Hmm, somehow I don't get sensible results.
Glorfmorax has 24 batteries, Thorinax has 2 and Arnax 4.
Durinorax is located twice as far as Curnorax: D=2xC
Durinorax is 300 miles closer than Smurnorax: D=S-300
Once Arnax reaches Curnorax, Glorfmorax would have to travel 50 more miles to go twice as far as the planet Smurnorax:
AxC=G(2xS-50)
where A and G are the speed in batteries times 1000mph.

Inserting the three equations into each other gives for the distance to Smurnorax of s=13.0434782609 miles. This makes the distances to Curnorax and Durinorax negative!

Don't know if I or you made a mistake. Anyway fun idea. I like it!