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# Car battery..........

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hello..........

anyone who have an idea to decrease the car battery's Ampere ?

thank you......................

:) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :)

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You have to explain what you mean, it

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example:

normally car battery is 12V 75A

the problem is how to reduce the Ampere to 30A or smaller value, but the value of Volt is not change, still 12V.

thank..............

You can

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The battery is not a constant current source but it is a constant voltage source. The 12V/75A specifications mean that it will hold the terminal voltage to 12V for current form 0A to 75A. In practice you will not get exactly 12V over the range but voltage will be closer to 12V. So don't worry about the current if you require only 30A.

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Hi Suraj,

The battery is not a constant voltage source! The voltage changes with load and state of charge. And the 75A(h) is not the current it

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yourwins,
What are you trying to accomplish? Are you needing a current limiter so as to not exceed 30 amps to something connected to this battery? Please state what you want to accomplish and I am sure others will be able to help with the circuit.

MP

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A car battery is switched at the rotor. The rotor turns delivering the path to ground, through the spark plug, for your switched voltage. When you apply 12 volts to the autotransformer the voltage is stepped up. When the rotor loses contact the transformer is grounded out. When the stator lines up you get the 12 volts through the autotransformer and on to the spark plug.

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This makes no sense to me Kevin:

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Hi,

I agree with MP.
We need to know what you are trying to accomplish ???.

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• 2 weeks later...

Something like this...............

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Hi Yourwins,
Are you trying to protect your wiring from melting or causing a fire by limiting the current to 30A?
Why not do the same as car manufacturers, use a 30A fuse or breaker and a label that says, "Do not exceed 30A".

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