Minty/LiPo Charges But Stops After A Few Seconds

[bemental]

Hello again Ada Forums.

Finished my solar Minty build, tested the setup with an iPhone 4 charge for a few hours (which was successful) then proceeded to Sugru the finished product into it's case.

Recently the setup has stopped performing as desired, charging any device for approximately 10 seconds then cutting off. The solar lipo board is charging the 6600mAh battery, but there seems to be an issue on the load port.

I've tested the load port voltage w/o the Minty attached with varying results. I would have assumed that with the lipo charging circuit setup that the voltage leaving the board would be a constant (based on the battery?).

Results:
Bare Board w/ no Inputs (solar, wall wort, etc): 2.7v
Board w/ Solar: 3-4.7 (depending on light source)

I'm not sure where the problem is, and while the Minty seems to be working well enough I haven't narrowed it down yet. Posted a link below with pictures just in case.

I made one modification to the Minty because of a faulty capacitor issue I had after building (capacitor fault, didn't allow anything to flow through it). The local Radio Shack didn't have the right spec cap so I replaced the original 220/6.3v with a 330/10v.

Any help troubleshooting would be well appreciated!

Pictures: http://campl.us/jMGMwbfG03U


The "extra" device with the AA's in it is the AA Saver from Ray's Hobby. I needed a way to put a charge into the system/salvage almost dead AA's during times of darkness or cloud.

[adafruit]

try to divide and conquer - does the solar charger work for charging the battery? test the mintyboost separately and with different cables/batteries/setups?

[bemental]

220/6.3v with a 330/10v

This shouldn't be an issue should it?

[bemental]

I'm convinced there's an issue with my Minty because everything else seems to be working fine.

I've tried cleaning the Minty's contacts with 92% alcohol and have re-soldered any joints I've found that look cold.

Suggestions?

[bemental]

Also, (sorry for the spam), I'm concerned with the voltage coming off of the solar lipo board, I can't seem to get the voltage coming off the load port to be above 1.7v., even with the solar connected and lipo battery full.

What the heck is going on here?

[adafruit]

please try to test only -one- item at a time. test the mintyboost first, use AA batteries WITHOUT the solar setup involved.

[bemental]

Will do. I'll have to de-solder the JST connectors I have on currently since I don't have anything suitable to test otherwise.

Will post results upon completion. Thanks again for the help!

[bemental]

Looks like there's an issue with the battery.

I tested the Minty solo by attaching a spliced USB cord to its inputs and plugging the cord into the wall. Powered and charged an iPod Touch, iPhone 4S and a Nook Simple Touch.

Tested the solar lipo circuitry by utilizing the barrel plug connector and USB inputs with the Minty attached. Powered and charged same devices fine.

Battery alone is not providing enough juice to the Minty. This is the 3.7v 6600mAh battery from Adafruit. I've soldered and re-soldered my connections to make sure they're solid. Under load I've tested for voltage and am getting such small readings that they aren't worth noting.


Suggestions now?

[adafruit_support_bill]

I tested the Minty solo by attaching a spliced USB cord to its inputs and plugging the cord into the wall.

You fed 5v directly into the Minty? That is not a good test of a boost converter. Power it with 2x AA cells to see if it can boost 3v to 5v.

[bemental]

Will do!

[bemental]

Here's what I've got:

Input to Minty is 1.7v, output is 5v. Certain devices realize that they are connected to a USB power source, but end up discharging instead of charging.

Question. What are typical voltages supposed to be coming off of the solar lipo board? I know that the PCB itself needs 5v to operate, but what can we expect coming off the board?


Thanks again for helping troubleshooting. It is MUCH appreciated.

[bemental]

Addendum:

I think the issue might be with the cap that I added to the Minty. I've managed to get upwards of 5v coming off the solar lipo PCB without having the Minty attached, but I'm not sure that the setup can handle (for some odd reason) the larger cap (10v 330uf) in replacement for the default cap (6.3v 330uf), even when I have 5v+ going into the solar lipo board.

Is this logical? Even with the solar panels attached and the 3.7v 6600mah battery?

[adafruit_support_bill]

Input to Minty is 1.7v, output is 5v.

The Minty is designed to run on at least 2 AA batteries. The ideal input voltage for the boost circuit is in the 2.5-4.5v range. With only 1.7v input, the boost efficiency is not that good and it will not be able to keep up with the current demands of most devices.

The replacement capacitor should not be an issue. For these purposes, 330uF is 330uF. The larger 10v replacement just has a higher voltage tolerance.

Depending on the state of charge on the battery and the amount of solar energy available, voltages off the charger board will typically be in the range of 3.7-4.5v.

[bemental]

Even when I use the barrel plug from a wall outlet at 5v DC to the solar lipo board the Minty can't keep up.

I've tried this with both the battery inline and removed.

At my wit's end!

[adafruit_support_bill]

But does the minty charge the phone when you power it with 2 fresh AA cells (3v)?