AGM Batteries

[Capt Chad]

I just got an add from West Marine bragging about their AGM Odyssey 8Ds lasting up to 3x as long as conventional batteries. Who's running 8d AGMs? These are dual purpose batteries and that's how I would be using them. Our 46 is set up with the house load and one motor coming off 1 bank and the genny and the other motor starting off the other. The don't appear to have any more amp hours. The claims of added life and no need to add water are appealing. I know 3x the life is BS but do they actually last longer? They're $850 so they would have to be considerably better than my interstates.

 

[Pascal]

I have lead acids on my Hatt but every bigger boat I ve captained has had AGMs. The AGMs never lasted significantly longer than my lead acids. Maybe a few months more. I usually get 4 years here in sofl with lead acids on smart chargers. I have never gotten more than 4 to 4 1/2 years out of AGMs even when used for generators which never gets discharged like a house bank would.

 

[SEVEN]

The price is usually about double, the wait is outrageous. I’m sticking with Lead acid.

 

[zigzag930]

I'm not currently a fan of LiFePo4 and don't want to start that discussion here, but I personally like good quality LA batteries and prefer them over AGM on large boats, where slamming, wave action, etc is a minimum. On smaller center consoles, etc - AGM has it's place and I think they may be a better solution due to the "ride characteristics" of small, faster boats.

Just my $ .02

 

[Dan Mapes]

Had a set of Deka's on ours and they died faster than LA's. Never again. LA's on the same charger always did better in spite of monitoring the charge profile etc..
And now we have the LiFPOs that everyone is talking up. Way more expensive and without extra equipment they will fry your alternators.

 

[SKYCHENEY]

I had a set of Odyssey batteries in a diesel truck. One failed after about a year but was replaced under warranty. Then I used another AGM (it was a Diehard) for my generator battery and they too failed early. So, I'm just not a fan of AGM's.

 

[jim rosenthal]

I just purchased a 4D (the 8D's little brother) for the house bank on my Hatteras 36. This is an AGM battery from Renogy, bought on the web, for $360. No core charge and they pay shipping. This was about half of what local marine and battery shops charge for an AGM 4D.

The only problem was that they sent it UPS and they didn't give the driver an assistant- it weighs 131 pounds. Other than that, it was fine.

My prior house bank was two Odyssey Group 31s in the two 4D cases. After taking those out, I removed one 4D case, left the other in and secured it, and fitted the Renogy 4D. So far so good, but she isn't in the water yet.

If this battery lasts me a few years, it will turn out to be a very good deal. If it fails earlier, especially if there are headaches with the warranty, I may be sorry I bought it.
(note that my charger has an AGM charging profile, which it is set to. There is a separate starting bank which cranks both engines, and a third battery for the genset.

Also, I did get ten or eleven years out of the Odysseys, but they don't make a 4D that I know of, and they are far more expensive then Renogy was.

 

[Boatsb]

They make a great 4d. I belive the one you would want is the odp-agm4d . The parent company is enersys and I believe American made