I got this charger together with 48V 20Ah Headway pack. Seller says it worked. Chargers cable do not have marks plus or minus, tester showed nothing to me too (zeros).
why did you remove the diode?
Because power with tester goes to both ways. Not only from anode to cathode. But diode is fine, i put it in back.
try turning off power to the charger, apply voltage of correct polarity to the output, and then check to see if the relay will function. it should click when you apply voltage to the output.
I tried - yes, relay didn't worked. I measured that relays magnet pins are shorted inside. Today i changed the reel with new one, but nothing solved. Connecting battery pack to charger I do not hear reel connecting sound.
I am getting nervous