need help identifying a battery charger.

[just a number]

I can't find a model number on it. I know it's around to 20 years mark(type of wire used). it's rate at 12/50A or 6V 135A. it's 120V input. it has a load tester built in. if anybody has info for me that would be great, a manual would be even better

here's a couple of pics.

 

[bison]

Obviously it is an Exide.
Open it up!,there might be a wiring diagram sticker inside the back panel,it may show model and # as well

 

[just a number]

I forgot they used to put the diagrams in there.at: that'll be tomorrow morning job.

 

[ak diesel driver]

me thinks that's more than 20 years old