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  #1  
Old September 1st, 2019, 03:38 PM
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Default drained batteries - help

the previous owner set up the truck with dual 12V batteries connected in series. Something drained them to the point of not being able to start. Questions are: 1. can I jump start from a 12V car and should I? 2. can I charge the batteries one at a time with a12V charger?
I have a 24V charger on order but want to start the truck sooner.
these may seem like stupid questions but I'm new to 24V vehicles systems.
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Old September 1st, 2019, 04:09 PM
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Usually trying to jump start a 24 volt system with your 12 volt car doesn't work because you are only hooked to one battery of the 24 volt system. Charging each battery separately with a battery charger will work fine, just takes a little longer. Just hook your charger up to each battery separately and you'll be fine.
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Old September 2nd, 2019, 05:44 AM
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There isn't any stupid questions here. So don't be afraid to ask

Yes, you can charge them one at a time.
Not sure if its necessary, but I always disconnect the short lead tying the two batteries together before charging individually.
Mine is wing nutted so that I can easily remove the jumper while I maintain the two batteries during the idle winter months.



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Old September 2nd, 2019, 02:19 PM
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Along similar lines, I have a leaky alternator, probably a bad diode. If I were to leave the batteries connected, I would be greeted with dead batteries. So, I disconnect the link between the two 12V batteries and only connect them when I want to drive the truck. One day, I will get off of my fat (yes!) arse and replace the alternator and see if that fixes the problem.
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Old September 3rd, 2019, 05:49 AM
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Default Battery draining...

I am not purposefully trying to sound patronizing here...but one thing I learned was to turn off the light switch on the dash. If you forget and leave it on (it's easy to do for new Mil Vehicle owners because it's a strange gizmo) the battery drains.

Or so I learnt. haha
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Old September 3rd, 2019, 09:21 AM
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As Don said, the most common cause of the drained batteries is a bad alternate diode. I will flatten the batteries overnight and in some cases if the battery is discharged totally will ruin the battery so it won't hold a charge.

I will disconnect the batteries when I am not using the truck to prevent the batteries from being drained.

Leaving the ignition switch on is another common problem but usually results in a dead coil instead of a dead battery.

Use military-style battery terminals they handle lots of current. and you only need a 9/16" wrench to remove the cable from the terminal. I used a wing-nut terminal on my deuce and a half because it was all I had handy at the time and it melted down.
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Old September 3rd, 2019, 12:56 PM
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thanks for the input, guys (or gals). I was considering putting a battery cut off switch between the batteries, the same as disconnecting. has anyone tried this?
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Old September 3rd, 2019, 12:57 PM
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Quote:
Originally Posted by jeepdan View Post
There isn't any stupid questions here. So don't be afraid to ask

Yes, you can charge them one at a time.
Not sure if its necessary, but I always disconnect the short lead tying the two batteries together before charging individually.
Mine is wing nutted so that I can easily remove the jumper while I maintain the two batteries during the idle winter months.



the previous owner's set up is the same as yours, except with Optima yellow tops.
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Old September 3rd, 2019, 01:01 PM
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I have done it on several of my jeeps. Use a high amp rated switch or it might melt down on you.
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Old September 3rd, 2019, 01:17 PM
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does a 24 volt 50 amp sound about right?
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