[ForSale-Swap] Power supply question

[Andy]

Regarding the original question ... the answer is "it depends", but
usually this is not a good idea without a little extra help.  That
"extra help" is often in the form of either a power diode or resistors
(or both), between each supply and the point where they join; but even
then there can be problems.

Two identical batteries can usually be paralleled without problem
because the two will output exactly the same voltage (and if they
don't initially, they will equalize to one another fairly soon).  But
power supplies don't do this so readily.

One problem with power supplies is when they don't output precisely
the same output voltage.  And they 'never' do.

What happens to the power supply with the slightly lower voltage?
Does it try to pull down the output of the other supply?  Or is it
happy to sit there and do nothing?  Both cases are definite
possibilities, depending on the design of the regulator.

So one bad result, may be that the two "fight" one another and large
current flows from one supply into the other.

Another result may be that one power supply sources all the current
and the other sources nothing ... unless you add something for load
sharing.

I think you made the right decision by keeping them separate.

Andy