How much automotive power supply noise can the arduino toler

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petespaco
 
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How much automotive power supply noise can the arduino toler

Post by petespaco »

I want to power an arduino from a cheap lighter socket "car charger" rated at one amp while an older car engine is running.
During a static test powered from a 12 volt lead acid battery, with no load, I see 5 volts DC with a 250 kHz ripple of about 40 mv. With a simple arduino uno project connected and running properly, I see about 100 kHz and about 30 mv ripple.
-Will this work long term, or will I ruin something?
- Will ignition or other system noise from a car engine hurt the arduino?

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Re: How much automotive power supply noise can the arduino t

Post by adafruit_support_bill »

"12v" automotive power systems are actually closer to 14v when the alternator is spinning and charging the battery. The Arduino Uno is only rated for supply voltage up to 12v. That fact, coupled with the electrical noise from the alternator, spark plugs and other sources in the system make it quite a hostile environment for electronics.

I'd recommend a DC/DC converter to help isolate you from the noise and to reduce the voltage to a safe level. The UBEC is one option: https://www.adafruit.com/product/1385

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petespaco
 
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Re: How much automotive power supply noise can the arduino t

Post by petespaco »

The cheap car charger already takes care of reducing the voltage from whatever the car's engine is doing to down to about 5 volts for the USB connector. So this isn't an issue of plugging the Arduino in to the barrel connector.

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Re: How much automotive power supply noise can the arduino t

Post by adafruit_support_bill »

The Atmega processors can usually tolerate a less-than-perfect 5v rail. 30mv ripple should be workable unless you are doing any critical analog stuff.

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