Is it possible for the solenoid to put a strain and/or drain the battery down? We have the stereo unplugged and we're gonna watch it a few days and see how the charge runs. We left it unhooked (battery) several days and it held charge. Now we're wondering if maybe the starter is acting up. It wouldn't turn over while ago and the battery was 11.45v. It was the exact thing yesterday and it cranked. We check it all the time to try to get a clearer picture.

He took the battery off and charged it a about 1 1/2 hrs but it didn't seem to be doing much according to the gauge on the battery charger. It was over 12 volts when he put it back on and it cranked right up. Could it be the battery was too low even though it cranked at that same 11.45 yesterday? Maybe the starter acting up?

We have already talked about having the starter replaced anyway just to add another new part since it seems we've done a lot of that in the last 4 months.

 

I doubt that the solenoid is killing your battery. The solenoid gets power from the ignition switch and through a start relay. If the ignition is off, the relay contacts should go open and the solenoid windings get no power. On rare occasions the contacts in the solenoid that actually connect the battery to the starter will stick closed and keep the starter engaged, but this will end up with the starter getting destroyed.
Turn off all electrical things in your car. Disconnect the Positive battery cable. Get an ammeter good for about 20 Amp, and connect it between the Pos battery post, and the terminal on the battery cable you just disconnected. There shold be less than 1 Amp being drawn, if more current is flowing, then something in your car is not going OFF, or there is a short somewhere.

 

A failing battery combind with a failing charging system can make it seem like you have a draw. If you do not have a amp meter as Pete said you can just use a test light. Disconnect the positive terminal and use the test light to connect the postive terminal to the battery. It should light dimmly. Try it on a car that does not have issues first so you can see what to expect. With either ways of check watch the door lights and under hood lights cause problems if not planned for they will show a draw. Once you have the means to see the draw just start pulling fuses until it goes away.

Common draw issues. Failing lighter or lighter socket. Failing glove box switch, Under hood light on all the time.