Hi Guys

Can any one advise me on the best way to assess correct battery rating. We always use 7ah even for systems with an expander and 12 pirs. Is this right?

We install mainly Scantronic 9751's in the domestic/new housing market

Do you add up all the components and then what? Is there a chart somewhere? Has any one got an easy to work formulae?

What the difference between the two bell settings? sab and scb?

Best

Chris

Edited May 9, 200718 yr by ChrisJarvis

sab=power in alarm drawn from control panel, scb=power in alarm drawn from bell battery, however on both settings power for strobe is usually drawn from the panel.

As for battery rating, you need to measure the current drawn then divide the battery Ah by current drawn , this will give you a standby time in hours, if its not enough it needs a bigger battery.

eg system drawing 350ma, 7ah battery. 7/0.350=20 hours

sab=power in alarm drawn from control panel, scb=power in alarm drawn from bell battery, however on both settings power for strobe is usually drawn from the panel.

As for battery rating, you need to measure the current drawn then divide the battery Ah by current drawn , this will give you a standby time in hours, if its not enough it needs a bigger battery.

eg system drawing 350ma, 7ah battery. 7/0.350=20 hours

thanks for that

chris

This formula isn't quite right. You cannot completely drain the battery as it will not operate below a certain voltage and it will become damaged if discharged this much on a regular basis. You need to divide the battery capacity by 1.25. So a 7Ah batt is only really good for 5.6Ah.

This formula isn't quite right. You cannot completely drain the battery as it will not operate below a certain voltage and it will become damaged if discharged this much on a regular basis. You need to divide the battery capacity by 1.25. So a 7Ah batt is only really good for 5.6Ah.

i think we are also supposed to factor in a sounder ring time too - like the fire guys - so its more like 12hrs standby plus 20 mins ring - might be the 7amp battery is now only good for 4 hrs - lots of 19amp batteries going in!

There was a speadsheet on the scanny website that helps you work it out, but you need to register first.

i think we are also supposed to factor in a sounder ring time too - like the fire guys - so its more like 12hrs standby plus 20 mins ring - might be the 7amp battery is now only good for 4 hrs - lots of 19amp batteries going in!

plus the panel has to charge it twice as fast as before - i seem to remember now

Standby_Battery_Capacity_Calculation___Fire.pdf

This is what we use for fire....you can adapt the figures to suit..... surely you have an official calculation in your BS somewhere for battery stanbby ??

Standby_Battery_Capacity_Calculation___Fire.pdf

This is what we use for fire....you can adapt the figures to suit..... surely you have an official calculation in your BS somewhere for battery stanbby ??

sure Jef would know

sure Jef would know

meeeooowwwwww !