AGM batteries

How's this? Seems reasonable, better than West Marine, at least.
22A8DD7B-CD17-43EA-B593-D7224E187BF7.jpeg
 
AGM several advantages. google them.
 
I put 5 GRP 31AGMs in my 410 in 2012. When the next owner sold her last year, they were still going strong. I've had the same AGM in the waverunner since 2009 - it, too, is still going strong. I'm an AGM believer.

I just hate the fact that I now have D8's, and the AGM versions are 240 Lbs., and cost $800+ each - I have 6. Do I treat my lead acid D8's very gently and tend to the water frequently! Mine are starting their 4th year.
 
  • Like
Reactions: RBB
Not offended at all. Simply for the lack of maintenance on them. I've always understood they were the best option.

Talk to me
There is no lack of maintenance. They need to be maintained just like a flooded wet cell. If you don't they won't last as long as a flooded battery. If you get 7 years now, you probably are doing it right and you won't do better. They are not cost effective. BTDT, and now I only use AGMs on my jetski, where they get jossled around real bad.
 
Kinda figured they were flooded batteries, but what did you mean when you said they started to leak?

Oh shoot sorry about that.

It looked as if there was a loose battery post and some fluid was on top and in the battery tray. All 3 were rounding out their 5 year life span and this particular battery did not pass its stress test so I replaced all 3.
 
I got the AGM's for both my 400DA and later my 52DB at Batteries+. The Group 27 AGM's in the 400DA had a 5 year replacement warrantee; I think they were called "X Power". The 8D's on the 52 have a 3 year. The 52 is being changed over to lithium later this year.
A word of warning regarding lithium - the charging system must be designed around the batteries. They are not plug and play. Consideration for protection of the alternators as well as a dedicated lithium specific charger is required. The lithium technology is however safe but needs to be implemented correctly.
Tom
 
Sams club, group 31 AGM, Duracell marine battery, 179$. The first set I purchased for 159$. I had 4 since 2016, but 2 were not lasting the day (as mentioned, they were drained a few times, and they did not bounce back), so replaced port side in early 2020.
 
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.
That guy would be fun at parties :)
 
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.
The analysis done in the video is specific to a solar application and based upon a rigid charge and discharge protocol. RV and especially marine battery systems are vastly different in in charge and discharge regiments (frequency and mass). The comparative batteries used in the video are not really applicable for marine as they are energy banks specific for land based systems. Albeit, with enough work and investment one can install anything on a boat. The important factor we face in a marine environment is weight/energy density* Energy density/volume = weight/volume for a given equal energy density of a battery bank. This factor, cost aside, sways us to the lithium technology. Secondly, marine systems are critical on voltage operating range and cannot deal with any significant voltage drops such as the video describes in allowing a lead acid bank routinely operate at less than 11 volts consequently the boat must recharge more often than a fixed solar based system. Remember in our marine systems we have demands for 12V or 24V direct current, not just inverted AC power as the video is centered around. The video is rather mute on the time for absorption charging in a lead acid battery bank and the real benefit that lithium brings to how long we must run the alternators or generator to properly charge a lead acid bank to float; but again the video is about a residential solar system. As to the failure point on the Battery Management System (BMS) that the video presents; I would agree that first a robust system must be designed around the battery support systems and certain cautions must be provided but no data is given on BMS failures, none..... Actually, the BMS provided by the major lithium battery manufacturers (MasterVolt, Battleborn) have MTBF which lends little concern however I'm in the camp of a BMS for each battery rather than one for the entire bank (MasterVolt) as in a bank of 4 Lithium batteries a failure of one BMS can be tolerated; you do need to know it failed however which could be a problem. So, there is technical reason and good economic reason that the big blue water boats are being built with lithium battery banks. So, in summary I fully agree with the data in the videos (both parts) however there are factors in our marine environment that change much of the rationale.
 
Your batteries started to leak?

Ive been using Optima Bluetops since bought the boat. All are wired in series. All three are coming up on 6 and 7 years old.

I did notice a leak around the negative post yesterday. How does this happen?
 
The battery thing is over analyzed imo. I switched to these because I wanted no touchy batteries. Hated the add water thing with lead acid.With a good charger they will last 7 yrs+. Proper charging is key! That makes them a good value for me. Lithium is dam cool but at almost 1k a clip my boat bucks are better used elsewhere. I'm just a weekend worrier though.
Screenshot_20210226-073444_Chrome.jpg

20180506_154613.jpg
 
The battery thing is over analyzed imo. I switched to these because I wanted no touchy batteries. Hated the add water thing with lead acid.With a good charger they will last 7 yrs+. Proper charging is key! That makes them a good value for me. Lithium is dam cool but at almost 1k a clip my boat bucks are better used elsewhere. I'm just a weekend worrier though.
View attachment 100248
View attachment 100249
Where did you buy them?
 
My Sam's doesn't carry 8D AGM's and won't order them. Has anyone gotten 8D AGM's from a Sams?
The wet cell AGM's they have are 2019 manufacture dates
 
On this topic, has anyone added more batteries than the boat was originally designed for?

On my 310, my port side AGMs are pretty much shot after 4 years. No one's to blame -- we abuse the hell out of them because the admiral whines about the generator noise, so it is what it is.

With that in mind, I sure wish I could add a third or even fourth battery to the port side pair that feeds house power with the idea that it would be more tolerant of our (mis)use but there's no obvious/easy way to stuff more batteries into the engine room. I've been tempted to compromise and make the port side a 3 battery array and leave the starboard engine to one battery. I don't love the idea, but we are not really overnighters and on an inland lake, so the risks of being stranded are not a real issue.
 
A word of warning regarding lithium - the charging system must be designed around the batteries. They are not plug and play. Consideration for protection of the alternators as well as a dedicated lithium specific charger is required. The lithium technology is however safe but needs to be implemented correctly.
Tom

I'll second that! I learned the hard way am am taking back my lithium and switching to FireFly. No reworking the charging system and will outlive my ownership of the boat (slightly cheaper also).
 

Forum statistics

Threads
112,945
Messages
1,422,754
Members
60,928
Latest member
rkaleda
Back
Top