Battery Size for Group 31's

[Madifonzo]

I am looking to replace my Interstate Group 27's with Group 31's. Any 280 Dancer owners see a reason these can't work? Perhaps the size?

Also, I there consensus on 29's vs 31's?

 

[Alegria]

I suspect the 31s won't fit in your existing battery trays. So expect to replace them as well. Other than that I don't see an issue.

Sent from my XT1575 using Tapatalk

 

[be_prepared]

Sometimes the 31's will fit into a 27 tray, but often they are just about a half inch too long. The Group 27 trays are usually specified as "Group 24/27" and the bigger trays are Group 29/31. A typical group 27 is 12 1/2 x 6 3/4 x 9 3/8, and the Group 31's are usually about 13 x 6 3/4 x 9 3/8... each manufacturer can be a little different though, and they may have differences between battery types also, flooded ones might be different dimensions that AGM's for example. And starter vs deep cycle vs dual-purpose, from the same "group", could have different dimensions.
Fun eh? Still, given all that, the 31's will give you extra capacity, and that's a blessing on the hook or mooring.

Make sure that if you change battery type, say from a flooded lead acid battery to an AGM, that your charger is rated to properly handle the new battery type.

 

[bbwhitejr]

I replaced a 27 with a 31 and added an additional 31. The 31s that I bought are sort of tapered on the bottom and they fit the tray that the 27 came out of perfectly. It filled it completely up and I bought a matching tray for the other battery. I looked long and hard for Grp 31 trays, but did not find much selection. Measured the 31s and they were a perfect fit.

Bennett

 

[Madifonzo]

I have read that it's the gel batts the need a special charger. My factory charger should be fine on AGM's? I am leaning towards the Optima blue tops.

 

[Mike Blake]

I have read that it's the gel batts the need a special charger. My factory charger should be fine on AGM's? I am leaning towards the Optima blue tops.

I have had Optima blue tops for 5 years. I went with a new smartcharger. The blues will fit in where the 27's were with no problem. I may be wrong but I think the old charger won't work well with the AGM'S

 

[carterchapman]

I had original chargers and AGMs on my '05 340 and now on my '03 410. They work fine with AGMs. Gels are the batteries that need a special charger setting not AGMs...

The new owner of my 340 is going on 8 years with Sears Platinum AGMs and I am on 6 years with Optima Blue Tops on my 410.

 

[66pony]

I have Group 31's in my boat and they fit the factory trays.

 

[Madifonzo]

I am reading that you can't mix battery types on the same bank. Since I really don't need a deep cycle blue top on the starboard motor I am considering to continue to use the Group 27 Interestate. Anyone if there is an issue with this with respects to the boats factory charger? Are the banks separated when on the charger too? I think they are since they offer 1,2,3, etc bank chargers. I think my boat comes with a 2 bank smart charger.

 

[Madifonzo]

Getting ready to pull the trigger on my battery buy. My question-can I run all AGM's on one bank and a standard lead acid on the other (dedicated starting better for my starboard engine). I am wondering if there would be an issue for the charger.