Batteries Lead Acid vs AGM

Another common AGM myth I hear is "Can be recharged faster"

True in part.. LIFELINE Agm's can be recharged, in bulk mode, as much as 10 times faster than flooded wet cells.. PROVIDED you have 10 times teh converter (Anyone got a 2,000 amp converter out there? You are not going to charge faster than the converter can make 12vdc (Well 13.6 vdc) You might cut 5 minutes off your total recharge time in the average install if you are lucky.

TWO: this only applies to some brands.. Notably LIFELINE. Other brands may or may not be faster.. It's up to the maker.

I had MK/DEKA (East Penn battery company) AGMs

In my motor home I had, and still have, the OEM flooded wet cells.

I had some older Marine/Deep cycle that pre-dated the purchase of the motor home, They have died and been replaced as well

And a pair of MK/Deka AGM's that were purchased a year AFTER the motor home.. They were also the first to die, and I mean DIE!!!

Hi,

There are a few more negatives with AGM.

1. over charge them and they will gas. There is no way to replace the electrolyte so the battery life span and capacity will both be adversely affected.

2. charging profile varies by maker and needs to be followed "to the letter" for best longevity.

3. if left partial charged they will sulphate and there is no method to easily reverse this process--without "violating" #1 above.

4. equalization is possible on some AGM's, and is not recommended on others, but it does take much greater care to do the procedure.

5. life span is no longer than flooded cells but cost is considerably more.

If I had pockets deep enough for AGM I'd go for six two volt cells.

Advantages have already been covered by others posters in the thread.

AGM advantages;
Will accept a charge faster and at higher rates than wet cell.
Storage discharge rate is 1% per month. Wet cell 10% per month.
Can be mounted in any position except inverted.
Will not freeze until -90 degrees F, even if fully discharged.
Do not gas off.
Maintaining water level is eliminated.
No corrosion issues.
Disadvantage;
Cost more.

If you are considering AGMs, here's some more to consider. I am lazy and forgetful. I have the best intentions to perform all maintenance regularly on my motor home and we all know that the road to hell in paved with good intentions.

Most batteries require regular maintenance to keep them at full potential and to last as long as they "should". I found that most of the time, when I got around to taking a peek inside my batteries, you could already see the top of the plates. They always seemed to die an untimely death. Now, I have LifeLine maintenance free batteries (AGM). They haven't even been looked at in 6 years and are still going strong.

Maintenance free batteries are WAY more expensive than regular acid flooded batteries but, for those who are somewhat forgetful like I am, they are WAY CHEAPER than buying acid flooded batteries every 2 years because you didn't maintain them. Only you know which category you fit into.

Yah I gotta go with flooded for bang for your buck. Having said that we just put two group 31 AGM's in our little C. The battery cabinet is horribly hard to check battery's and it was worth it to go to AGM's. Our A has 8 x flooded 6 volts in it but it is much easier to check the water in that coach.

Hi,

Best bang for the buck is flooded jars.

Your subject is badly worded

AGM batteries are Lead Acid,, The full name is Sealed, Valve Regulated, Lead Acid, Absorbed Glass Mat.


I assume you mean "Flooded wet cells v/s AGM"

Properly maintained, (Water as needed) Flooded wet cells will last as long or longer than AGM in RV use.

They cost a fraction of what AGM costs (Epically if you get GC-2s at Sam's Club).

HOWEVER AGM's have a far lower "Self Discharge" (internal leakage) rate, (Hold their charge longer between re-chargers if not used to power stuff)

SOME (LIfeline) AGM's can take a whoming bigger charge, some can also discharge faster, and deeper.

All in all, I'd save my money.. but that's me. I tried AGM, did not like 'em, but again, that's me. Many like 'em just fine.

With an AGM you have zero maintenance and zero corrosion on your battery terminals. Mine are going on four years and look and work like new. They are expensive but my four batteries are a little tough to get to so for me they were worth every penny. My Xantrex inverter/charger has an AGM setting which keeps them charged properly.

Most of the better inverter/chargers have settings for AGM or lead-acid so that it uses the correct voltage while charging.

Yup,

Also need to know what converter, charger or inverter charger you have.

An AGM battery will accept a re-charge a lot quicker than a wet cell due to lower internal resistance. But if all you have is a 20 amp charger, most of the "advantage" will be lost.