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How to resuscitate a dead fatshark battery
#1
Before I explain this trick I want to be clear that what I am explaining below is a little risky. If someone has tips on how to carry out this quick suggestion in a safer manner I'd be grateful for some input. If you decide to try this out you do so at your own risk. Neither I or anybody else around here is going to be responsible if you get hurt or set something on fire. Always practice safe battery handling. Unseen has provided some great clarity below as to what the risks are

Now that I am done with the warnings... let's zombify a fatshark battery!

So the very first LiPo that I ever killed was a fatshark battery. I had left it plugged in after sim time and when I came back it was 0v. Since then I've been killing quad lipos left and right with gusto but the new fatshark battery seemed to do just fine even with a little abuse. Until today... I went out and flew at a park during a road trip... then packed everything away hastily and forgot to unplug power... This evening I went to fly again and it was still plugged in.. . I knew it was dead. 

At 0v most automated chargers will not push a charge to a battery. They throw an error instead. 

This time I have a little more confidence experimenting with things so I decided to give something a try and it seems that it's worked. 

Here is how to zombify a fatshark battery on an automated charger:
  • Discover dead battery
  • Test dead battery for any voltage (if it has 6 or more volts then it may charge still... give it a try just in case)
  • If there is zero volts, set the charger to NiMH @ 0.5 amps
  • Charge for 3 min attended! (Do not, I repeat, do not leave this battery charging unattended... this is the riskiest part)
  • I personally kept the battery in my hand while it was charging so that I could feel if it or the leads warmed up at all
  • Stop the charge
  • Check for voltage with a meter or the one built in on the charger if it has one
  • Mine had 7v at this point so I put it on standard lipo charge
  • Charge fully on lipo charge and keep a close eye on it!
carl.vegas
Current Quads: Operational: Diatone GT2 200 In need of repair: Bumble Bee, tehStein,  Slightly modified Vortex 250 
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#2
This procedure will revive an over-discharged Li-ion battery (the Fatshark battery pack contains Li-ion cells, not LiPo cells), but you should be aware that discharging a Li-ion under 2.5V may either be harmless or can permanently damage the cell making every charge a risk thereafter.

Whether it is harmless or not depends on the type of Li-ion cell that is used. If the cell has a built in protection circuit, then this is harmless as the protection circuit won't actually let you reduce the cell voltage to less than 2.5V. It simply disconnects the cell from the terminals if the voltage becomes too low. Your trick with using NiMH charging will reset the protection circuit.

If the cells do not have a protection circuit, your trick will still work, but the cells are now inherently dangerous as discharging them below 2.5V will cause permanent physical changes inside the cell which can lead to internal short circuits. Once this kind of damage has been inflicted to a cell, it might charge OK for quite a few more cycles until one day, a hard short will develop internally. When this happens, it causes runaway heating of the cell and within seconds, the cell will blow the safety vent at the positive terminal and vent hot gases and maybe even flames.

If the two cells in the Fatshark pack don't have their own protection circuits then it's possible that the battery pack implements over-discharge protection itself. If so, it's also harmless if the voltage drops to zero as the cells themselves won't be allowed to go below 2.5V.
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#3
Unseen,

Just to be sure... my FS battery clearly is labeled as a Lithium Polymer. If this hasn't always been the case then I can clarify in my OP and title that it only applies for LiPos. If this situation still applies with Lithium Polymer please let me know and I'll delete the post.

Also, after finishing the charge when measuring voltage it's only @ 8.28v which I expected to have some loss in the battery which is why I am calling it a zombie battery. I probably should be clearer in the OP that the battery will almost certainly never be the same after extreme abuse.
carl.vegas
Current Quads: Operational: Diatone GT2 200 In need of repair: Bumble Bee, tehStein,  Slightly modified Vortex 250 
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#4
Carl, I think you should change from LiPo Killah to LiPo Torturer, I see how you bring it back to life just so you can kill it again!
Windless fields and smokeless builds
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#5
(29-Aug-2017, 10:31 AM)Tom BD Bad Wrote: Carl, I think you should change from LiPo Killah to LiPo Torturer, I see how you bring it back to life just so you can kill it again!

lol

We shall see... In this case its just a little damaged after being zombified (assuming that unseen's warning above doesn't apply to LiPo FS battery). I expect it to last several more charges if I understand what I've done correctly. I did a little bit of research and it seemed sound as a way to at least get it going again in a pinch but if it'll potentially short and heat up in a few more cycles then I'll kill this how-to and dispose of the battery
carl.vegas
Current Quads: Operational: Diatone GT2 200 In need of repair: Bumble Bee, tehStein,  Slightly modified Vortex 250 
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#6
I kill goggle batteries on a fairly regular basis as my goggles do not have a voltage indicator and I don't want to plug an individual checker into the balance lead and have it banging me in the head and then at some point going off in my ear.  I do TRY to switch to another battery before the one I am using goes dead,,,,,,,,but,,,,I'm usually having too much fun and forget to do it. ANYWAY...I use the same method to revive my batteries...with one exception.  I set the NiMH mode to .5 amps.  It puts less stress on a potentially damaged battery.  It takes a little longer to make it chargeable, but it's only a few minutes.  I too am in eyesight of the battery at all times will doing this.
"Damn the torpedoes!!!  Full speed ahead!!!"
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#7
(29-Aug-2017, 11:18 AM)sirdude Wrote: I kill goggle batteries on a fairly regular basis as my goggles do not have a voltage indicator and I don't want to plug an individual checker into the balance lead and have it banging me in the head and then at some point going off in my ear.  I do TRY to switch to another battery before the one I am using goes dead,,,,,,,,but,,,,I'm usually having too much fun and forget to do it. ANYWAY...I use the same method to revive my batteries...with one exception.  I set the NiMH mode to .5 amps.  It puts less stress on a potentially damaged battery.  It takes a little longer to make it chargeable, but it's only a few minutes.  I too am in eyesight of the battery at all times will doing this.

Good advice on the amps... I have updated my post to say 0.5 amps @ 3 min (assuming it should be about right on timing)
carl.vegas
Current Quads: Operational: Diatone GT2 200 In need of repair: Bumble Bee, tehStein,  Slightly modified Vortex 250 
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#8
(29-Aug-2017, 10:10 AM)Carl.Vegas Wrote: Unseen,

Just to be sure... my FS battery clearly is labeled as a Lithium Polymer. If this hasn't always been the case then I can clarify in my OP and title that it only applies for LiPos.  If this situation still applies with Lithium Polymer please let me know and I'll delete the post.

Also, after finishing the charge when measuring voltage it's only @ 8.28v which I expected to have some loss in the battery which is why I am calling it a zombie battery. I probably should be clearer in the OP that the battery will almost certainly never be the same after extreme abuse.

I'm pretty sure if you crack open the case you'll find two 18650 Li-ion cells inside.

LiPo is a misnomer in our hobby anyway. They are effectively Lithium Ion cells, just in a plastic bag instead of a metal tube. Genuine lithium polymer cells, where the electrolyte is a solid polymer don't actually exist commercially. (See: https://en.wikipedia.org/wiki/Lithium_polymer_battery)

Therefore, unless the LiPo cells are protected from being discharged under 2.5V, the same risks apply, regardless of if they are called Li-ion or LiPo.
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#9
(29-Aug-2017, 05:09 PM)unseen Wrote: I'm pretty sure if you crack open the case you'll find two 18650 Li-ion cells inside.

LiPo is a misnomer in our hobby anyway. They are effectively Lithium Ion cells, just in a plastic bag instead of a metal tube. Genuine lithium polymer cells, where the electrolyte is a solid polymer don't actually exist commercially. (See: https://en.wikipedia.org/wiki/Lithium_polymer_battery)

Therefore, unless the LiPo cells are protected from being discharged under 2.5V, the same risks apply, regardless of if they are called Li-ion or LiPo.

Why would they lie! Cry my world is ruined.

Also... whats your thoughts? Take the thread down or leave it up and add extra warning? I'll take your advise either way.

Of course on my own battery... I am going to keep trying it out until it's all the way dead or heats up on charge because: reckless
carl.vegas
Current Quads: Operational: Diatone GT2 200 In need of repair: Bumble Bee, tehStein,  Slightly modified Vortex 250 
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#10
I don't think it's bad advice per se.

Battery safety is important, and the first and most important rule is never to leave a battery charging unattended. The second most important rule is never to charge batteries where they could cause a larger fire if the worst was to happen.

Reviving a discharged battery will only increase the risk of fire if the battery isn't protected to start with. Even if you increase the risk of a catastrophic failure, as long as you are present when it happens and don't have your battery charging on a flammable surface, the worst that will happen is that you'll fill the room with noxious fumes and damage the surface that the battery is on.

Considering the physical abuse that our flight batteries are subjected to, I'd say that the risk of having a flight battery that was damaged in a crash burst into flames during charging is much higher than the same thing happening to a 'resurrected' Fatshark pack.

It's all about managing risk sensibly and understanding the factors that contribute to risk in a realistic way. If you understand and accept the risk profile of bringing a fully discharged lithium battery back to life and always take the correct precautions when charging, I don't see any reason not to do so. Having a realistic discussion in this thread would seem to be the best way of making those who maybe don't understand the risks more aware of them and that can only be a good thing.

In the end, a lithium battery contains a highly reactive alkali metal and various toxic chemicals which can, when things go wrong, react violently in a self-fuelling fire. Just about every major electronics manufacturer has had product recalls due to lithium cells catching fire because of production mistakes.

However... The media loves stories like this as they sell newspapers and advertising spots on TV. Unfortunately, this blows most people's perception of the risks completely out of proportion. If you look at how many mobile phones and other lithium powered devices exist on the planet and how often they spontaneously burst into flames, the actual risks are very small. If they weren't, insurance companies would have clauses in their policies which refuse cover if your house burns down due to a lithium battery fire. That they don't have such clauses tells you lots about the real risk. Insurance companies are the best references you can find about the actual risks of any bad thing happening as they study risk in minute detail.

That being said, the fact that the risks are smaller than many might think is no excuse to ignore the two basic safety rules that I mentioned at the start of this wall of text!
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#11
OK, up it stays... OP updated with a link to your comment about what the risks are so that people can decide for themselves.
carl.vegas
Current Quads: Operational: Diatone GT2 200 In need of repair: Bumble Bee, tehStein,  Slightly modified Vortex 250 
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