# Letting backup battery pack die?



## FastFokker (Sep 18, 2012)

Yes, true.


----------



## xlink (Mar 12, 2012)

It happens on any power outage that lasts more than a half hour. I thought the relay dropped out when the batter ran down or is that just the new ones?


----------



## kbsparky (Sep 20, 2007)

Most emergency lights have internal circuitry to prevent excessive discharge of the battery. 

They shut down once the battery output voltage drops below a set point.

This prevents the damage to the battery you are avoiding.


----------



## Bbsound (Dec 16, 2011)

And they are supposed to last 90 minutes


----------



## Southeast Power (Jan 18, 2009)

Bbsound said:


> And they are supposed to last 90 minutes


If they cannot last 90 minutes, change them.
Only one way to find out.


----------



## xlink (Mar 12, 2012)

Bbsound said:


> And they are supposed to last 90 minutes


It's a tough crowd that takes you to task on every detail.

3.2.7.4 (Canada) 2 hr for a building within the scope of 3.2.6, 1 hr for a building of Group B major occupancy or 30 min for a building of any other occupancy; or, 9.9.12.3 is 30 min.

Now, it's your turn. From what authority do you get 90 minutes?


----------



## Sonny1027 (Mar 20, 2009)

xlink said:


> It's a tough crowd that takes you to task on every detail.
> 
> 3.2.7.4 (Canada) 2 hr for a building within the scope of 3.2.6, 1 hr for a building of Group B major occupancy or 30 min for a building of any other occupancy; or, 9.9.12.3 is 30 min.
> 
> Now, it's your turn. From what authority do you get 90 minutes?


US: NFPA Life Safety Code 101
*5-9.2.1** Emergency illumination shall be provided for a period of 1 1/2 hours in the event of failure of normal lighting. Emergency lighting facilities shall be arranged to provide initial illumination that is no less than an average of 1 footcandle (10 lx) and a minimum at any point of .1 footcandle (1 lx) measured along the path of egress at floor level. Illumination levels may decline to .6 footcandle (6 lx) average and a minimum at any point of .06 footcandle (.6 lx) at the end of the emergency lighting time duration. A maximum to minimum illumination uniformity ratio of 40 to 1 shall not be exceeded.


----------

