relay power ability
Printed From: the12volt.com
Forum Name: Car Audio
Forum Discription: Car Stereos, Amplifiers, Crossovers, Processors, Speakers, Subwoofers, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=134469
Printed Date: June 15, 2024 at 9:20 AM
Topic: relay power ability
Posted By: pts760
Subject: relay power ability
Date Posted: July 02, 2013 at 3:36 PM
I want to use relays to break the speaker output on a amp that puts out 100 watts a channel at 4 ohms. I'm building a speaker selector for a customer with a house boat.
According to my calculations a SPDT 30A/40A relay can handle up to 576 watts at 14.4 volts at 40A(Power= voltage x current)and 432 watts at 14.4 volts at 30A. Are my calculations correct? Should I be okay to do this? Has anyone done this?
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I drink current, eat ohms, and bleed voltage
Replies:
Posted By: soundnsecurity
Date Posted: July 02, 2013 at 4:05 PM
amps equals the square root of power divided by resistance, so 100watts divided by 4 = 25, square root of 25 is 5amps, well within the range of a 30A relay
Posted By: itsyuk
Date Posted: July 02, 2013 at 5:09 PM
radio shack sells a little 4PDT relay that is rated 7 amps. i have used these many times in the past for this very purpose. the largest amp i have used these on is a JL 300/2. no problems.
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yuk
quiet rural missouri, near KC.
If your system moves you physically and not emotionally, you have wasted your money.
Posted By: pts760
Date Posted: July 04, 2013 at 12:33 PM
Awesome. Thanks for the info
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I drink current, eat ohms, and bleed voltage
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