Hi I have two dead laptops in my room. One doesn't boot at all and the other has a dead screen. I opened up the dell battery and found 6 lithium cells.
According to the rating on the pack, it's 11.1v @ 4.8Amps. I want to reuse the cells for a spare led torch if I can.
here's the questions
1)Are I correct in saying each cell should be 3.7v
3x 2.4 -2.6v
3x 2.2v
So am assuming the 2.4 ones are good and the 2.2v ones are bad?
Do the cells have individual protection circuits attached?
Are you aware of the hazards lithium batteries can pose if not charged/discharged correctly? (If not, check out BatteryUniversity)
Yes of course. The hazard is plastered all over youtube. My favorite is this video
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I plan to use one of sparkfun's charger instead of building my own. Am I correct in saying the batteries are 18650 cells. I'm unsure they do have protection. HOwever I can add a protection ic can't I? AFAIK it's an original battery since the laptop was from work. They were giving them away.
Cells out of a Dell laptop battery will not have internal protection (I know because I was going to re-cell mine) they are plain cells. All the magic is done in the battery's internal circuit.
Ah OK. I was going to use a comparator to detect when an invididual cell voltage was 3v or below. Then shut off the entire pack. So I could use a MOSFET on the output of the pack. Also temperature monitored. What sort of temperature should be the cut off