Battery blues.....help!

[Sklptrljay]

So I am in a time crunch to get this fixed, so I thought I would get some help here. Here's what is going on:

On Monday my wife's 99' Suburban wouldn't start and I had to get to work so I threw the battery from my C/10 in and problem solved until the weekend (so I thought). When I started the engine I read 14 volts across the battery posts.

So on Saturday evening I put the battery back in my C/10 adjusted the carb and went for a test drive (20 min drive) and was going to buy a battery for the Suburban on the way back. The truck was running great, I stopped to gas up and when I went to leave, nothing. The lights and other electrical worked, but no crank, not even a click from the solenoid. My first thought was the starter got too hot and was fried. Sat for about 20 minutes until I got a jump start from my wife (in my commuter car) and what do you know, it fired up and drove fine to my house.

At home I read 14 volts across the battery in the C/10 too. I removed the positive cable while it was still running and the engine did not die. I think that means bad alternator? Just weird that after putting it in the Suburban I started having an issue. Not running I am reading 12 volts across the battery.

So what do you think? I won't be able to work on anything until this evening (Sunday) so I'm going to be under the gun to figure out what the issue is before going back to work.

Thoughts?