Any really good reason to upgrade to AGM?

pianotuna wrote:
Hi,

Always teasing us, eh? What brand are these AGM's? Thanks in advance.

Don,

The two 12V AGM batteries we've had in our Class C all these years are the model shown at the bottom of this chart. I believe they are/were made by C&D Technologies for Interstate. As you can see at the top of the page, they're intended to be for "Wheelchair" use - which just happens to about match the type of perfomance needed for RV use. Note that their float voltage range is 13.5V-13.8V:

http://www.interstatebatteries.com/content/product_info/wheelchair_spec.asp

Here's the spec sheet for another excellent Fullriver 12V AGM battery that you can see also has a recommended float voltage range of 13.6V-13.8V:

http://www.dcbattery.com/fullriver_dc115-12.pdf

My "theory/idea/position" - and what has worked for us - is that if one wants to not spend money to replace a stock 13.6V fixed voltage converter that came in their RV while at the same time upgrade to AGM batteries ... just install AGM batteries with a float voltage range that matches what the converter's nominal output voltage is.

Charlie D. wrote:
Tag on my pin box of my fiver sez-:

SAFETY BREAK-AWAY SWITCH WILL NOT OPERATE unless connected to a power source equivalent to or greater than an automotive type 12 volt 12 amp hour wet cell battery." Something to think about when selecting replacements.

That is about the size of a small lawnmower battery. I would think anyone installing house batteries in a trailer would be using a size larger than that.

There are basically 2 reasons for upgrading..Generally they do not apply.

1: Access: In some RV's accessing the batteries so you can check the Fluid level and add DISTILLED water if needed, also for cleaning, is kind of not easy. AGM's you do not add distilled, when they run dry they die.. And they need very little cleaning.

2: You can get small AGM DEEP CYCLE (group 24,27,29 It is very hard to find true DEEP CYCLE in those sizes except for AGM.

Of course the popular GC-2 six volt battery (used in series wired pairs to make them into a 12 volt batter equal to a 4D) those are DEEP CYCLE batteries.

What is the difference... If you routinely run em down between 50 and 75 percent state of charge.. DEEP CYCLE last longer than MARINE/deep cycle.

At 13.62 volts float, the Lifeline AGM under my bed consumes .008 ampere. Eight milliamps. At 13.22 float, where it is now, it consumes .006 ampere. Stick that in your pipe and smoke it. Readings agree on three instruments.

David .... it looks like yer floatin' it a wee bit too high ... and probably shortening it's life from 13 years to 12.93 years ... unless you can crack it open and figure out how to add some H2O and seal it back up. :B

Have heard that AGM batteries do not work well in cold climates. Any one know for sure?

I think you are confusing absorbed glass mat with lithium technology with regards to cold temperature. A typical AGM has 1.300 specific gravity electrolyte soaked into it's mats and will run rings around a flooded battery at -20c.

My battery's lifespan is going to be longer than my own St. Peter is going to say "Lose the Lifeline" if I show up at the Pearly Gates lugging the AGM.

The battery sits under my bed, tapping it's foot... I just know it...

mpierce wrote:

Charlie D. wrote:
Tag on my pin box of my fiver sez-:

SAFETY BREAK-AWAY SWITCH WILL NOT OPERATE unless connected to a power source equivalent to or greater than an automotive type 12 volt 12 amp hour wet cell battery." Something to think about when selecting replacements.

That is about the size of a small lawnmower battery. I would think anyone installing house batteries in a trailer would be using a size larger than that.

. I was pointing out the need for wet cell batteries

myredracer wrote:
Am I correct the basic WFCO 3-stage charger isn't the greatest thing for an AGM? Don't really want to have to go out and buy a new converter/charger right away.

WFCO is fine if it actually charges in boost mode at 14.4 volts. Many fail and just undercharge AGM (or flooded) at 13.6 volts.

If spending money I recommend a better working converter first.
I recommend Progressive Dynamics with Wizard or IOTA with IQ controller. PowerMax is also great if you are always plugged in.

Since you do not camp off grid this stuff is not critical by a long shot. All lead-acid does prefer to stay at 100% charge so don't let it run down between trips.

leeper wrote:
Have heard that AGM batteries do not work well in cold climates. Any one know for sure?

All lead-acid loses capacity in the cold. AGM does provide some additional resistance to damage from freezing. Just don't push your luck too hard. Best to stay close to full charge as the temperature drops below freezing.