Hello Moviedude,

The Type VIIC U-Boat had 2 dual e-motors which could be run as generators to recharge the batteries. The e-motors ran the U-Boat while submerged, and a few times while surfaced (i.e., when reversing was removed from the diesel engines). One dual unit configured as parallel armatures / generators which charged the batteries configured in parallel for high amps, and in serial for a low amp charge. These e-motors were huge, heavy, and would require a heavy diesel engine to run one as a generator...

It would require something like a tractor trailer platform to house both with cooling and you could get 1650 Amps charge for about 110 - 170 VDC.

The Type VIIC U-Boat had about a dozen converters (Much smaller) which ran on DC and generated various levels of A/C voltages...

Regards,
Don_

"A man's got to know his limitations..."
Harry Callahan, SFPD