L

LyleM

Active Member
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
 
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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
 
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.
 
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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!
 
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.
 
SteinAir is now selling USB Chargers for Ipads, Iphones, Ipods, etc.. They offer two types of chargers: a black DC power plug insert charger and a black Panel Mount charger.

12vdc adapter, 5v @ 1.5a output
 
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iPad and voltage -

Want to jump in on this thread and give my two - cents.

On our trip to OSH last year from Washington State -our iPad battery quickly drained. We were using the ELF GPS with it. I had it plugged into a lower priced USB adapter charging less than 500ma - or half amp. My wife was using it in the back seat - until it stopped working. I would strongly suggest only going with the 2.1 amp device so it will stay on during flight and still charge. Of course when the iPad is all charged up the draw on the battery declines as it's completed. I threw away all my USB port adapters that were less than the 2.1 amp ones as worthless. Hope this helps - so max drain on a iPad is 2.1amp and add 15% that you should account for in your calculations. Also -if you have Go Pro cameras - or other devices using a USB port to charge with. The 2.1 amps covers these with extra power to spare. You can charge two at the same time.
 
Charge adapter

I ended buying the 2.1 device awhile back. It sounds like I did the right thing. Thanks
 
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