At SILICON CHIP we regularly get requests from readers wanting to power some electronic equipment in their car. Often they want to run a laptop computer in the car or perhaps charge 12V SLA batteries or whatever.

In the past, our standard answer has been to advise them to modify the SLA battery charger circuit from the July 1996 issue. However, that was a bit of hurdle for many readers, so we have improved and updated the circuit to make it capable of delivering any voltage from 13.8V up to 24V DC.

Main Features Steps up 12V to between 13.8B and 24V Maximum current 2A Charge 12V 6.5Ah or bigger SLA batteries Efficient switchmode design Fuse and reverse polarity protection Power indication