Battery upgrade question

[xdude]

Looking at replacing my bank of 4 group 27 flooded batteries and was wondering if it is worth it to spend the extra on AGM batteries. Also would I have to upgrade alternators and charger or can you use the same charging system as a regular flooded type battery? Thanks for any help

 

[JimFromMD]

I upgraded from 4 group 27 wet cell batteries to 4 group 31 AGMs. I also upgraded my charger from 30Amp to 40amp based on the guidance from the folks at ProMariner when I inquired. Ended up with a Promariner Pronautic p 1240 and have loved it. It also provided the AGM charging profile (supposedly not necessary, but I felt better), charges quicker than the 30Amp, and has a multi speed cooling fan so it's quieter than the original too. Did not change anything with the alternators.

Due to the price and discount coupons you can find, I gave the Autocraft Farm and Tractor AGM battery a try. So far so good at 3.5 seasons, and we'll see how they are doing again here in about 3 weeks!

I think this is the battery, but I recall it having more CCA than 950. I can verify soon.
http://shop.advanceautoparts.com/p/...battery-group-size-31-950-cca-31p30/2100010-P#

 

[ZZ13]

Since James (JimFromMD) and I are pals I am comfortable giving a different view than his (ha!). For me, wet cell Group 27 batteries are some of the best value items on my boat. But I am a generator user and don't run long hours on just battery power. Spending 3 times as much money just to mainly start the engines doesn't pay off for me, as for what I researched the lifetime of the AGM wasn't really any better than the wet cell. So, if you need to run on batteries for long periods then the AGM folks will probably post all the benefits of buying them over wet cell. But if you spend most your time on AC power (either at the slip or running the generator), then $80 a battery for wet cell group 27 may be a pretty good deal.

 

[CliffA]

So, if you need to run on batteries for long periods then the AGM folks will probably post all the benefits of buying them over wet cell. But if you spend most your time on AC power (either at the slip or running the generator), then $80 a battery for wet cell group 27 may be a pretty good deal.

+1 ....:thumbsup:......

 

[JimFromMD]

Since James (JimFromMD) and I are pals I am comfortable giving a different view than his (ha!). For me, wet cell Group 27 batteries are some of the best value items on my boat. But I am a generator user and don't run long hours on just battery power. Spending 3 times as much money just to mainly start the engines doesn't pay off for me, as for what I researched the lifetime of the AGM wasn't really any better than the wet cell. So, if you need to run on batteries for long periods then the AGM folks will probably post all the benefits of buying them over wet cell. But if you spend most your time on AC power (either at the slip or running the generator), then $80 a battery for wet cell group 27 may be a pretty good deal.

Good point Bill! I hate running the generator unless I need to for 110v stuff, or to charge the batteries. Most of my equipment can run off 12v and I go that way. I do a lot more on the hook time w/o the generator going. Also liked not having to do the battery fluid maintenance, keeping the chemicals correct etc.

 

[CougarCruiser]

Another consideration is access for maintance. You should check the water levels of wet cells a couple times per year and top off as necessary. If access and maintenance are easy, then wet cells can offer very similar performance for less than half the cost (or more) per battery.

Consider upgrading to group 31's, or even a set of 4 golf cart batteries. That would improve capacity as well, and cost far less than agm's.

 

[bbwhitejr]

Replaced 1-group 27 deep cycle house battery with 2-group 31s-lead acid from Sam's for $94 each. Also installed a Promariner 1240P. Agree with Bill. All of my research did not prove 3x the cost as I do not believe the AGMs will last 3x as long. Just my $.02.....

Bennett

 

[xdude]

I spen a lot of time on the hook and only run generator to recharge. Just wondering what is best set up within reasonable price. Do group 31's have substantially more capacity than 27's when comparing apples to apples?

 

[blaster]

I can't comment on performance yet but I just purchased a group 27 100ah AGM battery from battery sharks.

http://www.batterysharks.com/Univer...slZ3e2b1DvKr0op87DysjRmrxeEIdCPg1EaArVK8P8HAQ

It was $189 shipped to my door with a 5% off coupon code. I'm using it to power a motor guide trolling motor. The rep said it should provide between 500 and 1000 charge cycles. They mostly sell them for solar systems but they said it should be great for my intended use, we shall see.

 

[bbwhitejr]

I spen a lot of time on the hook and only run generator to recharge. Just wondering what is best set up within reasonable price. Do group 31's have substantially more capacity than 27's when comparing apples to apples?

Someone more knowledgeable than me can anwer that question. I should have looked closer into that, but for the $94 deal at Sam's for the Duracells(made by Deka-same battery as the Deka per their customer service), I jumped on the 31s. There was not much difference in price between the 27s and 31s at Sams.

We spend a lot of time on the hook as well and generally run the gen at night for the AC and battery charger. I had a 20amp and the one Gp 27. On the 2nd night, we would start to run short on DC power. With the 2-31s and 40amp charger, I hope those days are behind us.

Bennett

 

[blaster]

Doesn't the group size refer to the dimensions of the case? Obviously a larger battery has the potential to provide more power but doesn't necessarily do so. I have seen group 27 batteries with more amp hours than group 31 batteries. Also the AGM batteries don't spill, they don't require maintenance, and are more shock resistant. That said, I have wet cells in my Sea Ray. For my new CC I am going with AGM.