[Nut-upsuser] Fwd: Cyberpower usbhid-ups wrong battery voltage

Arjen de Korte nut+users at de-korte.org
Wed Apr 2 13:20:52 UTC 2008

> So if we see battery voltage 12V and PbAcid chemistry and
> nonsense PhyMin and PhyMax in respect to current voltage,
> we might do the heuristic decision to set those values
> to 9.8 and 14.4 as you suggested and everything would
> look good?

First of all, you'd get the same result for 7 and 15 for instance, so the 
values mentioned should be regarded as examples only. Note that PhyMin =
PhyMax = 0 is a perfectly legal value and quite a number of UPS'es use
Assuming a first order relationship between logical and physical values,
you'd need at least two different readings (preferably spaced apart
widely) to get to the real PhyMin and PhyMax values.

Second, using observed measurements to decide what to do, has proven to be
a very support intensive solution in the past, so this won't happen under
my watch. So basically we can only work with the physical value that is
reported here and have to work with that. Since there is no guarantee that
this won't overlap with correct values that don't need fixing, this will
have to be based on ProductID only.

Lastly, this problem is due to the UPS firmware being broken, which is the
responsibility of the vendor (CyberPower). If someone provides me with the
correct conversion values, I'm willing to include this in the subdriver.
So far CyberPower hasn't been very supportive when it comes to NUT,
therefor I'm not going out of my way to fix the problems they created.
There are UPS vendors that provide much better support/help in this area.

Best regards, Arjen

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