egeezer Mine is 750 mA, and as I indicated above has not only been successful in maintaining a charge for months, but worked to trickle charge a mostly dead battery that was enough to make the starter relay chatter but no more.
Good lead-acid batteries self discharge rate is very low once the SoC (State of Charge) is below 70 - 80%, and it is normally dwarfed by the parasitic draw (28 and 77 mA for two of my vehicles) which is presumably present in all modern vehicles. Wonder if the designers ever heard of a sleep mode.
Once I couldn’t find my main charger so I’ve used a 500 mA float charger to resuscitate a battery that was showing around 2V. (glove compartment light was left on) Took a few days or maybe a couple of weeks, but eventually it was back to over 12V.
egeezer I remember when I worked at a filling station/garage decades back, we had a 60 amp charger that we wheeled out when needed.
The recommended max rate for lead-acid is around 25 - 30%, so *chargers* normally go up to around 25 - 30A, and higher current modes (if exist) are usually marked as “jump start”, “engine start”, “boost”, etc.
Charging with a somewhat lower current (10 - 15A) is a bit better, even though flooded cells can tolerate minor overcharging reasonably well.
