I had a go at fitting the mobile phone charger today, it was tight but it fit. I had to use longer screws for the mounting board and made some spacers from gear ferrules from my stash of bike components. I thought i'd check the weight of the different battery packs, the new one is half the weight. This is good.

Its a good job I did this as it turned out I didn't have enough batteries to supply the pi and the motors. More on this later.

I then spent the first part of the afternoon writing some code to test the motors, I will post this shortly. I then spent 3 hours debugging it because it did not work.  After this I realised that the battery charger I have says that the battery is full when in fact it is flat.  The only conclusion I have drawn so far is that I am a massive dickhead for not checking it sooner.