bq24074, both LEDs lit, but not charging

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blanghor
 
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bq24074, both LEDs lit, but not charging

Post by blanghor »

I just got the bq24074 solar charge controller and connected a 6V solar panel via the barrel jack and a 3.7V LiPo battery via the jst connector. Both the red and green LEDs are lighting up, and stay lit all day, but when I attach a load (Particle Boron) to monitor the battery charge, the battery slowly drains and never gets re-charged by the solar.

It's possible that I connected the LiPo with reverse polarity for a few seconds when I was getting started, but not for long. Do you think I fried the board? Would both LEDs be lit in a failure state?

Thanks

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adafruit_support_bill
 
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Re: bq24074, both LEDs lit, but not charging

Post by adafruit_support_bill »

Reverse polarity damage usually happens pretty quickly. It is hard to predict how it will behave once the damage is done.

With no load or battery and the charger plugged into USB, what voltage do you measure on the battery terminals of the charger?

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blanghor
 
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Re: bq24074, both LEDs lit, but not charging

Post by blanghor »

Thanks for the reply. With USB-C power connected, and battery and load disconnected, I measure 4.397V across the Battery terminals on the board.

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adafruit_support_bill
 
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Re: bq24074, both LEDs lit, but not charging

Post by adafruit_support_bill »

That sounds a little high. I'd expect it to be more like 4.2V. What is the voltage between the VBUS and GND pins on the header?

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blanghor
 
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Re: bq24074, both LEDs lit, but not charging

Post by blanghor »

I'm getting 4.903V between GND and VBUS at the same time as 4.397V between the battery jack pins.

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Re: bq24074, both LEDs lit, but not charging

Post by adafruit_support_bill »

OK. First measure the voltage on the unconnected battery leads. Then connect the battery and measure the voltage between LiPo and GND when the charge indicator is on.

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blanghor
 
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Re: bq24074, both LEDs lit, but not charging

Post by blanghor »

Sorry for the delay, just saw your reply here. I measured 3.893V across the battery when disconnected, then when plugged into the controller board, with no charging source connected, it still read 3.893V. Then with USB-C connected and green charging indicator shining bright, it read 4.125V.

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Re: bq24074, both LEDs lit, but not charging

Post by adafruit_support_bill »

Sounds like it is charging then. If it is not working with the solar panel, then the panel output is probably not keeping up with the load demands. What panel are you using? Is it outdoors and in full sun?

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blanghor
 
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Re: bq24074, both LEDs lit, but not charging

Post by blanghor »

I was using the Medium 2W panel, and in full sun I got it charging. I thought it would be able to charge at least a little on an overcast day. But I think you're right, I just need a bigger solar panel. I tried a Voltaic 10W panel today and that worked well.
Thanks for the guidance!

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Re: bq24074, both LEDs lit, but not charging

Post by adafruit_support_bill »

Good to hear. Thanks for the follow-up.

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