Anyone recommend PowerStar batteries?

A 3,000+ CCA 8-D AGM might raise an infrared thermometer 1.3 degrees F by stuffing 900 charging amps into it. If anything the terminals themselves would start to rise to uncomfortable temperature. This is yet another reason why Lifeline chose beryllium copper battery posts.

Tell you a little secret...

Hydrogen atoms are so tiny they rise with tremendous force and penetrate battery compartment seams like they aren't even there. An AGM would have to enter full thermal runaway before it would vent enough to reach Stoichiometric air fuel ratios. But here's the trick---if the AGM is NOT tightly enclosed into a small space, venting hydrogen will rise about three feet per second at 20C. It will jam into the ceiling and pass THROUGH fiberglass or plastic like it wasn't even there. The atoms seek to rise and they will quickly vent to open atmosphere. The key is the battery can not generate enough hydrogen fast enough in any but totally absurd forced overload conditions during thermal runaway. The word FORCED has meaning. It is destructive testing.

The electrical chemical effects of an AGM in thermal runaway would demand say an ambient temperature of 140F ... AND ... forced voltages in the 17.0 range. This is enough to cause a FIRE somewhere else that has nothing to do with the battery.

ANY lead acid battery, flooded, gel, AGM can enter thermal runaway under the wrong conditions. But no way in hell can an AGM emit a scarce 3% of the hydrogen of a flooded battery. I've seen flooded batteries blow up. They blow up because they spew and vent enough electrolyte to CREATE A CHAMBER OR CHAMBERS within the battery. The chamber fills with hydrogen and oxygen both given off by a gassing flooded battery. A spark occurs because of a short in plates that are warping then touch, and presto you have one hell of a miniature fuel air bomb. An AGM does NOT HAVE THE ROOM inside to accumulate more than 5% of the total amount of gas that a flooded battery can.

Monster AGM battery banks enclosed in cinder-block usually painted with epoxy building CAN vent enough hydrogen and O2 to reach Stoichiometric concentrations. Usually battery spaces have secure windows an doors. The ratio of battery area to containment space ratio might be A HUNDRED TIMES greater than one or two AGM batteries on the open area of an RV. Again, the batteries should not be tightly enclosed.

People who manufacture and sell batteries must take the legal safe route when it comes to recommending ventilation. They would be crazy not to, because one path exonerates them utterly (RV catches fire, AGM battery melts, blood-sucker glides his client into suing the deep-pockets battery company because he scanned the documentation given to his client and decides that there is enough of a loophole in product liability prevention and goes to trial.

Meanwhile back at the ranch the "vent" issue loses any and all perspective. Reality gets thrown out the window. Large cruising sailboats have battery spaces with AGM or flooded batteries measuring in TONS. Oh! We need a register as well as a draft vent. Let's drill a six inch hole four feet below the waterline.

I myself would balk at putting more than (4) group 31 AGM batteries inside an RV measuring 30' or less. And I SURE would not leave connected a battery charging potential greater than battery float maintenance potential if the rig was unattended. Only a fool enables a great recharge potential then walks off.

Sorry to vent...

But the AGM battery venting fallacies got to me. Find a half-truth then exploit it. I've purposely exploded more batteries than I will ever remember. Commercial fishing draggers, long-liners, and purse seiners demand facts not hyperbole. One King Crabber I revamped had 22 8-D batteries in the engines space. Yes the engines breathed. Through baffled vent intakes.

-Finished-

I've been looking at various batteries for a while now and even started a thread asking about venting AGM batteries. The general consensus is all batteries must be vented. Speacking to the seller of some AGM 8-Ds he said the gassing isn't the only issue with AGMs, but also heat build up too. Mex said a small tube was enough for gassing, the seller wants two vents, one top, one bottom for the heat.

I wont mention to my 4 year old marine battery that it wasn't suppose to run our trailer all this time. The one trip we had hook ups was more damaging than the rest of the time on solar.

Flooded Lead Acid must be ventilated... you need AGM for what you're looking at using it for.

I once left my four 6v's sitting in my kitchen for a couple months, while working out of town. When I walked in the door, I could smell the fumes, and my eyes were quickly irritated... and that was in an open concept house... imagine in a small closed in space. Moreover, during charging, gassing is greatly increased.

Good points about the asian-made batteries. I'll stick to USA, and possibly Canada.

As for the 6v golf cart batteries, sometimes I'll be in a camper shell on a pickup truck without much ventilation and the batteries would be in there with me. The longest I'd be in it would be 8-10 hours. I'm trying to avoid non-AGM because I hear the traditional flooded acid batteries can give off hydrogen and oxygen, potentially creating conditions ripe for an explosion. Should I worry about this or does that not apply to my situation?

These Asian AGM batteries sold online are all likely made exactly the same in the same factory and have different labels attached. The ones which state charging voltages right on their sides, all state the same charging voltages, the only difference is the maximum charge amperage changes with the battery size/capacity.

They do not have the low self discharge nor the High current acceptance ability of higher quality AGMs.

Since they do not have the low self discharge, and must come over on a slow boat, and likely sit in some warehouse before being ordered through the internet, One might get an unused but already sulfated battery with only 80% of its original design capacity left.

So where is the money saved in that?

Like cheap tires, cheap agms do not save the person cycling them money in the long run. Spend the extra for a fresh AGM made in the USA.

chuck3,

I've been doing a lot of reading on batteries lately because I want to do some dry camping in the future. I'm certainly no expert, but I can tell you this - the marine batteries that come with most RV's are pretty much worthless for dry camping. They are fine for those who always camp with electric hookups, but for dry camping you need true deep cycle batteries. In my experience, most of the 12v batteries that are being sold as deep cycle are really just marine batteries. From what I have read, your best bet for getting true deep cycle capability is either to go with 2 6v golf car batteries in series (Trojan T-105 is very popular), or go with an AGM deep cycle battery. That one you are looking at looks more like a marine hybrid, even if it is AGM. If you choose AGM, from what I've read, Lifeline is really good. Pricy, yes, but it will last. Just my 2 cents!

For tent camping, and portability, your best bet is probably a modest sized 12v AGM, or at least a sealed lead acid that cannot spill if tipped over. A modest portable (i.e; foldable) solar kit would be a nice addition, as well.

(man i love spending other peoples' money! :) )

I would suggest Golf Cart batteries.

Downside: they need to be bought in pairs, they often have a higher core charge, they tend to be a little heavier, and are slightly taller than GC-27's.

For two GC2's its 160lb and 235 amps.

No problem, and thanks for the clarification. It sounds like nobody is in favor of the battery I listed, so I'll keep looking. The Vmax batteries seem to be really good but they're pricy. I may have to go with those since the last thing I want is to buy a bad quality battery that won't work when I need it.

chuck3,

I was actually being somewhat sarcastic... my bad... but none of those marine hybrids are suited to regular deep cycling. They are intended for light duty cycling, and as a back-up to the marine engine's starting battery... thus the 'hybrid' design. I recommend staying away from any and all marine batteries for your intended use.