My AGM Batteries Singing Their Swan Song . . .

[tpenfield]

My boat was built 8 years ago and put into service about 7 years ago. I think the AGM batteries ( 31AGM) are starting to die out. I believe that 7-8 years would be about a normal replacement cycle for AGM batteries.

I think it may have been the cause of my voltage warning issues last year. This year when I run fairly heavy loads on the inverter, the voltage goes down below 12.0 and I get a warning on the inverter system. It all worked fine last year and earlier in the season this year. Today . . . not so much.

Anyway, 7-8 yrs is OK on these batteries? (Interstate 31AGM Marine)

 

[flashback]

They're kinda picky on charge/discharge but I say you did good...

 

[Scott Danforth]

I would run Odysseys

 

[flashback]

I would run Odysseys

I have one in my motorcycle and it's doing well after 6 years. I don't ride like I used to but the batt holds up with a maintenance charge.

 

[alldodge]

Not bad for the years

Not all AGM's are created equal, unless you have a true high end AGM, they get charged like a lead acid

High ends are ones like, Odyssey, Lifeline

 

[tpenfield]

Thanks for the tip about Odyssey. I think I will be going the route of my LiFePO4 design and will look into the Odyssey batteries as the starter batts.

I already told the Admiral to pick a couple $K off the money tree.

 

[airshot]

If I got 7-8 years from my agm 31's, I would be very happy !!

 

[alldodge]

If I got 7-8 years from my agm 31's, I would be very happy !!

Agree

 

[tpenfield]

These batteries are about $400 each and weight 72 lbs each.

So the 7 batteries $2,800 and 504 lbs.

So, I'll be looking to my LiFePO design to spend about $2,000 and save about 400 lbs,

 

[airshot]

These batteries are about $400 each and weight 72 lbs each.

So the 7 batteries $2,800 and 504 lbs.

So, I'll be looking to my LiFePO design to spend about $2,000 and save about 400 lbs,

So are many others like myself, one of the reasons agm batteries are increasing in price....fewer are being made !

 

[Lou C]

Coincidentally that's about how long I've averaged with my Deka group 27 dual purpose flooded batteries, they consistently last about 7 years before they won't hold a charge. Minimal electronics on this boat though. Ive thought of going AGM but cost wise these are a good deal, I think the last time I paid about $175 for one.

 

[airshot]

The agm batteries I bought in 2019 have about doubled in price today....no wonder more folks are looking at Lifepo4 batteries, they are comming down in price !!

 

[tpenfield]

Quick Update . . .

Last weekend I was covering the boat for winter and went to charge the batteries before buttoning things up. FWIW - I have left the battery charger on in maintenance mode over the winter, but this winter I may let my solar charging system do the maintenance charging over the winter.

Anyway, I noticed the voltage was sitting a bit low and wanted to do a few hours of charging before letting the solar system 'take over'. My boat can charge the batteries either through the Xantrex 2000 inverter or the Pro-Nautic 12-30 charger.

So, initially I let the Xantrex do the charging . . . It went up to 75 amps to the batteries and was drawing 14 amps of AC to do it . Never seen it go that high . . . So, rather than run the risk of a fire, I disabled the inverter charging and switch over to the Pro-Nautic charger. Well that pegged at 30 amps to the batteries and stayed there for a few hours.

So, as not to let the thing keep running at its maximum current, I shut is all down and buttoned the boat cover up. This got me to thinking that one (or more) of the batteries probably has died and is sucking down the rest.

Thoughts?

i plan on checking it in a couple of weeks. But . . . It looks like I'll be accelerating my LiFePO4 battery conversion in the spring.

https://forums.iboats.com/threads/lifepo-batteries.765395/

 

[alldodge]

One or more have a problem

 

[Scott Danforth]

I would find it before the cold weather.

A drained battery will freeze and bust the case. Then you have to deal with leaked battery acid

 

[alldodge]

I would find it before the cold weather.

A drained battery will freeze and bust the case. Then you have to deal with leaked battery acid

Agree to find, might cause issues with others if it's in parallel with others

You sure about that, I have a pallet or old Bats (3 years or so now) and some have 3 to 4V and they haven't froze

 

[Scott Danforth]

I have had multiple freeze cracked batteries over the decades. Cleaned up a few from the workbench at dads place back in 2019.

I wouldn't trust a discharged battery to not freeze

 

[airshot]

I have been around auto/ boat batteries for a loooong time, never saw a discharged battery not freeze and split open when subjected to 20 degrees or colder. Due to the acid a battery needs to drop well below 25-30 degrees to freeze and split.

 

[flashback]

I don't normally leave them lie around long enough to freeze, the 10 bucks for a core is good beer money!

 

[alldodge]

When I buy Lifeline or CAT Bats they don't take a core. One of these days I plan to take them to a junk yard which last time I checked (2 years ago) they were paying 25cents a Lb