This is why you do not mix batteries old and new and why fire investigators need to pay more attention to this as a possible fire source.
I do occasional Sub contract work for one of the national alarm servicing companies and
I was called Friday night for an emergency alarm service call at an upscale department store when there burglar alarm system went blank..
Upon arriving all the keypads are saying low battery. No Ac and some are totally blank.
I find a well installed Radionics /Bosch system from 10 years ago and there is a main panel and a booster panel underneath for zone expander extra power supply etc.
I open the top box and find a miss matched set of 12 volt 7 amp batteries on the same parallel harness a Elk battery installed in 12/05 and an Ultratech battery install 06/09
The mismatched set started the problem when the Ultratech battery went low and started over drawing the power supply and overcharged the older Elk battery bulging it out and finally leading to the 16 volt 40 VA AC Transformer to start melting and bulging and then popping the over current device.
The transformer and batteries where hot enough to cause first degree burns.
Luckily the batteries where enclosed in a metal housing as well as the transformer because if this had been any other storage room junk would have been up against the transformer and possibly the batteries and thru a process known as pyrolysis a fire could have been the result. Luckily this time only the batteries got hot and transformer ruined but it could have been much worse.
Building codes require areas around alarm systems and electrical equipment to be clutter free of junk but we have all seen rooms stacked to the ceiling and this is a classic case where a fire can develop despite what manufacturers and there shill engineers claim otherwise why would they require air space around there equipment. And what if that overload on that transformer was one of these poorly designed ones out of China and overload took longer than it should to pop. Here clearly is a case where a fire could develop and be ignored by many investigators as a cause but as you can see from the pictures if it was hot enough to melt plastic it was hot enough to start paper, And after said investigator got on scene found the room and control all burned up they would have no idea there was mixed batteries and caulk it off to something else. As everything would be consumed including the transformer.
I have filed a complaint with the CPSC over these problem Ultratech Batteries and will no longer buy them they will not last more than couple years and are causing all kinds of problems as you can see including popping 120 vac. breakers on fire alarm boosters.
The industry does not want to address the problems going on in batteries and transformers and it is just a matter of time till another fire develops. and once again the wrong cause is cited. It is a shame how many fires in this country investigators get wrong or blow off a cause because they can not simulate it in a lab.
So what are the rules when it comes to batteries in series or parallel?
1- Never mix old with new batteries always use fresh sets made at same time and bought at same place.
2- Never put 2 different amperage batteries together
3- Never put different manufacturers’ batteries together.
4- use proper sized wiring to charging transformer
5- make sure alarm can allows air flow around batteries. pop pot a knock out or 2 if needed
No comments:
Post a Comment