USB Won't Connect When Battery is Plugged In

Development Boards ESP32
1

I have a WRL-24408 SparkFun Thing Plus - ESP32-S3. If I don’t connect a battery to the board’s battery connector, the board is detected by Windows as COM3 when it is plugged into the computer.

However, if I connect a battery, Windows does not see the board. Nor does the charge light illuminate.

I noticed that the programming resistor for the charge controller is set to 2k, corresponding to 500 mA. Could it be that the inrush current when connecting the device is too high and it is shutting down the port?

Thanks,
Michael

2

With the battery unplugged from the board, measure its open-circuit voltage. Typical single-cell LiPo should be approximately 3.7–4.2 V. If it’s very low (<2.5 V), the charger may behave differently or draw high current.

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3

Battery measures 4.15V. It is a brand new battery. I found that if I plug in the USB first and then the battery, the system works and the battery charges. I let it charge for several hours. Still the same behavior.

Thanks,
Michael

4

Can you share a photo of the wiring to/from the battery? I’m worried the polarity might not match

5

Polarity is fine. If I plug in the battery and not the USB, the device runs fine. Also, the fuel gauge chip indicates the battery is discharging.. If I then plug in the USB, it fails to connect to Windows, does not appear in Device Manager, and the charge circuit indicator light remains dark.

If I plug in just the USB, it enumerates under Windows and I can program the device. If I then plug in the battery, the USB connection remains good, the battery charger light illuminates and the fuel gauge indicates that the battery is charging.

The battery is almost fully charged.

Thanks
Michael

6

I should also mention that if I start with battery plugged in and then plug in the USB, the device still runs fine even though it does not connect.

7

More information: If I connect the battery, the device runs (as I mentioned before). If I plug a USB power supply into the USB port, the system continues to run AND the yellow charging light illuminates.

8

Even more info. If I plug the battery into the WRL-24408 the following USB-C connections work:

Plugging a dumb 5V USB-C charger lights up the charge light on the WRL.

Plugging a PD-compliant charger lights up the charge light.

Plugging a USB-C end into the device and USB-A into my computer enumerates and charges.

Plugging a USB-C end into the device and USB-C into my computer fails to enumerate or charge.

Plugging a USB-C end into the device and USB-C into my wife’s computer fails to enumerate or charge.

Plugging a USB-C docking station into my computer and then connect from the device to the docking station works perfectly with either USB-A or USB-C.

9

A bit odd - Are you on PC or Mac?

10

its interesting, I think I am having the exact same problem, but on a completely different device!

11

Your USB-A work around above is a god-sent! Thank you so much.

there is still something peculiar going on here that I would love to get to the bottom of, but I can atleast take this bit off the critical path of my project. I was about to add a hardware hard power switch to the battery as a workaround. switching to a USB-A cable is far better for me!

Thank you again!

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