[Nut-upsuser] Where are usbhid-ups driver parameters defined - and what do some of them mean?

[Arjen de Korte]

Citeren Richard Chapman <rchapman op aardvark.com.au>:

> I am using the usbhid-ups driver with a Belkin UPS.
> upsc shows several parameters which I would like to both understand  
> and probably change. In particular the following part of upsc output:
>
> battery.charge.low: 30
> battery.charge.warning: 30
> battery.runtime: 120
>
> My questions are:
>
> 1) What is the difference between battery.charge.low and  
> battery.charge.warning? I presume these are % thresholdsWhich of  
> these triggers the low battery event?

The 'upsc' is meant to be used by shell scripts and therefor the  
verbosity of the output is limited and we assume when you run this,  
you already know this. You're not the first to ask this, so maybe we  
should add a '-v' option to make the output more verbose and also  
display the descriptions of variables that are listed in  
data/cmdvartab. You can also take a peek in docs/new-names.txt from  
the distribution archive for a complete overview.

> 2) Is there some way to change these? 30% charge seems to me to be  
> sailing a little close to the wind. As the battery ages - I'm sure  
> the UPS will cut out long before "zero" is reached. Also - if it  
> comes back up with  < 30% charge - and another power fail occurs  
> soon after - that is not good. Are these set i the source code - or  
> is there another config file somewhere. upsrw doesn't appear to be  
> able to change these.

In that case either the driver author didn't know how to do this, or  
your UPS doesn't support changing these values. I would guess the  
first applies here, since in many cases it would be possible to change  
at least battery.charge.low.

If you're worried about the above, you need a UPS that also supports  
battery.charge.restart, to postpone restarting the load if the battery  
hasn't been recharged. Most consumer grade UPSes don't support this.

> 3) What exactly is battery.runtime.

The estimated runtime on battery remaining. In case of the usbhid-ups  
driver, this value is reported by the UPS itself. But please note that  
not all devices will give a useable value to work with. So before  
using this for just about anything, please make sure that for *your*  
UPS this is usuable.

Best regards, Arjen
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