Batteries, I suspect....

Post by **Cal_Gary** » Mon Nov 17, 2008 7:14 am

This past Saturday I intended on making my maiden voyage in the M37 that's been dwelling in the apartment parking lot for the past 4 1/2 years. My destination was (of course) the closest gas station and back. Never moved an inch-batteries are dead. Both batteries are three years old, never got much charging since the truck never moved much, but I occasionally put the charger on them overnight to keep them warmed up. I also have a battery isolator switch that I use every time, and all the battery cables are new with the ends and posts shiny clean. The batteries still lose their charge, and I should also mention that they were sitting on the metal box bottom with no wood-could it be that they are discharging thru the metal floor?

My belief is that my batteries are likely toast from non-use, don't you think? Any advice is appreciated. I may have to run them by Auto Zone to test/trade them in....
Thanks,
Gary

Lifer · Post by **Lifer** » Mon Nov 17, 2008 11:56 am

Batteries have to be discharged and recharged on a regular basis in order to stay in serviceable condition. All batteries will lose their charge when unused due to sulfation (a chemical reaction between the acid and the lead plates). When the plates are badly sulfated, recharging becomes virtually impossible. There are chemicals you can buy which claim to "restore" such batteries, but I don't believe what their ads say they'll do. Just a waste of money, as far as I'm concerned.

You should take your batteries in to be tested and recharged if possible. If they're shot, of course, you'll have to replace them.

Post by **Cal_Gary** » Mon Nov 17, 2008 12:36 pm

Thanks Lifer. I'll pull 'em tonight and get 'em tested tomorrow.
Gary

Wayne64 · Post by **Wayne64** » Mon Nov 17, 2008 12:51 pm

Cal_Gary, after you get the new batteries do a simple test before they are fully hooked up. Put your cables on with the exception of the ground. get a 24v test light and with all switches off put it in series between the battery negative and the ground cable. If you have a civilian radio with memory pull the fuse for the test. If the light lights or even glows you have a short somewhere that will in time drain the batteries. I'm new to the M37 but that is how I always checked my wiring if I suspected a short.

MSeriesRebuild · Post by **MSeriesRebuild** » Mon Nov 17, 2008 3:44 pm

Checking for a short is a good thing, it may well be a problem if wiring is starting to go.

No the batteries won't discharge from sitting on a metal surface

Post by **Cal_Gary** » Tue Nov 18, 2008 6:56 am

Thanks to all! I should mention that I'm running it as a 12V system with two batteries wired in parallel for the extra cranking power. The wiring is a brand new Painless kit and with the battery isolator switch there is no draw when the switch is off. Your guidance seems to confirm it has to be the batteries since I've eliminated shorts as a potential problem. I'll let you know what I find out.
Gary

Post by **Cal_Gary** » Thu Nov 20, 2008 6:56 am

Batteries tested yesterday-one was toast so I have replaced it. Will try another test run this weekend.
Gary

MSeriesRebuild · Post by **MSeriesRebuild** » Thu Nov 20, 2008 9:34 am

Not a good idea to replace just 1 battery in a 2 battery system. replacing both at the same time is the smart thing to do.

Post by **Cal_Gary** » Thu Nov 20, 2008 3:26 pm

Thanks Charles! I'll see about funding in the next month for the 2nd battery.
Gary