My MH came with two of the NAPA Commercial 12v batteries (part#7236) as my coach bank. I read people chatting about having 220amphour, ect. I don't see that rating on this battery. Is there a formula to find out? From the NAPA web site:Battery Application CommercialBattery BCI # BCI # 31SBattery Cold Cranking Amps @ 0 Degrees F 950Battery Cranking Amps @ 32 Degrees F 1,190Battery Load Test Amps 475

An AH rating may be available, somewhere, but this is really a heavy duty starter battery ... not a deep cycle battery designed for RV use. Consequently amp-hour specs are usually not provided. It is designed for short high current draw for starting engines, not for long moderate current draw over many hours. The physical design of the plates are quite different .... a proper deep discharge battery has much heavier plates. The GC2 type battery, in pairs of 6V types, is pretty much the standard for motorhome use - and these are also costlier .... but they tend to have longer life spans and provide more amp hours per discharge cycle than starter batteries ... or even the mid-way Marine Deep Cycle types.

130 amp hours each is my guesss. the key spec was the #31A group 31 battery is about 130 amp hours. HOWEVER: From the ratings I'm guessing a Marine Deep cycleThus two are 160 AMp hours but you can't use all that, IN fact you can't even use 130 of it, only about 100 amp hours are usable after that damage sets in on the batteries.. So the GC-2, where you can safely use HALF the battery, (It is a DEEP CYCLE not a MARINE/deep cycle) is a better choice.. Or better yet, upgrade to 2 pair of GC-2Each pair wired in series to get 12 volt, is treated exactly as a SINGLE 12 volt battery.

I would guess 220 combined is about right. Maybe a little more.Do you need more power? What are you charging with?Many house batteries are chronically undercharged and lose capacity.

Our used TC came with a NAPA battery like that. Called "HD Commercial" and I could not find any AH for it, but it weighs 56lbs as a 31 so I figured not much. I did find a similar NAPA battery somewhere Googling around that was about 1,000 CCA and had about 80AH.IMO, if you will be on shore power mostly, they will be ok, but if you plan some off-grid 50-90s, swap them out for proper deep cycle batteries for the house bank.

A 15 plate 2% antimony battery. Thousands hit big rig dealer parts shelves and were retailing for $79.95 exchange. Not at all a cyclavle battery as Ed Gee so nicely put it. Flooded 31 batteries are problematic no matter what plate configuration is used. I recommend a plain "pass" on that BCI group size. The batteries are 13" in length so 11" 3-cell golf car batteries would fit if your intentions are to boondock. Always plugged in? Those NAPA batteries would be fine and dandy. There are no issues with 31 VRB absorbed glass mat batteries.

NAPA Commercial 12v Battery ( Amp Hour? ) | Good Sam Community

18 Replies

RJsfishin
Explorer
Nov 30, 2016
I just bought 2 a week ago at Cosco for 84.95 each. They are listed as an Interstate battery now.
MrWizard
Moderator
Nov 29, 2016
Sam's club 6v
Will be in the automotive department
Not on the store shelves next to the tools and hardware
wolfe10
Explorer
Nov 29, 2016
Interesting. It came up right away for me, but they are not available in all states:
http://www.samsclub.com/sams/duracell-golf-car-battery-group-size-gc2/prod3590228.ip?searchTerm=347700

And, MI is one of the states they are offered in.
JimInMich
Explorer
Nov 29, 2016
wa8yxm wrote:
You said you know about six volt and were hoping to save the cash... Here is a surprise for you.

Question: Do you have a SAM's club membership? A Pair of GC-2 at Sam's might actually cost LESS than that Group 31.. if they fit (Check first) you get more power, and DEEP CYCLE power at that. for about, or less, than the same money.

I checked Sam's web site, no golf cart batteries listed during search. I called my local Sam's club, they do not have them in stock. Person told me if they are not available on line, he couldn't order them for me either.

As for saving the cash statement, if I don't need to buy them, I'm saving the cash ( no use buying something I don't need right away ), right?
j-d
Explorer II
Nov 29, 2016
wa8yxm wrote:
The GC-2 is the single most produced 12 volt lead acid battery

SIX volt, right?
wa8yxm
Explorer III
Nov 29, 2016
You said you know about six volt and were hoping to save the cash... Here is a surprise for you.

Question: Do you have a SAM's club membership? A Pair of GC-2 at Sam's might actually cost LESS than that Group 31.. if they fit (Check first) you get more power, and DEEP CYCLE power at that. for about, or less, than the same money.

The GC-2 is the single most produced 12 volt lead acid battery, this means it is also the most Bang for your Buck. Mine are DEKA G-20s 230 amp hours, bit more expensive but by the time I added in the cost of a Sam's Membership, which I do not have... We are talking "Lunch at McDonalds" more expensive.
j-d
Explorer II
Nov 29, 2016
I think I remember, couple years ago (?) an OP mentioned those batteries here on RV.net. The Diesel Pusher crowd was excited about them for chassis batteries.
theoldwizard1
Explorer II
Nov 28, 2016
Any battery that advertises "cranking amps" or "cold cranking amps" is a starting battery or a dual purpose battery. The best house batteries are "deep discharge". The best bang for the buck, are a pair of 6V golf cart batteries.
2oldman
Explorer II
Nov 28, 2016
Those aren't deep cycle batteries which is why no ah rating.
MrWizard
Moderator
Nov 28, 2016
Jim
If you are going to dry camp boondock then plan on replacing those batteries and start budgeting for it

You will be ok 'right now' for the occasional overnight stop
But not for extended no hookup

You can save your money while you wear these out,