Help! '61 C10 battery won't hold charge

[bigfunsixone]

Problem began a couple weeks ago. Hadn't driven it for a couple weeks due to some bad weather. Had to jump it, drove for forty minutes, stopped it and started and it fired up right away. Drove for a bit more that day and it had no more trouble starting. Four days later, same thing. Had to jump it, drove for over 30 minutes, fired right up after being shut off. Now about a week after that, jumped it, drove for 30, but had no charge after I shut it off and tried to start. Before all this, never had a problem. Choke is ****ed up so cold starts were always a pain, but the battery was never the issue. I'm hoping it's just the voltage regulator, but maybe the battery's bye-bye or the generator's junked. Any thoughts? Just bought a digital multimeter to learn how to do charge tests. I'm a total greenhorn in the garage.

Thanks.

[PGSigns]

Any mods to your 61? Has it got a generator or an alternator? You can put the battery on a charger and then load test it to see if it is good. Will need to know what else you have to help with testing procedures.
Jimmy

[bigfunsixone]

Generator. System converted to 12v from original 6. No mods, no radio. Basically all stock replacements. Stock heater and fan, horn doesn't work, dome light doesn't work. Don't know if horn and domelight themselves aren't functional or if it's just the wiring. Headlights, taillights, brakelights all work. Anyway, not really anything that could be drawing power from what I can tell.

[GMDad]

Your truck was 12V from the factory. How old is the battery? Might have a dead cell. I just went thru this 2 weeks ago on my 86 C10. Had worked great all winter for the little bit of use it got. I jumped it drove for 20 mins and was completely flat. Tried charging but no use. New battery in and no problems last 2 weeks. Just a lighter wallet... lol
If you take your multimeter and turn it to 20 volts and put the leads on the battery terminals (red on positive and black on negative) with the truck running the meter should read 14.5V or fairly close. With truck not running it will read about 12.3V if the battery is any good.

[TopFuel1966]

If you have a wet cell battery and it's more than four or five years old then you have probably found your problem. A battery with a shorted cell can turn in a stellar performance one minute and be half dead a short time later.

[leonphelps]

take the battery out and bring it to an auto parts store. they will load test it for free at any large chain. the voltmeter thing is for little kids. your voltage can be ok, but amperage may not. harbor freight sells load testers for $20.

[bigfunsixone]

Thanks! Y'all rock. It is an old battery, and from Walmart which automatically makes me doubt its quality. For some reason I thought it originally came with a six volt. Maybe that was for 50s and before. I'll go do a load test this week. Thanks again! I don't know any mechanics. The help is much appreciated!

[GMDad]

Lots of experience and knowledge on this board and they like to share. Just ask away when you get into unfamiliar territory. These trucks are a lot of fun to drive and work on

[Clif Dzzzz]

Experienced the same problem for months on end......installed new wires.....new connectors...new alternator.....new battery....discovered the wires from my alternator to the regulator were switched.......solved all my problems with battery discharge.....so simple....so much headache...

[bigfunsixone]

Just want to say thanks again to all y'all! Ended up heeding the advice and took the battery to my local napa and had a load test. Needed a new battery, bought it, and since then the truck has been a champ. All the advice is seriously appreciated. If I relied on real life connections alone to help me, then this would've been a SNAFU. Lots of carpenter friends, no mechanic friends. I truly appreciate the help. Luckily this was one of the easiest problems to fix. But I am a complete greenhorn who is not mechanically-minded, so I am seriously appreciative.