I have a battery box on the back of my TW200 for a storage container. My motorcycle battery went dead and I didn't have the $$$$$$ for a battery at the time. I had an old car battery laying around and it fit right in the battery box. I ran it for about a month until I bought a new motorcycle battery.
Different story: I gave someone a jump and they disconnected the jumper cables wrong and fried something on my van. Anyway, I had a portable solar panel and on top of the van it went for a while. It was fine driving in the daytime but I was limited at night driving. I ride bikes 90% of the time so I was in a hurry for repair. I replaced the alternator and no fix. I put the old alternator back on and started real trouble shooting. After some time I figured out the real culprit. The main wire from the alternator got burned. The fusible link didn't even give way.