Register for the iXsystems Community to get an ad-free experience and exclusive discounts in our eBay Store.

UPS configuration - master/slave

subhuman

Member
Joined
Nov 21, 2019
Messages
121
Inxsible said:
No I didn't do this because the default low battery level for my UPS is 20%. I think that's the default for all, but I could be wrong. I would change it only if you want to override the default low battery level to anything other than 20%. Going lower risks not cleanly shutting down all devices before the UPS loses all battery power depending on how many devices you have connected.
I would agree with you here. Even if someone tested it and a lower threshold value gave them enough runtime TODAY, that doesn't mean you'll still have enough runtime in the future when the batteries are a little older.
During my research I found that taking the UPS batteries that low in charge will kill the batteries much faster.
Also true. Every UPS I've seen uses lead-acid gel cell batteries, and one characteristic of lead-acid batteries is they lose a bit of their max capacity every time they're discharged.
 

Sir SSV

Member
Joined
Jan 24, 2015
Messages
96
I would agree with you here. Even if someone tested it and a lower threshold value gave them enough runtime TODAY, that doesn't mean you'll still have enough runtime in the future when the batteries are a little older.

Also true. Every UPS I've seen uses lead-acid gel cell batteries, and one characteristic of lead-acid batteries is they lose a bit of their max capacity every time they're discharged.
My ups is set at a default of 20% from Eaton.

I did a test this afternoon/evening and noticed that the nut package in pfSense uses this 20% value to initiate a graceful shutdown. It left the shutdown procedure far too close to the shut down of the ups.

I ended up adding under Extra arguments to driver:

ignore lb
override.battery.charge.low = 30

essentially this tells the nut package the low battery level is 30% and to initiate a graceful shutdown. No need to adjust the low battery values on the ups.
 
Top