Has anyone got any experience with the baby "jump start" battery boxes?
Right now specifically interested in using one as a 12V power source for the alarms and anti theft devices on Her Ladyships BMW K1200LT which flatten the bike battery in about 6 weeks - 2 months. Garage in separate block so no power. I figure that she can easily pull something that small and, basically, portable off every week and take it back to her flat to recharge overnight. Presumably when it goes back on again it will top up the main battery whilst looking after the alarms et al. If I find one that works for her I plan to get one to do same job on my P38, which usually needs a top up charge a couple or four times a year if I'm not out and about much.
Problem is deciding on what is a good brand, which capacity specification to believe and whether a separate 12 DC output alongside the jump start one is useful. far as I can see most of the usual suspects quote the capacity for the USB 3.2 / 5V output in milli amp hours to get nice big numbers. Real 12 volt capacity seems to be around 1/3 of those numbers. Say 1 1/2 to 3 amp hours for the under £100 market.