Battery problem

[PeachesU]

Hey guys I have 71 that I just bought and wasn't thinking and left the dome light on, needless to say it killed the battery and I had to jump it. Well I had a retard moment and crossed the wires and sparks flew. I thought I just shorted the bat because I could jump start it just fine. So I went and bought a new bat and it started up just fine but after letting it sit for a week I went out and tried to start it again and no juice. It'll start after charging for awhile but won't hold the charge. Any help would be greatly appreciated.
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[Longhorn 70]

The first thing I would do is test charging voltage while it is running. If that checks fine, around 13.8 volts at idle, get the battery charged either by running for a while or pulling the battery and chanrging.

Then make sure everything is turned off in the truck not even a door open. Next pull the negative battery cable and connect an ammeter between the negative battery cable and the negative post of the battery. This will tell you if there is a current draw when the truck is at rest. You should see little or no current flow.

If both of things are good, you may have a bad battery.

[chevy72blu]

I agree with Longhorn. To add, if you are not getting a charge from the alternator, take a look at the voltage regulator. I can imagine that popping during the short; cheap and simple fix.

[PeachesU]

Thanks guys I will try that out and let ya know how it goes. And I'll post pics of the truck, it's a beauty and I can't believe I did that to it.
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[PeachesU]

Ok so I thought I could figure it out but I'm lost. Sorry I'm new to all this. My bat is still draining. I checked the volts on my alternator while the engine is running and it's at 14.25 so it can't be the alternator right? So now to do the ammeter test I switch my multimeter to dca 20m correct? And if there is any number showing up I have a drain somewhere correct?
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[Koffer]

another way is to charge the battery up ,turn everything off in the truck, pull the neg. term.off the battery and then take a test light putting one end on the term wire and other one the battery post. If it lights up you know theres a draw. I would 1st start unplugging the voltage regulator (you may have fried it )and if the light go out thats the one .
The higher the draw the brighter the light .
If that doesn't do it , start pulling fuses one at a time till you find which ckt has the problem . then it comes down to using the wiring diagram to see what that fuse feeds and disco each thing from there till to find your problem

[Longhorn 70]

Koffer's method is a great way to test for current draw. The only thing it may not show is a very low current draw.