Just a quick update on this. I was planning to work on this during the day yesterday, but for some reason the post office conspired against me. Normally my mail is delivered between 10 and 11AM, but for some reason yesterday it wasn't delivered until 5:30PM. Unfortunatly I had dinner plans for yesterday, so I didn't get home and get a chance to play with the new stuff until about 10:00PM. :: sigh:: I'm typing this at 10:12AM and today's mail was just delivered. I have no idea what was up yesterday.
But anyway, I spent a few minutes playing around with the USB power meter last night and the first thing I discovered was that I couldn't get my iphone or ipad to charge at 2 amps at all... just a bit over 1amp was the best I was seeing. Even using a real apple charger and cable. I was a bit concerned that my meter wasn't working properly or didn't support i devices (which wouldn't have surprised me at all because apple always does their own thing). But in looking around online a bit it seems like the devices automatically reduce their charge current as their SOC increases (which makes sense... we're all well aware that our cars do that too). Both my iphone and ipad had a pretty high SOC at that point, so I decided to leave them unplugged overnight to try to reduce the SOC and see how I fared in the morning.
My phone wound up completely dying overnight (which was good in this case), but my ipad still had like 70%. I did some tests this morning and with the apple charger and cord and a dead iphone it was drawing about 1.9 amps. Close enough to 2 amps for me, so it looks like my meter is working with the iphone
. For comparison, I used the meter on the stock usb plug in the car and the apple cord and saw that it was providing about 1.1 amps.
I figured I'd go with baby steps and connected my new 'high power' USB adapter to power in the car and still used the apple cord and again saw a power draw of about 1.9 amps, so I was pretty happy about that. I replaced the apple cord with the little tesla cord that goes between the USB plugs and the dock and again I was getting about 1.9 amps. Then I plugged in my USB to mini USB adapter and attempted to run power to the USB plug in the console and I was only seeing about 1.4 amps, which was a bit of a disappointment. I suspect that it may be the cheap USB to mini USB converter that I'm using. I had a mini USB to USB converter also, so just for fun I tried to connect my USB adapter to the USB to mini USB converter, then my existing mini USB to USB converter, then the apple cable and with that configuration I was only getting 1.1 amps. Of course it's also possible that the cable going to the stock USB port is causing the power drop as well.
So now I'm not sure if it's worth continuing. 1.4 amps is better than 1.1 amps, but not significantly better and I'm not sure it's worth going through a lot of trouble for only a .3 amp gain. I may also see if I can find another USB to mini USB adapter, but it's kind of a weird adapter that has a male USB plug and a female USB socket on the other side.
The other thing that's worth noting is that my Anker 4 port cigarette lighter to USB adapter that claims to be able to provide 2amps of power to each port was also only showing about 1.4 amps with the stock apple cord.