Expansion board 3.0 battery power not enough juice?

[macbum]

I just got 2 expansion board 3.0 and they both exhibit the same issue. I plugged an Li-Ion battery into the board and the 2 LEDs that lit (USB and LED) are very dim. My SiPy module does not power up or run. When I plug the USB cable in, the battery charges. What's going on? It looks like the expansion board battery power hardware is defective?

The problem doesn't exist in the PySense that I have. It works and as I expected. This is using the same battery. Both boards have the firmware updated and working properly with the USB plugged into my PC.

[Radec]

@wolli01 Yes, I can remove the cable when the Lopy is charge by Lipo after starting. When USB connected, I remove the cable but it's not necessary.
I updated Lopy with the new firmware and no change.
It's work only with the jumper cable connected when the expension board and lopy start.
Maybe on other people have an idea ?

[Wolli01]

@radec Yeah, it works for me with the override now, too.
Is it now possible to leave it that way or do I have to remove the jumper cable when charging the USB?

[dan]

@graham pull P8 (G15) high, and if you need the SD card, use a 10k pull-up

[Graham]

@dan We've been purchasing Expansion Boards (v3) from Sparkfun, I have 23 of them that have this fault (the entire batch).

Latest firmware, they are not stuck in DFU mode, charged 3.7V LiPo (tried several). Something is certainly up.

What is the official work around to get LiPo working with Expansion Boards that have this issue?

[alexmrqt]

Hi @dan,

Thank you for your reply.
I found out that cutting a trace on the expansion board (as suggested here -> https://forum.pycom.io/topic/3227/fipy-on-expansion-board-3-0-does-not-work-with-external-power-supply/8) solved the problem.
I have a few other (and intact) boards on hand. I'll let you know If I manage to reproduce and solve the problem in the way you suggested.

[dan]

Hi @alexmrqt,

Your board might be stuck in DFU mode. Could you run the dfu-util update process and try it again?

[alexmrqt]

Same problem here. Battery works fine with expansion board 2.0 but not with expansion board 3.0.
When connecting P8 to 3.3V, as suggested by @Radec, it works, but only sometimes... Most of the time, the yellow LED of the expansion board light up and nothing happen (and, I'm not confusing P8 and P9).

[Radec]

EDIT :
I found the solution :
https://github.com/pycom/pycom-micropython-sigfox/issues/167
"Connecting P8 (G15) to 3V3 and resetting the module"

It's work !

I have same problem with my new expension board 3.0 (brand new).
When battery power connected, the Lopy does not start. Led USB and LED light up.
I try the battery with other expension board 2.0 and other 3.0 and it's work... . :( So my battery is not defective.

[cp-boettch]

I have the same problem. I check two new 3.0 Boards with different LiPos.
And Lopy1/Lopy4 -> can't start.
Ina219 measurement:
0.1 Watts
4.1V 31.3mA

[macbum]

I'm still waiting for an official fix/answer from Pycom.

[robert-hh]

@r-groesbeek It it hard to guess about the reason without any knowledge of the expansion board 3 schematics and the code of the PIC. Just form reading the notes here I assume, it's a problem with the PIC, not releasing the ESP32 on startup w/o power at the USB port.

[r.groesbeek]

@macbum said in Expansion board 3.0 battery power not enough juice?:

Anybody? Nobody else has this issue? This is frustrating.

I'm having it too... with 3.7V lipo's.
Connecting just a powerbank to the USB port works, but a Lipo 3.7V to the jst2 connected does not startup the Pycom board.
It does however keeps it running when disconnecting the powerbank.

Maybe it has not enough juice to power the expansion board and Lopy4 up?

[r.groesbeek]

I have the same problem, what kind of Lipo are you connecting to it?
I'm using PKCELL LP785060, 3.7 V, 2500 mAh

[dan]

Hi @macbum, I'm looking into this, will update you when I have an answer. Thanks for waiting

[macbum]

Anybody? Nobody else has this issue? This is frustrating.

[macbum]

@jcaron Battery is fully charged. Voltage read using PySense indicates 4.34 volts and my multimeter reads 4.14 volts. Firmware is 1.17.5.b6.

[jcaron]

@macbum What's the charge level of the battery? What battery voltage does the Pysense report?