Starting Batteries

[jeepsrule]

OK after digging through many old posts on batteries and replacing them. I'm asking for opinions on what to replace my chassis batteries with. It seems some recommend larger starting batteries and some recommend deep cycle batteries.

If you have replaced your original two starting batteries what did you go with??

[Mr_D]

Deep cycle batteries are not made to give the high amperage draw that starting a DP requires. Stick with the OEM size or larger starting batteries. Ours are now 9½ years old, as are our house batteries (U-2200's) and still doing just fine.

[slickest1]

I just went through this. After an alternator failure My 1 year old big 8d starting battery died. Had it checked and they thought the plates inside were most likely broken. I replaced it with the same 8d heavy duty battery. These have 1155 cranking amps. I had not used the coach for a month after I replaced the battery and when I went to use it the battery was dead. I recharged it and the next day it was dead. Took it in and they tested it and it was the same as the first. After reading through my manuals I found in my manual for the 2000 watt inverter that you should not use starting type batteries in a coach because they don't handle the charge from the converter very well. They say the plates inside are too thin and they can warp. I since replaced the battery with 2- 12 volt heavy duty deep cycles wired in parallel. Combined they have 1350 cranking amps which starts the coach better. I still have an alternator problem so that may be what caused the battery to fail. Nevertheless I am glad I switched to 2 batteries as they are much easier to handle. Good luck.

[Steve Ownby]

If it were me, I would replace with the size that was OEM. I suspect that is 2 group 31 12 vdc batteries with about 900-950 CCA each. Your coach may or may not be equipped to charge the chassis batteries from shore or generator power. If not you should address that issue with an after market battery charger (minder) type product, otherwise parasitic loads with slowly cause them to discharge.

[Diplomat Don]

jeepsrule......If your coach is like mine, it came with two 12 volt Interstate batteries. They gave me GREAT service with never a problem. Many didn't know tht you could slice the labels, revela the battery caps and fill them them. Mine lasted over five years and I replaced all six batteries last year as a preventative measure. I would go with the same batteries if you didn't have any issues. They're now about $125.00.

[jeepsrule]

Thanks all for the suggestions. I have been maintaining mine but after 6 years they are not holding a charge well. I have two as Don mentioned and I'm probably going to put in a couple replacements of that same size.
In my manual for the Magnum Inverter/Charger I don't see anything about type of chassis batteries, it does talk about house batteries and they recommend AGM for optimum performance. I replaced my four house batteries last year with Interstate 6volt batteries and they are performing well. So now I'll start hunting prices on starting batteries.

[SpursMVP]

Yep...we just replaced ours with the Interstate 31-MHD batteries. I found the interstate website to be VERY helpful as it walks you through the planned use. For example, the batts we pulled out were made in China and built for over the road trucks.

As always I also like a national brand so if something goes bad...just take the receipt and batt to a dealer for a quick replacement.

[moisheh]

The latest trucking magazines are touting a new Group31 from Trojan. Comes with a 4 year warranty. I haven't seen them in the marketplace yet. For truckers #31 batteries are almost generic. Every HD truck dealer sells pallet loads and thus they have very good prices. Check any KW or Freightliner dealer.

[wa8yxm]

For the chassis I would forgoe Deep Cycle and stick with starting.. The largest starting battery that will fit. Look at the Cranking Amps rating, (Or Cold Cranking amps if cranking is not listed seperate)

Cranking amps is how much current the battery can push at 32 F (0C)
Cold Craking is at 0F-19C about)

These batteries are NOT designed to be run down very far, But they can be run down very fast.

DEEP CYCLE, (NOTE Marine/Deep Cycle are really starting batteries) are not designed to deliver as fast, but they can deliver more of their charge.

That said.. On my coach the starting battery is less than 100 amp hours. the HOUSE batteries are over 200 Amp hours. So "Not as fast" means they both can deliver about the same amount of current... But the house batteries.. WILL NOT FIT in the starting battery tray. They are much much bigger (about 3 times the battery)

So the conclusion: I would get the battery with the most cranking amps that fits in the tray for starting.

And the battery with the most usable amp hours (DEEP CYCLE) for the house.

This is exactly.. How it shipped from the factory.

[vito.a]

I just replaced my chassis starting battery a few months ago. I searched the internet for the best deal on a large 8D starting battery and Advance Auto had by far the best price. They even had a 20% discount if I paid for it online and then picked it up in the store.

The hard part is lifting it up into the slide out tray. The guy at Advance helped me lift it into the trunk of my car. I then backed up to the motorhome battery compartment and lifted out the old battery into the trunk and lifted the new one from the trunk to the motorhome battery tray.

[Pogo]

I am looking for a pair of 31p-MHD, 950 CCA. I checked with NAPA and with Batteries Plus. The prices are a tiny bit better at NAPA, but I know that there are NAPA stores everywhere if I need to replace them in warranty. (or out)
I am assuming that since I gave them the above ID information and CCA, there is no difference between a motor home application and a large truck application. Right? And, do you know who makes NAPA batteries?

[Twomed]

WHO MAKES NAPA BRAND BATTERIES? « Batteries | Compare Reviews and Trusted Advice from Battery Experts

They often discount prices at the end of the month to move inventory dates...ask the manager,