[Nut-upsdev] OPTI-UPS PS (PowerSeries)

[Peter Selinger]

Niki Denev wrote:
> 
> > 
> > You can start by measuring both the value for 100% charge and the
> > value when the UPS triggers the low-battery status.
> 
> I think that i'll have problems here...
> I have just ran this test, and the results look very confusing.
> The UPS have an LCD display that has five bars that show the
> battery charge (20 percent each).
> At this point (100% charge) the battery voltage string returned
> from the Q1 query reads 2.40 (i have once noticed it to jump to 2.50
> for a very short period)
> Then i have disconnected the power of the UPS.
> The battery voltage variable started to go down.. it went from 2.40
> to 2.00 and shortly after this the UPS began beeping faster. (the LCD
> showed 40% charge) also i noticed one of the status registers to be
> flpped to On.
> The LCD then showed 20% charge... but the variable stayed at 2.00.
> And the other thing is that it went down in a very non-linear fashion,
> sometimes 2 bars on the LCD dissapeared without the value to change.
> I've attached the continous output of the Q1 query during a short
> power interruption.

It's normal that the relationship between battary voltage and battery
charge is non-linear. A typical 12V (nominal) battery might show 12.8V
when fully charged. As the battery discharges, initially the voltage
does not decrease much, for instance, when the battery charge reaches
15%, the voltage might still be 12.0V. Finally, as the battery gets
close to empty, the voltage will drop very rapidly, for example,
at 5%, it might drop down to 10.0V (at which point the battery will
practically be unusable for power generation).

So if you want to calculate charge from voltage, this would certainly
not be a linear function. Usually this would be done via a table
lookup. Charge should be roughly proportional to the expected runtime
(for a fixed load).

-- Peter
 
> (228.7 228.7 228.7 025 50.0 2.40 31.0 00000000 00011100
> (228.7 228.7 228.7 026 49.5 2.40 31.0 00000000 00011100
> (228.7 228.7 228.7 025 49.4 2.40 31.0 00000000 00011100
> (228.7 228.7 228.7 025 50.0 2.40 31.0 00000000 00011100
> (228.7 228.7 228.7 025 50.0 2.40 31.0 00000000 00011100
> (228.7 228.7 228.7 025 49.5 2.40 31.0 00000000 00011100
> (228.7 228.7 228.7 025 50.0 2.40 31.0 00000000 00011100
> (228.7 228.7 228.7 025 50.0 2.40 31.0 00000000 10010100
> (017.4 017.4 230.0 026 00.0 2.40 31.0 10000000 10010100
> (000.0 000.0 233.7 026 00.0 2.40 31.0 10000000 10010100
> (000.0 000.0 234.9 026 00.0 2.40 31.0 10000000 10010100
> (000.0 000.0 234.9 026 00.0 2.40 31.0 10000000 10010100
> (000.0 000.0 234.9 025 00.0 2.40 31.0 10000000 10010100
> (000.0 000.0 234.9 025 00.0 2.40 31.0 10000000 10010100
> (000.0 000.0 233.7 026 00.0 2.40 31.0 10000000 10010100
> (000.0 000.0 233.7 026 00.0 2.40 31.0 10000000 10010100
> (000.0 000.0 233.7 025 00.0 2.40 31.0 10000000 10010100
> (000.0 000.0 233.7 025 00.0 2.40 31.0 10000000 10010100
> (000.0 000.0 233.7 026 00.0 2.30 31.0 10000000 10010100
> (000.0 000.0 233.7 025 00.0 2.30 31.0 10000000 10010100
> (000.0 000.0 233.7 026 00.0 2.30 31.0 10000000 10010100
> (000.0 000.0 233.7 026 00.0 2.30 31.0 10000000 10010100
> (000.0 000.0 233.7 026 00.0 2.30 31.0 10000000 10010100
> (000.0 000.0 233.7 026 00.0 2.30 31.0 10000000 10010100
> (000.0 000.0 233.7 026 00.0 2.30 31.0 10000000 10010100
> (000.0 000.0 233.7 026 00.0 2.30 31.0 10000000 10010100
> (000.0 000.0 233.7 026 00.0 2.30 31.0 10000000 10010100
> (000.0 000.0 233.7 026 00.0 2.30 31.0 10000000 10010100
> (000.0 000.0 233.7 026 00.0 2.30 31.0 10000000 10010100
> (000.0 000.0 233.7 025 45.0 2.30 31.0 10000000 10010100
> (225.0 225.0 233.7 026 50.0 2.30 31.0 10000000 10010100
> (233.7 233.7 233.7 026 50.0 2.30 31.0 10000000 10010100
> (233.7 233.7 233.7 025 50.0 2.30 31.0 10000000 10010100
> (228.7 228.7 233.7 026 50.0 2.30 31.0 00000000 10010100
> (228.7 228.7 233.7 026 50.0 2.30 31.0 00000000 10010100
> (230.0 230.0 233.7 026 49.4 2.30 31.0 00000000 10010100
> (230.0 230.0 233.7 025 50.0 2.20 31.0 00000000 10010100
> (230.0 230.0 233.7 026 50.0 2.20 31.0 00000000 10010100
> (230.0 230.0 233.7 025 50.0 2.20 31.0 00000000 10010100
> (230.0 230.0 233.7 026 49.4 2.20 31.0 00000000 00011100
> (228.7 228.7 228.7 025 50.0 2.20 31.0 00000000 00011100
> (228.7 228.7 228.7 025 50.0 2.20 31.0 00000000 00011100
> (228.7 228.7 228.7 026 50.2 2.20 31.0 00000000 00011100