[redpoint5]

I don't think the solar panels are a good idea unless you have overcharge protection for the battery.

EDIT: Perhaps wire in LEDs/diodes across each cell to balance and provide some level of overcharge protection. I had a solar panel connected to supercaps that had LED balancers, but the sun was overpowering the LEDs ability to bleed excess charge.

30 mA still seems too high of a parasitic load. Do gauges really consume that much when the car is off? My vehicles are all down below 10 mA now.

I'd run the 20 Ah battery to avoid using the solar panels, which will probably overcharge the 7.8 Ah battery.