why cant my truck hold a charge?

I'd have to check wiring circuits for battery and generator. It sounds like the charging system isn't working for some reason. With a fully charged battery, everything off, use a digital voltage meter across battery posts, note the reading. Then start the vehicle, take second reading across battery posts, the second reading should be higher than the first if charging system working. Does your charge lite on the dash work? With engine running, it's the alternator that should carry the load. The charging system has fusible links and fuses.

charging 2

Another thought is excessive amp draw with everything off, draining the battery?

If your charging system turns out to be charging properly, check for dirty cables/terminal but if everything turns out to be ok, disconnect battery with everything off and try just touching battery post with the terminal and see if you see a big arc, if you do, you may have something shorted or left on that's causing your battery to drain

It is not charging properly, only putting out approx. 10 to 11 volts, not near enough, it should be about 14.5v. min. The battery alone with all off shows 12.5v