Slick 60's

Well i drove my Uni to work today but when the day started my truck wouldnt turn over. Easy enough just jump it off. Well it took awhile to chrage it but it cranked up so I let it run for a bit, turned the truck off and then tried again. He cranked right up...so went to work parked (in a crappy spot), turned it off and then re tried to start it. Already the battery is dead again.
Did I not let it charge enough? Could the battery be done with, I hope not cause it is pretty new? Or is my alternantor done?
Any tips, im sure this happened before to everyone and it has happened to me on my daily driver but since he is older guy wanted to know what i should do.

could be a diode in the alternator

Could be the battery


Advance/Autozone will test for free.

Might not hurt to check your battery posts & cable connections.
they get crusty sometimes.

the posts and wires are very clean...i think cause i let it sit for the past 5 days it was drained but it hasnt been cold at all here in Atlanta...damn damn.

has to be one of the more irritating scenarios, a 5K lb. piece of $#!+ that wont move itself.
i just dealt with this the other day on my 65 towtruck.did you hear me cussing?
out plowing snow at night,heater fan slows down ,lights start going dim, plow motor begins to almost kill engine, then alt gauge is @ +60 but not charging, finally all gauges quit. next morning bat is dead.
i took it out, put on the charger all day and cleaned all the connections very good, reinstalled and had no difficultys. the battery is several years old and should be replaced.
heres the irritating part
i just cleaned those things all up not more than 3 months ago.
battery is under the floor so it gets a lot of sand, road spray etc on it all the time.

Going by your description, I'm gonna say it's a dead alternator or regulator.
Jumping the battery & letting it charge for a while from another car will give it enough reserve to start the truck. However, if your charging system isn't charging, the engine will run off the battery until it's dead...using heater, lights, wipers, etc will drain the battery even faster.

Charge your battery with a charger (not good to leave the battery dead too long or it really WILL be dead), then have your alternator tested at a parts store/shop.
If they both check out good, it should be the regulator...or something as simple as a broken/bad wire.

no stores nearby to test my stuff.

when truck is running, carefully remove + battery cable, if engine dies, alt is not charging. if it keeps running its working properly. put the cable back on.

Could be a dead cell in the battery it self this stops it holding charge.


Alan,

Simple checks w/o disconnecting anything...

Grab the handy-dandy digital multimeter, read the battery voltage with nothing on. Should read about 12.2-12.6. A reading of 10 something is a dead cell, generally, or a discharged battery. We'll find out shortly.

With the engine running, an alternator will give about 14.2-14.6 on a battery that has been slightly discharged, 13.8 on one that is fully charged.

Shut the engine off, wait 15 minutes & check batt volts, if it has dropped to 10 someting, there is a dead cell.

If with the engine running, you see less than 13 something the alt is gone. The regulator could still be the culprit. Measure at the alt output, 14 or higher is good (bad reg), less than 12 is bad. If more than 15 (at the battery) the regulator is gone & boiling the battery.
Generator testing is similar, but you must rev up the motor a bit (1400 RPM) to get its ouput.

PJ

Silly me, forgot to mention to check the grounds, these things are 40-some-odd years old... clean clean clean makes it work better, & makes the other tests a bit more valid.

PJ

Good idea to also check the cables. You can clean the posts all you want but if the cables are cruddy it wont make any difference. Want to ask how I know????????

allright guys...well it was a dead battery. went to a shop to check the system (i thought for sure it was the alternator since it was not keeping any charge) anyway within 1 minute the test read dead battery. Went and got another one in the store and she started right up. Weeknd went well except some little punk called the cops while i was driving cause they thought i was drunk. I guess if you swerve to miss the huge potholes in Atlanta they figure its not that you want to make sure you are safe but that you are drunk. 2 hours later and 4 cops later i was back on the road...what a weekend for me and my slick.
anyway thanks for all of your responses and i still learned a little more about voltage so it wasnt a complete disaster.