I had one for my Porsche, and it was essential to keeping the thing topped up. I think it was made by Ring.
My Aston needed something more substantial so it got plugged into the mains, via a C-Tek something or other.
Nowadays none of my cars need such frippery. The Citroens divert power away from high-drain things to ensure the starter will have enough juice, and the Mini doesn't have anything electrical beyond the radio presets when it is switched off.
I had one for my Porsche, and it was essential to keeping the thing topped up. I think it was made by Ring.
My Aston needed something more substantial so it got plugged into the mains, via a C-Tek something or other.
Nowadays none of my cars need such frippery. The Citroens divert power away from high-drain things to ensure the starter will have enough juice, and the Mini doesn't have anything electrical beyond the radio presets when it is switched off.