I went to turn on one of my maglite mods, and it didnt come on at all. First thing i checked were the batteries. On reads 4.1v, and the other 0.0v. Pcb tripped I’m guessing
They are olight branded 3400mAh and were very recently charged. The light only runs at a little over 3 amps, so it shouldn’t trip. It hasn’t tripped I for the year or so I’ve used it anyway…
Any ideas as to why it decided to shut off? And as to how to reset it? My i4 won’t restart it, and I’ve tried applying some voltage. It’ll come up to 1.4v and no further.
Do you have any dumb chargers? Because they can be used to force the protection back again. If not try leaving your battery in charger longer?
You can also use another fully charged 18650 to recover the protection by touching positive to positive and negative to negative with the help of a wire.
If neither those work I usually take the battery apart and charge the cell (bypassing the protection) and the protection should reset (and wrap it with heatshink again)
Pos to Pos, Neg to Neg. with your other cell. 2 Knives. Should reset. Odd that your still getting 1.4 volts. The last cell I remember resetting was reading Zero.
I’ve tried the 18650 trick, and that’s what I meant, it would only come up to 1.4v.
Unfortunately I don’t have any dumb chargers (I think) but I was thinking about just yanking the pcb out like you recommended. If I can’t get it back, that’s what I’ll do
If it shows 1.4V than its probably an unprotected cell. If the protection is tripped there is no voltage on the cell. A cell which is once discharged so low shouldn’t be used again for performance and safety reasons.
So check if they are protected.
If yes, Remove the PCB and measure directly on the cell which voltage you have. If it’s still the 1.4V you should trash the cell.
Something went wrong.
If you are reading a voltage of 1.4v from the li-ion then it’s gone. Going down that low will have caused internal damage. It may get violent at a random time in the future. Don’t attempt to charge it anymore. I would suggest removing the protection board to verify that it uses a seiko chip. I believe olight branded batteries all use seiko.
Where did you get this battery from? Could you share details about the mag mod it was in?
Protection acts as a switch which disconnects the battery from the bottom contact in event of over-charge, over-current or over-discharge. This causes you to see 0v but the battery is not actually at 0v. The over-discharge cut off point is usually 2.5v, it is never anywhere near as low as 1.4v. When you reset protection that has tripped due to over-discharge what you should see is it instantly come back to around 2.5v or higher.
Two things can cause the cell to get lower than the over-discharge cut off point. 1) The protection just failed to work. Which should not be very likely with a quality chip like seiko. 2) A very slow drain, like the parasitic drain from the electronics in some badly designed side switch / “e-switch” lights. Protection chips have trouble responding to very low current drains. But since the drain is very slow it should only happen in a light that has been sitting unused for a good awhile.
I forgot to mention, you really shouldn’t use another 18650. People sometimes say to just use another 18650 to reset the protection, because it’s quick and easy but your really shouldn’t imho. There is no restriction on the current, so it could be delivering multiple amps. 2xAAA or 2xAA is what I usually suggest if one doesn’t have a charger which can reset protection. AAA or AA cells can’t deliver much current.
Also when reseting protection, you only need to apply power for a second. You’re not looking to “charge” the tripped battery, you’re just signaling the protection chip to reconnect the cell. Then you check the voltage of the li-ion which had be tripped. If it reads around 2.5v or higher, you just charge it in a normal li-ion charger.
I have used 3 different multimeters, and they’re all saying the same thing.
How often do 18650s just quit like that anyway? I don’t think I’ve heard of it happening like that. It wasn’t even in use when it quit, just sitting on the shelf. It had been charged just a few days earlier and used for a few minutes a day.
The mag mod is an MT-G2 with a Zener modded qlite, running at the stock 3.0A. It still works fine, I tested it on my power supply.
You recharge all the batteries for this light together and always keep them together, correct? Series cells must always be the same. Same brand, type, voltage / charge level, capacity and same age / wear. If anything is mismatched then one can discharge faster then the other. And that could do this.
I avoid series cells. There are many chances for problems. Also more of a chance that the batteries get violent. Most reports of exploding flashlights have been series cells.
Hmm. That light doesn’t sound like it should have any parasitic drain. Did you build it? It’s using the stock mag switch or some other click switch, right. Not any kind of e-switch / momentary button. And the switch totally cuts off power to the driver, correct?
It shouldn’t happen. Not with a quality battery, quality protection and a light with zero parasitic drain. Which is all what you seem to have.
But something happened. It could be something that we are missing or something that happened unnoticed. If not, then there are still a couple possibilities. Very rare tho. Li-ion can develop internal shorts. A small short could drain the cell to zero. If it’s small and unable to carry much current it could possibly do this slowly without overheating the cell, causing it to vent. This should be very rare for quality cells.
All of my builds have dedicated cells, to minimize the series problems and they are always charged together at the same charge rate. That’s why I was so confused, the other one still reads nearly full, but it’s dead. Yes it’s still the stock mag switch. The tailcap read 0 microamps with the switch off
Just a thought, but could one of the channels on your charger be faulty? Do you put the same batteries in the same slots as you take them out of the torch/flashlight?
Might as well pull off the protection board and check if it acts any different. There is a slight chance that the short is in the protection board or the chip.
Well, after I cut the olight wrapping off, I was greeted by the familiar green Panasonic ncr18650b wrapper, but there was no pcb on the negative end. A little more digging, and I see “made in china” does Panasonic make 18650s in china? Even further in, I get to the bare metal cell, pop off the rubber positive end, cut the little spot welded strip to the button top, and test the cell contacts. 0.03v…….huh. The confusion intensifies. The protection pcb was potted in rubber positive end.
I just can’t bring myself to beileive that a quality cell would just fart out like that….strange. Makes me think that’s its not a legitimate cell
I will post pictures if you want to see, but It’s kinda hard to do with no desktop computer.
