Lithium Ion charger bq24074 not switching off

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nsedoglavich
 
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Lithium Ion charger bq24074 not switching off

Post by nsedoglavich »

Hello, I am using Adafruit Universal USB / DC / Solar Lithium Ion/Polymer charger - bq24074, with a 6 V solar panel and a Lithium Ion Cylindrical Battery - 3.7v 2200mAh (also from Adafruit). One thing I notices is that when I plug in the USB as a power source, the charging LED (red) is always. This indicates that the battery is perpetually getting charged, but never reaches a full state (when the LED would turn off).


Even if it is getting charged at C/4 it should be charged fully overnight. Is this something anyone has come across? It sounds like a faulty battery situation or charger not switching off the charging mode, but wanted to check.

Nemanya

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adafruit_support_mike
 
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Re: Lithium Ion charger bq24074 not switching off

Post by adafruit_support_mike »

What voltage do you see across the LiPo connected to the charger?

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nsedoglavich
 
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Re: Lithium Ion charger bq24074 not switching off

Post by nsedoglavich »

While the battery is connected to the charger and the charger is powered by USB supply, across the OUT and GND pins i get 4.38 V, while across the LiPo and GND pins it reads 2.69 V.

When I disconnect the battery and test the voltage, across the battery is get 2.69 V, meaning the battery is below the cut off voltage.

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adafruit_support_mike
 
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Re: Lithium Ion charger bq24074 not switching off

Post by adafruit_support_mike »

Yeah, the charger may be refusing to try charging the cell, or the cell's internal protection circuit might not be letting the BQ24074 try to charge it.

Do you happen to have one of our MCP738x charger boards? Those have an automatic trickle-charge feature when a cell's voltage is below 2.9V. For an otherwise healty cell, it only takes about 30 seconds of trickle charge to get it back up to a safe charging voltage.

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nsedoglavich
 
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Re: Lithium Ion charger bq24074 not switching off

Post by nsedoglavich »

Hi I don't have the MCP738x charger. I have two BQ24074 units, and only 1 battery. I don't really want to by a different charger just to see if it works. The BQ24074 unit was advertised to be be good for this task, so I suspected that the battery might be in issues. I will buy another battery to see if it is battery related.

Can you try anything on your end?

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adafruit_support_mike
 
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Re: Lithium Ion charger bq24074 not switching off

Post by adafruit_support_mike »

There's nothing we can do on this end. A new battery will be your best option.

Did you get the existing LiPo from us?

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nsedoglavich
 
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Re: Lithium Ion charger bq24074 not switching off

Post by nsedoglavich »

Yes, see my first post. I got both items from you.

Nemanya

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Re: Lithium Ion charger bq24074 not switching off

Post by adafruit_support_mike »

Thanks for the reminder.

If you got the LiPo in the last 30 days, we can replace it for free. Send a note containing a link to this page and your order number to [email protected]. The folks there will help you.

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