Batteries calculation ?

[Wiz]

As Buz mentioned.

i have paid for,sat  all FIA/BFPSA training schemes and i will continue to use their method i was taught and if it's wrong then i'm not to blame.

Graeme, the method is not wrong as such. But it might give you a calcualtion that requires a higher battery capacity than the BS recommendation. Just don't use the BFPSA method calculation in an argument over whether a system's batteries have sufficient capacity or not, without re-checking using the BS figures. I'm sure that the BFPSA will admit their advice is based on the BS recommendations but that the BS takes precedence in any argument.

[Allen Higginson]

As Buz mentioned.

i have paid for,sat  all FIA/BFPSA training schemes and i will continue to use their method i was taught and if it's wrong then i'm not to blame.

Graeme, the method is not wrong as such. But it might give you a calcualtion that requires a higher battery capacity than the BS recommendation. Just don't use the BFPSA method calculation in an argument over whether a system's batteries have sufficient capacity or not, without re-checking using the BS figures. I'm sure that the BFPSA will admit their advice is based on the BS recommendations but that the BS takes precedence in any argument.

Like wot I said.

[Wiz]

As Buz mentioned.

i have paid for,sat  all FIA/BFPSA training schemes and i will continue to use their method i was taught and if it's wrong then i'm not to blame.

Graeme, the method is not wrong as such. But it might give you a calcualtion that requires a higher battery capacity than the BS recommendation. Just don't use the BFPSA method calculation in an argument over whether a system's batteries have sufficient capacity or not, without re-checking using the BS figures. I'm sure that the BFPSA will admit their advice is based on the BS recommendations but that the BS takes precedence in any argument.

Like wot I said.

Yes. Spot on Buzz.

[Graeme]

As Buz mentioned.

i have paid for,sat  all FIA/BFPSA training schemes and i will continue to use their method i was taught and if it's wrong then i'm not to blame.

Graeme, the method is not wrong as such. But it might give you a calcualtion that requires a higher battery capacity than the BS recommendation. Just don't use the BFPSA method calculation in an argument over whether a system's batteries have sufficient capacity or not, without re-checking using the BS figures. I'm sure that the BFPSA will admit their advice is based on the BS recommendations but that the BS takes precedence in any argument.

Wiz

that was not aimed at your goodself in case it was taken in such a way?

G

[Graeme]

Further readings in BFPSA books, Unit 5, Maintenance course, page 33, issue August 2006.

I found the following:

---------------------------------Start of BFPSA wording---------------------------------------------------------
Most batteries are designed to be fully discharged over a 20h period.

Design load = C / 20h.  

De-rating Factor is:

The alarm load is usually much higher than the stand by load and this high current has to be allowed for in the battery calculation as the de-rating factor.

When the alarm load exceeds the design load then the battery could be considered of highly stressed and de-rating factor should be assumed to be D=2,

Example1:

The design load for a 2Ah battery would be 2Ah/20h = 0.1A

Example2:

The design load for 10Ah battery would be 10Ah/20h = 0.5A

For some systems the alarm load is quite low, perhaps nearly equal to the stand by load. In this case the battery is not stressed and factor D=1. This can make a small reduction to the calculation battery capacity.
-----------------------------------------------------End of BFPSA words-------------------------------------------

This is quite different to what wiz mentioned about BS version:

My question is:

1  -  If the batteries are stressed means: (Alarm load > design load) and (D=2) what equation revealed that?

2  -  If the batteries are not stressed means: (Alarm load = stand by load) and D=1 what equation revealed that?

I haven’t got a clue what’s going on in here

Benz, I demand that you read my previous posts again and reconsider your latest comment:

This is quite different to what wiz mentioned about BS version:

You will find that much of what I have previously been explaining to you, you have now suddenly uncovered in your BFPSA book. Therefore it certainly is not quite different.

I would also point out that what I have been trying to get over to you is partly what BS recommends and partly my knowledge of the behaviour of batteries (which is not mentioned,as such, in BS). Both these elements are included in your latest BFPSA quote. Therefore I have previously mentioned every factor you now highlight in the BFPSA advice. You will also note that I have correctly highlighted the BFPSA advice that varies from the BS recommendations. I have even explained why they might use some different calculation figures, but explained that I do not agree that they should give this advice.

You do me a great dishonour by rubbishing my advice.

You seem to have an in-built system of misunderstanding, ignoring, disbelieving anything that I am telling you despite the fact that it is you that has asked for the advice in the first place. I appreciate that I may be poor at putting my points accross, although I have trained dozens of fire alarm engineers over the past 25 years with great success. Therefore I must assume that you either do not read my posts properly or are unable to understand them.

I'm sure you'll understand why I may well, in the future, choose not to join in on any of your posts.

Finally, I would, however make one final comment about the latest BFPSA advice you have quoted as follows:

When the alarm load exceeds the design load then the battery could be considered of highly stressed and de-rating factor should be assumed to be D=2,

Please note that the nearest equivalent advice in the BS recommendation quotes a figure of D=1.75 and finally, and most importantly, and as I explained at the very beginning, the BS recommendation is that any specific de-rating factor be obtained from that actual batterys' manufacturer, and in the absence of such, the figures of 1 or 1.75 should be used. BS never mentions the de-rating figure of 2.

In respect of your last two questions, the answers to both is that it is based on the behaviour of batteries to different discharge rates found through experience and testing by the manufacturer. There is probably a precise formula to calculate the behaviour and it will almost certainly include elements of chemical reaction. I do not know this formula. I suggest that you ask a battery manufacturer about it.

i can ask if the guy on here selling axes,also has a gun?

[Benzerari]

It is 1 when the system alarm load is equal or less than 1/20th of the battery's stated capacity. It is 1.75 when the battery's alarm load is greater than 1/20th of the battery's staed capacity.

If:  Alarm load <=  C/20       ------->   D=1  

But BFPSA said:

(   For some systems the alarm load is quite low, perhaps nearly equal to the standby load. In this case the battery is not stressed and factor D=1. This can make a small reduction to the calculation battery capacity. )

If: Alarm load = Stand by load = I1 T1, and (Not = C/20)        ----->   D=1

The difference is: you are comparing the Alarm load with the 1/20th of full battery capacity = ‘C/20’, in order to set D=1. And BFPSA are comparing Alarm load with the standby load = I1 T1, In order to set D=1.

It is the same answer only when setting D=2 for BFPSA and D=1.75 for BS.

When alarm load > (design load = C/20)

This is what justifies what I said: (This is QUITE different to what wiz mentioned about) BS version:

Also you keep saying the same thing with a negation way:

You will find that much of what I have previously been explaining to you, you have now suddenly uncovered in your BFPSA book. Therefore it certainly is not QUITE different.

Finally I said (the cup is half empty) and you said (the cup is half full), sort of…etc

I am not rubbishing your advice Wiz, I am trying to decipher what you said, in a (No winner and No loser fashion), I just feel happy, only when I learn some thing new from any one…, or when some one say, your answer was useful and informative to me…etc, and that’s it

Have a nice day

[Wiz]

In the land of the blind the one-eyed man is king.

[Benzerari]

In the land of the blind the one-eyed man is king.

Fortunately this is not a forum of the blind and hence there is no one-eyed man to be king.

[Allen Higginson]

In the land of the blind the one-eyed man is king.

Fortunately this is not a forum of the blind and hence there is no one-eyed man to be king.

Me thinks that that proverb has soared skyward without meaning!!!

[Wiz]

In the land of the blind the one-eyed man is king.

Fortunately this is not a forum of the blind and hence there is no one-eyed man to be king.

Me thinks that that proverb has soared skyward without meaning!!!

Along with much that went before!

[Benzerari]

In the land of the blind the one-eyed man is king.

Fortunately this is not a forum of the blind and hence there is no one-eyed man to be king.

Me thinks that that proverb has soared skyward without meaning!!!

You mean the proverb not the answer to the proverb, if so you have quoted the wrong quote Buzz, as the answer to the proverb is not the proverb itself

This thread has been deviated enough from the original post, so it is this thread that has soared skyward without meaning

[Allen Higginson]

Fortunately this is not a forum of the blind and hence there is no one-eyed man to be king.

Me thinks that that proverb has soared skyward without meaning!!!

You mean the proverb not the answer to the proverb, if so you have quoted the wrong quote Buzz, as the answer to the proverb is not the proverb itself

This thread has been deviated enough from the original post, so it is this thread that has soared skyward without meaning

....and hopefully never to land again!!!

[Graeme]

amen.

[Benzerari]

Very careful, if measuring EMS panel’s batteries! If the LSA batteries and the lithium battery are quite flat, you may loose the configuration (program) when disconnecting the mains to measure I2 (Alarm current), as the system will be warm started! Since batteries failure monitoring in EMS panel is not like other analogue addressable systems, EMS batteries failure can be cleared out either them selves or manually then it takes longer time to come back again… as it may not

[Graeme]

if the batteries are replaced every 4 years then there should be no danger of them dying when the 240v is removed.

EMS are a pain to do load tests as the battery leads are such a way that it is difficult to see what lead goes where.