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Abbott glucose meters under recall for catching fire.

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Helio_Centra:
The issue is if you connect them to a third party USB charger they can draw too much current and the battery overheats. Lithium cells burning is generally a bad thing. This leads me to believe that they planned on their low amperage charger limiting the current and used really cheap charging circuitry within the meter.

The recall: https://www.fda.gov/medical-devices/medical-device-recalls/abbott-recalls-readers-used-freestyle-libre-freestyle-libre-14-day-and-freestyle-libre-2-flash

Louis Rossmann ranting about it:

Teardown photos of the device: https://fccid.io/QXS-LIB01/Internal-Photos/Internal-Photos-2414553

The photos are not very high res, but you can see that the lithium cell has a protection board and a 3 wire connection with a thermistor. Maybe their charging circuitry doesn't use the temp sensor? I can't see well enough to reverse engineer it.

Helio_Centra:
I was trying to figure out how powerful the charger they supply with it is.

All the photos of the charger I've found are blurry and low res. But the teardown photos show the text on the pouch cell says it is 1.4 Wh (which is about 380 mAh at 3.7V), and the manual says it will take 3 hours to charge it. At 380mA it would take 1 hour to charge which means the OEM charger must be more like 130mA, which is laughably low for USB.

My back of the envelope math doesn't take into account the loss from dropping 5V to 4.2V in the differences in current draw from empty to full, it is just meant to get a general idea.

SiliconWizard:
From the very short description of the problem, it looks like they are saying that the internal charger actually doesn't limit the charging current by itself and relies on the external adapter for that.

If this is true, this is mind-blowingly stupid. I don't even get it.

Helio_Centra:
Relying on the charger to limit the current for USB is incredibly stupid. Nobody is gonna follow their warnings to only use the OEM charger, people use whatever USB power supply is handy to charge their devices.

And this is a medical device, diabetics might need it to stay alive.

mikeselectricstuff:

--- Quote from: Helio_Centra on June 08, 2023, 10:23:34 pm ---Relying on the charger to limit the current for USB is incredibly stupid. Nobody is gonna follow their warnings to only use the OEM charger, people use whatever USB power supply is handy to charge their devices.

And this is a medical device, diabetics might need it to stay alive.

--- End quote ---
And if they can't even get something as simple as USB charging right, what else have they screwed up?

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