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One Cold North Dakotan
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3,150 Posts
Discussion Starter #1
I'm having a problem with my bronco killing batteries. The truck's been sitting almost 100 miles away from me for the last 6 months or more when I go to school and I've been driving a dodge ramcharger.

Anyway I've been back to where the truck is a few times over the months, and the battery that I was using in it gradually started to not keep a charge long, and when cranking it over, it would sometimes die on cold starts. Not a big deal, I'd jump it with the dodge.

Anyway the second to last time I was out there I'd jump it, get the truck running and leave it idle for a few minutes and it wouldn't have enough juice in it to turn over the next time I needed to start it. It wasn't the newest battery, probably 4 or 5 years old, and I did deep cycle it a fair bit when the truck was being a bitch to start.

So, the last time I was out there I knew that battery was pretty much shot, so I just swapped out the dodge's battery and put it in the bronco. It had been cranking over the 360 in 20 below weather fine. It worked good for a while but gradually over the weekend it flattened out too and wouldn't hold a charge.

So.. now my friend had to jump start the dodge with his truck. It worked fine for that weekend, but when I got back to school it would not start the dodge! It would just slowly groan as it tried to turn over.

I'm wondering if the alternator in the bronco has been overcharging the batteries?? That's the only thing I can think of. I did have a battery come loose from it's hold downs and get messed up by my fan, soaking the alternator pretty bad over a year ago. However, the truck has been starting fine until 3 months ago or so.

It's not a big deal, I need to swap in the 3g now that I have a decent sized amp and subs, along with some other little extras that will take more juice.

So, I am going to replace the alternator with a 3g, along with all the wiring too, and do a dual battery setup. I heard that on the 3g the voltage regulator is inside the alternator instead of above the fender by the starter solenoid right? Does anyone have any ideas what's going on, or think of anything else to replace?
 

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Former owner of Shadofax
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17,025 Posts
I'm having a problem with my bronco killing batteries. The truck's been sitting almost 100 miles away from me for the last 6 months or more when I go to school and I've been driving a dodge ramcharger.

Anyway I've been back to where the truck is a few times over the months, and the battery that I was using in it gradually started to not keep a charge long, and when cranking it over, it would sometimes die on cold starts. Not a big deal, I'd jump it with the dodge.

Anyway the second to last time I was out there I'd jump it, get the truck running and leave it idle for a few minutes and it wouldn't have enough juice in it to turn over the next time I needed to start it. It wasn't the newest battery, probably 4 or 5 years old, and I did deep cycle it a fair bit when the truck was being a bitch to start.

So, the last time I was out there I knew that battery was pretty much shot, so I just swapped out the dodge's battery and put it in the bronco. It had been cranking over the 360 in 20 below weather fine. It worked good for a while but gradually over the weekend it flattened out too and wouldn't hold a charge.

So.. now my friend had to jump start the dodge with his truck. It worked fine for that weekend, but when I got back to school it would not start the dodge! It would just slowly groan as it tried to turn over.

I'm wondering if the alternator in the bronco has been overcharging the batteries?? That's the only thing I can think of. I did have a battery come loose from it's hold downs and get messed up by my fan, soaking the alternator pretty bad over a year ago. However, the truck has been starting fine until 3 months ago or so.

It's not a big deal, I need to swap in the 3g now that I have a decent sized amp and subs, along with some other little extras that will take more juice.

So, I am going to replace the alternator with a 3g, along with all the wiring too, and do a dual battery setup. I heard that on the 3g the voltage regulator is inside the alternator instead of above the fender by the starter solenoid right? Does anyone have any ideas what's going on, or think of anything else to replace?
definitely need to have the alternator tested.
 

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Registered
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2,279 Posts
It's possible it could be a coincidence but that does sound suspicious. I'd say get the alt tested regardless of whether you are replacing it or not. Most places will do it for free (ie Schuck's) so there's really no reason not to since you are taking it off anyway. That way if the alt is bad you know you fixed it, but if the alt isn't you know the problem is elsewhere.

Also, if you are leaving your battery unused that long I'd put it on a battery maintainer and preferably disconnected from the truck. Just a suggestion but I'm also overly cautious. I have a battery maintainer mounted in the truck so the battery gets plugged in anytime I don't see myself driving it within the next month or so.
 

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Premium Member
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5,103 Posts
It's possible it could be a coincidence but that does sound suspicious.
How old was the dodge battery?? You may have just happen to have them both bite it around the same time....

I would also check all your power leads and make sure nothing is grounded out. If you have an amp in your truck, extra wired in equipment, make sure none of them are grounded out....

Also, what everyone else said. :toothless
 

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One Cold North Dakotan
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3,150 Posts
Discussion Starter #6
The dodge battery was probably at least 4 years old also. It's possible they both died at the same time.

My amp isn't put in the truck yet and nothing else was left on.

I'll bring the old alternator back with me to get it tested. I think AutoZone does it?

Pantsman, I'll have to look into a battery maintainer. They don't seem to be too expensive. Is it safe to leave on with the battery out of the truck in a garage while I'm at school though?

Thanks all.
 

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10,128 Posts
You need to check to see if you have a draw somewhere. To do this take your positive cable off the battery, put a test light on the positive terminal and on to the positive cable. The light should be dim. If it is as bright as it would be if you placed test light on positive and negitive then you have a draw. To find your draw, keep your test light hooked to post and cable and start pulling fuses until the light goes off. Whatever fuse made the light go off would and should be your problem.
 
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