Problems with mintyboost v3 and iPhone4

[jasonkwan]

Hi,

I assembled two mintyboost v3 kits, hoping to be able to charge mine and my wife's iPhone 4. It seems with both of them start charging, and then at some point the "Charging is not supported with this accessory" message comes up. Now obviously my first thought is that I've done something wrong somewhere, given that this is my first soldering project and also in light of this post: http://forums.adafruit.com/viewtopic.php?f=15&t=16791&p=84580&hilit=iphone+4#p84580. Could someone give me some pointers as to what to do in terms of troubleshooting? The connections look good visually, but should I just try to re-work each one?

The voltage readout when I was assembling each one was a little on the low side (I think 4.93 and 4.97V if I remember correctly), but at the time I just thought this was within the error of the meter.

Any help greatly appreciated!

Jason

[jasonkwan]

On other strange thing that happens is that sometimes before the "not supported message" comes up, the iPhone spontaneously reboots. I'm not sure if this gives any useful information.

[adafruit_support_bill]

What voltages do you measure on the 2 data pins?
If you post some photos of the front & back of the board we can have a look for any assembly issues.

[jasonkwan]

OK, here are pictures of the front and back of the two mintyboosts. As you can see, for one I tried fusing the data lines but it didn't make a difference so I didn't do it for the other one. I measured the voltages:

Across the power lines: the fused one was 4.98V and the other one was 5.00V

Across the data lines: the fused one was 2.95V and the other was was 2.92 and 2.91V.

(All these readings are with new Duracells)

Any idea what is up?

[jasonkwan]

Anyone? I really want to get this resolved.

Jason

[adafruit]

are you using good batteries? we've never heard of an iphone4 issue :/

[jasonkwan]

I am using new Duracell AAs. Is there a particular brand that works really well?

Maybe my expectations are too high. On the website when you say "3/4 full recharge" I took that to mean "three or four recharges [for one set of AAs]". Now looking back at the FAQ I see it is more likely you meant 0.75 a full recharge.

I tried it again, starting at 44% battery. It went up to 55% and then the iPhone rebooted. After it came back up the battery indicator was flicking between the charging indicator (lightning bolt) and the external power indicator (electrical plug icon) rapidly. Shortly after this the device rebooted again. I would estimate that the batteries at this point were about 55-60 degrees C.

So, it seems like I only get 10% increase in charge and I have to put up with spontaneous reboots. Is this a consequence of the batteries dying really quickly?

Jason

[adafruit]

well, go back and make sure your mintyboost is how it should be with resistors and data lines. are you using a proper 'official' charging cable?

[atmikev]

I had the same issues. Used some energizer lithiums, got 4.98v out of Vcc, and 1.98v for D+ and D-, and I got an error saying that "charger was not designed for this device" or whatever (same error message as above).

Hooked it up to the 5v (measured to be 5.00v) supply on my breadboard though and charging started immediately. Only kept it hooked up long enough to add an additional 1% of charge, but it seemed to be working fine. I didn't need to solder together D+/D-, fyi.

Didn't have time to try a 3v source to simulate the batteries but I'll post my results when I do.

[jasonkwan]

Well I converted one of the mintyboosts to run on three D batteries and now it is fine. The first time it charged the iPhone from 47% to 100%. Then I tried when it was really run down, and it charged no problem from 13% to 100%.

I'm just wondering, out of interest what the problem likely was? My theory is that it is a combination of AAs being a bit puny and the iPhone 4 battery having enormous capacity.

Now I just need to find a case the right size!

Jason