Power loss and battery trouble issue

[newalarm]

So, the other day, we lost power for second time this year. We have underground lines so it does not happen often. We immediately started having battery trouble issues.
 
Here is our setup. We have control in house with the stock 8Ah battery. I have a p212s in this box with a 12Ah battery attached to it. We have a box in garage that contains an expander Module M1XIN that runs off the p212s. 
 
Here is a history of events:
 
5:51  Ethernet and low battery trouble.
6:04 Telephone fault issue and AC failure trouble and Power supply
6:27 CALL FROM MONITORING COMPANY RE: LOW BATTERY SIGNAL
9:44, 9:59, 10:52 Power supply (trouble i guess)
10:24 CALL FROM MONITORING COMPANY RE: BATTERY TROUBLE and EXPANDER MODULE AC POWER LOSS (GARAGE ZONE I BELIEVE).
10:52 Low battery restore
10:53 AC fail restore and Ethernet Restore and Telephone Line Restore
12:00 Control low battery trouble
 
When I got home at 9:30, i checked voltage on batteries. 8Ah was 11.99v, the 12Ah was 12.67
 
I checked batteries again once I got back from work at 4:53, 8Ah was 13.06 and 12Ah was 13.06. Battery trouble light on keypad was still on. The next morning, battery trouble light was still on, but by the time I got back in evening, everything was back to normal.
 
I thought the batteries would run much lower before having battery trouble. Does not system not test the batteries on regular basis?
 
We have a router that I use to check into system via ekeypad. When power is down, router is down. I was thinking of getting an UPS to connect router into this as well. Is there an issue with connecting an Elk to the UPS as well?
 
thanks.

 

[RAL]

When you checked the voltage on the batteries the first time, had the system shut down, so there was no load on the batteries?
 
It's normal to see a battery's voltage rebound once the load is removed.  For example, if the battery is under a load of say 1A, when the voltage drops to 10.5V, the low voltage cutoff disconnects the load from the battery.  Once the load is removed, the battery voltage could rebound back to 12V and perhaps more.
 
How much the voltage rebounds depends on the load and the condition of the battery.
 
What happened between the first time you measured the voltage and the second time?  Was there any load on the batteries?  Was the power restored so they were charging again?  Or were they still disconnected and simply rebounded further?
 
Plugging the M1 into a UPS is not recommended.  That will prevent the panel from detecting an AC power outage until after the UPS gives out.  If you want to extend the M1's battery backup time, the right solution is to use a larger battery.

 

[newalarm]

Sorry I forgot to specify that detail. Power came back on around 1 or 2 PM. When I left the house around 1030, the alarm was working on battery and properly. The battery trouble light light was on on the keypad. Not sure if it Completely shut down. But it seems like some components lost power.

Tested the batteries the first time power was out but system is functioning properly, except for the battery trouble notice. The second time I tested the batteries, the power had been back on for a while.

That is what I figured for the UPS. So I guess I can use one for my crappy modem and VOIP Box.

 

[RAL]

Sorry I forgot to specify that detail. Power came back on around 1 or 2 PM. When I left the house around 1030, the alarm was working on battery and properly. The battery trouble light light was on on the keypad. Not sure if it Completely shut down. But it seems like some components lost power.

Tested the batteries the first time power was out but system is functioning properly, except for the battery trouble notice. The second time I tested the batteries, the power had been back on for a while.

That is what I figured for the UPS. So I guess I can use one for my crappy modem and VOIP Box.

 
Ok, I think I follow your sequence of events. From what you describe, it doesn't sound like it shut down due to a low voltage cutoff.  
 
The battery trouble condition occurs when the battery voltage drops to 11.2V, and the M1 will disconnect the battery if the voltage drops to 10.2V (earlier I misstated it as 10.5V).
 
How quickly the battery drops from 11.2V to 10.2V depends on the load it is under and the condition of the battery.  For a new 8Ah battery that has a load of 0.8A (i.e. C/10), it would probably take a bit over an hour to drop to 10.2V.  So signalling the battery trouble condition a little ahead of time gives you a reasonable warning.
 
Once power is restored, the battery trouble condition will continue to be displayed on the keypad until the next time a battery load test is performed and the battery passes.  The M1 does an automatic load test once every 24 hours.

 

[42etus]

  For a new 8Ah battery that has a load of 0.8A (i.e. C/10), it would probably take a bit over an hour to drop to 10.2V.

In theory, shouldn't a 8Ah battery last for about 10 hours at a 0.8 amp draw?

 

[Del91574]

In theory, shouldn't a 8Ah battery last for about 10 hours at a 0.8 amp draw?

No. This is where datasheets and discharge tables and rates come into play, combined with boilerplate tables.
 
Since I'm too lazy to type it out: http://electronics.stackexchange.com/questions/92333/understanding-batteries-and-loads

 

[RAL]

In theory, shouldn't a 8Ah battery last for about 10 hours at a 0.8 amp draw?

 
I probably wasn't clear in what I was trying to say.  With a load of C/10, it will take about an hour to drop that last volt, from 11.2V to 10.2V.  But before that, it will take about 8 hours to drop from 13.2V to 11.2V.
 
So, with a C/10 load, it won't quite last 10 hours. The batteries are spec'd based on a C/20 discharge rate.  When you go to higher discharge rates, the more capacity you lose. 
 
At C/10, you'll probably get a bit less than 9 hours.  Increase the load to C/5, and it'll last less than 4 hours.
 

 

[ano]

Unless you got your batteries off the assembly line, chances are they weren't brand new the day you got them, and they age in the store on the shelf as fast as they do in your alarm. Get as new of a battery as you can, buy one 50% larger than you need, and replace it every three years at the most.

 

[42etus]

DEL,RAL & ano , Thanks for clearing that up. I have always been somewhat ignorant regarding batteries and their capacities.

 

[JimS]

If you are wondering about the battery run time you could disconnect power to the system on a day where you were around to check on it from time to time and measure battery voltages and see what shuts off when..

 

[Del91574]

Or just perform the calcs and go with that being a best case scenario, with battery age, condition and temperature coming into play to decrease the duty times.

 

[JimS]

That might be fairly accurate if the battery is reasonably new but not for an older battery.  Either way there are a lot of variables.

 

[Del91574]

That might be fairly accurate if the battery is reasonably new but not for an older battery.  Either way there are a lot of variables.

No real variables involved besides age and temperature really, if the calcs are followed and the industry standard safety margin is allowed for. The power calcs are performed with a full alarm load, and if a DIY chooses to not use that value, frankly, that's ignorant and a poor choice in system execution.
 
Anyone that keeps a SLA battery in service past 4 years or 25% of it's initial load rating is already pushing it's duty rating in itself.
 
My apprentices test FACP and NAC batteries almost daily on one of my sites (we have THAT many devices) and you can plot the age and duty vs. loading to accurately predict it's life, albeit sometimes the unforeseen happens (the vent valves failing is always a favorite).

 

[newalarm]

Thanks for all your responses, and sorry for not getting back sooner.
 
Since I wrote this, we have had two more power outages, in the middle of the night this time. Joy. Last one was sunday night and yesterday evening, I still had battery trouble light on. It eventually went away after I originally wrote this back in november, after 24 hours.
 
I will pull the info off the panel and review it, as well as review the load on the panel. Though When i did my calcs, I did them for max amp possibility (worse case scenario if everything is going off).
 
What is weird is that it seems to give battery trouble light even though batteries are around 12.5v each (that was saturday night when power went out and batteries were running system).
 
What brands of batteries do people recommend? I have Elks but i thought it might be easier to get something locally.

 

[RAL]

What brands of batteries do people recommend? I have Elks but i thought it might be easier to get something locally.

 
I've had good experience with Power Sonic batteries.  I've bought them on eBay from a seller called ecomelectronics. The batteries I received were fresh, with recent date codes. 
 
I replaced the original 7Ah battery with a pair of PS-1290s (9Ah), which are the same physical size.  Just make sure that the battery you choose to order has the terminal type you want (F1 for the Elk). F2 terminals seem to be more common.