Several years ago we met some travellers on the CSR. They had been there for about a day and a half, with a flat battery (dry cells). WE decided it was time to show some city slickers a bush trick, so we made a fire and chucked two billies on, one for a cuppa and one for the battery, a short time later the billies were boiled, so it was cuppa and damper time, and give the second bily time to cool down time.
The travellers were getting anxious, but I told them a bit of patience and we would get them on their way.
About 20 minutes later, and a good amount of coals ready, we dug a hole, dropped all the coals in it, put about 1 1/2 inches of sand over the coals, put the battery on top with some top water from the second billy in it, and left it there for about 1/2 hour. Then we pulle the battery off the sand, put it in their car, and much to their disbelief, their car kicked over straight away, and i told the guy to top his battery up now, and he will have no further problems. A couple of hand shakes and they were on their way.
About 3 months after that we got the most beautiful hand knitted jumpers in the mail, from the same people, with the brief note explaining how their entire way of thinking about aboriginal people had changed because of our actions. To me that made it completely worthwhile.
Regards
Tjupurula