Cigar socket battery chargers

[S1mon.]

Do these cigar socket charger things actually work?
Cars sat in the garage on axle stands and i can't get to the battery & I know its going flat.
I have one of these trickle chargers Optimate type things that i have plugged into my bike. Thing is if i get one of these adaptors to plug in the cigar socket will it help until i can get a proper lead on it later.

[S1mon.]

Cheers for that, will get myself one of those then, Save me a bit of bother later.