A G M Batteries

Bud99 wrote:
Are A G M Batteries worth the extra money? Do they outlast wetcell Batteries or am I just as well off buying 2 wet cell batteries for use in my 5th wheel?
Thanks,
Bud99

Different skill sets are required for each type battery. AGM batteries are NOT without procedures to follow to obtain maximum life and output. Charging requirements and equipment can be different from flooded(wet cell) batteries.
SO what should be done is find out what is needed to be done with each type battery.
YOU CAN START HERE

This outta be interesting.

Bud99 wrote:
Are A G M Batteries worth the extra money? Do they outlast wetcell Batteries or am I just as well off buying 2 wet cell batteries for use in my 5th wheel?
Thanks,
Bud99

Do hornets nest.. The following is my opinion this is based upon both research AND Experience.

Are they worth the extra money NO (With one qualifier below)
Do they outlast PROPERLY CARED FOR wet cells.. Again NO
Are you just as well off buying wet cells.. Most likely.

Now, the qualifiers
In some cases it is very hard to get to the batteries for maintenance,, AGMs are a maintenance free design and there is one feature all wet-cell designs (Both flooded and Maintenenace free) have the AGM's Lack... A "This side up" sticker.

This means you can mount them any way you need to mount them On end, On side, even upside down though that is NOT recommended.

In my expierence,, I put a pair of Group 31 MK AGM's on their own circuit, Just them and a couple thousand watt Inverter/converter.

These were the last batteries to be installed in my motor home.. The other batteries consisted of the Flooded Wet Cells (GC-2 format) Interstate U-2200's installed at the factory and some older Maintenance free Marine/Deep cycle (Purchased BEFORE the Motor home)

The AGM's were last in.
They were also first out due to failure in 2011
I did not replace the Interstate U-2200's till this year.

I was not pleased.

In doing research: Many brag about how long the AGM's last compared to other batteries.. Strangely LIFELINE the #1 AGM maker, is not one of those so bragging.

This one went 11 pages...

AGM.. better? 10/28/13

Can't tell you about length of life or wether they are worth the bang for the buck. However for us trey are worth it. They are essentially zero maintenance and that's important to us as they are hard to get to in the Little class C we have. We installed two group 31 AGM batteries a little over two years ago. They also seem to take a charge faster from the 320 watt solar array we have. We turned the controller output down a bit for when in storage and we crank it up a bit when we are using it. Our converter goes into bulk mode at 14.4 volts and they seem to handle it fine. I'll defer to the experts on the board for how things should be done but we don't really treat them that special. The only other thing I noticed is that the voltage drop is very minimal under heavy inverter usage. Again I'll leave that to the experts on wether that is imaginary or real.

Hope this helps.

It is a specialty situational thing whether the AGMs would be worth it to YOU.

Besides the situation where you cannot get at your batteries for hydrometer and water level checks easily, making AGMs better, the other thing that really came to light in previous threads here was (as mentioned above) little voltage drop under heavy load.

This comes into play where you have only room for say two batteries. With Wets you could need four batteries to run your 2000w inverter that runs the microwave , toaster, kettle, etc. You could do it with two Wets except the voltage drop with two batts, once they get below 75% SOC can make the inverter alarm sound. With four Wets you can run all that till you are down to 50% SOC with no inverter alarm. You will recharge at 50% anyway, since you are a good RVer. :)

Now the deal is, testing by members on this forum shows that you can get the no-alarm down to 50% with only two AGMs, so you don't need four batteries when space is limited. That does not mean you can run the high amp items as long as with four batts, since that is an AH issue, but only that when you do run them , you can run them at lower SOC.

Since the whole point of inverter- powered microwaving , toaster, kettle etc is to be able to do that early in the morning long before campground generator hours would let you do that, and it is early morning when your batteries are lowest, you want to be able to run that when down to 50%, and if you only have room for two batts, then AGMs will let you do that.

However if you have room for four batts, then you can get both the 50% operation AND have lots of AH in the bank to run the things longer.

my experience
i have 3yr old "surplus" AGM's removed from (internet backup server power) when they were three yrs old..sat on float for 3yrs
they have been in daily use for 3yrs, now 6yrs actual age..3yrs daily use, that about 1100 charge/use cycles

they are still good.. just a few weeks ago i did a series of Load tests on them with a carbon pile load tester, each and every battery tested good

each battery weighs 100# and each one is 139 ampHrs

As you can see, everyone has their opinion and most can back it up with some sort of a study or article. We've used Lifeline AGM's for 6 years on 2 coaches and have found that the AGM performed as well as we could have wished. The big selling point for me is no need to add water, and absolutely no corrosion....EVER. At each maintenance cycle I use an air hose to blow the dust off the batteries and that's it. No clean up, no hold down corrosion and no terminal corrosion or cleaning. Also no need to remove to clean the battery tray, counteract the rust and repaint. To me, this makes AGM's worth it.

By the way, we boondock extensively, have 560W of solar panels on top, and use the RV a lot. 32,000 miles in 16 months.