cannesdo wrote:
Is there some part of a solar system that cuts power to the rig if the batteries get near the half-way point, or wherever it's healthy for them to stop putting out power? Is that what the controllers do?
No the solar controller just manages charging voltage. Direct power from a solar panel is 18 to 30+ volts and needs to be controlled.
You need get the battery load (inverter) figured out and reduced.
Even a large inverter only draws two amps from the battery at idle.
Once you have the load figured out then get new batteries and solar. No sense in killing your new batteries.
You may need a DC-AC clamp-on ammeter to really get in and find where the power is going.