Our coach has a sanicon, as well as an electric toilet. They need power to run. Upside is there is no stinky slinky, no smell, no mess, and no chance of ever developing a "poo pyramid"
We have 4 house batteries and a 2000 watt inverter. Managing power is a 24 hour thing. We always have enough battery left in the morning to run the coffee pot and hair dryer, but soon after the genny needs to run for a couple hours. And around dinner time, a couple more to get a good charge in for the evening and overnight.
You don't want to run electric resistance heating devices on 12volts. Such devices are rated in watts, and often 1500 of them.
Watts = voltage times current, or current equals watts divided by volts.
So 1500 watts at 12 volts needs ONE HUNDRED AND TWENTYFIVE AMPS. That's 4 gauge wires, and less than 12 feet from the battery to the device.....
At 120 volts, those same 1500 watts only need 12 and a half amps. 14 gauge wire will supply that. My 2000 watt inverter will supply that (your 1000 won't :( ) and my coach does in fact have 3 feet of 4 gauge wire between the battery. So it will do this... sometimes, we've even run the microwave and the hairdryer at the same time... but glancing at the power panel scares me... just because the system will deliver the power while pulling a constant 200 amps out of the batteries, doesn't mean it is a good thing.