Some questions regarding the Solar charger PID 390

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DJTraxler
 
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Some questions regarding the Solar charger PID 390

Post by DJTraxler »

I have some questions regarding this board. I needed to remote the electrolytic cap in order to the mint tin lid to close. I used about 2.5" of twisted wires to do this. Is the length of the wire a concern? Is the twist in the wires a concern?

The board in the tutorial has 6 pins between the JST connectors. Mine has only three. I'd like to mount external LEDs for CHG and DONE. I'm assuming the the C pin is the anode of the CHG LED, that the D pin is the anode of the DONE LED, and that the + pin is for the cathode for both LEDs. If I found a common cathode bi-color led, could I put the 1k resisters between the anodes and the C and D pins?

By the way, I am quite pleased with how you do business. My orders have always been completely correct and delivered promptly.
Solar charger with MintyBoost in a mint tin.
Solar charger with MintyBoost in a mint tin.
DSCN32152014-08-31_01sm.jpg (94.36 KiB) Viewed 368 times
Thanks!
Dave

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adafruit_support_bill
 
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Re: Some questions regarding the Solar charger PID 390

Post by adafruit_support_bill »

You capacitor install should be fine as is.
The C & D pins go to the cathodes of the LEDs. the + pin goes to VCC. C & D are pulled low by the charger chip to turn on the LEDs. You can wire your external LEDs with a series resistor between the C or D pin and the + pin.
The schematic for the latest rev is below:
Attachments
schem.png
schem.png (27.59 KiB) Viewed 352 times

DJTraxler
 
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Re: Some questions regarding the Solar charger PID 390

Post by DJTraxler »

Bill,
Thanks for the reply. And thanks for the updated schematic.
I was wondering where I'd find a pin out of P$6 to remote the PWR LED.
By the way, I believe the pin out of the power connector are wrong. The way it is now would connect the sleeve of the power plug to USB GND and nowhere else. I think the BRK contact should be connected to USB GND and the sleeve to GND. Just my 2 cents.

Regards,
Dave.

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Re: Some questions regarding the Solar charger PID 390

Post by adafruit_support_bill »

P$6 is not broken out. Your best bet would be to tack-solder a jumper from the cathode of the led, or the /PG pin on the MCP73871. http://www.adafruit.com/datasheets/MCP73871.pdf

I think you are right on the power plug. I'll check with the board designer.

DJTraxler
 
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Re: Some questions regarding the Solar charger PID 390

Post by DJTraxler »

Once again, thanks for your help.

Looking at the size of the leads on the chip, no way am I tacking anything to it. Even though /PG is on a corner. And the led is mighty small as well. So I think I'll forgo a PWR led on the outside of the mint tin. The older I get the harder it is to see SMT devices.

On, yet one additional question. How much drain is there on the the battery if I leave a MintyBoost plugged into the load connector?

Once I've added the external C/D LEDs and painted the tin, I'll send some pictures of the finished product. Where should I send them?

Regards,
Dave.

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Re: Some questions regarding the Solar charger PID 390

Post by adafruit_support_bill »

The minty boost will draw a few mA when idle. Most of that is from the resistor dividers for the D1/D2 pins. If you are not using it to charge phones, you could omit those for a lower quiescent current drain.

Photos, you can post here in the forums. The better projects often get featured in the blog.

DJTraxler
 
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Re: Some questions regarding the Solar charger PID 390

Post by DJTraxler »

I decided to pass on an external power indicator (P$6). The charging/done LED will be lit, indicating that there is power to the device.

I've added the external indicator LED. I used just the red and green diodes of a common anode RGB LED.

The tin needs to be painted. After that I'll label the connectors. Still, it's not too bad looking for a prototype.

Some things I'd do differently next time. 1) I'd move the boards all the way to the front of the tin. This would make more room for the big capacitor at the back of the tin. 2) I'd position the cap all the way to the end with the MintyBoost, making more room to unplug the LiPo connector. 3) I'd push the MintyBoost all the way out, again making more room for the LiPo. If the LiPo isn't positioned properly, either the lid will not shut, (a good clue that it needs to be slid forward) or the top of the coax power connector presses against it when the lid is shut.

I enjoyed assembling this kit. I learned a bit, such as how to solder small resistors to LED leads. You solder the other resister lead to the connecting wire first. This gives you something to hold on to while soldering it to the LED. I also learned that flux cleaner can remove double-sided foam tape adhesive.

One last thought. It works! Just finished charging my cell phone with it.

Once more, thank you for your help!

Best regards,
Dave Traxler

Here are some pictures of it. I thought someone might want to see it.
Front is to the bottom of the photo. Added the external LED indicator.
Front is to the bottom of the photo. Added the external LED indicator.
DSCN32272014-09-18_02.jpg (291.73 KiB) Viewed 297 times
Showing the external "charging" LED lit up.
Showing the external "charging" LED lit up.
DSCN32332014-09-18_02.jpg (113.94 KiB) Viewed 297 times

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Re: Some questions regarding the Solar charger PID 390

Post by adafruit_support_bill »

Nicely done! Thanks for the follow-up.

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