Amp draw for GDL 39 & I Pad?
 

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

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

Amps
 

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

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

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.

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.

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!

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

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.

Amps
 

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