Li-Ion undervoltage

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gjk_baker
 
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Li-Ion undervoltage

Post by gjk_baker »

Looking for some advise on the safety of an undervoltage Li-Ion

Here is the situation, using 18650, trying to decide if I need a protected battery

Will be protected for overcharging by the Feather Sense . However the charger doesn't provide under voltage protection
Average current 1-1.5mA, so it is very low. Traces and wires are small (will act as a fuse for a dead short)

Is there a safety issue if the battery discharges to nothing, due to customer in action.

thx

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adafruit_support_bill
 
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Re: Li-Ion undervoltage

Post by adafruit_support_bill »

The charger can't control the discharge rate, so overcurrent/undervoltage protection has to be either in the battery or in the load-circuit. Discharging below 3v is not dangerous in itself, but a cell that has been discharged much below 3v can be dangerous to re-charge (In fact, most charge controllers will refuse to charge an over-discharged cell).

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gjk_baker
 
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Re: Li-Ion undervoltage

Post by gjk_baker »

I am using the Feather Sense it uses MCP73831, it doesn't have battery undervoltage detection

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adafruit_support_bill
 
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Re: Li-Ion undervoltage

Post by adafruit_support_bill »

As I said, the charger can't control the discharge part of the cycle, so it cannot protect against undervoltage. You either need to buy cells with protection circuits, or plan on discarding them when they are over-discharged.

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