Battery keeps draining in just a few hours?

[meanwire]

:-[ I recently went out to start my '77 Bronco and it was grave yard dead. Jump started the Bronco, went to church, got out of church in a couple hours and it was dead. So I put it on the battery charger and the battery didn't hold a charge. Went down to get a brand new battery figuring that was the problem. Everything was fine till the next morning, the Bronco wouldn't start. So I put the brand new battery till it was at full charge. Went out the next morning and it still wouldn't start, what gives? Keep in my mind that I keep my Bronco in the garage. I didn't have this problem before. This is driving me insane, anybody have any idea where the battery is bleeding to? I went as far as to removing the stereo, CB radio and any auxiliary lights. Please where do I start on fixing this dilemma. Thanks in advance for any advice or suggestions!

 

[DirtDonk]

There are a few tests to perform, but the first place I'd look is to the voltage regulator. Unplug the connector and see if it still drains.
You can test for the drain though, without waiting overnight and hurting your battery even more. Pull the negative cable off the battery and hook a test light or ammeter if you have one, between the battery post and the now disconnected cable. If you have a light, you have a drain.
If pulling the plug on the regulator does not fix it, pull each of the fuses in the fuse panel until you see the light go out.
If it doesn't go out after all of that, well, keep looking! Maybe a bad diode in the alternator itself at that point. If so, disconnect the main output from the back of the alternator and see if it goes out then.

Good luck.

Paul

 

[meanwire]

Where is the voltage regulator located and what does it look like?

 

[broncnaz]

on the firewall or pass side inner fender its either a blue or blac square box or a silver/gold rectangle both have 4 wires hooked it. Since its a 77 then I believe it will be on the pass side firewall above the heater hoses.

 

[stupidboy]

I,ll put money on it being a bad diode in the alternator, when this happens the alternator will still charge while its running, but in the shut off mode is draining the battery faster than you can say...............

 

[BroncoDawg]

Gotta love the knowledge here on CB!!!!!!!

 

[Steve83]

To drain a normal vehicle battery in 4 hrs, it would have to pass ~20-35A that whole time. Have you ever put your hand in front of a headlight? That's only ~5A of heat, and it produces a LOT of visible light. A starter pulls ~200A, but only for a few seconds, and it has a LOT of mass to absorb that heat. If something as small as a voltage regulator or diode was draining it that fast, you'd see smoke or light.

So it has to be a bad battery self-discharging, or never taking a full charge. Get it tested with a MidTronics pulse tester. Almost every dealership (of every brand) is required to have at least one for warranty testing, and it only takes a couple of seconds to test, so it shouldn't cost much. Just be sure to FULLY charge the battery before you take it to be tested.

Jump-starting & driving DOES NOT RECHARGE a battery, and it can destroy the alternator. Don't do it.

http://www.batteryfaq.org/

 

[DirtDonk]

Or a combination of the above can do it too. With a battery that's drained down that low enough times, even a small drain might bring it down in short order too I would think.
An older, or just plain tired battery, in the cold weather, will drain faster than a good battery would.
Especially in the cold weather! Don't know if you're gettin' cold up there too meanwire (good name under these circumstances I'd say), or if it's just wet. But you could be experiencing the perfect storm of the discharge world.
So get the battery fully tested like Steve said (unless that's been done already), but definitely check those other things too. This IS an EB after all. And "all of the above" applies quite often around here.

Paul

 

[Broncobowsher]

Charge the battery, leave the cable off of it overnight. Next day, hook it up, try to start.

No start, bad battery. It can't be the rig if it isn't hooked up.

If it is the rig, at that rate of discharge, I am going to second a bad diode in the alternator. Most parts stores will do a free test and it will show up.

 

[kyle]

^^^Voltage Regulator.

 

[aaron6920]

I had the same problem and the guys helped me. As mentioned above look at that voltage regulator. Do you have a multimeter?

 

[orangecrush4u]

I had the same issue it was my alt, when my volt regulator went it over charged by 18volts burnt out my fuseable link. its one of the two.

 

[stupidboy]

With a charged battery leave it hooked up overnight and the first thing in the morning feel the alternator. It will be hot. Bad diode!

 

[Broncobowsher]

With a charged battery leave it hooked up overnight and the first thing in the morning feel the alternator. It will be hot. Bad diode!

If you wait until the battery is dead it will go cold again.

Charge the battery, leave the cable off, let everything get cold, hook up the battery and come back in an hour. bad alternator will get hot.
Want to rule out the voltage regulator while at it, unplug the regulator. If the alternator gets hot without the regulator hooked up it has to be diodes and not a stuck regulator.

 

[stupidboy]

I had this problem several times with a 66 corvette, I hate diodes, but ya do it how Broncobowsher says, that will be better.

 

[Pa PITT]

A draw that bad you should see sparks fly when you put the cables on the battery, if the battery is charged..
...What kind of alternator set up do you have now.. Old stock alt. then you have a voltage reg but if you have a one wire you may not have a regulator .. ''Listen to me'' a picture would help us see any issues.
... I'm the king of having no pictures.
Let us know....

 

[meanwire]

I want to THANK you all for your help, without your help I'd be lost. After much reading all of your advice I was able to fix the problem. The draw ended up being a bad voltage regulator. Again THANK YOU!!!;D