Ask HN: How to keep a mobile office running without power?

In two about weeks we'll move our startup from the city to a a big outdoor soccer camp (we do a soccer app). We're planning to rent a mobile home and stay there for a week and we don't know how often we'll be near a regular power-outlet, so we're looking for a solution that let us keep using our laptops continuously.

Either by having a big battery pack inside the mobile home that can power us for at least 24 hours - preferably more - and then be recharged somewhere. Or even better, some sort of solar-power arrangement so we don't have to worry about re-charging.

What can we do that's still not to expensive to be able to power 3 laptops continuously?