Amp draw for GDL 39 & I Pad?

[LyleM]

I might buy a Garmin GDL 39 and an I pad to display the information. I'm not having any luck getting this information from the manufactors. In planning the electrical system for my RV-8, how many amps does the GDL 39 and the I Pad draw if I plug them into my 12 volt system? I need the numbers so I can plug them into the VP-X Pro. Thank You

[ColoCardinal]

per Garmin, the GDL: Power input: 10 to 32 VDC, 3.5 W max.
The I pad: ■Built-in 42.5-watt-hour rechargeable lithium-polymer battery
■Up to 10 hours of surfing the web on Wi-Fi, watching video, or listening to music

[LyleM]

Knowing the watts doesn't really help me. I need to know the amps. Thanks

[UnPossible]

My EE classes were along time ago, but I believe you divide the power in watts by the voltage to come up with the amp draw, which in this case should be around 0.3A.

Hope this helps,
Jason

[BobTurner]

Above is correct, volts times amps gives you watts.
As to the iPad, you cannot charge it directly from 12 volts. You will need a 12 volt to "2 amp" USB converter. How much current it draws depends on the efficiency of the converter, but I'd allow for 2 amps for it.

[humptybump]

I have two different 12v:5v converters for charging my iPad. One is a single and lists 14W. The other is a dual and lists 2.4A. That means they agree at 12V. You are looking for 2A or more at 5V.

[BonitaRV8]

I read somewhere the I pad draws 2 amps max at 5 V. I bought two Blue Sea 1016 Dual USB chargers, one for the front and one for the rear. They will run on 12-24 V input 5 V output and good to 2.1 amps. They are about the size of a cigarette lighter and have a nice water proof cap!

[humptybump]

Originally Posted by BonitaRV8

I read somewhere the I pad draws 2 amps max at 5 V.

One place you will find that data is the Apple Support site.

[BonitaRV8]

So, you only need .5 amp at 5 volts to run you I pad and anything more than will charge it but, at a rate proportional to the amperage. I'll hook up my fluke meter with a 12V supply to the USB charger I bought and measure what it draws. Should be slightly more than the 2.1 amps due to the inefficiency of the USB charger.

[LyleM]

Thanks guys. I learn something with this project every day.