Understanding unexpected amp draw.
I have a 12v accessory plug socket that has a light on it and I was curious how much keeping it plugged in would affect my battery. (everything I read said it wasn't an issue, but curiosity sent me ch...
Forum Discussion
Really simple the multi meter is giving you the total power used 5.76w
While the USB is displaying 5v power 4.5 watts
480ma x 12v , 5.76w input
900ma x 5v , 4.5w output/load
1.2w aka 100ma conversion loss from 12v down to 5v
20ma at 12v for the led
So conversion loss is only 80ma at 12v or approx 0.96 Watts
Approx 17% conversion loss, typical and normal
While the USB is displaying 5v power 4.5 watts
480ma x 12v , 5.76w input
900ma x 5v , 4.5w output/load
1.2w aka 100ma conversion loss from 12v down to 5v
20ma at 12v for the led
So conversion loss is only 80ma at 12v or approx 0.96 Watts
Approx 17% conversion loss, typical and normal
