In article ,
Harry Bloomfield wrote:
It would be brilliant if it had some way to make it start charging
automatically after a power failure. You could then use it to build
a very cheap but effective backup power unit.

Really that is its only disadvantage, but a fairly common one on this
type of charger. I have another similar charger which does not need a
button to be pressed - its disadvantage is that if there is a power
cut, the charger will draw power from the battery and discharge it - I
use this one for my bike. Fine if it just a short power outage, but
there have been occasions when I have accidently tripped the socket
circuit in the garage and next time I go in a week later, the bike
battery is completely flat.

Yes. The Lidl one clicks when you switch it on, so I'd guess it has a
relay and diode to prevent damage by wrong connection etc.

I have one permanently installed in the old car and can confirm it draws
no current whatsoever from the battery when not charging.

--
*Did you ever notice when you blow in a dog's face he gets mad at you? *

Dave Plowman London SW
To e-mail, change noise into sound.