Switching Between Different Power Supplies

Hello Everyone!

I am working on a large RC/autonomous rover that has 4 wheelchair motors and will be outside for many hours. I have decided on a few different ways of powering it. I currently have a 12 volt, 35 amps and hour sealed lead acid battery, I may get more, not sure yet. I also am thinking of getting a 100-200 watt solar panel to charge the battery(s) and run the rover. In addition, I have a 1000 watt gas generator with 3, 12 volt 30 amp AC adapters.

So the issue I have is switching between these power sources automatically, and gracefully. I was going to just use automotive relays to switch between the generator or batteries but this feels wrong. Is there any way I can get or possibly make a “black box” that will take different 12 volt inputs from the battery/AC adapters/solar and make a single 12 output? Ideally the generator will only run if the battery is low and there is no solar.

Thank you all for your help!

The simplest method is to power the rover from the batteries and put a diode in series with each power source to the batteries. Which ever source has the highest voltage will supply all or most of the current to the rover and any excess current will charge the batteries. NOTE - The power sources must be regulated to less than about 14.5V and [u]This can only be done with lead acid batteries[/u]! Other types of batteries can be damaged.