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Drop amps from 25A to 8A


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I have a 13.8V / 25A power supply that I would like to use in testing. I'm looking to drop the amps from 25A to around 8A while keeping as much voltage as possible. I've thought about using a resisitor, but it would have to be in the neighborhood of a 200W / 1.725 ohm resistor to work. Any suggestions on how to pull this off without needing a huge resistor?

Thanks in advance.

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The power supply doesn't provide 25A all the time. It provides only as much as the load needs.
If you reduce its output current with a resistor then a load will receive a reduced voltage.

13.8V at 8A is a load resistor of 1.725 ohms. Its power dissipation is 13.8V x 8A= 110.4W.
If you connect two 1.725 ohms resistors in series then each one will have 6.9V and each will dissipate 6.9V x 4A= 27.6W.

Maybe you want to LIMIT its max current to 8A. An electronic circuit might be added to its circuit to do it. Attach its schematic.

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Thanks for the reply, I guess my math was wrong. I was using P = V squared / R which would be 13.8 squared (190.44) / 1 = 190.44W. Yes, I want to limit the maximum amperage running through so that it doesn't get all the way up to 25A. Having a way to vary the max amps would be really nice. I'm currently experimenting with Peltier modules and I don't want to fry it by putting too much amperage through it. It's probably just me, but I don't see any link to a schematic that would limit the amps to 8.

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