if the voltage can be lowered to ??

thank you for the info

Hi,

Agm's are not all the same. Lifeline wants a BIG FAT charging amperage. Others may not want more than c/5 (mine).

Some folks have had good luck with a 13.6 volt charge rate with Universal Batteries

So the real answer is find a battery that mates well to your existing converter or find out how to set up an inverter/charger to the parameters the particular AGM needs.

Yes, AGM is the only thing that is maintenance free.

But I will never buy another battery from Universal. Made in China. They do specify both 13.x float voltage and 14.x Absorption voltage, and my solar controller gives them precisely what they want.

The only little problem is that they somehow gone completely sour by sitting several months in storage before I installed solar. They self-discharged to 55-60% which is right at the allowed minimum - according to the manual - and developed a HUGE self-discharge current afterwards. This wasn't the agreement :). Manual didn't say anything about that. By "huge" I mean 3%C a day.

The recommended charging voltage is different for AGM's but only by a tiny amount.. Few converters are that well regulated and in fact how hot it is makes a difference as well and few are compensated for temp.. So the difference is too small to matter.

The big difference is something called Acceptance.. Some AGM's can accept a re-charge (Bulk mode) that is very, very, very fast, as much as 10x what a Flooded wet can take... (Specifically Lifelines are like this). Others the recommended max is about the same as Flooded so again, for the most part no differnece.

OPTIMA (A special case of AGM) has less capacity per cubic foot Recommend against unless you are in "Rough Service" (IE: Wave Runner, 4-Runner)

I have found AGM's do not, as is often preached, last longer... In fact I do not see how a "Sealed" type (Valve Regulated) can outlast a properly maintained flooded wet.. But they are nice if you have access issues.

wa8yxm wrote:
I have found AGM's do not, as is often preached, last longer

Because AGM are more sensitive than flooded to proper charging regimen, and not too many people have it "proper".

I have a speed charge 75 amp Schumacher smart charger that has an AGM setting on it, and I see no difference whatsoever in the charging rate. It charges everything at 15+ volts.....sometimes over 16.
I have been using AGM batteries (SLA) for many years in electric bikes, scooters, handicap and others, and in cordless 24v lawn mowers, and in my experience they do last longer than liquid, and they don't need any different charging voltage.

I suggest you all read my little ditty on AGM batteries. In all my years of testing I never encountered an AGM battery that was anywhere near as hysterically sensitive as a flooded cyclable battery. Where are some of you getting your information from?

AGM batteries are costly. Manufacturers do not want warranty returns. They expend a lot more effort providing literature and strict operating rules. But reality trumps myth. There are good brands, average brands and mediocre brands.I just chatted with Gerd Henke. Manager of an importing warehouse in Texas that imports batteries from "all over the world". They offer low prices on AGM batteries. Interested? I had a six month old Johnson Control fracture the #4 intercell strap in my toad. I was forced to replace it with a calcium calcium $125 lightweight. Calcium calcium batteries have a disturbing habit of failing utterly after a single deep discharge. Conclusion. I need to upgrade to a proven dependable starting battery. Two guesses where I'm going with this. You can call the auto club. I can scream at a jackrabbit.

Camping World, in Sandy,UT, seems to almost only offer AGM batteries. Excide brand, around $250 or about $100 more than a flooded cell, so they are close to where we are and may be where I head. Thank you all, a conflicting discussion but a good one, I'll be able to chime in next time, maybe, with my 'expertise and experience'.