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Old 06-10-2019, 04:20 PM   #26
LH Lead-Foot
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Join Date: Jan 2018
Location: Omaha, NE.
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Re: too many amps, need better alt?

I bought a nice one at Sear's (If they are still open), but check Harbor Freight and they make simple amp clamps that plug into your DMM. The instructions will just have you turn to DC Volts, them multiply the reading by 100 or what ever they say. They may be cheaper.
Look, it's nice to know what you have for current or amps in a circuit, but it not needed for the most part, if everything is working.
Go to "Youtube" and watch a video on "Voltage Drop" on DC volts and check a couple until you find a good one, to the point. You don't need some guy in a lab coat with 13 steps of math...just the facts. After that, you will come more familiar with you DMM and how to use it and what it's showing you.
Its all good!
I have broke several SnapOn tools over the years, but I knew why each time.
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Old 06-10-2019, 09:00 PM   #27
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Location: Cypress, TX
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Re: too many amps, need better alt?

You don't need a current clamp. You have 5 ft of 6AWG wire = 0.0019755 ohms.
Use a multimeter set to volt range. Put the + volt meter lead on the wire where it comes out of the alternator, and the - lead on the same wire 5 feet later where it goes into the distribution block. Measure the voltage with accessories running and the truck idling at about 1000 to 1500 RPM. If possible touch or attach the leads directly to the wire instead of to any terminals or eyes you have attached to the ends of the wires, unless you've soldered them on. Then use the formula to calculate the amps.
I = V/R
where I is amps, V is the voltage, and R is the resistance ( 0.0019755 )
Let's say for the sake of demonstration you read 0.172 volts. The current would be
0.172/0.0019755=87 amps.

Wire resistance values:
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