Battery Buyers = Good News

[DRFerron]

Originally Posted by Maine Sail

On boating forums WM is a common abbreviation for WEST MARINE and yes Wal*Mart does own Sam's, but they sell different batteries......

Sorry, we were talking about Wal Mart in the chat room so I had it on my mind!

[Skipaway]

Originally Posted by Maine Sail

Deka / East Penn deep cycle marine batteries and NOT the dual purpose/starting versions. This is GOOD!!!

Would this be a good time and place to comment on the deep cycle vs. dual purpose batteries, and what to look for? (I hope so!)

[mitiempo]

Skipaway

Are you looking for batteries for your house bank?

Deep cycle does this best as they are designed to handle more discharge cycles. And deep cycle batteries can still start an engine without a problem. The dual purpose are not as tolerant of constant cycling and are better suited to a small day use powerboat.

[aeventyr60]

Originally Posted by Skipaway

Would this be a good time and place to comment on the deep cycle vs. dual purpose batteries, and what to look for? (I hope so!)

Take a look at "Dyno" batteries in Seattle, over by Fisherman's Terminal. Excellent heavy duty batteries. Got almost 7 years out of my 6V golf cart batteries from them.

[btrayfors]

Great info, Maine. As usual :-)

FWIW, I believe West Marine still has a price matching policy, and will match any advertised price from a competitor on any item in stock. Certainly worth asking.

Bill

[hellosailor]

Skip-
Deep cycle conventionally means thick plates, designed to last a long time. A thick plate cannot supply as high an impulse current as thinner plates, so an SLI (Starter-lights-igntion) battery uses thinner plates.
A "dual purpose" battery uses plates somewhere in between.

What do thick and thin mean? Varies with the maker.

And the makers will all tell you, you can use deep cycle batteries for starting with no problems, as long as your battery bank is large enough to supply the impulse power your starter needs. i.e., you don't use a 50AH rated deep cycle battery as a starter for a big diesel. But a 400AH bank won't blink at the power need. (Depends on what you call "big", I know.) And on the other hand...yes, I've used a 17AH AGM backup battery to start asmall diesel. It didn't mind in the least, but I would use it that way on a daily basis.

[Skipaway]

Thanks for the comments. All sounds logical. BTW, I have two Group 27 batteries on a [Off - 1 - Both - 2] switch.

I was looking at the Costco Group 27 Marine battery ($83; was $69 in Sept 2010!). It is labeled as Starting/Deep Cycle, 750 MCA, 115 Amp Hours, reserve capacity 160.

So I really don’t know if it is a true Deep Cycle, but it sounds like a dual purpose. I’ll check next time to see if there are more details or manufacture identified.

[mitiempo]

It's not a true deep cycle.

For the best deep cycle for the dollar get two 6 volt golf cart batteries and wire them in series. Thicker plates, handle many more cycles than any dual purpose and most any 12 volt battery as well.

[xymotic]

Originally Posted by btrayfors

Great info, Maine. As usual :-)

FWIW, I believe West Marine still has a price matching policy, and will match any advertised price from a competitor on any item in stock. Certainly worth asking.

Bill

Yes... but.

It has to be the exact same item, and since these are rebranded with different part numbers etc they actually shouldn't * price match.

*but sometimes you can get a super nice mgr @ wm so I guess it is worth asking.

[asdf38]

Hmm I'm pondering my choices. I have a blue sea charging relay waiting to be installed and want to simplify. I currently have two group 27 house batteries and a standard car starting battery. With my small 1GM10 and nothing to run off the batteries except lights and the depth finder I'd like to simplify and cut down weight and complexity if possible.

Given my light load what do you think about this option?

House: Group 27 wet deep cycle
Starter: Group 24 dual purpose

The dual purpose would only be the backup starting battery/backup house battery if the house failed. The group 27 house would be expected to do all the work normally (I assume a good group 27 house can start my 1GM10). Or should I stay away from dual purpose batteries all together?

Edit: Also, thoughts on an even smaller backup/starting battery? Perhaps jetski/tractor size?