This actually quite a good trick to provide an appropriate (eg. charged) 'alternate' DC power source to maintain the minimum voltage and current to hold the computer, radio and alarm setting for your car while swapping your car battery (I have myself used 2 small 9 Volts batteries in series via alligators clips for this purpose): just make sure that it is connected on the correct side of the cables where voltage and current will be maintained after the main car battery is disconnected! Hope it works for you and have fun!
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This actually quite a good trick to provide an appropriate (eg. charged) 'alternate' DC power source to maintain the minimum voltage and current to hold the computer, radio and alarm setting for your car while swapping your car battery (I have myself used 2 small 9 Volts batteries in series via alligators clips for this purpose): just make sure that it is connected on the correct side of the cables where voltage and current will be maintained after the main car battery is disconnected!
Hope it works for you and have fun!