UPS questions

[wayner]

I have an APC UPS and I am using the UPS functionality built into unRAID. 

 

My UPS is (I think) a 550.  The UPS plugin lists my battery as being at 100% charge and the UPS load is at 4%.  But the runtime is listed as only 7.6 minutes!  Where does the runtime come from?  Does the daemon know how many Wh my battery has?

 

I am not sure how old my battery is, so perhaps it doesn't hold  a charge very long.  Should I be replacing my battery?  I think I also have a 750 model that I could use instead so I could switch to that I guess.

[ashman70]

The batteries should be replaced every 3-5 years.

 

If you plug more things into the UPS the load will increase and the runtime will decrease, that is how it works. However if the battery is old those number may not be too accurate.

[wayner]

I understand that the more load, the less time the UPS will last, but my UPS has a very low load at 4%.  So why is the runtime so low?  Does the UPS test the battery and know that it is old and doesn't hold the charge very well?

 

You would think that at such a low load level the UPS could run for quite a while.

[ashman70]

A runtime of 7.6 minutes is actually quite high.

[wayner]

But that is below the 10 minutes that is the default for "runtime left to initiate shutdown".  So if my power flashes off for 5 seconds will it shut down my system immediately?  Or is it smart enough to abort the shutdown command if power is restored?

 

Or should I switch the runtime left to initiate shutdown down to 5 minutes?

[ashman70]

I would switch it to 5 minutes.