USB Power Cords for CHIP Computers

I am starting this topic because it may be of interest to some of you having trouble getting your CHIP computers to run consistently.

During my explorations of Ferrite Isolators on SNR, I made some measurements of the charging voltage of the Boston Power battery connected to the CHIP. Using a setup as follows:

I discovered the optimum voltage on the BATTERY/GND pins on the CHIP was 3.6 vdc.(See the 2 wires coming over the gold label on the CHIP’s CPU going to my volt meter). I found that some of my USB cords (4 ft to 10 ft) only provided 3.2 vdc at the same pins. Not enough even thou I’m using a 2.1 amp wall wart because of cable loss when loaded!!

Check your system and see what you get. Ken

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Are cheap USB cords lowering the voltage at the far end of the USB cord?

I am using the power cord that came with the RavPower battery, but with a 2A USB charger instead
of the battery. Is this cord any good?


Made something the other day for this type of monitoring.

Built an Arduino shield that is basically a voltage monitoring shield. 5 channels that can read between 0-50vdc. Basically a voltage divider network.
It is built on top of an ethernet shield so you can spit the data of each channel out over the ethernet via udp packets or you can just use the serial cable connected to the arduino and view the values in the serial monitor window.
For reading the UDP packets there is a python script you can run on your client computer that will poll the arduino board for whatever channel you want to receive data from. The shield will not spit out the udp packets unless they are called for, so as not to clog up the network just sitting there sending out values if you dont want them.
In my case I just connect the chip wires to the arduino voltage shield just like you did to your meter.
This lets me log the voltages over time etc.

If you want I can send you the Arduino code, the python code and the specs for the shield components if you want.

My original post dealt with the Boston Power Lantern battery, but in doing some more generic testing with 7 of my USB power cords going directly into a bare CHIP outside of my Lantern package, I found the following which I posted on APRS - Making it Work.

Zoltan, I been double checking my USB power cords to address a question asked in my post USB Power Cords for CHIP Computers and have found with USB cords that will boot up the CHIP, and with USB cords that WILL NOT boot up the CHIP, voltages from CHG-IN to GND all read 2.489 vdc.

I have tested 7 USB power cords so far - - 2 10 footers which give a 2.49 voltage reading and flash a single light on the CHIP but won’t boot the CHIP; 3 10 footers and 2 4 footers that flash on, stay on, give a 2.49 voltage reading, and boot the CHIP.

There has got to be something else going on here Ken

PS The more I think about USB cords and chargers the more I feel Outernet shoild supply vetted cords and chargers with future Lantern sales. If one uses a DIY kit, you should power it from a battery pack - - not a USB wall wart. Ken

So you all see the dilemma - - the truth is not obvious when working with the CHIP :cry: Ken

I’m using a stock Raspberry Pi adapter and was functioning very well (check if compatible with your local mains connector).

@kenbarbi for measuring the micro usb cable loss CHG-IN is not a good choice, if powered from micro USB, CHG-IN only gives you internal leakage those different supply chains inside the AXP209 IC… You might want to measure micro USB connected voltage loss on C18 for example (really tiny SMD part so microscope is advised… :frowning: )

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