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These pics show the output voltage and current that is put out by the USB and Power Outlet (cig lighter). For those not familiar with the iPhone and iPad power requirements.

iPhone requires an output current of 1.1Amp @ 5Volts
iPad 2.1Amp @ 5Volts

This is the current required charging the devices when flat.

The maximum current that can be obtained from the USB outlets is 0.5Amp

The maximum current that can be obtained from the power outlet is dependent on what charger unit that's plugged into the power outlet.

Note: One pic deleted so number count (on pics) is missing one.
 

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Yeah, they're USB 2.0 slots, if I'm not mistaken. I seem to remember reading at work that 500 mA is the limit in that specification and the USB standards body didn't increase that limit until USB 3.0 or 3.1. Why they didn't put USB 3.0 in there, I don't understand. Especially since it's the standard these days and it doesn't really cost anything extra in most retail products I've seen lately in the PC parts market anyway.
 

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The USB spec is 500 mAh but there aren't any laws requiring mfr's to adhere to the spec. Different manufacturers have different ways of informing the device how much current can be delivered. Apple does it by providing different voltages across the data pins.
Reverse engineering Apple?s recharging scheme | Hackaday

A lot of it will depend on how the Mazda USB ports present themselves. The easy way out if you don't need data input across the wire is to just get one of those low-profile high-current accessory adapters.
 

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And that's at 12V (120W). 120W at 5V is 24A. Even if the charger is only 75% efficient, that's still 18A. That's a lot of phones to charge.
 

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And that's at 12V (120W). 120W at 5V is 24A. Even if the charger is only 75% efficient, that's still 18A. That's a lot of phones to charge.
All well and good stating at 12V you have 120W (10A) and at 5V 120W (24A). However, you won't get 24A as the outlet and wiring are not able to handle 24A. Let's say Mazda allow a 50% in wiring capacity (I would bet it's more like 20%...if that) that would only allow 15A.
 

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I brought a USB hub that i can power by using both ports this hub has 3 ports and charges my samsung s8+ whilst using android auto and works great.
 

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All well and good stating at 12V you have 120W (10A) and at 5V 120W (24A). However, you won't get 24A as the outlet and wiring are not able to handle 24A. Let's say Mazda allow a 50% in wiring capacity (I would bet it's more like 20%...if that) that would only allow 15A.
Current to the outlet is going to be limited by whatever size fuse is on the circuit. That's the purpose of the fuse, to burn out before the wiring does. I don't know what size fuse is in there for the power outlet, but I'd guess either a 10A or 15A fuse. If the outlet is rated for 120W, then I'd guess it would be a 10A fuse.

You could get a theoretical maximum 24A at 5V (before considering losses due to conversion efficiency of the transformer and other contact and conduction losses) on the output of a charger plugged into the socket by connecting a step-down transformer to the outlet. The power conversion is happening downstream from the outlet, so the wiring in the dash is still only carrying, at most, 10A.

You could step the voltage down by using a voltage regulator or some simple load resistors to cause a voltage drop down to 5V on the line, but you're still going to have a maximum theoretical current of 10A going that route, but that's usually plenty for most applications.
 

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Yes, they're very commonly available at most department stores, electronics stores, Amazon, or even most gas stations. I got one from an end-cap by the registers at Target for around $5 a while back. Has two USB ports on it. One outputs up to 2.1 Amps and the other outputs around 1 Amp. I'm not sure if it'll output full current to both ports if both are in use simultaneously, though.
 
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