Also depends on the drain to the battery due to any alarms, trackers, or the radio.
I was always led to believe it takes 20 mins of running time to replenish what a cold start takes out of a battery.
How accurate that is I don't know but it doesn't sound far off to me.
Works both ways, you can even plug a charger into them, not a full on 4 amp jobbie tho@Alan Reynolds
I had always thought that cig lighters in vehicles was a one way jobby. I didn`t realise that the juice could flow both ways. Is that something to do with diodes? Someone on here will know.
On drive. It would work out cheaper than diesel & time. Do batteries have to have one lead disconnected when charging?Is it kept in a garage or on your drive? A Lidl conditioning charger would do the trick.
A lot need the key in & the ignition on though, so it doesn’t work.Works both ways, you can even plug a charger into them, not a full on 4 amp jobbie tho