[oil pan 4]

Its not an alt delete if the belt is still turning the alternator. Most of the parasitic losses are from just turning the alternator at 3 time crankshaft speed.

Solar panels don't work very well on vehicles because:
1 you don't get 8 hours of useable light (8hrs was mentioned in an earlier post)
2 useable solar panel light is limited to 5 hours a day in the best areas, make that 0 hours a day up north, in winter, clouded over, with panels covered with ice and snow.
3 On the roof of a vehicle your solar panels will virtually always pointed far from the optimum solar panel angle for your location and season. So your 5 watt panel becomes a 2 watt panel when pointed almost straight up with the sun 60 to 70 degrees off orthogonal.
4 charging losses, it take about 2 amps just to raise a fully charged large truck batteries voltage up normal resting voltage of 12.8 to 14.4v. The problem then is to fully charge a lead acid battery you need to bring it up to 14.8 to 15 volts and hold for a short time depending on temperature and last depth of discharge (and maybe a few other factors).