Pump when battery full

System

I acquired a cabin that has a fairly small solar power system in it. There are are 100 watts of panel, a 15 amp controller and a battery. With my typical electrical usage at night, my batteries are topped off by about noon and the panels really do nothing the rest of the day. Is there some circuitry or device I can build that would detect that the batteries are at 13v and turn on a pump for irrigating a garden, then turn off when the batteries got down to 12.5v or so? That way, it wouldn't drain the batteries on cloudy or rainy days.

This would save a lot of manual checking now.

Thanks for any help.

System2

Re: Pump when battery full

Hmmm, I found something from a post back in 2006 that seems to indicate I need a relay driver. I guess I'll try to find some information about that.

What pump would someone recommend for pumping water up about 90'? It's fresh water and a low flow rate is fine.