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Did I break the battery circuit?

Posted: Thu Nov 24, 2022 4:13 am
by bozzaglia
Ok I messed up! I know you recommend to use only Adafruit batteries but I live in Italy and it’s hard to find them.
So I went on Amazon and got a battery with a compatible JST connector for my brand new Feather nRF52840 Express.
I did try to verify the board receptacle polarity, but couldn’t find it indicated on the board, nor on the board support page, so I went ahead and hooked up the battery... to my horror, after about 30 seconds I realized the board had gotten very hot and faintly smelled like fried plastic!!
So after I unhooked the battery and let it cool down I tried to connect it to my pc and everything seems to work fine: CIRCUITPY drive works, my code works, the board seems ok, except it doesn’t seem to work on battery power, nor to charge a battery. I tried plugging in a smaller battery with the right polarity I had used before and the yellow charging led doesn’t come on when plugged into USB.
Should I assume the battery circuit is fried and get a new board or is there some additional check I can do?
Thanks in advance
Angelo

Re: Did I break the battery circuit?

Posted: Thu Nov 24, 2022 9:08 am
by dastels
First let's confirm that your battery had the wrong polarity. Can you post a clear closeup of its connector? It does sound like that's what happened, though. And if you get no activity on the charge LED then, yes, the charger is likely fried. If it doesn't run on a known good battery, then the power switching circuit is probably gone as well (the FET that disconnect the battery from powering the board when the USB 5v is present).

Dave

Re: Did I break the battery circuit?

Posted: Thu Nov 24, 2022 10:03 am
by bozzaglia
Here it is. And yes I could have compared the new battery with the old one that worked, but didn’t think about it :-(

Re: Did I break the battery circuit?

Posted: Thu Nov 24, 2022 10:15 am
by dastels
That's not what I asked for but it sounds like you've compared it with the known-good battery. So that's pretty conclusive. Take it as a learnign experience.

Dave

Re: Did I break the battery circuit?

Posted: Thu Nov 24, 2022 10:57 am
by adafruit_support_bill
Correcting the polarity on a battery JST connector is not difficult. You can use a toothpick or similar pointed object to press on the metal tabs on the underside of the connector and gently pull the spring contacts out of the shell.

Take care not to let the bare contacts touch each other - and re-insert them in the correct locations.

Re: Did I break the battery circuit?

Posted: Thu Nov 24, 2022 5:11 pm
by bozzaglia
This should be the picture that Dave asked for. The previous one was from the amazon product page. I think the polarity matches.

And Bill, thanks for the tip, actually to my surprise today I was able to find an Adafruit original battery so I ordered it. I think it should have the original jst connector that shouldn’t be such a pain in the neck to unplug every time..

And finally tonight I tried again the good polarity battery after charging it (yesterday was drained) and it works in powering up the feather. The only thing that seems not working is the yellow charging led...

Re: Did I break the battery circuit?

Posted: Thu Nov 24, 2022 6:23 pm
by dastels
Yes, that is definitely the wrong polarity for Adafruit boards.

And it does sound like the charger has been damaged. The real check is to see if it will charge a battery (with the right polarity ;) ).

Dave

Re: Did I break the battery circuit?

Posted: Thu Dec 01, 2022 8:22 am
by bozzaglia
So I assumed my feather charging circuit got fried and ordered a new feather... before redoing all the soldering I checked to see if the battery charging light comes on (with an Adafruit battery) and it looks like it doesn’t... :-(
See picture: with the battery plugged in and the board hooked up to my pc via USB power and data cable, I only get the big led changing colors and one of the small leds blinking blue.
Any explaination?
The board is pristine, I just pulled it out of the bag and didn’t install anything on it yet.

Re: Did I break the battery circuit?

Posted: Thu Dec 01, 2022 9:54 am
by dastels
What happens without a battery connected?

The charge LED should flicker a couple times when you connect USB.

Dave

Re: Did I break the battery circuit?

Posted: Thu Dec 01, 2022 9:55 am
by dastels
Also, does the board work with only the battery connected (no USB)?

Dave

Re: Did I break the battery circuit?

Posted: Thu Dec 01, 2022 10:44 am
by bozzaglia
No, the charge led does not flicker when connected to usb without the battery hooked (however I’ve read it “might” flicker, not that it always does).
Yes, the board seems to work only with the battery attached. Again it’s brand new I didn’t install anything on it yet, so I can only see the LEDs lighting up...

Re: Did I break the battery circuit?

Posted: Thu Dec 01, 2022 11:57 am
by dastels
Run down the battery by leaving the board running for a while and then connect USB to see if it will charge. I'd try this on both boards.

Dave

Re: Did I break the battery circuit?

Posted: Sat Dec 03, 2022 10:33 am
by bozzaglia
Dave, I did what you suggested and NEITHER of the two boards charges the battery!!
As I wrote, one of them is brand new, never installed anything on it, never hooked it up to the wrong battery. I am 100% positive!
I am starting to feel like I’m not supposed to complete this project.....:-(

Is it possible that the charging function needs to be activated somehow?
The QTPY BFF has an on/off switch...
I am getting desperate here ...

Re: Did I break the battery circuit?

Posted: Sat Dec 03, 2022 12:18 pm
by dastels
Charging is just there. The switch on the BFF is just to disconnect power to the board: an on/off switch that has no impact on the charger.

OK. I'll get some other eyes on this.

Dave

Re: Did I break the battery circuit?

Posted: Sat Dec 03, 2022 7:33 pm
by bozzaglia
Ok thanks... hope some good news come out...