Apologies if this has been answered before, but I could only find posts on getting a cell from 0V, not to 0V. XTAR has sent me this cool new charger to review, and they have requested that I demonstrate the feature where it can sense a 0V cell and start charging it. But almost all my cells are protected. I do have a few 16340 IMR cells and a couple Panasonic hybrid 18650s. I think my wife's e-ciggy uses some unprotected 18650s, so I should have some battery capable of going down to 0.
I know it's not good for the cell, but I'm happy to have one of my cells take one for the team if it will make for a (hopefully) compelling demonstration in the video. So, any thoughts on how to safely get one of my cells to 0V for testing purposes?
Thank you, fine folks of BLF!
And here's a couple random photos of the charger with a USB power bank charging one of my protected AW 16340 cells. They had me at USB:
I don’t believe it measures internal resistance, though it does claim to be able to revive any cell in its list of compatible chemistries from 0V. It’s actually a fairly simple charger. It measures capacity starting from when you put the cell in—there’s no charge test or anything like that where it discharges the cell first. It’s still a pretty nice charger.
Just hook a 100 or so ohm resistor across it and let it sit for a week or so. This will drain almost all the electricity from the cell. Check the voltage cell voltage with a meter. It should be near zero. Then short out the cell for a couple of more days with a jumper wire.
You will probably see some electrochemical rebound in the cell voltage when you take the short off, but the cell should be pretty darn drained.
I have a bunch of cells at or near 0v, or even below .
I’d be happy to hand them off to you if you happen to make it to Seattle, or I could put them back in the dead laptop pack they were in and send them to you.
I’ll charge cells that came out of a pack at 2v, but 0v seems dicey.
Actually, now that I think more about it, I think Bort is right. I doubt the 0v function is for dead unprotected batteries, its for protected batteries where the protection circuit has kicked in and needs a boost before it allows proper charging again.
direct drive a led on a non protected li-ion and it should deplete it fairly well, just leave it till it no longer lights up, then leave it a bit longer still. This is probably a “real world” test of what might happen to a battery.
Thanks for all the great ideas. I knew you guys would come through. Hmm I suppose Bort is right. I would hate to do that to one of my good cells anyway. And thanks for the offer, eas. Seattle is a great city. Hmm I think I’ll just run some protected cells down until they trip the circuit and see what this charger does with them. It’s not going to be a highly technical review anyway. Let someone like HKJ do that. I just make sure it hits all the basic bullet points for its design, which is a mobile USB charger. At .5A per channel, I don’t think anyone is going to unplug their I4 or Opus and wait 7 hours to charge a cell. But this is sure one hellava cool USB play toy
> I doubt the 0v function is for dead unprotected batteries, its for protected batteries where the protection circuit has kicked in
Can you check this with the people who sent you the charger for review?
I’d think they ought to clear that up — very clearly — in whatever they print in their ads or send out with the charger.
“Our engineer says that for protected cell, 0v activation function can wake up it immediately, and for unprotected cells, if the voltage is below 2v, our charger will bring it back to life by using small flow current.
For unprotected cells, if the voltage is below 2v, many of the other chargers wll not be able to charge it, but the battery is still usable.
With this charger we will be able to know if the battery is really dead or just can be charged by other chargers.
For unprotected dead batter, our charger will first using small fcurrent flow to charger it, and after ten minutes, the led screen will show NULL.
Hope this will help you.
Best wishes.”
> we will be able to know if the battery is really dead or just can be charged by other chargers.
> For unprotected dead batter, our charger will first using small fcurrent flow to charger it, and
> after ten minutes, the led screen will show NULL.
Huh?
When you see NULL, what does that mean?
— Does that mean the unprotected dead batter can be charged by other chargers?
— Does that mean the unprotected dead batter is dead and probably dangerous to keep around?
> we will be able to know if the battery is really dead or just can be charged by other chargers.
> For unprotected dead batter, our charger will first using small fcurrent flow to charger it, and
> after ten minutes, the led screen will show NULL.
Huh?
When you see NULL, what does that mean?
— Does that mean the unprotected dead batter can be charged by other chargers?
— Does that mean the unprotected dead batter is dead and probably dangerous to keep around?
I took that to mean that if the battery hasn’t been noticeably revived by the charger after 10 minutes, it considers it a lost cause and tells you “null”. At least that’s the way I read it. Either way I’m getting a collection of discharged cells to test with, and I’ll try to indicate that clearly in my written and video reviews.
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