Car Battery Ripple Test shows 0.480 V (480mv)

[kisshmet]

My Montero 2012 shows in my battery tester gadget the ripple test of 0.480 V. Is this normal or is it a bad sign?

Sometimes when I am in the NLEX with speed of around 90-100, there is a noise, looks like coming from the aircon belt, but when I turn-off the aircon, the noise disappears immediately. I don't know if this is related to the high ripple that I get from the car battery tester.

Any helpful comments is highly appreciated!

do you read your car alternators ripple while the car is stationary and while the aircon is on or off?

at stationary the rpm is just below 1000rpm which is way below the rpm at 90-100kph which is a tad below 2000rpm so that means your engine works harder during high speed so i believe that causes the noise you are complaining about

turning off the aircon at that speed disengage the compressor of the AC..so when you turn off the aircon then you lighten the load of the engine

0.48V is close to 1/2 a volt which is relatively small voltage over the total output voltage of 13.5V or higher from the alternator

the ripple voltage is typically small simply because its the average voltage measurement from the up (charging cycle of the capacitor) and down (discharging cycle of the capacitor) voltage cycle the cars electrical system generate converting AC to DC (rectifier circuit)

a halfwave rectifier normally has a higher ripple than a fullwave rectifier. its not just the diode you need to check when it comes to rectifier circuit, you also need to check the capacitor.

a poor capacitor or faulty one will normally display a high ripple voltage because its the job of the capacitor to refine the DC voltage that will charge the battery of your car

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