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AGM West Marine Battery Experience

jreddington

Member III
I'm looking at a battery replacement for my '84 E-28. Current bank are (2)Group 27 flooded dual purpose batteries. At least one seems to have trouble keeping charge and it's date is 2003.

West Marine has Group 27 AGMs on sale for $200. Anybody have experiences (good or bad) with these batteries?

Also, with AGMs in general, what are experiences when doing a direct swap from flooded and charging only on the alternator? I have the OEM alternator. Not sure what the output voltage is. Still on the hard :mad:so can't fire up and check.

Don't want to have to invest in a sophisticated alternator regulator. If my output is the typical 14.4 - 14.8 V will they give me the expected longer life for AGMs?

Would love Lifetime batteries, but they cost twice as much and only have deep cycle, not dual purpose.
 

Tom Metzger

Sustaining Partner
Good news

You can start your engine with any deep cycle battery you might choose. Fairly few people with straight deep cycle batteries actually switch to a starting battery to start the engine. It just doesn't take that much current to do the job.

I think the real question is why do you want to spend $200 for a battery to replace one that now costs less than half as much and has lasted five or six years?

The advantages of an AGM battery are that you can mount it in any position and it Will accept a faster charge. You don't need one and can't use the other.

YMMV
 

jreddington

Member III
Thanks for the input, Tom.

I've thought about the deep cycle option before. When I bought Lady J about 12 years ago, she came with 2 dead dual purpose batteries. I 1st bought 2 dual purpose, which seemed to last only a couple years. Then bought another two that lasted I think three seasons. This pair (from West Marine) has gone for five years but it seems my average for these types are less. The short life of the 1st two sets have me thinking about the AGM option.

Dual purpose also seems to be the "classic" recommendation from West Marine for this application, dual batteries on a sailboat, used for both house and start. I guess I've been concerned that pure deep cycles won't have the "oomph" for starting but this is just an 11 hp Universal M-11.

Also, my 2000 Miata is still going strong with it's original OEM AGM battery. That's way longer than any other battery I've had for my cars. I figure if I get twice the life for twice the price, that works out. There is some value in the battery acid spill avoidance with AGMs. Not sure if I would take advantage of the no-freeze issue with AGMs, or just take them home for the winter like I've been doing with my present batteries.

I was also comparing West Marine Group 27 flooded dual purpose and deep cycle prices to these AGMs. Looks like I can get another brand (Sportsman) from Defender for about $90 for either dual purpose or deep cycle flooded batteries.

If deep cycles are OK for starting, maybe going this way will get me a good way towards my goal of extended life.

Will have to think about it (Trade offs - Trade offs).
 

Tom Metzger

Sustaining Partner
As long as I am myth busting today I should mention that most of us at my marina on Lk Champlain leave our flooded cell batteries on the boat over the winter. I disconnect mine to eliminate any leakage, but a lot of people don't bother.

As a matter of course I make a trip to the boat in January or February to check on things and while there I put the charger on the house bank. The voltage usually 12.5 volts when I get there which indicates virtually no discharge from mid October. I find approximately the same voltage when I return in mid April.

This is considerably colder than CT, but I wouldn't bring them home from there either.

Again, YMMV.
 

rwthomas1

Sustaining Partner
The simplest thing to do is just replace with standard, cheap, flooded deep cycles. IMHO, it is quite likely that your alternator is not completely charging the batteries and they have died prematurely due to sulphation, at least the first two sets. Keeping a stock alternator/regulator setup in place is fine if you live on a dock and can plug in for a nice long charge. How you use the boat is a factor as well. If you spend a significant time motoring the stock alternator/regulator will have a far better chance of keeping up with charging the batteries. Given that you have a fairly small bank the (likely) small alternator will produce enough amps to charge but the internal regulator is not really up to the task. Assuming you have a fairly standard alternator it is not hard to modify it for use with an external "smart" regulator. Even if not, a Leece-Neville alternator is not a huge expense. Lastly, the AGM will likely be slightly overcharged by the internal regulator on the stock alternator. AFAIK, AGM's charge faster than flooded batteries but have a lower float voltage so the internal regulator may try to charge them like a flooded design when its actually doing damage.

Tom and I have differing opinions on this topic, and so do many others. The reality is if you get 4-5 years from flooded batteries, Defender has two for $180, thats $36 to $45 per year. Put two new batteries in and forget about it.

RT
 

Mark F

Contributing Partner
Blogs Author
I've had good luck with West Marine's AGM batteries so far. I have one bank (of four) group 27's that power my electric inboard. West's batteries are made by a big battery company in PA (can't remember the name).

I also have a bank of four group 31's (Universal Battery) for the motor but one of those went bad after 8 or 9 months. I am in the process of getting a replacement, we'll see how that goes :).

The price on the Universal's through - http://www.batteryconcepts.net/yuasa/ub121100.html -
are really good. I paid $200 ea a year ago and now they are $165. That's for group 31 AGM's.
 

Chris A.

Member III
I got TWELVE YEARS out of the Lifeline AGM bank that came with our boat. I agree that a lot depends on size of the bank, extent of discharge, how you are using the boat, your charging procedures, etc. I replaced the house bank last summer, wanted to purchase Lifeline AGMs again due to what I considered amazing durability, but just couldn't spend $400 a piece for group 31s. So I replaced the house bank with AGMs from East Penn (Seamate I think?) at about half the price of the Lifelines. Replaced the dedicated starter battery with a Lifeline AGM group 24 starter battery. Some of mine are mounted on their sides. I do have a high output alternator with a smart regulator and do charge from shore power routinely.

I also think flooded batteries are a great option, tolerant of various charging schemes and a real bargain compared to gels and AGMs.

FWIW,
 
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