Battery Choice for Coach Conversions

[HB of CJ]

Ok all you rocket scientists....are there now better choices for my planned RV battery bank than the old tried and true T-105 lead acid batteries?  Watering batteries has now become a physical chore.  Ouch!

I know a little bit about ni-cads since they were in my solar cabin years ago, but are there now some new battery types that would work better in a coach conversion?   Thanks in advance. 

[Jerry Liebler]

HB,
   The tried and true T105s are certainly the most economical deep cycle battery.  But they do require watering and spew explosive and corrosive fumes.  Sealed AGM technology batteries offer similar capacities, life and energy storage density but at about 3 times the cost.  Sealed nicads would cost much more.  Gel cells are much less rugged compared to AGMs but if free would be a good alternative.  So if you want sealed you should shop for AGMs 
Regards
Jerry 4107 1120

[FloridaCliff]

HB,

I have been using AGM's for almost 3 years and have been very happy with them.

The sealed part is a major plus as I have not had a single corroded connector.

The ones I obtained were from a large commercial UPS and were already 4-5 years old.

They will last, if treated correctly.

Cliff

[TomC]

In my opinion, AGM's are the ONLY way to go.  No watering, no gassing, can mount in any position (although they prefer you not to mount upside down, but they will work).  Have seen 8D AGM batteries on their sides in large yachts up on a shelf out of the way.  You can stand them up on end-think about that with an 8D!  I have two 8D Lifeline AGM's and am very pleased with them.  I use Interstate 31 wet batteries (2) for starting with a solenoid jumper between the two banks of batteries for either emergency starting or charging the set with the big engine.  Good Luck, TomC

[H3Jim]

Yeah, what TomC and Cliff and Jerry said.  I have 6 4D's, AGM.  Spendy, but I would not go any other way. 

With solar keeping them fuly charged all the time, I hope to get at least 8 years from them.  I ahve two mounted on their sides.  No worries about watering them, very few worries about outgassing (only the emergency, or grossly overcharged situation).

[Don Fairchild]

So what are the ah's of the 8D agm's

Don

[H3Jim]

My 4D's are around 200 AH, 128 lbs each, I think the 8D's I looked at were 250 AH's and about 150 lbs each

[Don Fairchild]

Jim,
   what type and size of solar panels do you have. Do you run your ac off the inverter. what size
Is your inverter and is it a tru sign wave or modified.

Don

[Tony LEE]

4 X 12V 260AH AGMs side by side in the centre bay with rubber tube matting over the top and then use the batteries as a shelf for storing other stuff in plastic crates.

At the charge/discharge rates I use, ventilation doesn't seem to be compromised and the chargers are temperature compensated anyway.

I did consider normal flooded batteries but the ventilation problems and need to access the tops for checking made it just about impossible without losing lots of space, so the extra cost wasn't much of a consideration.

Doing the math using depth of discharge of 70% for AGMs vs 50% for flooded, plus the ability of AGMs to be more fully charged from the engine alternator than flooded, and the $/AH (usable) comparison isn't as different as you think

[H3Jim]

Don, I have 4, 150 watt panels putting out a max of 37 volts, going into a charge controller that limits voltage to 31 volts.   Panels are BP, and measure about 31" by 62" x 2"  There was a break in period of less than a week, but now I get lots of power.  Full by 10 am usually.  The controller has a feature that once the house bats are full, up to 2 amps goes to charge the start bats, thereby keeping them full as well. I still have room up top for several more panels, or my first choice is to add a deck up there with the extra room.

I have a Trace, 4024 inverter. true sign wave. I can run 2 of my three airs while going down the road if need be, but the bus air works great and puts out 9 tons.  While using my 13kw Wrico generator or plugged in to the grid, I can easily run all three low profile Carrier airs.

While I can run the air off battery power, I would prefer not to hit the bats that hard, and so far have not spent a night in really hot humid place where I needed to.  I will be adding a ceiling fan in the bedroom to help with that.

[TomC]

Lifeline AGM 8D = 255 amp hour and 156 lbs each.  Good Luck, TomC

[Songman]

Jim, I definitely want to meet you one of these days and see that solar setup. I had a guy over here today giving me an estimate on putting solar on the house. PG&E says I used $529 worth of electricity this last month! No way I did but they hit me like that every month. No wonder I can't get a bus conversion done!

[pvcces]

Henry, an intermediate choice that we have been very happy with is L16s. They are much more efficient than the golf carts that they replaced were. They run 350 AH and weigh 125 pounds.

We had 6 golf carts and now have 4 L16s. They have a smaller footprint, as well.

For what it's worth.

Tom Caffrey

[niles500]

Lifeline AGM's and NAPA maintenance free sealed Group 31's - Priceless

[HB of CJ]

Thank you everyone.  Looks like AGM's for sures.  Songman...Five $big ones$ for PG&E monthly in the pretty city is pretty normal from what I hear.   Family still there.  Grin and bear it!