I'm sorry I can't do photos at the moment as I'm in the middle of installing some new panniers and top box, however it's not difficult to explain.
The invertors are available from Halfords, Maplins and I'm sure ebay as well. They come in various sizes, I chose a 150w which is about 125mm x 30mm x 50mm. It comes with a car type cigarette plug which incorporates a fuse. I bought a suitable connector plug and socket from maplins. I wired the socket direct to the battery via an inline 15 amp car type fuse. I chopped off the cigarette lighter plug and fitted the new connector plug after passing the lead through a hole in the top box (via a grommet). You need to be careful to check the positive and negative connections on the new connectors match that used by the original cigarette lighter plug.There is an on/off switch on the invertor and whenever it's switched on there is 240v available at the units output socket.
If I was to use a back up battery I would use a similiar system of connectors to connect both batteries in parallel, ie +ve to +ve and -ve to -ve. Then I'd connect them when I wanted to charge both batteries and disconnect them to conserve the spare battery. A switch would make this a bit easier.
__________________
If you think you are too small to make a difference you have never spent the night with a mosquito.
|