Yes, it can be a major problem with the wirings or the fuse boards. The condition of the wires also matters a lot. So, you must consult electrical contractors bergen county NJ bloomfieldcooling.com for the professional help.

Said, all right , thanks , burned the contact on the wire of the transformer

well it could be as simple as a bad circuit board but i have no idea on how to test it , best solution is to contact the manufacturer of the charger or local battery company where charger was purchased.

Thanks, checked again everything, everywhere all OK, maybe it does not work , switch time, before it all goes

saw the photos
looks like a standard charger
one question - did you remove the DC fuse from the neg power cable? or does it have a shunt in it? cannot see it clearly enough, looks like it has a small shunt.

anyway, problem is in AC circuit if it gives AC error so input AC voltage should be present at junction block where it comes into contactor on left.
If no AC voltage there then go back to breaker box on wall where charger hooks to and check buss there. (may need electrician to check this).

Yes, Sent , thanks for the help

Can you take some photos of this charger outside and inside and datatag and send them to my gmail? My gmail is in my signature.

Charging in the same range 48v , recheck again all the contacts , thank you

Well the ac error indicates a power source failure of some kind
Isvoltage to charger correct?
If charger can be setup for multi range voltage source is it set to correct one?
The same as voltage supply?

The fuses are all integers, wires all over the place when the relay starts to click manually

check the buss fuses on power supply?
should be 3?
if 1 blows out error will occur

Error E21