AGM battery

Thanks, it makes sense, kind of!

Hi Coach,

Don't confuse voltage drop with capacity.

Look at the number of amp-hours at the 20 hour rate. Optima is a great battery but has by its design less amp-hours per unit volume of space consummed. I.E. there is lots of empty space that could be filled with flat pasted plates.

Another good measurement for "house" battery banks is called "reserve capacity". Again Optima has less per unit volume of space occupied by the jar.

An Optima has 55 amp-hours. Reserve capacity 140 minutes.

A lifeline group 27 has 100 amp-hours, reserve capacity 189 minutes; the group 31 is 105, reserve capacity 195 minutes.

The group 27 is probably a similar overall "foot print" to the Optima.

If you compare the Optima with a flooded battery, voltage drop under heavy loads may be better (i.e. lower) because of the large surface area and low resistance of the Optima. Optima claims 350 cycles to flat dead. Other AGM makers don't recommend that sort of abuse, but have a similar cycle capacity. Of course, a flood battery can't tolerate being driven to flat dead more than a very small number of times.

If you compare The Optima with the lifeline, under heavy loads, it *might* have a slightly better voltage drop but not enough to level the playing field.

Coach-man wrote:
OK, I do not mean to steal the thread or sound like an idiot, BUT I am curious about the statement "Optima has the lowest capacity to foot print because of their spiral cells".. Everything I have ever heard about Optima's is that it is about the spiral design that gives them more power in the smaller foot print? I have purchased Optima's and by any measurement CCA's etc. they are smaller than a similar rated traditional battery, so I am confused as to where you got your information??

We have two group 31's in our little C. Excellent batteries and very little voltage drop under heavy inverter loads. Also seem to recharge quicker with solar. When our 6 volts die in our big coach we will replace them with four x 8 D's AGM's next year.

OK, I do not mean to steal the thread or sound like an idiot, BUT I am curious about the statement "Optima has the lowest capacity to foot print because of their spiral cells".. Everything I have ever heard about Optima's is that it is about the spiral design that gives them more power in the smaller foot print? I have purchased Optima's and by any measurement CCA's etc. they are smaller than a similar rated traditional battery, so I am confused as to where you got your information??

flyingfarmer wrote:
Anybody have experience with AGM battery in your RV? In particular the Optima yellow or blue top. Or I guess any other type of AGM battery. Any reason not to use them?
Thanks,
Dave

We installed two Optima Blue tops in march of 03 in our trailed and they are still in the trailer doing a great job. Be sure and use the Blue Tops if you go with Optima.

Denny

Hi flying,

AGM are fine. Optima have the lowest capacity to "foot print" because of the design of their spiral cells. I'd prefer a more traditional design. A group 29 AGM usually comes in at about 100 amp-hours.

It is important to follow the directions of the AGM maker regarding charging profiles. If they are not treated correctly, lifespan can be reduced FAST!

Lifeline makes a wonderful AGM. Prepare to have deep pockets.

flyingfarmer wrote:
Anybody have experience with AGM battery in your RV? In particular the Optima yellow or blue top. Or I guess any other type of AGM battery. Any reason not to use them?
Thanks,
Dave

I have used the Optima Blue Top for years. I have two of them in our 5'ver. I also have two yellow top in the F350. They have been in there since January 2013 -- just about 2 years with no problem whatsoever.

Enjoy the road. We do.

bidgon68

If it's for the house battery, just be sure to get a true deep cycle battery. I agree that they are about the best in many ways, but pricy.

Brian

I use two Group 34 AGM. There is nothing other than price that keeps people away!