Battery ptoblems

Can anybody give me advice on an electrical issue I am having? I recently replaced my alternator and battery. I am still experiencing an issue where my battery is not being charged properly. The first battery overcharged and was venting/extremely hot. I was told the regulator was probably bad on the alternator So I purchased both a new battery and a refurbished alternator. I had a test done on the old alternator and it passed however I already had it out so I decided I would just put the new one in. Last week I had three lights appear (abs, e-brake, and Trac control) they showed up but dissappeared....they showed up a second time, I shut the truck down. Immediately tried to restart it and it was dead. (Read 8 volts) I removed the negative and after waiting approximately 20 minutes the battery voltage had climbed back up to 11.5 volts which then allowed me to start the truck (thought this was strange)....I figured that maybe my battery I had recently purchased had a bad cell so I took it back and swapped it for a third battery. I am now @ a point where I've removed any and all wiring I have added (light bar, third brake light for my topper, and an aftermarket double din radio ) the alternator will read 14 volts from the post on the alternator itself to ground but only 11.5 across the battery terminals, however....sometime the reading (from the positive post on the alternator to the negative terminal on the battery) will drop from the 14 volts expected, down to 2 or 3 volts....my next step is to remove the alt and have it checked. IS there anything I should do prior to pulling this thing again? Thank you for any and all advice and reading this nonsense. I hope I've conveyed this issue properly.

 

What kind of battery are you running?

 

Do you have a local shop that does automotive electrical work? Generators, alternators, regulators, window motors, etc?

I find that having my stuff tested and/or rebuilt locally almost always works out better than reman bits from a parts house.

They should also have the equipment and skill to help you sort out your current issues...........

 

Your observation I highlighted above makes me believe you have a faulty wire or connection between the generator and battery, most likely on the negative ("ground") side. To track this down you need to make some voltage drop readings, with the engine running and headlights on:

• Measure the voltage between the generator output terminal and the battery positive post--in theory it should be 0.0 V, however 50 to 100 mV is OK. Anything over .25 V is not good, anything over 1.0 V is bad--in either case check the wiring between the generator output and battery positive terminal;
  
  
• Measure the voltage between the generator body and the battery negative post--once again in theory it should be 0.0 V, but 50 to 100 mV is OK. Anything over .25 V is not good, anything over 1.0 V is bad--in either case check the wiring between the generator body (ground) and the battery negative terminal;

To locate the wiring fault conduct point to point voltage drop tests.

• For the positive side check the drop from the battery post to battery terminal, then battery terminal to the generator output--same as above anything more than 0.25 V indicates an overly resistive junction.
  
  
• On the negative side check battery post to terminal, terminal to engine block, engine block to generator body--more than 0.25 V is bad;

Most likely you will find a bad ground connection, that is why the battery is being overcharged--the regulator (in the generator) is getting a false "ground" potential because of the poor ground circuit, it thinks "ground" is a 1 or 2, or maybe even 3 volts higher that it really is so when it thinks it's charging the battery to 14.8 volts it's really pushing it to 17 or 18 volts--a bad thing.

Less likely but possible is the positive feed from the generator to the battery, however that will generally result in undercharging...

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BTW, being old I had to make paragraphs so I could read that glob of text.