It is a so called "Ladetafel" or charging panel. It was used with various types of charging generators to charge batteries. Three 12 Volt batteries could be connected and charged at the same time.
Hello
You have some explanations in german tm : L.Dv.706
This document is avialable at this url : http://www.cdvandt.org/L-Dv-706-Die-Sammler.pdf
see page : 89 to 92 : schematic diagram and user guide (nc accumulator)
Regards Rv12p2000
the voltage input is 65v and 9 a
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