AGM vs Wet Cell Starting Battery

[Junk Fisherman]

Long story short- I need a new deep cycle so I have decided to replace my boat starting battery since it is 5 years old.  It is a size 27 Duracell wet cell and it has been great.  If I didn't need the battery for something else I would keep using it for the year.  My troller batteries are also 5-year old Duracells and the are still going strong.  

 

I am going to go with either a Duracell 31 AGM or the Wet Cell.  The AGM is twice the cost.  I have searched two different sites and couldn't find this answer so I am making this post.  Besides no maintenance, what are the important advantages of the AGM over the wet cell?  How many years can I expect to get out of an AGM?  I am leaning towards getting the wet cell Duracell and save the extra $100+.  I would already be buying a bigger battery than I already had and I easily got 5 years out of my old one.  What are your thoughts?  

[WRB]

1st to consider is physical size 27 vs 31. 

2 things kill batteries; overcharging is #1 and exposed battery plates is #2 for wet cells. You eliminate #2 with AGM but nor #1.

If you get 5 years with a wet cell, 10 years is within a AGM charged correctly.

Tom

[Jig Man]

AGMs are typically lighter and last longer than flooded cells.  They are maintenance free and can be mounted in creative ways.

 

 I switched to them as soon as they came on the market.  I don’t know how long they will last because I replace them by the end of the sixth year.

[Deephaven]

Wet cell or lithium.  AGM's are way overpriced now for their performance.

[Way2slow]

I just put three new batteries in my pontoon a couple of days ago.  I went with a Duracell Deep cycle flooded cell for the cranking, and two 27, AGM's for the TM. I was really wanting to go with group 31's but, I could not find two of the same battery, so I had to settle for the group 27.  By the way, Duracell batteries are EastPenn batteries, which are pretty good batteries.  I had to join Sam's Club to get the group 27's and they only had three, one after I got mine.  Those were the only local ones I could find.

 

Now, to explain why I didn't go with an AGM cranking battery.  My motor is a 2009, 90hp, two stroke Mercury.  Older motors, and a lot of newer motors, don't have charging systems designed for AGM batteries and can cause damage to the charging system, and possibly damage to the AGM battery.  So, no matter how good the AGM's sound, if the motor's charging system is not right for them, they are not a good choice.  

 

And yes, they are over priced, but since I had not been using my Javelin much, it spent more time on the maintainer, the on the water.  With the MK330 charger I was only getting about two years out of the flooded cells.  Batteries like to be cycled regularly.  The AGM's would give me three to four years.  Which the math does not support buying AGM's.  Every two years, you can buy a flooded cell for the same it's going to cost you to buy and AGM every four years.  Plus with a flooded cell, you get a good bit more reserve minutes.

My wife is loving this pontoon, so it's looking like it may be put in the water a lot more than my bass boat was. 

 

My preferred battery is still the Trojan SCS225, but the only place that sold those locally was a battery distribution center that has since changed hands and they only handle the golf cart batteries.  Shipping jack the price up too much for me to order batteries. 

 

[gim]

If you’ve gotten 5+ seasons out of your Duracells, I’d stick with them. That’s a good life span for that type of battery. I’ve considered upgrading to an AGM or lithium battery too but I’ve gotten the same lifespan and performance out of my interstates so I’m sticking with them.

[E-rude dude]

AGM 

mModern electronics draw constant power.

You can find AGM’s locally for a deal if you look around. My local farm supply store carries a store brand that is a Duracell with their sticker on it. Half the price that Batteries Plus charges for Duracell.