House battery not charging properly. Bypass solenoid?

First you must find out if the control voltage of the solenoid is there before you throw the baby out with the bath water.

Of course you can bypass the solenoid. Just pile up the big wires on one side or the other.

Before doing that check the small terminals on the solenoid. You should be getting 12 volts on one and zero on the other. This is the control voltage. If you have a blown fuse somewhere the voltage might not be there.