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Guests
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Joined: 01/10/2003
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Posts: 52

Posted: 12:01am 27 Feb 2006

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hopefully a quick and easy question? (12v 7AH SLA)

if a batt is rated at 7amp hours does that mean it should supply 7 amps for one hour? NOW the important part of the question, what would the expected voltage be after 1 hour?? asuming the batt had been fully charged (charged and then floated at 13.8v for 2 days)

peter
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Joined: 15/01/2006
Location: Australia
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Posted: 11:27am 27 Feb 2006

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battery capacity must be specified at a particular

discharge rate, the discharge rate will affect the available

capacity of the battery. the discharge rate is usually specified in

terms of number of hours to dicharge the battery from full to flat

eg 1 hour rate (C1) your battery could have a discharge rate of

7A for 1H or 14A for 1/2H so what you need is the hour rate for your

battery. The voltage after 1 hour would depend on your discharge rate

regards peterc

RossW
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Joined: 25/02/2006
Location: Australia
Posts: 495

Posted: 07:20pm 27 Feb 2006

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Richard said hopefully a quick and easy question? (12v 7AH SLA)

if a batt is rated at 7amp hours does that mean it should supply 7 amps for one hour?

As another poster has mentioned, it depends on the C rating.

Lets assume one of the better batteries, http://www.intercel.nl/datasheets/yuasa/NP7-12.pdf

The 7AH rating is at the C20 rate. C3 is 5.25AH, C1 is 4.2AH

Quote NOW the important part of the question, what would the expected voltage be after 1 hour?? asuming the batt had been fully charged (charged and then floated at 13.8v for 2 days)

They say a fully charged battery, discharged at 6A will discharge down to 9.6V (terminal voltage)

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