Devices acknowledge charging source, but won't charge.

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twinegarner
 
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Devices acknowledge charging source, but won't charge.

Post by twinegarner »

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Hey all, I've just soldered together a Mintyboost v3 at my first soldering project. The soldering isn't the tidiest I admit, but nothing is bridged to my eye, and joints seem pretty solid. pins 1 and 4 test at 4.97v, 2 and 3 at 1.97. Batteries are fresh out of the package. When I plug in a device (tested so far: Galaxy nexus, iPhone 4s, GoPro Hero 2) devices recognize they are being charged, but battery charge indicators hold steady or go down. Galaxy Nexus shows fluctuations in charging indicator. Battery and IC do not heat up.

Full disclosure - I was a bit hasty to case up my recent project and put the board in raw into an altoids tin, believing the case was aluminum and non-conductive. Did I short it?

Thanks in advance!
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adafruit_support_bill
 
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Re: Devices acknowledge charging source, but won't charge.

Post by adafruit_support_bill »

Solder looks OK and your voltages are fine. Can you measure the voltage with a phone plugged in?

What kind of batteries are you using?

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twinegarner
 
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Re: Devices acknowledge charging source, but won't charge.

Post by twinegarner »

With a phone plugged in, I get 4.65v and 1.8v. Batteries are Duracell alkalines.

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adafruit_support_bill
 
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Re: Devices acknowledge charging source, but won't charge.

Post by adafruit_support_bill »

With a phone plugged in, I get 4.65v and 1.8v.
That is a significant drop. Most phones will drop out of charge mode with voltages like that.
Batteries are Duracell alkalines.
Duracell makes many kinds of alkaline cells. Not all of them are suitable for charging a modern smart-phone. Standard alkaline battery chemistry is not very good at delivering high current. The high internal resistance of these cells causes the output voltage to drop under high-drain conditions.

The "Duracell Ultra" is specially designed for high-drain applications. For other battery recommendations, see the bottom of this post: http://forums.adafruit.com/viewtopic.php?f=15&t=22377

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twinegarner
 
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Re: Devices acknowledge charging source, but won't charge.

Post by twinegarner »

Picked up a pack of Duracell Ultras and can now confirm that charging is happening. Batteries are toasty, chip is hot to the touch, and phone charge raised from 59-72% charge in about 15 minutes. Odd thing is, that under charging, pins 1 and 4 are still reading 4.65v. Perhaps my volt meter is faulty.

Anyhow, thank you so much for the help!

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adafruit_support_bill
 
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Re: Devices acknowledge charging source, but won't charge.

Post by adafruit_support_bill »

under charging, pins 1 and 4 are still reading 4.65v.
It is really a question of whether it can maintain that voltage under a full charging load. When the phone detects a charger, it will try to pull current from it. Virtually all chargers will have a drop in voltage under load. But if the voltage drops below some minimum threshold, the phone will back-off. Some phones will continue charging at a lower rate. Some will give up entirely.

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