Did I break the battery circuit?

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bozzaglia
 
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Did I break the battery circuit?

Post 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

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dastels
 
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Re: Did I break the battery circuit?

Post 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

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bozzaglia
 
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Re: Did I break the battery circuit?

Post 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 :-(
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dastels
 
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Re: Did I break the battery circuit?

Post 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

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adafruit_support_bill
 
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Re: Did I break the battery circuit?

Post 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.

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bozzaglia
 
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Re: Did I break the battery circuit?

Post 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...
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dastels
 
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Re: Did I break the battery circuit?

Post 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

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