group 27 or 31 batteries

I am looking at buying 2 new batteries to run my 12 volt motors, how much more weight is the 31 than the 27? what would you guys recommend? I do run some longer days and wondering on which to purchase? I run a 16.5 sylvan tiller with a 40 hp and currently use 27s and also what brand would you recommend? I am kinda looking middle road somewhere around 150.00 per batt. thanks in advance

I’m not sure on the weight difference but I recommend Interstate. I got a fantastic deal on my last battery at the interstate batteries store in Coon Rapids.

I’d also recommend the group 31 whether you need it or not. The bigger the battery the longer it should last. More accurately, the less you drain a battery the longer it will last. I’m talking years longer.

biggill is the interstate dual purpose or just deep cycle

You skipped over 29’s. I run 2 – 29’s for my 24v motor. Erase 27 from your mind straight away.

The SCRATCHA!

I use 2 group 29s in my 16-foot tiller (also 40 hp). On my second pair. Got em at Wal Mart. Think I got 6 years out of last pair.

I’ve never come close to running em down. With average use could go 3 days probably.

31s probably more than you’ll need but probably couldn’t hurt though would be even heavier.

Oh. And I run a 24 volt.

The SCRATCHER wrote:

biggill is the interstate dual purpose or just deep cycle

All of their deep cycle marine batteries were dual purpose from what I can tell.

I agree above with the 29 series. I just remembered that interstate may not even have a 31. I could be wrong though.

thanks shockers and everyone else for the info! the scratcher is hoping to make 1st trip the 9th or 10th to P4

Interstate make 31 in their virgin lead AGM series. I don’t know in the regular line of batteries. SBC sells Interstate maybe one of their guys will chime in here.

I run x2 29s on my trolling motor and a rough day on P4 or up north with 8 hours on the water won’t drain them. They are fleet farm cheapos I believe that are a few years old

The 29,30 and 31 group batteries are all basically the same. If your using it for starting and accessories get it the duel purpose. For the trolling motor straight deep cycle will run much longer. Only maybe 5 pounds difference between 27 and the 29-31. For a 12 volt system I would go as big as possible.

Crappy Fisherman wrote:

The 29,30 and 31 group batteries are all basically the same. If your using it for starting and accessories get it the duel purpose. For the trolling motor straight deep cycle will run much longer. Only maybe 5 pounds difference between 27 and the 29-31. For a 12 volt system I would go as big as possible.

I will respectfully disagree.
For a 40hp that the OP mentioned you would not need dual purpose as the amp draw is not high enough. Even if he was using for a starting a deep would provide plenty of amps plus extended reserve o run low draw items like a troller and graphs.

The last two times I was at the interstate store the guys there talked me out of the dual purpose battery. Basically there’s no reason for it if you have enough cca to start your motor with a deep cycle. With a 40 hp you’ll have more than enough.

I would go with the biggest battery(s) you have room for and not worry about the little bit of weight difference there is. It will stick out in your mind more the days your batteries died than the days you had power to spare.

With everything that’s been said, price might make your decision for you if you are thinking AGM.

Home depot carries the Exide 31 series deep cycles for $120. 5 years on the three in my boat. The thought that a deep cycle cant be used as a starting battery is flawed. The 31 has started my Yamaha F150 fine for 5 years. They offer plenty of CCA for most outboards. Heck, 95% of the starting batteries use is running electronics and accessories anyway.

both new batteries will go to trolling motors! I have a separate battery for starting would I just do 2 deep cycle is the battery you got a exide nautilus 31 deep cycle

The SCRATCHER wrote:

both new batteries will go to trolling motors! I have a separate battery for starting would I just do 2 deep cycle is the battery you got a exide nautilus 31 deep cycle

Exide Nautilus 31MDC

gixxer01 wrote:

<div class=”d4p-bbt-quote-title”>The SCRATCHER wrote:</div>
both new batteries will go to trolling motors! I have a separate battery for starting would I just do 2 deep cycle is the battery you got a exide nautilus 31 deep cycle

Exide Nautilus 31MDC

Would like to get the Exide nautilus 31mdc but our Home Depot doesn’t carry them.

I had two Interstates in my boat that lasted over 6 years. I got a deal from my father in laws shop in Rochester on deka marine master dc31dt and those have been a great battery but I will never know how long they will last as I traded my boat off last fall. They did also have a 3 year warranty.

gunsmith89 wrote:

deka marine master dc31dt

This is what I have used for the past 15 yrs. I replace them at the first signs of getting weak, usually at around 5 years of heavy use. I have had some go 8 years though. I’m sure for the average angler 6 years + would be expected. They are the best battery I’ve used and I’ve used Interstate and Optima Blue Tops.

Update:

I’ve had to replace 2 of 3 Exide 31 MDC now. All three were new as of August 2012.

All batteries are connected to, charged and maintained by a Minn-Kota 330D after every use and, for the most part, all winter long.

The starting battery was the first to be replaced on March 2018 (5.5 years use) due to my negligence. I left the key on over winter with the charger unplugged and it froze.

Checked the batteries today and found that “someone” unplugged the charger and I have another dead battery. This time a trolling motor battery. Being it’s a 24V motor I will be replacing both batteries.

So…6.5 years on the trolling batteries and 5.5 negligent years starting the Yamaha F150.

Hopefully I do a better job maintaining the new ones.

That’s not bad, might get a couple more years if you’re lucky.