My 2013 Chateau came with a Harris Battery brand 12 volt deep cycle battery. It's a group 27 battery with 160AH with a date of 02/13. I contacted a local place about adding a second battery (group 27) and same AH, but it's a different brand. Is there any issues of connecting the two together in parallel? The person (not a tech) made mention that they don't like to mi batteries, but is going to leav it to the techs on whether or not. Won't know an answer until I take the RV in to have some other things added next week. Not sure if I should just go ahead and get 2 new 12 volt batteries elsewhere (which will be cheaper than getting 2 from them) and maybe go with group 31's if they will fit, or just go ahead and get the 1 battery from them of the smae size, but different brand. Thought about going to the GC batteries, but think another 12v would more than suffice. Plus if one of the gc batteries goes bad, then i'm out of power. I know thats a long shot, but sometimes "Murphy" likes to come visit.Any advice?

Hi Brian,It is best to have identical batteries of the same age.This is what is balanced and best for twin twelve volt batteries.As it often doesn't cost a dime more to do this, I think it is worth the trouble.If you wish to understand the "why" surf here:correctly interconnecting multiple twelve volt batteriesOthers may say it doesn't matter--but unless there is a compelling reason to not optimize charging and discharging why not do it the best possible way?

I would revisit the two 6v GC battery application. You could keep your existing 12 v for backup if you're worried about 6v failure. The mixing of two different batteries in parallel may be a charging issue. Your Grp 27 doesn't have 160 AH measured at the conventional 20hr. rate, BTW. Mfg's are using a different measure and pasting that on the label so that it appears that the buyer is getting more for his buck, it isn't so. I would guess that you have 70-90 AH at the 20 hr rate. I have heard of one Forum member having a failure of 6v batteries. There have probably been more but my experience with 6v batteries tells me that they are the most durable SLA battery. If you opt for the 12v batteries, I would buy two new ones and, as you mentioned, not at the RV service place.

wbwood wrote:My 2013 Chateau came with a Harris Battery brand 12 volt deep cycle battery. It's a group 27 battery with 160AH with a date of 02/13. I contacted a local place about adding a second battery (group 27) and same AH, but it's a different brand. Is there any issues of connecting the two together in parallel? The person (not a tech) made mention that they don't like to mi batteries, but is going to leav it to the techs on whether or not. Won't know an answer until I take the RV in to have some other things added next week. Not sure if I should just go ahead and get 2 new 12 volt batteries elsewhere (which will be cheaper than getting 2 from them) and maybe go with group 31's if they will fit, or just go ahead and get the 1 battery from them of the smae size, but different brand. Thought about going to the GC batteries, but think another 12v would more than suffice. Plus if one of the gc batteries goes bad, then i'm out of power. I know thats a long shot, but sometimes "Murphy" likes to come visit.Any advice?I run two group 27 batteries with no problems.Doesn't matter the brands, as long as they have the same AH etc, so they drain down and recharge at the same rate.

Westend: not sure. Only know what the label on top says. 20 hr rate. 160ah. And there is no room to have a third battery. hddecker: one that I saw on display appeared to have exact numbers as the one I have, just different brand names. i would think that up to 6 month date would not make much of a difference.

Where does this info come from ??Correct, a group 27 does not have 160 amp hrs at 20 hr rate, but will have more like 105 to 115. 70 to 80 amp hrs is a group 24.A battery from Feb of this year is near new, and can very well be used w/ any brand new 12v deep cycle battery of any size. If you think a group 24, can not be run in parallel w/ a group 27 or even 31 or even an 8-D, and still charge and discharge the same, you are badly misinformed !But if I was getting 2 new batts, they would be 6v, a no brainer IMO.

12 volt battery question | Good Sam Community

red31
Explorer
Aug 07, 2013
JiminDenver
Explorer II
Aug 07, 2013
RJsfishin wrote:
pianotuna wrote:
Hi,

I suspect the real value is more likely 80 to 90 amp-hours for a group 27.

Where you get this info ?
There ain't a 27 alive that don't do 100 amp hrs, and most do 105-115

My Interstate grp 27 is rated for 95 ah.
pianotuna
Nomad III
Aug 07, 2013
Hi RJ,

Thanks for the correction. I'm always glad to be wrong when I "low ball" a figure.

I thought the group 29 were the 105 to 125 amp arena, and the group 27 90 or so.

RJsfishin wrote:
pianotuna wrote:
Hi,

I suspect the real value is more likely 80 to 90 amp-hours for a group 27.

Where you get this info ?
There ain't a 27 alive that don't do 100 amp hrs, and most do 105-115
RJsfishin
Explorer
Aug 07, 2013
pianotuna wrote:
Hi,

I suspect the real value is more likely 80 to 90 amp-hours for a group 27.

Where you get this info ?
There ain't a 27 alive that don't do 100 amp hrs, and most do 105-115
wbwood
Explorer
Aug 06, 2013
Thanks.
MEXICOWANDERER
Explorer
Aug 06, 2013
This really isn't of earth-shaking importance. Adding another GROUP 27 BATTERY is what you are looking to do, and you can pick nits until the cows come home and in the end it would add up to be a waste of your time and money. Go interstate, sears, Costco, Sams or Wal-Mart. They all will work equally well and continue to do so given the health of the 1st battery.
RWDIII
Explorer
Aug 06, 2013
wbwood wrote:
RWDIII wrote:
wbwood wrote:
Trying to avoid buying two new batteries. Would prefer to only buy one more.

The battery is the same as the person shows here.

The battery website says Reserve Capacity @ 25A: 160 . Doesn't say 160AH on there.

Just get the batt and do it.Match them as close as you can.
I had a starting batt (series 31 )1050 cca for 4 years and it worked fine.
The consensus here said it would be the the ruin of me,
I would have my birthday taken away and probably get sent to Vietnam.
Your not the only one to confuse AH with RA and CCA

I didn't confuse them. I just posted what it says on the label. No matter what the numbers are or what they meant. My question is that if there is one of of another brand with the same numbers and a date within a few months, would it be ok?

YES
pianotuna
Nomad III
Aug 06, 2013
Hi,

I suspect the real value is more likely 80 to 90 amp-hours for a group 27.
mena661
Explorer
Aug 06, 2013
X2 Canadian Rainbirds
Canadian_Rainbi
Explorer
Aug 06, 2013
As others have said, there is no way a group 27 lead acid battery will have a 160AH @ 20 hr rate. That number is more like the reserve capacity. What you have will be somewhere around 105 AH.

That being said, a group 27 deep cycle (or marine/deep cycle which is more likely what it is) of any manufacturer should pair OK with yours as yours is relatively young, IF and it is a BIG IF, your battery has been well maintained, never discharged below 12.2V, never left discharged, never run low on electrolyte and when fully charged has a Specific Gravity of at least 1.265.