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Amps measurement of a battery

rajansn24

Oct 9, 2016
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Sir,
I have a 12Volts battery and I wanted to measure the amps. Can you tell me how to measure the amps of the battery?
 

BobK

Jan 5, 2010
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You can't. A battery does not produce a certain current, the current depends on the load that it is driving. If you were to measure the maximum current it could supply, it would depend highly on the state of charge and would decrease rapidly if the battery was fully charged to begin with.

Do no try to place an ammeter across the battery terminals, this causes short and could damage the battery or even cause a fire or explosion.

Bob
 

davenn

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Sep 5, 2009
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Do no try to place an ammeter across the battery terminals, this causes short and could damage the battery or even cause a fire or explosion.

and will probably destroy the ammeter
 

duke37

Jan 9, 2011
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Do you mean that you wish to measure the storage capacity which is quoted in Ah or mAh?
 

davenn

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Do you mean that you wish to measure the storage capacity which is quoted in Ah or mAh?

that probably is what he really wants :)

But of course we need the battery type etc ... should be written on it anyway
 

Audioguru

Sep 24, 2016
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Maybe he wants to measure "Cold Cranking Amps"? But it probably does not get cold in India and probably their car batteries are small.
 

rajansn24

Oct 9, 2016
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Sir,
I am using 12Volts / 30Ah battery. plz tell me how much charging current and charging time will it take?
 

davenn

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Sep 5, 2009
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Sir,
I am using 12Volts / 30Ah battery. plz tell me how much charging current and charging time will it take?


what type of battery ? lead-acid ? LiPO ?, ....... something else ?
all have different charging requirements
 

(*steve*)

¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd
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Jan 21, 2010
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the battery specs will tell you the recommended charge current, but roughly speaking:

(time to charge in hours) = 1.2 * (capacity in Ah) / (charge current in A)

If you wanted to charge it in 24h, the current would be approximately 1.5A
 
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