Parallel PC Power Supplies

[Tom Frank]

I posted in the following forum a question about hooking up two PC power supplies in parallel to get a 12 v. DC power source with higher current capability:

http://www.rcgroups.com/forums/showthread.php?t=344893

It was suggested I ask here for broader exposure, so rather than cross posting the same thread here, if you have additional good advice I'd appreciate your posting at the above link.

Thanks!

[Chippie]

My gut feeling on this, is to go with diode isolation.....

Connect both -ve's together
Connect both +ve's together but thru a diode in each wire.
The diodes need to be capable of passing the appropriate load current(go for schottky...for lo v. drop).

What happens is:

As you load up, because of tolerences, both ps's will not perform the same...so as you crank up the load, one ps will start to load up to its max, the volts will droop...as it does the 2nd psu will start to supply current until it saturates...

I've setup psu's on different systems before today and that's how we do it...but a slight offset in voltage output is required...

If you think about it....???

Anyone offer alternative thoughts...??

[Tom Frank]

My gut feeling on this, is to go with diode isolation.....

Connect both -ve's together
Connect both +ve's together but thru a diode in each wire.
The diodes need to be capable of passing the appropriate load current(go for schottky...for lo v. drop).

What happens is:

As you load up, because of tolerences, both ps's will not perform the same...so as you crank up the load, one ps will start to load up to its max, the volts will droop...as it does the 2nd psu will start to supply current until it saturates...

I've setup psu's on different systems before today and that's how we do it...but a slight offset in voltage output is required...

If you think about it....???

Anyone offer alternative thoughts...?? Got a similar reply in the above forum link, using something like an STPS3045CP (dual) Power Schottky Rectifier on the + supply leads. Seems to be a simple thing to try if I can find the component part, and since I'm using just one of these supplies successfully now to charge my 8 cell NiMH packs, I doubt the second power supply will even be needed much. The second would likely only be needed if I go to larger, higher voltage packs or use the "motor break-in & lathe" power feature of the charger (a Duratrax ICE), which I would not need with my brushless motors.

[Warbird_SIN]

I'm using 2 PC power supplies in parallel since one year already.
I only connected the + and - poles. No diode used.

Works fine for me.