[Nut-upsuser] Questions about FSD (Fast Discharge)

excelsius at free.fr excelsius at free.fr
Wed Apr 21 15:58:29 BST 2021

Hi, sthank you. Sorry to answer only now.

Le 26/02/2021 à 23:29, Roger Price a écrit :
> On Thu, 25 Feb 2021, Jey via Nut-upsuser wrote:
>> Hi :)
> Hi!
>> I use NUT on Home Assistant, the version of the add-on is 0.6.2. Home 
>> Assistant is installed on a Raspberry Pi 4b.
>> A have a APC 1400, the UPS is connected with USB to the Rasp.
>> I'm working to built an automation, to receive notifications when 
>> there is a power cut.
>> So I used OB DISCHRG (On battery discharge) to detect the power cut 
>> and trigger the automation.
> It is sufficient to use OB.  Not all UPS's show DISCHARG


>> Then I use OB CHRG to detect that the power is coming back and the 
>> battery is charging.
> It is better to use OL which says that you are receiving utility 
> power, and therefore charging.
>> Then OL the normal operation, with a full battery.
> OL should appear before battery.charge = 100%

Nop, "OL" is coming when the battery is fully charged.

>> In the same time I send notification to follow the % of battery (97 > 
>> 93 > 90 etc). It's working.
> I assume you do this by monitoring variable battery.charge.


>> During my real test, the load was to light (3%, only a rasp pi), so 
>> it was slow to empty the battery. So I connected and started my main 
>> PC, than the load was 18%.
> If you want faster testing, you could also connect a 60W light bulb.
>> Then the battery fell to 48%, and instead to have OB DISCHRG, I had 
>> FSD OB DISCHRG (Fast Shutdown On Battery Discharge).
> What is the value of battery.charge.low in your setup?  It is 
> surprising to see FSD appear with no LB status.  Do you have upsmon 
> running?  What is your system shutdown criterion in upsmon?  Do you 
> rely on the built-in emergency shutdown on OB LB?

I use Network UPS Tools, on Home Assistant (HASS.IO) on a Raspberry Pi 4.
I don't see any "battery.charge.low"
I don't know for UPSMON.

>> Then I re-plugged the UPS to charge it.
>> And I was surprised to see FSD OL CHRG until the 100%.
> FSD is held fixed in upsd.  upsd does not turn it off, since it is 
> assumed that there will be a system shutdown followed by a system 
> restart which clears ups.status.
>> Then, I had FSD OL, even everything was back and normal, and the 
>> battery fully charged.
>> I saw today, few days later, than now it's only OL (Online). I 
>> imagine that FSD disappeared after a reboot or when I disconnected 
>> some USB cables.
>> So, I have some questions. I didn't find this kind of information on 
>> internet.
>>  - please, could you explain why FSD is coming ? Is it depending of 
>> the load, or the % of battery?
>>  - Why FSD didn't disappear when the current was back and the UPS was 
>> charging the battery or full?
>> - Is there a list of all "modes" that NUT can show? (because my 
>> automation didn't work any more when FSD appeared, so I would like to 
>> know all modes).
> What do you mean by "mode" ?  The possible status symbols, OL, OB, LB, 
> ...?
Yes, status.

Thanks for your help :)

> Roger
> _______________________________________________
> Nut-upsuser mailing list
> Nut-upsuser at alioth-lists.debian.net
> https://alioth-lists.debian.net/cgi-bin/mailman/listinfo/nut-upsuser

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://alioth-lists.debian.net/pipermail/nut-upsuser/attachments/20210421/b0987274/attachment.htm>

More information about the Nut-upsuser mailing list