AGM batteries

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ddurand

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I need to replace 2 of my 3 Group 27M deep cycle batteries. I can get plain flooded for $100, AGM for $200 and Odessey AGM for a little over $300.

Is going to AGM worth the extra? For now until a slip is available, my boating is by way of trailer. aGM self discharge less than regular flooded. An possible advantage when trailer boating.
 
They don’t last longer than flooded batteries but you don’t have to check water level and they can spill. I like AGMs in cars but on boats where the batteries are accessible I don’t see the benefits.

if you switch to AGM make sure you charger can be set for them
 
I used them on the boat once. I would never do it again. Waste of money.
 
In reading the benefits it says the AGM batteries can better withstand pounding from waves.
 
PascalG said:
They don’t last longer than flooded batteries but you don’t have to check water level and they can spill. I like AGMs in cars but on boats where the batteries are accessible I don’t see the benefits.

if you switch to AGM make sure you charger can be set for them
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Why do you like them in cars? I have two group 65 original batteries in my diesel pickup that need replacing.
 
Because they won’t leak and corrode the battery tray and whatever is under. Been there done that.
 
AGM batteries perform a bit better than flooded cell batteries, typically do not leak and need no maintenance or electrolyte level checking. On many boats checking the electrolyte level and topping it off is very difficult.
 
rwidman2 said:
AGM batteries perform a bit better than flooded cell batteries, typically do not leak and need no maintenance or electrolyte level checking. On many boats checking the electrolyte level and topping it off is very difficult.
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It was a nightmare to service the batteries on my BW Conquest, impossible to check electrolyte without pulling them. It was much easier on me when I went to AGM's in it. I also have a AGM in the baby Whaler even though access is easy. My sole reason is the AGM 'seems', at least to me, to hold its charge longer when the boat sits inactive for a few months. I'm usually able to tilt/start without charging after storage which was not generally the case with flooded batts.
 
$100 for wet cells?? Do you belong to Sam's Club or Costco? Far less!

My last batteries (Energizer) from Sam's Club are now 5 years old and going strong for the new owner. They are Marine batteries (post and screw terminals) but nothing else special. Were in the high $60's, I think, then.
 
Lol. Battery prices have gone up quite a bit in the last 5 years ....
 
I know but batterie prices have been going for years even since EPA increased regulations under President Hussein Obama.
 
AGM in everything I have. Autos, boat, PWC, airplane ,diesel truck

Properly maintained, AGM is the cheapest battery you can buy. You get more start cycles per dollar expended.

I typically get 6 years out of an AGM battery. I say properly maintained. Do not leave an AGM partially discharged for long periods of time and make sure you have the correct charger connected to them.

A while back, one of my grandkids decided to play at my helm and left the big bilge pump on. It ran the battery down to nothing, no measurable volts. I decided, what the heck, slap a charger on it. It was 5 years old so it was end of life rescue. Sure enough, it over heated and blew the case. If that was flooded, I would have had a mess. Not a drop anywhere. Just a separation of the top.

There is a reason why the SEALS use them in their go fasts.

In my airplane I have dual Concorde 24 volts. I keep them continuously charged in the hangar with a specially made charger.

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I ve never had an AGM lasting over 5 years, even never fully discharged and on a quality charger set for AGM

that s been on different boats, with different chargers, either for the mains, gens or house.
 
At least for this summer I will be on a trailer vs slip with shorepower. Trailer will have no power. So AGM would help there with low self discharge. I do need to check the on-board charger and see if it can handle AGM. I do have a normal AC charger for use at home that has an AGM setting. But the cost is an issue. I think I can get AGM group 65 for my truck at maybe 50% more than flooded. But for the group 27M it seems less availability and more like double to triple. With the best Odyssey being four times.
 
Go with a group 31. Just a little taller. A tad more capacity. You can get Die Hard Platinum marine AGM at Advanced Auto Parts for 229. Good Johnson Controls made battery.
 
ddurand said:
At least for this summer I will be on a trailer vs slip with shorepower. Trailer will have no power. So AGM would help there with low self discharge. I do need to check the on-board charger and see if it can handle AGM. I do have a normal AC charger for use at home that has an AGM setting. But the cost is an issue. I think I can get AGM group 65 for my truck at maybe 50% more than flooded. But for the group 27M it seems less availability and more like double to triple. With the best Odyssey being four times.
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Boats I ran ate up Odysseys. They discharge once and they're done. I really think they're all hype for the price.
 
Odysseys are way too temperamental. Go with Johnson Control or Concorde units.
 
GeeBee said:
Go with a group 31. Just a little taller. A tad more capacity. You can get Die Hard Platinum marine AGM at Advanced Auto Parts for 229. Good Johnson Controls made battery.
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Those were some of the best betteries I have ever had.
 
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