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Saturday, May 19, 2012

Battery wiring harness supervison problem found.

I use the Honeywell Vista 32 ,128 and 250 FB and FBP product line  for Combination Commercial  Burglar and Fire Alarm Controls there a very dependable line of product. But recently I had a problem where the back up battery's did not last as long as they should have during a power failure.
The panels utilize a dual fused harness to allow 2- 12 volt  7 amp  battery's to be used in parallel to allow proper back up of 14 amps of power when needed which depending on how system is configured allows 24 or more hours of back up plus 5 minutes of sounder time. Only problem power was off 12 hours and panel went dead . Something it should not have done as battery's where new 6 months ago.
So I start my investigation by checking batteries and found one  depleted down to 7 volts and the other sitting at 12 volts. OK whats going on. more careful examination showed that only one battery was charging not 2 as should be. after careful examination of the fuses I found one of them blown which means the second battery was not charging properly and just sitting there with its original factory charge of 12 volts. I put in a new dual fused harness which corrected the situation. But then finding this problem I started looking at other panels as well and even with 24 volt systems you can still have the same problem when the packs are paralleled  particularly in aux battery charging boxes and controllers.
It appears none of the panels or auxiliary chargers fully supervise all of the battery's and the only way you will find this out is during a  long power failure or during annual test and checking each lead set to make sure it is working properly. Well we know that does not happen how many times have I written about bad alarm services . this is something UL and NFPA have totally missed when it comes to panel design and something they need to take a look at. Because many systems which need up to 72 hours of battery back up for a long weekend where the facility is unoccupied depend on this . Imagine closing the plant and going home on Friday at 5 PM  and power goes out at 10pm and stays out you have no idea its done so and battery's which are suppose to last 72 hours only go 12 hours and Saturday evening a fire breaks out. You have no fire protection. With more and more panels using IP based phone lines with no back up and no signals going out when power fails . You have a real mess on your hands . This is why it is imperative that it be known if battery's are operating properly. Because the only way some one will be alerted to a fire is a passing motorist who sees or hears the alarm and hopefully alerts 911  before a fire is so bad by time it is discovered it is a total loss.

1 comment:

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