AGM Batteries in the Arizona Heat

[Lynn1130]

This is probably a question for those in Arizona and other high heat climates but I am considering switching to AGM batteries. I would probably still stay with the two 6 volt battery setup just for space, weight issues and since I do mostly dry camping. The cost would be about three times that from what I pay for batteries now but if, the life span is true it would cost less over time to have AGM. But here is the kicker. Any batteries in vehicles in Arizona do not last more than 18 months to two years. With two years being on the long side. This is just the way it is here with outside temps and temps under the hood. I have found that RV batteries kept on trickle chargers will last a bit longer. But life is still short for them here.

So, for those of you in this type of climate do you use them and what kind of success, or failure, have you had.

Thanks

 

[Jimsryker]

Re: AGM Battereies-Arizona Heat

This is probably a question for those in Arizona and other high heat climates but I am considering switching to AGM batteries. I would probably still stay with the two 6 volt battery setup just for space, weight issues and since I do mostly dry camping. The cost would be about three times that from what I pay for batteries now but if, the life span is true it would cost less over time to have AGM. But here is the kicker. Any batteries in vehicles in Arizona do not last more than 18 months to two years. With two years being on the long side. This is just the way it is here with outside temps and temps under the hood. I have found that RV batteries kept on trickle chargers will last a bit longer. But life is still short for them here.

So, for those of you in this type of climate do you use them and what kind of success, or failure, have you had.

Thanks

Hey Lynn,

I just switched to AGM for all the reasons they provide. Mostly the lack of potenial acid damage and the more rapid recharge times. If you're gonna run the Gen. to recharge, I want to run it as little as possible. I know a box will mitigate the acid risk, but the cost of the box or boxes and then providing venting was more than I wanted to deal with. I live in the Temecula Valley and we get regular temps above 90 in the summer and often get days over 105. My GMC has/had AGM batteries. They recently failed but they were OEM for me and the date stamps indicate that I got over 7.5 years out of mine. I was surprised and then again not. It spends most of it's days parked inside the garage. While that area can get hot, it is just sitting there. I don't know that any of this even helps you, but I did want to point out the temps I get and the duration of the battery life I enjoyed. They were AC Delco's. I was able to replace them cheaper with some Sears DieHards and they had better numbers overall. Again, AGM. I recall my off roading days and the fights I had with the battery box in my Blazer. Acid would eat that right away....

 

[Bohemian]

Re: AGM Battereies-Arizona Heat

There are three disadvantages to AGM

Price per KWH
Weight per KWH
Volume of battery per KWH

All three highly significant.

Other than that they are superior in every way. Developed for military use and reliability.

An AGM battery is a lead acid battery. Completely the same chemistry. The glass mats are used as plate separators which allows closer spacing of the plates without shorts. Closer spacing allows thinner plates with more surface area and therefor more current ability. The mats are infused with the gelled battery acid solution. AGM batteries can be completely sealed as less H2 is produced and the H2 back to acid catalyst is more effective in these geometries. When completely sealed (at the factory) they can be used in any position, upright, sideways, upside down.

Now back to the 2-6V golf cart batteries in series vs 2-12V in parallel argument. The only advantage to the 6V batteries that makes then more efficient is that they come in generally larger sizes which makes them more efficient. 6V and 12V of about the same size are generally equal in efficiency. You would be better off with 1-12V than 2-6V of equal battery capacity in 12V use sizes. It's just simpler, slight bit less to go wrong.

 

[brianharrison]

Re: AGM Battereies-Arizona Heat

None of my research showed AGM last longer in heat than flooded.

Controlling charge rate is more important in AGMs as they are more sensitive to overcharge; float voltages at 2.2-2.3 V/cell (13.2-13.8 V for a 12V setup), even less in hot ambient temperatures.

Chargers with battery temp compensation is a must for AGMs, IMHO.

Brian

 

[Lynn1130]

Re: AGM Battereies-Arizona Heat

I think you would have to explain how one 12 beats 2 6s in amp hours when I am dry camping. I have not found that to be true with what I have but am not familiar with the AGM so I am interested in how that might be.

 

[Jimsryker]

Re: AGM Battereies-Arizona Heat

There is always the obvious when it comes to 6V. One fails and you are stranded. A co-worker recalls this happening to him and he recounted how it took a full day of driving to resolve the matter. I think that rarely happens, but it is something to consider and tech. has come a long way. I think it all comes down to weight, cost and amp hours. Try as I might, it all seems to be fairly equal when running the numbers. The only separation seems to be 6 volt and 12 volt. If you go with a single 12 volt, you are still susceptible to a single failure ending your fun.

 

[branson4020]

Re: AGM Battereies-Arizona Heat

I think you would have to explain how one 12 beats 2 6s in amp hours when I am dry camping. I have not found that to be true with what I have but am not familiar with the AGM so I am interested in how that might be.

You can get a single 12V battery with the same amp-hr capacity as 2 6V. It weighs about the same as the 2 6V batteries combined.

 

[Jimsryker]

Re: AGM Battereies-Arizona Heat

Exactly.... It all seems to be fairly equal and it all seems to come down to how much you are willing to pay. Two T-105 give you 225 amp hours at 124 lbs. you can opt to go into the "plus" range, but that equates to more money/weight and it doesn't stop from there. I think two 12's are better than two or four 6's. Weight vs. amp hours and your options when one fails. If it fails... All things being equal, I say go for the 12 volt batts.

 

[Bohemian]

Re: AGM Battereies-Arizona Heat

I think you would have to explain how one 12 beats 2 6s in amp hours when I am dry camping. I have not found that to be true with what I have but am not familiar with the AGM so I am interested in how that might be.

Go to Trojan and run the stats. I did. The only correlation is with size (volume and weight) of battery. In general, 6V are just built bigger than 12V. As I said, equivalent sizes have equivalent efficiencies for 12V use. Two small 6V with the same capacity as one large 12V with the total same capacity have the same efficiency.

Well, according to Trojans numbers. Oh, and battery engineering theory. Considering they use the same internal cells and differ only in external casings, it also makes common sense.

 

[skyguy]

Re: AGM Battereies-Arizona Heat

Despite the difference in cost of 2 6's vs 1 12v, I would rather wrestle 2 65 pound batteries than 1 130 pound behemoth! Don't know if I could even get the 130 pounder on board by myself...

 

[Lynn1130]

Re: AGM Battereies-Arizona Heat

Yeah, that is my thought and concern about one large battery. I keep coming back to this topic because of having to provide venting for the current batteries and would like to put the two batteries on a slide tray for ease of access but have not decided how to resolve the venting issues. I may have that conversation with my repair shop manager when I am in the next time.

 

[fredwrichardson]

Re: AGM Battereies-Arizona Heat

There are three disadvantages to AGM

Price per KWH
Weight per KWH
Volume of battery per KWH

All three highly significant.

Other than that they are superior in every way. Developed for military use and reliability.

An AGM battery is a lead acid battery. Completely the same chemistry. The glass mats are used as plate separators which allows closer spacing of the plates without shorts. Closer spacing allows thinner plates with more surface area and therefor more current ability. The mats are infused with the gelled battery acid solution. AGM batteries can be completely sealed as less H2 is produced and the H2 back to acid catalyst is more effective in these geometries. When completely sealed (at the factory) they can be used in any position, upright, sideways, upside down.

Now back to the 2-6V golf cart batteries in series vs 2-12V in parallel argument. The only advantage to the 6V batteries that makes then more efficient is that they come in generally larger sizes which makes them more efficient. 6V and 12V of about the same size are generally equal in efficiency. You would be better off with 1-12V than 2-6V of equal battery capacity in 12V use sizes. It's just simpler, slight bit less to go wrong.

Totally agree. Properly maintained AGM batteries (never discharge more than 50%) will last as long as a wet battery but temperature is very important. Ideal charging temperatures: 32°F – 104°F (0°C – 40°C). Wet batteries also suffer from high temperatures due to evaporation so wet batteries do not buy you much more when the temperature goes up.

 

[Bohemian]

Re: AGM Battereies-Arizona Heat

Despite the difference in cost of 2 6's vs 1 12v, I would rather wrestle 2 65 pound batteries than 1 130 pound behemoth! Don't know if I could even get the 130 pounder on board by myself...

Absolutely,

 

[lwmcguir]

Re: AGM Battereies-Arizona Heat

Our GEM car has the original 6 AGM 12v batteries and they are still getting us about 20 miles on a charge after 10 years. Not 40 or so like they did a few years ago. Still pretty darn good performance.
Large diesel tractors changed from 2 large 6v to 12v back in the 60's and never looked back. I would never use a pair of 6v for anything if I could avoid it.

 

[porthole]

Re: AGM Battereies-Arizona Heat

Our GEM car has the original 6 AGM 12v batteries and they are still getting us about 20 miles on a charge after 10 years. Not 40 or so like they did a few years ago. Still pretty darn good performance.
Large diesel tractors changed from 2 large 6v to 12v back in the 60's and never looked back. I would never use a pair of 6v for anything if I could avoid it.

Had those in our boat (8D's). Wrestling 175 pound batteries in and out of the boat every 2-3 years is a real pain in the butt.