UPS NMC Low Battery Duration

[clchee_apc]

This was originally posted on APC forums on 3/21/2009

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Hi,

I'm very confused about the term in NMS "+Low Battery Duration+"

I've read somewhere in the forum, and which most agreed upon that


Which is meant to define a UPS's Low Battery Condition based on the actual avail. runtime on actual load.


As I searched the UPS NMS Help files I found this:

Low Battery Duration*
Defines how long the UPS can continue to run on battery power after a low-battery condition occurs.


To my understanding it meant how long will the UPS be allowed to supply loads before issuing a low battery shutdown command to PCNS clients. If this is true then low-battery = how much time ?



Which is true ??



Regards,
C.L.Chee

Message was edited by: clchee

[BillP]

This reply was originally posted by Anonymous on APC forums on 3/31/2009

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Hi:

I apologize, I know the wording is a little odd on this. Basically, the Low Battery Duration is the time that the UPS considers itself to be in a "Low battery" condition. As soon as the UPS goes into this condition, it will signal a shutdown to any remaining PCNS clients that are running. Therefore, it will send the shutdown signal as SOON as it reaches this condition, as you mentioned.

Scenario:
Low Battery Duration is set to 2 minutes, UPS has 10 minutes of runtime. All PCNS clients are at their default settings. After 8 minutes, the UPS will reach a low battery condition and therefore will signal a shutdown to all associated PCNS clients.



Does this clear anything up, and do you have any additional confusions? I'd be glad to address it.


Thanks

[clchee_apc]

This was originally posted on APC forums on 4/4/2009

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Hi ArmyBoy

I TOTALLY agree with you. APC really has got some very intelligent UPS and powerfull software BUT documentation in plain simple english is almost unavailable.

AGAIN even after Caleb (CFMR) gave much explanation , I'm still very doubtfull about the *"Low Battery Duration"* issue.


The NMC help file states:
---------------------------------------------------
Low BatteryDuration
Defines how long the UPS can continue to run on battery power after* a low-battery condition occurs.
----------------------------------------------------


To my understanding, Low Battery Condition+ (min. remaining battery hours) is determined by UPS while* Low Battery Duration* is defined by user and it is supposed to tell the UPS the amount of time to wait before broadcasting operating system shutdown command to all connected PCNS clients. So, why must it wait at least 2 minutes ?? Why not allowed to broadcast immediately ?

{color:#808000}Therefore if it is left default (2 Mins) it would be the safest.{color}



Then comes CFMR's comment, the scenario turned completly upside down !!

So now Low Battery Conditionis predetermined by the user VIA Low Battery Duration+. Hmmmm then what's the meaning of "+after a low-battery condition occurs+" from the NMC help file meant ????

{color:#ff0000}Therefore if it is left default (2 Mins) it would be DISASTROUS. with 2 mins left, critical servers would never shutdown in time !!!!{color}





Oh boy, it getting more and more confusing by day.

[ArmyBoy_apc]

This was originally posted on APC forums on 4/3/2009

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I find it ridiculous that a company as large as APC, still does not have a published whitepaper on recommended general settings for their UPS's.
Its taken me several days of trawling the forums to try and get any clarity of their Network Management Card settings and definitions.

Its like the manual was written in Chinese and translated to Russian and back to English. No-one seems to have a clear view of the best procedure to set anything up.

How about someone from APC coming up with a "recommended settings" description to suit 90% of people (say a single UPS connected to a five Windows servers running PCNS), and having 30 minutes available runtime on the UPS....

What are the best settings to get say the servers to run for 10 minutes while the UPS is on Battery and then gracefully shutdown. Assuming all servers take 2 minutes to shutdown, but one is exchange and takes 7 minutes to shutdown, and one is a Domain Controller, which should shutdown last and turn off the UPS when complete....

Also - What if I have another UPS with no Servers attached - Just dumb switches. Will it simply run to exhaustion, or can I configure it to turn off when only 10 minutes Battery time is remaining?

Pretty simple stuff, but the UPS interface makes it extremely hard.
Low Battery Duration - WTF is this. Why do I have to tell the UPS when it has a low battery. Doesn't it know?
Shutdown Duration - OK I understand this. Delay from when Shutdown Instrction is recieved. (plus 2 minutes)
Maximum Required Delay - Fixed at 5 minutes for some odd reason. How does this relate to the above? I guess this comes from the PowerChute Menu option of the same name?).
Sleep TIme (Does this only apply when Manually putting the UPS to sleep from the control menu?)
If so - why isn't this part of the Control Menu Interface?

[clchee_apc]

This was originally posted on APC forums on 4/3/2009

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Hi CFMR,

The scenario that you've outlined made it clear.

However another question comes to mind. Why is the "+*Low Battery Duration*+" default to 2 mins. Obviously there won't be enough time for critical servers (eg. Exchange) to shutdown in time.
Finally, why is the *"Low Battery Duration"* highest limit is only up to 10 mins for Symmetra PX whereas i've seen SUVT systems with only internal batteries can go up to 30 mins.




Regards,
C.L.Chee

[BillP]

This reply was originally posted by Anonymous on APC forums on 3/23/2009

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Hello:

Both of these statements are correct. Basically, this is a setting that determines what the UPS considers to be a "Low Battery" condition. When PowerChute receives this low battery condition from the UPS, it will signal a shutdown. Therefore, your interpretation is correct. The default setting for this is usually 2 minutes, but can be changed from within the Network Management Card. On 3.x firmware you will find this setting under UPS tab - Shutdown - Low Battery Duration. On 2.x firmware, click on the name of the UPS on the left, then "Configuration".

Thanks

[clchee_apc]

This was originally posted on APC forums on 3/25/2009

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HI CFMR,


Thanks for your reply. Unfortunately the low battery shutdown concept still looks cloudy to me.



Let me take a real life example:



UPS NMC_
Remaining Runtime: 60 mins
Low Battery Duration: 10 mins
Shutdown Delay:180 seconds
Maximum Required Delay: 2 mins

PCNS Client_
No shutdown on events configured
No scripts configured
Turn off the UPS when the shutdown finishes - YES



From the UPS NMC info, am I correct to say that

available runtime = Remaining Runtime - Low Battery Duration - Shutdown Delay - Maximum Required Delay = 45 mins


Scenario-1:_ True / False ?

Power failure and UPS Running on Batteries. When Remaining Runtime = 15mins (10 mins +180 seconds + 2 mins)
UPS would broadcast to all PCNS clients to shutdown because UPS is on low battery.

Lets say PCNS clients require 2 mins to completely shutdown OS, the UPS will be on battery for another 1 min (shutdown delay expire) then shuts down.



Scenario-2:_ True / False ?

Turn off the UPS when the shutdown finishes - NO

PCNS clients require 2 mins to completely shutdown OS, the UPS will be on battery for another 3 minute (shutdown delay & Maximum Required Delay expires) then shuts down.




Regards,
C.L.Chee

Message was edited by: clchee

[BillP]

This reply was originally posted by Anonymous on APC forums on 3/27/2009

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Hi:

Here are a few quick definitions of those values, as noted in the help file of the network card:

Low Battery Duration:

Defines how long the UPS can continue to run on battery power after a low-battery condition occurs.

Shutdown Delay:

Defines how long the UPS waits before it shuts down in response to a turn-off command.

(i.e. if one of the servers tells the UPS to shutdown due to the "Turn off UPS when shutdown is complete" checkbox, it will wait this amount before shutting off, after it receives this command)

Maximum Required Delay:
Calculates the delay needed to ensure that each PowerChute client has enough time to shut down safely when the UPS or the PowerChute client initiates a graceful shutdown. Maximum Required Delay is the longest shutdown delay needed by any server listed as a PowerChute Network Shutdown client. This delay is calculated whenever the management interface of the UPS turns on or is reset, or when "Force Negotiation" is selected as Maximum Required Delay. "Force Negotiation" polls each client for information on the time it needs for a graceful shutdown. Two extra minutes to allow for unforeseen circumstances is then added to the calculated time. The negotiation can take up to 10 minutes. If you do not select "Force Negotiation", two minutes is used by default as the shutdown delay for all clients.


Does this clear anything up?

Thanks

[clchee_apc]

This was originally posted on APC forums on 3/29/2009

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Hi CFMR,

Thanks again for helping.

I've read that piece of info. That's where the confusion begins.


Low Battery Duration:Defines how long the UPS can continue to run on battery power after a low-battery condition occurs.


So when does the UPS send shutdown command to PCNS clients ?
Immediately at low battery or after low battery duration countdown expires ?




It's clear that the UPS self determines Low Battery condition. So what's the remaining percentage or time left that the UPS considers Low Battery ?




Regards,
C.L.Chee

[ictrosetti_apc]

This was originally posted on APC forums on 1/13/2011

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hello,
what I'm trying to achieve is to launch a script on a PCNS client so that when my symmetra reaches 15 mins it starts the scripted shutdown sequence.
i thought it was easier to configure but after many attempts to understand I finished on these forums for a clear up.

first thing i notice is that i cannot set the "low-battery duration" about 10 minutes) on the configuration page of my Symmetra.
as I read here (I was confused too about how using the battery time left), I've to use the low-battery duration field in my UPS to specify when sending the shutdown trap on the network.
what I don't understand well, is how to use the event "Runtime Exceeded". as I've seen it's the only event that can "query" (or use) the remaining runtime life of the UPS. i don't want to run my script when UPS is on battery because i cannot know the minutes left of battery.

also, what would happen after the shutdown, when the UPS restarts and recharges battery (since they will be at a low-battery level) ? does the "runtime exceeded" get raised again (thus launching my script again) ? or does it happen only when the Symmetra is running on battery ?

thanks for any help.
Francesco

[mhgebhardt_apc · Accepted solution]

This was originally posted on APC forums on 12/8/2009

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I am in the same boat as Armyboy... All I want PCNS and the NMC to do is shut down my servers gracefully - but NOT immediately after the UPS loses input power. I have my low battery duration set to 11 min. and as soon as I unplug the Smart-UPS 1500, the servers begin shutting down.

The amusing part of this is that before installing the AP9630 card ($250) so that I could use PCNS - I tried out PowerChute "business edition" that came with the UPS. The business edition SW seemed MUCH more intelligent in that I could play with the "threshold" of the remaing battery time - so that in the scenario of a power outage being 5 minutes - my servers would stay on.

I can not understand why the "Network Shutdown" version seems less intellegent than the "Business Edition". A quality white paper on PCNS would be nice...

Back to more trial and error at this point - way too much guesswork - spending hours to do something that should take minutes is frustrating to say the least.

Message was edited by: mhgebhardt