[Milsurplus] What is this battery charger for?

[Peter Gottlieb]

I have this odd battery charger made by Teledyne.

It takes two batteries, cylindrical, about 1 inch diameter by 10.5 inches long.

The label says:

CONTR. F41608-83-D-0044  SERNO 259-0744
BATTERY CHARGER
115/230 VAC 50-400 Hz
FSCM 45413  US  Teledyne Electronics
PART NO.  141454-1  NSN: (blank)

The unit is about 11x5x6 inches with a couple of handles and has a detachable 
power cord.  Looks like it has never been used.

For each battery there is a "CHG/DISCH" switch and a "PACK/CELLS" switch and two 
indicator lamps.

Does anyone know what this is for?

Peter