Warning: The following is dangerous and should only be attempted as a last resort. All care should be taken to avoid injury to yourself and your vehicle.
If you’ve ever found yourself stranded with a flat battery in a remote location you will appreciate the importance of this tip. It’s very simple and logical and yet very few will ever think of attempting this. We all know the jump start trick with a manual car but what if you’re parked in making it impossible to get out or it’s an automatic car? There’s also jump start leads but how many of you carry these on the off chance that you’ll need them?
If you’re stuck with no other options and you have a friend with you in another car you can try the following. Remove the battery from their car. Turn it upside down over the ground to make sure nothing leaks out. Be careful here as the acid can be nasty. It’s not immediately harmful but make sure there is some water on hand just in case you get some on your skin. If nothing leaks out take their battery and while still upside down place it over yours making sure to marry the correct terminals. Connect them one at a time as you would with jumper cables. You might experience a small spark or a small explosion. One can give you a shock and the other can cause some minor 3rd degree burns and send your car 20 meters into the bush.
So maybe an explosion isn’t the likely result but there is a risk so please be careful. Under no circumstances do this if the battery is leaking. The acid isn’t flammable but the gasses emitted are. You also run the risk of damaging your ECU or other electronics but these are the same risks you take with using jumper leads on modern cars. Treat this as if the battery was a jumper cable but with tiny tiny leads. Make sure you leave the ignition off and only switch it on after the connection is made. You should also get your least favourite friend to hold the battery.