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RV Dan · 02-27-2018, 02:41 PM

I have a 2003 Holiday Rambler Endeavor 40PBDD. My engine start batteries are shot and I need to replace. My engine is a Cummins 330on a Roadmaster chassis. There are two Group 27 batteries for the engine. I went to a local large Freightliner shop parts counter. They are fairly knowledgeable on Motorhome’s since they work on many of them. They said that my coach should have group 31 batteries instead of Group 27. I called Monaco customer service and they were no help. Can anyone with a similar engine/ chassis tell me what they have for batteries? Thanks in advance.

Chargerman · 02-27-2018, 03:22 PM

I would go with the higher output that they are recommending as long as they will fit in your tray. No harm in having a little more reserve. I would imagine that the cost difference is negligible but that’s just a guess.

RV Dan · 02-27-2018, 04:34 PM

They are the same price for group 27 or 31. I was not sure if I could do any harm. I assume not. 12 volts and CCA.

twinboat · 02-27-2018, 05:02 PM

GP 31 batteries are probably the most common starting batteries on large diesel engines. GP 27 are pickup truck batteries.

Chargerman · 02-27-2018, 05:02 PM

Sorry but I don’t know what the difference would be between the groups then but for sure it would not do any harm either way.

Mhcorrigan · 02-27-2018, 05:10 PM

Quote:

Originally Posted by Chargerman

Sorry but I don’t know what the difference would be between the groups then but for sure it would not do any harm either way.

Dimensions of battery

Mhcorrigan · 02-27-2018, 05:16 PM

Quote:

Originally Posted by RV Dan

I have a 2003 Holiday Rambler Endeavor 40PBDD. My engine start batteries are shot and I need to replace. My engine is a Cummins 330on a Roadmaster chassis. There are two Group 27 batteries for the engine. I went to a local large Freightliner shop parts counter. They are fairly knowledgeable on Motorhome’s since they work on many of them. They said that my coach should have group 31 batteries instead of Group 27. I called Monaco customer service and they were no help. Can anyone with a similar engine/ chassis tell me what they have for batteries? Thanks in advance.

Buy AGM sealed battery’s such as Odyssey. Cost more but last forever.

Chargerman · 02-27-2018, 06:17 PM

Yes they are very good but really only worth the cost if you know you are going to keep you rig longer than 7 years

OLYLEN · 02-27-2018, 06:18 PM

Not going to make a big difference on most starts, until you get to the lower temps and the grid heater comes on. Then the 31's will have a bit more power. Most 27's are in the 850 CCA and the 31's in the 950 CCA and a bit more reserve time. I alway look for the biggest most powerful battery that will fit the space be it start or deep cycle. Now as far as the AGM, NICE, but worth the cost difference, not for me.

LEN

RobRoy · 02-28-2018, 09:37 AM

Quote:

Originally Posted by Chargerman

Sorry but I don’t know what the difference would be between the groups then but for sure it would not do any harm either way.

" You may have heard common terms like a "group 24 battery" or "type 27 marine battery." These numbers are referring to the Battery Council International, or BCI, Group Number of the battery. These numbers define the physical dimensions of the battery case. This is important as some applications call for specific case sizes.

While the BCI does not determine the Amp Hours (AH) rating for the batteries, there is a correlation between case size and AH rating. For deep cycle batteries, the larger the case size the more capacity the battery will usually have. "

Hope This Helps

Gdawgs · 02-28-2018, 09:48 AM

Sam's has Duracell group 31 AGM batteries for around $150. I have 8 house AGM batteries and put 2 of these in for the chassis. Charge rate is different for AGM and wet. Good price.

RobRoy · 02-28-2018, 11:00 AM

Quote:

Originally Posted by Gdawgs

Sam's has Duracell group 31 AGM batteries for around $150. I have 8 house AGM batteries and put 2 of these in for the chassis. Charge rate is different for AGM and wet. Good price.

AGM charge rate is a little lower ....... did you adjust for it and if so ...how?

Thanks in advance

RV Dan · 02-28-2018, 04:49 PM

Quote:

Originally Posted by Gdawgs

Sam's has Duracell group 31 AGM batteries for around $150. I have 8 house AGM batteries and put 2 of these in for the chassis. Charge rate is different for AGM and wet. Good price.

The Freightliner truck Center near me has group 31 Alliance batteries for $85 Sams does not sound like a deal.

Gdawgs · 02-28-2018, 08:53 PM

I'm at about 800 AMP total for 8 AGM house batteries. The charge system charges all batteries so I put the rate at 80% according to the Magnum manual for this type of battery. It's different for wet and even different for the type of AGM you have.

The Sam's batteries are AGM so $150/ea. seems like a good deal for this area.