That's the kind of math you use Tsiolkovsky rocket equation for.

Best would be to do the EV equivalent of asparagus staging - you have all trucks providing acceleration, but trucks 1 and 2 are also being recharged by truck 3. You then jettison it once its battery runs dry, leaving you with trucks 1 and 2, the latter also charging the former. Again, drop truck 2 as it runs out of juice. This lets you get rid of excess mass as early as possible, maximizing the benefit of extra batteries and thrust.