Forum Discussion

allcool's avatar
allcool
Explorer
Oct 13, 2015

AGM batteries longivity ?

My buddy went to my storage unit in PHX and checked out my Toy Hauler this afternoon. Toy Hauler has been in storage since last April, the end of dune season. This year its in a 45'x12' big garage, so unfortunately it didn't get started/charged every month or 2 like years past when it was just in outside covered storage.

I'm 2500 miles away, so there has been no charging all summer.
The TH volt meter said 12.36v when he got there. Thats about the lowest its ever been. When I left it last April, it was charged up to 12.62v. The batteries are 4 years old now. They've been sitting for 7 months in the Phoenix heat all summer. Bet that garage the TH is in got up to 130°.

So anyone know if 12.36 is to low and batteries are damaged.???
My buddy started the genny with the 12.36 no problem he said, but couldn't let it run to long since its inside the garage. He did start the ac though and said the generator was running smooth. Guess I'm lucky the double dose of stabil worked for the genny carb this year...

So what you all think, is it going to be time for new batteries this year ?, or can I get another year out of it...?
Toy Haulers
  • PAThwacker's avatar
    PAThwacker
    Explorer
    Oct 26, 2015
    Average running on the 85AH was less than 1 hour each in a lake setting. I would recharge after 2 fishing trips once it battery reached 75%. I'm not new to battery care and had a defective battery.

    8 trips in one half of a year. Roughly 2 trips per month April to DOA August.
  • JiminDenver's avatar
    JiminDenver
    Explorer II
    Oct 22, 2015
    Foe what it cost to replace my AGM's, they had better last or it just plain stupidity for not learning how to take care of them properly.
  • full_mosey's avatar
    full_mosey
    Explorer
    Oct 22, 2015
    PAThwacker wrote:
    I had an agm 85ah battery for my trolling motor. Lasted 8 fishing trips with less than a hour of motor time and 3 recharges. 4th attempt at recharging and it was shot.


    8 trips should require 8 charges. How much time passed between charges?

    HTH;
    John
  • PAThwacker's avatar
    PAThwacker
    Explorer
    Oct 22, 2015
    I had an agm 85ah battery for my trolling motor. Lasted 8 fishing trips with less than a hour of motor time and 3 recharges. 4th attempt at recharging and it was shot.
  • drmopar's avatar
    drmopar
    Explorer
    Oct 21, 2015
    AGM Batteries are great, but you must know how to maintain them. I own a large Marina and RV Park. Been selling Batteries for over 30 years. AGM secrets? Total charging voltage should be at 14.4 volts, no more, or less. A lot of RV convertors are more like a power supply with fixed voltages, not really a good charger. The best way is to install a quality charger, or quality Solar. No discharge below 50%, keep cool when charging, purchase only high end AGM's. We sell Lifeline. The deep cycle Batteries, when properly maintained, can last up to 12-15 years. Some Marine chargers will cycle the Battery every 21 days. This really makes them last.
  • big_buford's avatar
    big_buford
    Explorer
    Oct 16, 2015
    allcool wrote:
    Thanks for the reply guys

    Is it true its not good for the batteries to be drawn down to less than 50% discharge, or the agm battery can be damaged. Also, if left discharged(less than 50%) for long periods of time or drawn down like that continuously, damage can happen. Is that wrong..?


    From everything I've read your statements are correct. Agm are usually a couple 10ths higher in voltage than flooded. Main thing for me would be get those batts charged back up right away!. As far as % charged while in use, the lower you discharge um the smaller number of cycles you get.

    Don't know I'd get too worked up using over 50% every now and then as long as they get charged back up right away.

    Sitting discharged for a long period of time is never a good thing.
  • Dirtclods's avatar
    Dirtclods
    Explorer
    Oct 15, 2015
    I'm plugged in twenty four seven and I exercise my batteries as well. I unplug for a week or two then plug back in and check my battery levels once a month along with running the genny for a 1/2 with a load on it and with this Orange County HEAT in California I've been visiting my Toy Hauler to escape the heat and enjoy the air conditioning Note: My rig is in my front yard. I ran AGM along with my regular battery had no charging issues now I run two 6 volts and I've never have looked back. I have the stock charging system that came with my trailer nothing special. I do keep an eye on the meter with one of these Digital Battery Monitor with 12-Volt Adapter:

    http://www.walmart.com/ip/Everstart-932W-Everstart-Battery-Monitor/16139506
  • allcool's avatar
    allcool
    Explorer
    Oct 14, 2015
    Thanks for the reply guys...

    Well, guess I've been thinking wrong. The SOC chart I saw said 12.5 was 50% discharged..? Now today, after looking at many different soc charts, they all seem to be different..? Looking at a google search, found charts anywhere from 12.1-12.50 claiming to be at 50%..? Whats correct? Most charts say 12.8-12.9 is full charge for agm, some say 12.7.

    IIRR, my agm batteries have never seen over 12.67v even when brand new off the dealers charger. Or after being charged correctly for 24 hours with a smart agm charger, then sitting over nite with no charge or load they are 12.62-12.67v. AGM Battery charger seems to do the same as my TH converter does.

    Is it true its not good for the batteries to be drawn down to less than 50% discharge, or the agm battery can be damaged. Also, if left discharged(less than 50%) for long periods of time or drawn down like that continuously, damage can happen. Is that wrong..?
  • Ava's avatar
    Ava
    Explorer
    Oct 14, 2015
    Hi, 12.36 volts is just over 70%. charged. Not bad for the time sitting. For your info 12.65 to 12.7 is fully charged. Every tenth lower is about 10% less charged.

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