23-09-2019, 05:05 PM
(This post was last modified: 23-09-2019, 05:07 PM by Reckless Rat.)
I think it depends on the cigar socket charger for the Sat Nav. Mine certainly wouldn't work nor the double usb socket I bought for phone charging. Strange that as you say usb only need 5 volts but neither would activate until I put 12v through them. Hence the step up box. Anyway, it works. I have a cut off switch so it isn't live when I'm not using the car so the battery doesn't drain.