[Nut-upsdev] REGRESSION: New "megatec" driver does't work for UPS that was managed by old fentonups driver

[Michel Bouissou]

Carlos Rodrigues a écrit :
> 
> The scale is just a wild guess.

Well, a double-scale gives a rather good guess, but with the UPSes I've
observed, a single scale is plain useless. For the true-life example I
gave, the same 12V value means "fully charged" when on battery and
"empty" when on AC...

> Just take the maximum value when the UPS is fully charged and on-line,
> and the minimum value when the UPS is almost discharged and
> on-battery.

If I do this, a single scale from 10.5V to 13.8V, the system will tell
"Only 45% charged" when the UPS goes to battery with full charge, or
will tell "Already 45% charged" when the system goes AC and starts
charging an empty battery, the whole thing being completely meaningless.

> Having two scales doesn't solve the problem because the values when
> on-battery also depend on the load being powered.

Of course, it cannot give a high-precision reading and will always be
more or less of a best guess, but at least with 2 scales you get usable
readings where with one scale you get completely meaningless readings -
better then forget about checking the UPS battery status with the CGI
for example...

Kind regards.