Panel Mount USB Charger

[flyunleaded]

I make a 3 Amp USB Charger with two ports that can be mounted directly in your homebuilt instrument panel.

The charger has the proper circuitry to "quick charge" the Apple iPad and iPhone, simultaneously, and there is a model to charge a Samsung Galaxy Tablet. Tablets and the newest iPhone require voltage signals on the data terminals of the USB connector to properly charge at the high power levels necessary.

Information about the chargers and online ordering here.

[eric]

Very neat device, Dean.

I've fooled around with building USB chargers, and I've found that the Apple devices don't adhere to the USB standard for current delivery. I've seen a couple of solutions, but I'm wondering how you handled it.

Do you have voltage dividers on D+ and D- to provide 2.8V and 2.0V respectively? Or, do you use a multiple-output regulator IC?

Do you find that your device reliably allows iPads to charge at a full 2.1A draw?

Thanks!

[flyunleaded]

Aug 19, 2012 15:43:12 GMT -6 eric said:

Very neat device, Dean.

I've fooled around with building USB chargers, and I've found that the Apple devices don't adhere to the USB standard for current delivery. I've seen a couple of solutions, but I'm wondering how you handled it.

Everything I know about Apple device charging I learned here.

Do you have voltage dividers on D+ and D- to provide 2.8V and 2.0V respectively?

Affirmative.

Or, do you use a multiple-output regulator IC?

No, this won't work. The voltage levels have to be on the data pins or the Apple device will only trickle charge no matter how much current the USB charger could supply.

Do you find that your device reliably allows iPads to charge at a full 2.1A draw?

My device uses a 5A charge pump, so whatever the iPad wants at 5 Volts, my device will supply it, and of course as the device's batteries recharge, current demand will taper off, so the 2.1A requirement is short lived.

Since my device has two ports, I support the Apple 2.1A spec on one port and the Apple 1A spec on the other port and my charger will charge your iPad and your iPhone simultaneously, or another device that may require 1+A in the second port, like a Samsung tablet.

[eric]

Thanks for the reply, Dean. Especially that Voltaic link; great information there. I had planned to do something just like this on my panel, since I enjoy electronic tinkering almost as much as aviation.

I have very little formal training, though. I just look for schematics I can understand and ape the relevant parts. Sometimes it works, and sometimes the smoke escapes. Fortunately, Digi-Key ships parts cheap and fast. It looks like your chargers are quite a bit more refined!

Thanks again for the info.

[hatzfan]

I'd like to learn more on the apps for the iPad. I'm far from a techy, but spoke with a tailwind builder who mentioned just installing two iPads and that's about it! Interesting. Thanks