A month ago I had an issue with the battery going dead, tested the alternator (good) and replaced one of the terminals and was good to go. Yesterday I was working inside the truck (see thread about smashed in door), anyways I had the radio on, and within 15 min., it went off. Battery was dead, unable to start truck. I charged the battery, got it to 12.4, 14.0 when I started the truck. And put on everything I could for a load test with no change. Everything seems to be ok, but I'm nervous about being stranded somewhere now. Is there a way to see if something is draining the battery? I only know the basics with a meter. Charging system seems ok for now. Going to be in the single digits the next few days, hope it's ok

 

Go over to the parts store and get the battery fully charged and load tested.

 

your in Wisconsin its cold. the battery if drained will die quick in the cold. Could be its on its last leg. My vic's battery died the other day in a similar scenario.In cold batterys die quick especially if there old.

 

After cranking the motor to start, you must see elevated voltage at the battery or the alternator is not charging.
It should show about 15 volts + and taper down to 14 after a few minutes as the battery recovers it's charge.
Note: the alternator can still be faulty and still charge but drain the battery after shut down due to a faulty rectifier stack.
One way to tell this is charge the battery with the heavy alternator lead disconnected.
Use care from shorting this lead to ground. Touch the heavy lead back to the alternator terminal. If it sparks even a little the alternator need to be replaced. This would your drain.
Good luck.

 

i got a 99 f150 v6 it quit charging about a week ago so i changed the voltage regulator and turned everything on and let it idle for about a half hr with no problems in fact drove it for 3 days no problems then all sudden on my way home tonight it just quit charging all together.. is there anything in the alternator short of the voltage regulator that can go bad?? any help is greatly appreciated idk where to start, i did a few continuity checks and tryed to check fuses.. i think i got the wrong owners manuel in my truck.... i did some reading about mega fuses for the alternator but i cant find them on the fire wall i traced the battery wires right to the starter relay any help with a very detailed description would be greatly appreciated i also can be reached on kik messenger if anyone has a tip or advice lmk thank you!!!!!!

 

Lets put it this way; you need to check out the system performance to spot all the issues.
Replacing parts is only a hope you got the problem without testing.
If the alternator has a lot of miles on it the brushes are likely worn down and hanging up in their holders.
You need to understand that cranking the motor takes a lot of energy from the battery for which the charge circuit has to replace.
As well, lights, heater blower, engine control systems all normally take power from the alternator.
If the alternator is not keeping up or stops outputting all the drain come out of the battery. After awhile this becomes a losing proposition and battery goes dead without the alternator functioning..
.
What is supposed to happen;
Battery voltage down is sensed by the regulator.
The regulator raises the alternator voltage output to near 15 volts forcing current into the battery.
As the battery recovers it charge by it's voltage rising, the regulator senses the smaller differences and reduces the alternator output to a 'float' level of about 14 volts+/- a few tenths.
You can see all this take place with a voltmeter under all the conditions from just after cranking to full recharge.
Check out what happens and you have your answers.
If any of it does not happen you have an issue to resolve.
Use good workmanship to clear issues so it does not leave you stranded any more than necessary.
Good luck.

 

Bluegrass, I took it to Autozone today and everything passed, but I'm not convinced. So your saying the alt could still be my drain? I'm trying to picture the set up, which alt lead is the heavy lead? The battery is charged and back in. So your saying disconnect this heavy lead, make sure it doesn't come in contact with anything. Charge the battery again with the connections still in place, and see if it sparks when the heavy lead goes back to the alt? Can't wait to try it, like you said I'm tired of being stranded. I did notice that when I get off the highway, there is like a brief hesitation, not even that, more like if you shifted into low 2. It's very brief, is this related at all, or just in my head? I don't want to get this thread too off topic. I'll let you know my findings. 0 degrees for a high in WI tomm. Thanks

 

There is only one heavy lead on the back of the alternator.
The other is a plug.
If no spark is seen then the drain is from some other cause for which you will have to hook up a series test lamp with one battery cable of a size that just lights from the drain current.
Remove the hood bulb so it's not adding the drain.
Then begin removing fuses until it goes out, to id the circuits involved .
Some body has to do the diagnostics or it won't get resolved.
Get a voltmeter on the system and begin looking at the performance as described above so you know what is happening.
Good luck.