[Nut-upsdev] CyberPower CP825AVR-G battery scale

[Charles Lepple]

On Dec 23, 2011, at 7:33 PM, Stuart D. Gathman wrote:

> Centuries ago, Nostradamus foresaw that on Dec 21, Cliff Wright would write:
> 
>> lsusb shows CP1500 AVR UPS. But maybe it is the Dynex DX-800U string
>> that needs to be looked for if it is the only one needing scaling.
>> Does the CP1500AVR need scaling?
> 
> I don't know.  Do I hook up a voltmeter across the battery terminals?  (Is
> that safe with a cheap voltmeter?)

Should be safe - just don't short the battery, or poke around in the guts of the rest of the UPS.

Before you do that... the scaling that we're talking about is usually evident from the voltage readings. Most of the errors are misplaced decimal points, but in this case, some UPSes read high by a factor of 1.5. Even without knowing what kind of battery is used, the full-to-empty range of an UPS is smaller than the voltage steps that you see between standard battery sizes.

We aren't trying to correct for calibration errors between units, just bringing the voltages in line with the nominal values.

Feel free to post the reported voltages from upsc, plus any observations about the battery pack(s). I did a quick search online, and I see at least two different CP1500AVR unit styles - do you have an URL that matches your UPS specs? I think I saw one which has four 12-volt batteries, so 48V nominal is likely.

-- 
Charles Lepple
clepple at gmail