AGM batteries

Don't take this question the wrong way but could you tell the reason to switch to AGM over a regular battery. The reason I ask is that it's not recommended that you discharge a AGM any more then 50%. what are the benefits.
 
I have 7 years on my flooded batteries and I’m looking to go the AGM route this time around. Is there a go to place for me to look or a brand to avoid?
I picked up some Group 31's at Sams Club last Spring. I believe they have an annual Spring sale. They're Duricells IIRC.
 
Don't take this question the wrong way but could you tell the reason to switch to AGM over a regular battery. The reason I ask is that it's not recommended that you discharge a AGM any more then 50%. what are the benefits.
Not offended at all. Simply for the lack of maintenance on them. I've always understood they were the best option.

Talk to me
 
If any of your friends/colleagues has a commercial account with Interstate, they might be able to get you a wholesale deal on their Marine AGM's, I have 4 of the Group 31's in my boat, 2 in parallel for house and one engine, a dedicated one for the 2nd engine, and dedicated one for the genny. 3 years on them, with a fair amount of time on the hook and mooring, handles both fridges and all other general loads with a recharge on the genny for a couple hours in morning when making breakfast and showering and nighttime cooking dinner, and running the blender for sundowners.
List price is crazy, but nobody pays that:
Interstate Batteries | 31M-AGM
 
I have 7 years on my flooded batteries and I’m looking to go the AGM route this time around. Is there a go to place for me to look or a brand to avoid?
7 years with flooded cells, I think you should get an award! We're lucky to get 4 or 5. I would switch to AGM's and add some flexible solar panels to the bridge if we sat more frequently on the hook. Would also need to update inverter/charger. AGM can be drawn down and recharged many more times than flooded. Lithium chemistry is coming along and really great in some applications but the high energy density still makes me nervous on a boat. I also think we might see some improvements with the old flooded cells. I can't believe the lead manufactures are just going to roll over as different storage technologies emerge.
 
...Simply for the lack of maintenance on them. I've always understood they were the best option.

Talk to me

If you are looking for zero maintenance and the “best option” you should consider lithium. Much higher cost up front, but they last longer and you get more capacity for less generator use. They are also capable of being fully discharged. Here is where I got my system: https://battlebornbatteries.com/marine-systems/
 
I just replaced my Costco Interstates after 8 years with DieHard maintenance-free from Advanced Auto Parts for under $100 apiece.
 
I know. My wife (aka "the Fleet Admiral") hates the generator running. She said get the best, so we went lithium.
Lith2.jpg
 
I know. My wife (aka "the Fleet Admiral") hates the generator running. She said get the best, so we went lithium.
View attachment 100204
Nice setup.
We don't mind the gen running. Besides the water splashing, you can't even hear it.
Classic sales tactic tho. Show me a really expensive product so the mid line ones are “cheap” now... Lol
 
Last edited:
I upgraded when my Group 27's flooded batteries started to leak 2 years ago with Group 31 AGM.

So far so good.

I purchased from batteries plus.

I needed them..... they had them..... I bought them. :D
 
Last edited:
We went with these.
This will be the 3rd season on these. The only issue is when they drop below capacity it does take a while running the gen to bring them back up.I have four of them working inline with the inverter.

56A4CC66-09A4-4515-855C-D3AE707D33D1.jpeg
 
This guy does a great you tube series comparing the cost/benefit of Lead Acid vs. AGM vs. Lithium (
). For my 340, I have one maintenance free group 31 for each engine and the generator. I added 2 L16 6V Lead Acids for the house bank. They have did not last very long, but I am to blame for that. I'm switching to 2 L16 FullRiver AGMs. I will update on how they perform going forward.

Based on everything I've read, Lithium still doesn't come close on the cost per kw/hr. You're better off going with Lead Acid or AGM unless you have money to burn. I ultimately decided to go with AGM this time around because they're less messy and the installation options are greater because they can be installed on their side.
 

Forum statistics

Threads
112,943
Messages
1,422,707
Members
60,927
Latest member
Jaguar65
Back
Top