On Friday, May 1, 2015 at 2:03:37 PM UTC-4, micky wrote:
Someone gave me an old car battery charger.

6 volts 10A and
12 volts 2A and 10A, determined by a slide switch.

A friend brings over a dead 12v battery.

On the charger, on 10A, it charges at 9amps.
On 2A, it charges at 7 amps.

Based on the meter on the charger.

What does it mean to be a 2 amp charger if it charges at 7 amps?



It means the battery is very low on charge. IDK exactly how
they come up with those ratings, but I would suspect that it's
rated at putting out 2A at a particular charging voltage. If
the battery is very low, or bad, it will present a bigger load,
the charging voltage will be lower, and the current higher. I
see that on my old Sears charger all the time. If it's on 2 or
10A, on either, if the battery is very low, it will initially
charge at a much higher current. After 5 or 10 mins, it starts
dropping down as the battery charges.




After an hour the charging rate dropped to 6 amps on the 10A setting,
and then it was 5 amps on the 2A setting.