Deep cycle battery

[Vcjp03]

Quick question,

I need to change my 4 coach battery they are 31C but would it be a big deal if i replace them with 27C instead.

Thanks

the reason is i got hard time to find 31C in my area

[Hikerdogs]

Originally Posted by Vcjp03

Quick question,

I need to change my 4 coach battery they are 31C but would it be a big deal if i replace them with 27C instead.

Thanks

the reason is i got hard time to find 31C in my area

27C batteries are far more common, but somewhat less powerful. We just went through the same scenario and opted for the 27C batteries. The last set of group 27C batteries lasted over 6 years, and since we don't do a lot of boondocking they are sufficient for our purposes.

The typical 27C deep cycle batteries have 85 - 105 amp hours while the group 31 batteries have 95 - 125 amp hours

A word for the wise. Our batteries were supposed to be fully charged when we bought them. After installation they wouldn't even power the television and satellite dish until they had been charged several hours. Unless you plan to drive several hours before using them be sure they pass either a load test or a hydrometer test as being fully charged before you install them.

[jimbo16720]

Originally Posted by Vcjp03

Quick question,

I need to change my 4 coach battery they are 31C but would it be a big deal if i replace them with 27C instead.

Thanks

the reason is i got hard time to find 31C in my area

Tractor Supply has 27c batteries for $85 rated 105amp/hr.

[wa8yxm]

Group 31 is 130 amp hours.
Group 27 is about 95

Group 29 about 100 to 105.

A pair of GC-2's 230 amp hours (These are six volt so you need two in series)

To be honest, that's all there is to it.

Oh, depending on the battery box you may need to drop a slab or wood or two in the box to "Fill in" the gaps. No problem there at all. Use scrap, it will be damaged over time.

[JimM68]

I wouldn't.
But then thats me I'm one of those who always gets stuck paying retail plus....

[whem2fish]

You can get the 29 at SAMs or Walmart I just got 2 for the boat they were about $85 each

[Hikerdogs]

The group number designates the physical size of the battery. In this case groups 27, 29, and group 31 batteries are fairly close in size.

Here are the dimensions for the batteries being discussed according to BCI (Battery Council International) BCI Battery Group Size Chart

Group 31: height 9 7/16" length 13" width 6 13/16"

Group 29: height 8 15/16" Length 13" Width 5 1/2"

Group 27: height 8 15/16" length 12 1/16" width 6 13/16"

Keep in mind all battery manufacturers do not necessarily follow the dimensions layed out by BCI. I have seen several batteries labeled as Group 27 with dimensions that vary up to 1/2" from the standard.

Also there is a range in the amp hour output because all batteries are not created equal. They all may have the same number of plates per cell, but there can be a difference in the physical size of the plates. Generally speaking the larger the plates the larger the output, and the heavier the battery.

[Gary RVRoamer]

Reducing the size from 31 to 27 reduces your battery capacity, i.e. amp-hours. You will lose about 20% of your stored power. If you seldom camp without shore power, you will never notice the difference, but if you want to spend a weekend camping "primitive" with no electrical hook-ups, you will wish you had the 31's instead of 27's.