Does anyone have simple solution to have the house battery cut out when
it get drawn down 50% or so?

Really I just want to cut out the circut my electric (wolfburg weekender
fridge, not full westy fridge) fridge is on.  The battery uses the
factory relay for chraging but I've added a separate fuse block and
wired up all my "house" equipment to it.   There are about 6 fuses
between stereo, amplifiers, lights, fridge (factory 12v socket under
passnegers seat)  etc...   Anyway I want to be able to leave my fridge
plugged in and just let it draw the battery down and the automatically
cut out before harming the battery...  Leaving it plug in that way in
the past killed my last optima by over discharging it too many times.

Just looking for the most simple solution...

Thanks,
Jon