Well, need some input: If two 100 amp hour lead acid batteries did the job for my usage in my old trailer, will one AGM 100 amp hour battery do the job in the new trailer. Typical usage when dry camping: up in the morning and after breakfast may or may not run generator, will as needed run lights, pump, exhaust fan, fridge light, radio and typical daily stuff. Evening time, usually after dinner, while she is doing dishes, clean up etc. run the generator for a couple hours give or take and make coffee if in an area not allowing gen operations early, then by evening, if the furnace runs, pump, lights etc then up in the morning and it starts again. So the new trailer will have led lights and old one had regular lighting. I am thinking I will be able to make it with one AGM group 31 100 amp hour instead of the two lead acid group 29 with a total of 200 amp hours. I am trying to eliminate the double battery situation without going ove about $250. Si input is welcome. Lifeline makes a GPL 31 XT with 125 amp hours. So I think I cando just one. Again, input is welcome.Thanks Jeff

Probably the biggest draw you'll have is if you run the furnace frequently during the night. If you can conserve battery power there, you should do fine. Having the generator running during the evening chores will help keep you battery at peak when you go to bed later.

jffnkrn wrote:Well, need some input: If two 100 amp hour lead acid batteries did the job for my usage in my old trailer, will one AGM 100 amp hour battery do the job in the new trailer.Depends on what you mean by 'did the job.' If you drew them down 25%, then the answer would be yes. Much more than that, no. AGM ah's are the same as LA ah's.

Take a look at this usage chart before pulling the trigger.RV 12 volt usage

for most peoples use I feel AGM,s are to coatly you can get two wet cells for less than a good agm.

I agree that AGM batteries are expensive, but they sure are nice - never any corrosion in the battery compartment, never any need for adding water, and mine lasted close to twice as long as any floating acid battery I ever had. I just wish my new MH had them. I will probably eventually go back to them, costly or not.Ed Headington

AGM vs Lead Acid | Good Sam Community

20 Replies

ncrowley
Explorer II
May 25, 2015
I purchased a system that waters all of the lead acid batteries through one hose. You replace the cell caps. It was easy to put on and now it is very easy to top off the water in all the batteries before each trip. It is called Pro Fill. I highly recommend it.
ktmrfs
Explorer II
May 25, 2015
AGM's are lead acid. AH are AH. if you needed XAH with a flooded cell lead acid you'll basically need the same AH capacity with AGM's. internal construction is different, but the chemistry for producing electricity is basically the same. one has electroylyte (Sulfuric acid) mixed with water and a liquid, one has the electroylyte (sulfuric acid) captured in a porus membrane. Chemical reaction is the same in either case.
westend
Explorer
May 25, 2015
jffnkrn wrote:
Well to all. First off thanks for the info, input, comments etc. I just purchased two simple group 27 lead acid batteries. maintenance never was an issue with me, so it should be in the future. During a few of my upcoming trips, I may disconnect one battery and do a simple test over a day or two cycle and see how well one does the job. That will answer the question for the future. In the meantime, I know the two batteries will handle what I need. In addition, I went onto some websites to double check pricing. it just so happens that this weekend Pep Boys has an online coupon "thirtyall" for a purchase. I ordered two batteries and picked them up within a mile of home. $148.51 out the door for two group 27. that helped make the decision and if I only get a couple years out of them, so be it as I will test, test and retest in all types of climates and usage cycles over the next 6 to 8 months. So thanks again, and I will give a report later in the year!!!!! Good Luck & Be Safe ! ! !
I'd caution that using one of those grp 27 batteries as a test platform and drawing it down significantly is going to make a mess of your complete pair. I would use them together and keep a good charging schedule. You sound like a user that would benefit a lot from a small solar array. You might want to check into that as the cost would be about the same as replacing batteries every two years. You also may be able to leave the generator and gas at home.
pianotuna
Nomad III
May 24, 2015
This is what is balanced and best for twin twelve volt batteries.

As it often doesn't cost a dime more to do this, I think it is worth the trouble.

If you wish to understand the "why" surf here:

correctly interconnecting multiple twelve volt batteries

Others may say it doesn't matter--but unless there is a compelling reason to not optimize charging and discharging why not do it the best possible way?

Here is a video of 3 twelve volt batteries that have been wired in an unbalanced manner for 2 years. They have been equalized. The test shows how CCA has been adversely affected.

unbalanced for 2 years
jffnkrn
Explorer
May 24, 2015
Well to all. First off thanks for the info, input, comments etc. I just purchased two simple group 27 lead acid batteries. maintenance never was an issue with me, so it should be in the future. During a few of my upcoming trips, I may disconnect one battery and do a simple test over a day or two cycle and see how well one does the job. That will answer the question for the future. In the meantime, I know the two batteries will handle what I need. In addition, I went onto some websites to double check pricing. it just so happens that this weekend Pep Boys has an online coupon "thirtyall" for a purchase. I ordered two batteries and picked them up within a mile of home. $148.51 out the door for two group 27. that helped make the decision and if I only get a couple years out of them, so be it as I will test, test and retest in all types of climates and usage cycles over the next 6 to 8 months. So thanks again, and I will give a report later in the year!!!!! Good Luck & Be Safe ! ! !
Shearwater
Explorer
May 24, 2015
AGM's have plenty of advantages over conventional lead acid batteries including faster charging and the ability to withstand amp-hour drawdowns.

However, routinely drawing down an AGM to 25% will shorten its life considerably. In your situation, I would recommend 2 100 amp-hour batteries of either type. If you want to spring for AGM's for their other virtues, go for it.
jffnkrn
Explorer
May 24, 2015
I may have misinformed the group by talking about amp hours. I will be using the batteries with less draw as my new trailer will have led lighting. Just trying to figure out if the benefit of one battery will do the job if draw will be reduced. I was able to go through the links that were sent, thank-you, and I believe my usage is probably about 75 amp hours in typical day, then with generator running etc. I may be ok with one battery. This taken into consideration that the AGM may drain power at the same rate as typical wet cell, but will charge faster???? Things that make you go HMMMMMMMMMMMMMMM.I have talked to a few "Sales People" Interstate, Napa, Batteries Plus and even Sam's Club, AGM charging and draw seem to be better by their opinion due to the manufacture education they received. Again, things that make you go HMMMMMMMMMMM..... Thanks all, I will keep reading and if you have more info, I will take it!!!!
holstein13
Explorer
May 24, 2015
As far as I understand, the only real differences between AGM lead acid battery and a typical lead acid battery is that 1) The AGM is sealed and 2) the fluid is in the form of a glass matt gel, and not a liquid.

It's still a lead acid battery with the same types of volts, amps, longevity, charge cycles, duty cycles, connectors, etc.

In extreme mobile scenarios (say a fighter plane that turns upside down) the glass gel would be superior because it doesn't expose the lead while moving. Maybe there's even a benefit for us while traveling. The other major benefit, and I think this is extremely important, is that you don't have to maintain it by adding distilled water, ever.

But your post seems to suggest some sort of benefit with regards to amp hours and I don't believe you'll notice any improvement there, whatsoever. So if a 100 amp hour lead acid battery is not sufficient for your usage, then a 100 amp hour AGM battery won't cut it either.
wa8yxm
Explorer III
May 24, 2015
If 200 amp hours did the job will 100 do it.. Perhaps.. perhaps not

NOTE: AGM batteries ARE LEAD ACID batteries.. The tales folks tell about how you can run them down much deeper,and charge them much faster.. Well..Only one brand makes high speed re-charge claims and I've never seen a company claim you can discharg them past 50%

Which is the safe discharge level for DEEP CYCLE (not Marine/deep cycle) Batteries of all types.
rjsurfer
Explorer
May 24, 2015
I'm OK with my Trojan 105's for now no need for expensive AGM's, not worth converting to in my opinion.

BUT in a year or two Lithium will be in my battery box's. Now that's worth converting to.

Ron W.