Hi, ill try answer some questions
(1) what type of batteries? I sssume standard 12V auto.
12V Marine batteries, they are under the seats and a pain to keep taking the charger in and out and changin connectors over, so i ran the cable to the shed and looped under the carport when not plugged in.
(2) How much current does your batter charger supply: 4A, 10A 20A, 50A?
4200ma
(3) Are you prepared to get inside the battery charger and do some minor modifications?
Yes i dont mind tinkering.
(4) If the answer to (3) is no would you be happy if the green LED were obscured
(5) What do you want to happen when the second battery is charged and the green light comes on again?
I would like it to go back the the first so its like a trickle top up charge till i get to it and turn it off, or alternatively if its not too hard just do nothing after the 2nd charge is complete
(6) A circuit diagram of the battery charger would be ideal, but I doubt that you would have that.
No diagram sorry.
(7) Could you upload a picture of the battery charger or a web link showing it.
Cant find a link but will take a photo tonight.