4 ms·

On a slightly related note, fun tip. If you have a ‘dead’ laptop or mobile phone battery that’s too dead to even recharge.. I have ‘jumpstarted’ some by connect

by ferros 6y ago

On a slightly related note, fun tip. If you have a ‘dead’ laptop or mobile phone battery that’s too dead to even recharge.. I have ‘jumpstarted’ some by connecting to a li-ion cordless drill battery for a few minutes. I’ve managed to get a few old mobile phones back to life using this method. Edit: as a safety note this is not recommended! Please read some of the comments below!

roland35 6y ago
I believe this can work but please be careful doing this! Tool batteries are capable of supplying very high peak current and could cause a small fire. Lithium ion battery fires are not trivial, water alone may not be enough to stop it.
- ferros 6y ago
  Good point - I didn’t add a disclaimer, not recommended! And probably not a fun tip but nonetheless saved my bacon a few times when I needed quick access to devices.
londons_explore 6y ago
This is, in general, a bad idea. Lithium battery charge circuits generally have a fully charged voltage (about 4.2v), a fully discharged voltage (about 3.2v), and a 'do not attempt to recharge below this' voltage (about 2.4v). The reason circuits are designed not to recharge a cell below the 2.4v threshold is because when you recharge below that voltage, gasses are typically generated which eventually (many months later usually) burst the plastic envelope of the battery, and the battery electrolyte then evaporates as a highly flammable gas, killing the battery and potentially starting a fire if there is a nearby ignition source. TL:DR:. 'dead' batteries refuse to charge for safety reasons, and tricks to bypass that safety mechanism might lead to a fire a few months down the line.
- ferros 6y ago
  Appreciate the explanation, not information that’s readily found when you search explanations on dead batteries.
floatingatoll 6y ago
You’ll need at least one B-class fire extinguisher to put out this fire, in case any of you decide to play your hand at setting a battery aflame.
progman32 6y ago
I've done this stunt a couple times, it worked on one device and caused the battery to puff up badly in the other. Much better to do this via a lab power supply limited to a hundred or so milliamps, or fake one with a 5v USB supply and a 47ish ohm resistor in series... Monitor visually until at 3v or so, then charge using original device. Then keep the device in a fireproof area or bag until you get a new battery.
- fortran77 6y ago
  I like to use an explosion-proof pie tin.
  - stordoff 6y ago
    My iPad's currently in a metal tin in the garage (concrete floor, well away from anything flammable) after I bent it a few days ago[1] until I can get it repaired. I suspect I'd know by now if the battery was damaged, but I don't really want to leave it in the house overnight. [1] Forgot it was there and put some stuff down on it - there's now about a 20° degree bend in the middle of the long side that goes about half way across the back. Somehow, the screen didn't break.
    - fortran77 6y ago
      https://www.youtube.com/watch?v=tBg4ximDrsk https://www.youtube.com/watch?v=tBg4ximDrsk
  - DonHopkins 6y ago
    What flavor of pie is the most explosion-proof? Or do you take the pie out? https://www.youtube.com/watch?v=J6oxIWaxbxw https://www.youtube.com/watch?v=J6oxIWaxbxw

by ferros 6y ago

roland35 6y ago

I believe this can work but please be careful doing this! Tool batteries are capable of supplying very high peak current and could cause a small fire. Lithium ion battery fires are not trivial, water alone may not be enough to stop it.

ferros 6y ago
Good point - I didn’t add a disclaimer, not recommended! And probably not a fun tip but nonetheless saved my bacon a few times when I needed quick access to devices.

londons_explore 6y ago

This is, in general, a bad idea. Lithium battery charge circuits generally have a fully charged voltage (about 4.2v), a fully discharged voltage (about 3.2v), and a 'do not attempt to recharge below this' voltage (about 2.4v). The reason circuits are designed not to recharge a cell below the 2.4v threshold is because when you recharge below that voltage, gasses are typically generated which eventually (many months later usually) burst the plastic envelope of the battery, and the battery electrolyte then evaporates as a highly flammable gas, killing the battery and potentially starting a fire if there is a nearby ignition source. TL:DR:. 'dead' batteries refuse to charge for safety reasons, and tricks to bypass that safety mechanism might lead to a fire a few months down the line.

ferros 6y ago
Appreciate the explanation, not information that’s readily found when you search explanations on dead batteries.

floatingatoll 6y ago

You’ll need at least one B-class fire extinguisher to put out this fire, in case any of you decide to play your hand at setting a battery aflame.

progman32 6y ago

I've done this stunt a couple times, it worked on one device and caused the battery to puff up badly in the other. Much better to do this via a lab power supply limited to a hundred or so milliamps, or fake one with a 5v USB supply and a 47ish ohm resistor in series... Monitor visually until at 3v or so, then charge using original device. Then keep the device in a fireproof area or bag until you get a new battery.

fortran77 6y ago
I like to use an explosion-proof pie tin.
- stordoff 6y ago
  My iPad's currently in a metal tin in the garage (concrete floor, well away from anything flammable) after I bent it a few days ago[1] until I can get it repaired. I suspect I'd know by now if the battery was damaged, but I don't really want to leave it in the house overnight. [1] Forgot it was there and put some stuff down on it - there's now about a 20° degree bend in the middle of the long side that goes about half way across the back. Somehow, the screen didn't break.
  - fortran77 6y ago
    https://www.youtube.com/watch?v=tBg4ximDrsk https://www.youtube.com/watch?v=tBg4ximDrsk
- DonHopkins 6y ago
  What flavor of pie is the most explosion-proof? Or do you take the pie out? https://www.youtube.com/watch?v=J6oxIWaxbxw https://www.youtube.com/watch?v=J6oxIWaxbxw