Bit confused now.

I read a reply by Peter James suggesting that the panel battery should have a capacity of something in the region of 10x total current draw in armed mode. I then read the ACT guidelines on testing which suggests a capacity of 1/10th alarm current draw. I vaguely remember BS4737 suggesting a capacity to allow 8 hours standby.

The system I am fitting has a total armed current of about 220mA therfore I selected a 2.8Ah battery. Using ACT's suggestion I reckon that the sounder and strobe alone will require a battery of about 4~5Ah.

Which is right as most compact panels are only big enough for 2.1Ah batteries?

The recomendation is that the battery should power the system for a min of 8 hours in standby mode (when the alarm is unset), but as a general rule we usually like to fit as big a battery as the panel allows, so if your panel could accomodate a 7aH battery then thats what i`d fit.

The current draw in armed mode is normally less than when in Standby mode, so Pete isnt far off with his recommendation.

Bit confused now.

I read a reply by Peter James suggesting that the panel battery should have a capacity of something in the region of 10x total current draw in armed mode. I then read the ACT guidelines on testing which suggests a capacity of 1/10th alarm current draw. I vaguely remember BS4737 suggesting a capacity to allow 8 hours standby.

The system I am fitting has a total armed current of about 220mA therfore I selected a 2.8Ah battery. Using ACT's suggestion I reckon that the sounder and strobe alone will require a battery of about 4~5Ah.

Which is right as most compact panels are only big enough for 2.1Ah batteries?

220 ma in alarm isnt alot are you sure youve fitted the bell ?

220mA in armed but not alarm - this is as follows:

4 x 18mA dual techs

1 x 50mA panel

1 x 85mA RKP

1 x 18mA SAB

Total = 225mA

Hope I'm right! Any comments

That looks about right to me Deryck, the 2.8Ah battery should do fine.

Is 50131 definately gonna be implemented in March Pete..? or is it likely to get post poned again..?

With regards to batteries I would point out that you should also alway write the installation date on the battery. BS 4737 states that the battery should be changed

when its capacity falls below 80% and if you phone the nice people at Yuasa they will send you the technical specifications on their equipment.

This will show ( temperature dependant) that the lifspan of a battery is 5 years.

This is a bugbear with me as all the big alarm companies do not to ensure the battery is changed. You only have to be in an area when their is a power cut to see the system that are in alarm via the external sounder. Also most alarm engineers I have spoken to who work for national companies have not even heard about the ACT battery tester and if they have their boss has the one and only unit locked in a cupboard. (incase it gets stolen)

Our boss must be rich then, we all have ACT battery drop testers - even the installer .

And we always put the installation date on batteries we have installed, the thing is we always advise customers that batteries should be changed every 5 years regardless of wether they have passed their Drop test, but we cant make them buy a battery if they dont want one. So you have to wonder why half of them bother having a service in the first place ?

Same here Pete, havn`t seen ANY 50131 compliant equipment.

The manufacturers are all being a little SLOW with this new standard.

We mark all batteries with install date and name of installing engineer.

Also we mark batteries that are removed from a job with contract number,removal date ,and reason for removal.These are then returned to the office,for safe disposal at a later date