2 or more power supplies in parallel?

[Chris W]

I found a great deal on some 12V 13A switching power supplies ($19).
While 13A is enough for most of what I want to do, I use a few things
that require more current. So I was considering getting 2 or 3 and
hooking them up in parallel. Will this cause any problems since one
will always be putting out a slightly higher voltage than the other no
mater how close you adjust them? Also, as an alternative, I was
thinking of maybe just putting a 22 Ah Sealed lead acid battery in
parallel to take up the slack the power supply couldn't. In this case
if I had 25A load would the power supply carry 13A and the battery carry

the rest?

--
Chris W

"They that can give up essential liberty
to obtain a little temporary safety
deserve neither liberty nor safety."
-- Benjamin Franklin, 1759 Historical Review of Pennsylvania

 

[scada]

I found a great deal on some 12V 13A switching power supplies ($19).
While 13A is enough for most of what I want to do, I use a few things
that require more current. So I was considering getting 2 or 3 and
hooking them up in parallel. Will this cause any problems since one
will always be putting out a slightly higher voltage than the other no
mater how close you adjust them? Also, as an alternative, I was
thinking of maybe just putting a 22 Ah Sealed lead acid battery in
parallel to take up the slack the power supply couldn't. In this case
if I had 25A load would the power supply carry 13A and the battery carry

the rest?

--
Chris W

"They that can give up essential liberty
to obtain a little temporary safety
deserve neither liberty nor safety."
-- Benjamin Franklin, 1759 Historical Review of Pennsylvania

I don't see a problem with running the supplies in parallel. Most supplies
you can "Tweak" the output voltage. Set them individualy for the desired
output, then parallel them. Even if they are off a little, it should not
harm anything. If you want to be certain, put a rectifier diode in the +
output (anaod to + terminal, cathode to load and other supplies). That will
prevent another voltage source from backfeeding into that supply. The
disadvantage is you will loose around 0.7V across the diode, but you may be
able to adjust the supply for that loss.