Can 2 same switching power supplys or chargers (o/p=12Vdc) be connected in series in order to charge a 24Vdc battery?Is blocking diode necessary??
If yes where to place it?

 

Can 2 same switching power supplys or chargers (o/p=12Vdc) be connected in series in order to charge a 24Vdc battery?Is blocking diode necessary??
If yes where to place it?

if the SMPU's have isolated outputs you can connect them in series and you dont need any diodes. Otherwise you cant connect them.

 

I don't think you can do this at all. If the supply is designed to output 12V it will be with respect to some reference. Depending on the topology of the supply the input may be above or below 12V. In the case of an isolated switching supply connected in series there will be three different ground references.

1. Input 1 Ground
2. Output 1/Input 2 Ground
3. Output 2 Ground.

With respect to Output 2 Ground the ouput volatage will be...ta da...12 Volts. Regardless of the value of Input 1 with respect to Input 1 Ground.