Wiring two RD Tech DPS power supplies in series.

[interflexo]

Not related to the "in series" usage application but I think relevant anyway:
When these RD DPS power supplies share the same Vin supply and the same Vin supply is powered off, if the output of one of the RD DPS is connected to a battery (charge application) the battery will be powering all the RD DPS that will exhibit a lit screen. This can be a problem in case of a long power outage that can result in excessive battery drain. The RD DPS power supplies show an on screen Vin of the battery voltage minus the MOSFET intrinsic body diode Vf. The small RD DPS may have a design based on a buck step down PSU and explains this at first sight "unexpected" behavior.