USBC/Solar Lithium Ion Charger not working

by newmexelectron on Thu Dec 06, 2012 2:17 pm

I have finally gotten around to using this charger that I bought from Adafruit and I am confused about a few things. I followed the tutorial and soldered the Cap on in the correct orientation... I also bought a solar charger and Lipo Battery from Adafruit use with the charger.
Good news, I am able to get a Power Good Light to come on when I have the Solar Panel and Battery connected... but when I unplug the solar panel and try to charge the battery via USB or the DCIN... I get no lights on at all.
The board looks fine without checking connections with a microscope... the SMD LED for the "DONE" indication looks like it really crooked... I don't know if it is functional as the solar charger may not be capable in my light to fully charge the lipo.

Does my description point to a common problem... or is further testing needed. I have tried multiple miniUSB cables on two computers... and I connected a 5V wallwart power to the DC in... Still no indication lights... I tried these things with two different batteries connected (not at the same time;))... and without a battery two.

Any thoughts?
Thanks.
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Re: USBC/Solar Lithium Ion Charger not working

by adafruit_support_bill on Fri Dec 07, 2012 5:43 am

With the USB cable plugged in, do you see any voltage on the positive terminal of DCIN?
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Re: USBC/Solar Lithium Ion Charger not working

by newmexelectron on Fri Dec 07, 2012 2:10 pm

update:
With USB plugged in and no Load or Battery hooked up... I get 1.3V when I measure from the positive terminal of DCIN (with Ground wire of Multimeter touching the Negative of DCIN).
I also took measurements off ....
the Load terminal = 0V
and
the Batt terminal= 0V

ok. here is where it gets interesting/telling

Before I did this test, I had the charger hooked up the the solar supply and Lipo... and as I stated earlier, this does cause the PWR Good LED to light up (if enough SUN)
So I think the measurement above is just power left over in the Cap, because I can measure the power at the DCIN WITHOUT any power source connected (no Solar and no USB) and I get the same VDC measurement as when I have the USB connected.

Hopefully I have described this clearly enough ... Let me know if further explanation or testing is needed. I am thinking the board has a problem... maybe the badly aligned DONE led is a bigger problem than I originally thought.
HEre are some pictures.
Thanks for the help. I am eager to get this sorted and my remote weather station is ready to go into the Wild! finally :)
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Re: USBC/Solar Lithium Ion Charger not working

by adafruit_support_bill on Fri Dec 07, 2012 2:22 pm

There should be a direct connection between the positive (VBUS) pin on the USB and the '+' terminal on DCIN (see schematic below). Check the solder joints on D2 as well as the USB socket itself. It may be an easy fix to get you up and running. If not, we'll replace it.

https://raw.github.com/adafruit/USB-DC- ... /schem.png
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Re: USBC/Solar Lithium Ion Charger not working

by newmexelectron on Fri Dec 07, 2012 3:29 pm

]thanks for the quick reply.
I was able to get a 4.8V reading by carefully testing the mini usb pads where the traces begin.... but this seemed to have power sometimes and not others... trying different usb cables didn't really matter, but wiggling the cord seemed to have an effect. I am guessing it there is a bad connection somewhere in that area...

more testing shown in the pictures below.. that I have continuity from the DCIN+ to the Pad coming off the MiniUSB+ leg... and independently, there is continuity from DCIN- and MiniUSB -pad.

I found an old WallWart that ouputs 5 Volts and I rigged up a better connection to the DCIN and that DID work... The Power light came on and so that is good.
I am leaning toward just not having the mini USB function at all and just solder up a better connection for my wall wart power that I can detach for Solar only use.

If you have any ideas as to how to fix the Mini USB connector I am all ears, but as you can see from the size of my multimeter probes... I am not outfitted with many tools for SMD work.

Thanks for your help. I think I would rather do without the USB option so I don't have to ship or wait for a replacement.

Once again, thanks.
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testedGood for Continuity
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Also Tested Good for COntinuity
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Re: USBC/Solar Lithium Ion Charger not working

by adafruit_support_bill on Fri Dec 07, 2012 4:10 pm

I am not a big fan of the mini-USBs. It doesn't take much misalignment on insertion to jam the contacts. I am forever replacing the ones on my son's headsets. :(
You should be able to make a nice robust connection to the DCIN pads. We have cables and adapters for barrel connectors if you need them.
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