Charging Issues

[nuffsaid]

Last week while on an adventure into the Big Horn Mountains of Wyoming with my trusty 02 Dmax towing my 11,500 5er with a 4 wheeler trailer tagging along, I hit a bad patch of snow/ice while climbing over a pass in the national forest and buried the truck in the snow, wishing I would have chained up prior (stuborn). So, I spooled out the 12k milemarker winch and wrapped the cable around a boulder and pulled myself to the center of the road where I could install my tire chains a little easier.

At that time, I noticed the voltmeter down in territory where it appeared to be discharging. It was getting dark and all the lights of the truck and trailer were on. I got the chains installed on the front axle and attempted to pull forward and managed to bury the front tires into the road base below the snow crust. Out came the winch cable again and this time when I went to power in, the lights went dim and the truck didn't move. The low charge light came on and now the transmission wouldn't go into any gears. UTOH. Luckily a guy in a dodge came along and since he couldn't get by, gave me a hand and even offered me a beer. I had him give me a jump and let the batteries charge for about 5 minutes. Gave the winch a try and the transmission was now working as well as the alternator. Out we came.

On Monday when I got back to work, I load tested the batteries, one only load tested to about 270, the other 370. The batteries are rated at 900 cranking amps and 700 cold cranking. They are 4 years old. While under the load test, the batteries both dropped to around 8 volts.

My biggest question is what made the alternator quit charging? I also tested the alternator and it put out 80+ amps @ idle after the load test.

The winch is rated to draw 370 amps at full load, and I have used electric winches for years and have had to wait on the altenators catching up, but have never had one quit charging. Any thoughts?
__________________

 

[Kspen90]

You may have a direct short somewhere with your winch. I know on the 2005 gm trucks there is a "breaker" that trips in the event of a short to keep the alternator from burning up or melting wires.
On edit you might have just been pulling too many amps for the alternator with all the lights and the load of the winch and tripped the "breaker" if our trucks are equipped with one like the 05's

 

[nuffsaid]

If there is a breaker, how do you reset it? I removed the solenoid from the winch and found a couple of burnt contacts and repaired them with silversolder, but also ordered a new solenoid. It is obvious that when using a winch, you will use much more than the capacity of the alternator, but it should just put out all it is capable of and not shut off, unless there is some sort of overload protection like you say.

 

[DAVe3283]

Based on how the batteries load tested, they were long gone. I'd bet that with new batteries, you won't see the problem again. Also, it is a good idea to replace batteries every 4-5 years, or sooner in extreme heat/cold. If nothing else, get them load tested when they hit 4 years so you know how they are doing.

If there is a breaker, how do you reset it? I removed the solenoid from the winch and found a couple of burnt contacts and repaired them with silversolder, but also ordered a new solenoid. It is obvious that when using a winch, you will use much more than the capacity of the alternator, but it should just put out all it is capable of and not shut off, unless there is some sort of overload protection like you say.

There isn't a breaker that I am aware of (at least on my truck the alternator output wires straight into the main junction box). However, the computer will act like a breaker if it senses a huge electrical draw. The computer controls the output amount of the alternator on our trucks, and if it thinks there is enough draw to damage something (i.e. cause a fire!) it can shut off the alternator, or reduce the output.

 

[nuffsaid]

I will probably replace the batteries within the next couple of weeks. If the computer turns off the alternator, will turning the ignition off and restarting correct the issue? No trouble codes were ever set and the low charge light didn't come on until the batteries were just about done. At that point I turned off the truck and it wouldn't restart without the jump. I could have got going without the jump, but I would have had to fire up the generator for the trailer and use the batteries to jump the truck. I am also thinking about upgrading to a 145 amp alternator since mine is only a 105