Question with MintyBoost v3 w/ iPhone 4S
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Question with MintyBoost v3 w/ iPhone 4S

by mfo on Fri Apr 13, 2012 8:51 pm

I've been a fan of the MintyBoost for a while, I even own a V2. Anyhow..

With the V3, it charges my 4S no problem as it came in the mail (I didn't have to short the USB). However...

It seems that lately the thing has been over heating to the point where it stops charging (even the batteries get really hot). When I say it stops charging, the MintyBoost keeps cutting in an out at about one minute intervals (as if every minute I'd unplug the phone and plug it back in). I checked for shorts, thinking maybe a part of the board was coming in contact with the case, but nothing. Now, I'm pretty sure that iPhones & iPod Touch's use a faster charging method when their battery is below 50%, and then once above 50% the charging slows to prolong battery life. Could the iPhone 4S be drawing too much current from the MintyBoost when it's below 50%, thus causing the heating issue? I'd really love to get to the bottom of this. Thanks in advance :)

-Chris
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Re: Question with MintyBoost v3 w/ iPhone 4S

by adafruit_support_bill on Sat Apr 14, 2012 6:24 am

Could the iPhone 4S be drawing too much current from the MintyBoost when it's below 50%, thus causing the heating issue?

That is very possible. If the boost converter overheats it will shut itself down. This could be what causes the 1 minute cycling.
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Re: Question with MintyBoost v3 w/ iPhone 4S

by mfo on Mon Apr 23, 2012 7:16 pm

adafruit_support wrote:
Could the iPhone 4S be drawing too much current from the MintyBoost when it's below 50%, thus causing the heating issue?

That is very possible. If the boost converter overheats it will shut itself down. This could be what causes the 1 minute cycling.


Thanks for the reply. Is there a solution for this, other than not letting the phone drop below 50% in the first place? Thanks.
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Re: Question with MintyBoost v3 w/ iPhone 4S

by adafruit_support_bill on Mon Apr 23, 2012 8:25 pm

In theory, the 4s should respect the current USB charging standard. If you short D1 & D2, it should not try to draw more than 500 mA.
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Re: Question with MintyBoost v3 w/ iPhone 4S

by mfo on Tue May 08, 2012 7:38 pm

adafruit_support wrote:In theory, the 4s should respect the current USB charging standard. If you short D1 & D2, it should not try to draw more than 500 mA.


By D1 & D2, do you mean the two center USB pins? If so, that didn't work =(

When the device is above 50%, it seems to respect the 500mA rule. When it's below 50%,it seems to go into rapid charge mode (until it hits 50%, then it slows down again) in order to speed up the charging process.

Any other ideas? :) Thanks.
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Re: Question with MintyBoost v3 w/ iPhone 4S

by adafruit_support_bill on Tue May 08, 2012 7:59 pm

Yes. D1 & D2 are the two center pins. When shorted, the device is supposed to assume it is a wall-charger and not exceed it's max charge rate (typically determined by the level at which the voltage starts to sag). In general the 4 & 4S seem to have been less problematic than earlier versions (especially the 3GS.)
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Re: Question with MintyBoost v3 w/ iPhone 4S

by mfo on Tue May 08, 2012 8:19 pm

adafruit_support wrote:Yes. D1 & D2 are the two center pins. When shorted, the device is supposed to assume it is a wall-charger and not exceed it's max charge rate (typically determined by the level at which the voltage starts to sag). In general the 4 & 4S seem to have been less problematic than earlier versions (especially the 3GS.)


So do you have any other suggestions?
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Re: Question with MintyBoost v3 w/ iPhone 4S

by adafruit_support_bill on Tue May 08, 2012 8:37 pm

The minty sounds like it is functioning as it should. What kind of batteries are you using? You might get a little more efficiency out of it using high-drain alkalines or NiMh. Check the sticky at the top of this forum for battery recommendations.
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Re: Question with MintyBoost v3 w/ iPhone 4S

by Antho on Fri May 11, 2012 8:31 pm

I've had that problem also, I heatsinked it an it works like a charm :) in Canada pennies are worthless now but they are made of copper, so I stack a few on the ic with some thermal adhesive, I get it high enough to touch the top of the altoids tin and voila the whole tin dissipates your heat. It hasn't given me that problem since then :)
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