Hello, everybody,

I have a UPS with two identical fans connected in parallel. Because they 
are loud, I want to replace them.

The nominal voltage of all fans is 12V.

Each of the old fans draws max 2.5W.
Each of the new fans draws max 0.96W.

If I only connect the new fans, the UPS reports a serious error (beeps 
unhappily).

If I add one of the old fans in parallel to the two new fans, the error 
goes away.

I think this is because the UPS recognizes a power consumption of only 
about 2W instead of 5W.

I don't think that a temperature sensor triggers the error, because the 
UPS works fine with two new fans and one old fan (all connected in 
parallel), even if the old fan is physically outside of the case and 
doesn't cool anything.

I consider connecting a resistor in parallel to the new fans.

If this is a good idea, the question is how big this resistor should be. 
If not, how can I get the new fans to run wihtout triggering errors?

An old fan has a measured resistance of 650 Ohm or 1320 Ohm, depending 
on the polarity.

Thank you very much.