Is 4.27V on a Li-Mn IMR considered an overcharge?

[CloudZ]

I just bought these two things:

18650 Li-Mn IMR
IMR 18650, LiMn 2000mAh Battery

Charger
BR-103W Multi-Volt Charger

I charged for the first time today, took it off the charger when the light turned green, the reading on my cheap multimeter said 4.27V. I see various sources saying 4.2 or 4.25V is as high as they should go. Should I be concerned?

EDIT: Yes, this is my first experience using a big battery mod

 

[tenshi]

yeah, I believe you shouldn't go over 4.20V +/–50mV/cell (or 0.00005V).

 

[Dontae92]

Yes that is a bit of an overcharge. Max is 4.25 to be safe (Per EH Specs) . But multimeters can be wrong, especially cheap ones. If you have a mod that can read batt voltage, see what it reads.

 

[CloudZ]

Yes that is a bit of an overcharge. Max is 4.25 to be safe (Per EH Specs) . But multimeters can be wrong, especially cheap ones. If you have a mod that can read batt voltage, see what it reads.

Alright, I've opened up a ticket with Madvapes to see what they say. It is completely possible that my meter is off by a little bit too. Also, my mod is a Bolt, so that doesn't help for checking.

It is interesting that 4.25V = good and 4.27V = not good. I assume a slight overcharge just reduces the lifespan of the battery and shouldn't cause a meltdown, which is something they say could happen if it gets charged up to 4.5V.

 

[Rader2146]

Personally...I wouldn't trust a cheap charger, and certainly not a cheap multimeter. You need something you can trust to accurately measure the voltage.

yeah, I believe you shouldn't go over 4.20V +/–50mV/cell (or 0.00005V).

50mV = .05v

 

[Dontae92]

one 4.27 charge isn't something you should be worried about for the battery (If you DMM is accurate), but over time it could effect the lifespan of the battery. Replace the charger with something better and get a good multimeter for future instances

 

[D4rk50ul]

Yes it's an overcharge and if it's really at that voltage you need a better charger as that can be dangerous.

 

[meatsneakers]

Had the same charger, destroyed two 18350 IMR's by overcharging to 4.30 a few times before I realized what was going on. Spend $20 and you'll get a reliable/safe charger.

 

[CloudZ]

I just charged for a second time and checked on a different multimeter. 4.24. Of course, I checked it at a friends place and forgot to bring my own MM. So its really close if anything.


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[Ryedan]

4.27 volts is not dangerous, but I think it will shorten the lifespan of your batteries a bit and it is getting closer than normal to the danger zone. Last year I bought a kit which included a really cheap charger. After that I bought a Xtar for about $20 and set the cheapie aside for backup duty. BTW, the cheap charger stops charging at 4.2 volts.

Also, if you took your freshly charged batts to your friends place after charging at home, they probably lost some voltage during the trip.

 

[D4rk50ul]

http://batteryuniversity.com/learn/article/charging_lithium_ion_batteries

 

[Ryedan]

Charging Lithium-Ion Batteries

From your link:

"Overcharging Lithium-ion:

Lithium-ion operates safely within the designated operating voltages; however, the battery becomes unstable if inadvertently charged to a higher than specified voltage. Prolonged charging above 4.30V forms plating of metallic lithium on the anode, while the cathode material becomes an oxidizing agent, loses stability and produces carbon dioxide (CO2). The cell pressure rises, and if charging is allowed to continue the current interrupt device (CID) responsible for cell safety disconnects the current at 1,380kPa (200psi)."

 

[D4rk50ul]

From your link:

"Overcharging Lithium-ion:

Lithium-ion operates safely within the designated operating voltages; however, the battery becomes unstable if inadvertently charged to a higher than specified voltage. Prolonged charging above 4.30V forms plating of metallic lithium on the anode, while the cathode material becomes an oxidizing agent, loses stability and produces carbon dioxide (CO2). The cell pressure rises, and if charging is allowed to continue the current interrupt device (CID) responsible for cell safety disconnects the current at 1,380kPa (200psi)."

Almost all charger accidents are due to overcharging, if the charger is already doing 4.27v it's faulty. Not all cells are created equal either, one might not mind while another could go into thermal runaway from one shot.

If you want to play with fire go for it, just don't give out dodgy info to newer users. Also you left out the next two paragraphs of that article. If you want to see what overcharging can do go check out the battery failure section of light forums.

 

[CloudZ]

I haven't heard back from Madvapes yet, but that is understandable since it is the weekend.

Tomorrow I will borrow a nice Fluke multimeter from work and check again in the meantime.

Thanks to everyone for the comments and info so far.

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[CloudZ]

Madvapes says there is nothing wrong with a 4.27V charge. I will still test with the Fluke tonight or tomorrow.


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[Ryedan]

Madvapes says there is nothing wrong with a 4.27V charge. I will still test with the Fluke tonight or tomorrow

There might be nothing wrong with it but meatsneakers had an issue with his identical charger and 4.27 is getting closer to overcharged. That charger is also pretty cheap. With all that, I would not keep using it as my primary charger.

I have a $120 charger I use for my model airplane batts. It has more bells, whistles and settings than you can shake a stick at. It charges lion's to 4.25 volts by default. I talked to the supplier and they told me it was safe and designed that way on purpose. After doing more research I decided to set the cutoff voltage to 4.18. I could afford to take a minute off my flight times, have the batts last a little longer and be a little safer in that if something did go wrong, I would have a little more leeway before it became dangerous. Given half a chance, I tend to err on the side of safety. Not saying my way is the only way, just trying to help by sharing the information I've accumulated.

 

[yzer]

Yeah, I got a single cell charger MTLC-0420-1000 with a Sigelei Zmax kit two weeks ago. It has a hot output of 4.2VDC @ 1000mA. It charges an IMR 18650 from 3.5V to 4.27V in a little over two hours. That's quick but there is no way I'm going to use it often with that terminating voltage. I'd rather have more charge cycles with the batteries.

I've got a bunch of cheap multi-stage single cell chargers YL-103A. I use these for batts in the 1000 mAh range. These are only 350mA output but they all terminate somewhere between 4.15V and 4.19V.

 

[CloudZ]

Fresh charge, the Fluke reads: 4.23V. My cheap meter still reads 4.27V. After about 5 draws, Fluke: 4.21V, mine: 4.25V. My RBA coil is 1 ohm, so about 17-18 Watts. I believe this particular Fluke retails around $120, my multimeter was about $20.

So yeah, I might be teetering on the edge so the battery might have to come off the charger when it starts flashing to help with the longevity, rather than waiting for solid green. I might want a multi-battery charger eventually, so I will pick up a better one then.

Thanks for the input, guys and gals, definitely prompted a good learning experience.

 

[CloudZ]

Also, if you took your freshly charged batts to your friends place after charging at home, they probably lost some voltage during the trip.

Charged it while I was there.

I am a mech. engineer (sadly, or not so sadly, not an EE ), so I sort of know how this stuff works but I am not sure on what is real or not in terms of battery specs and recommendations, safety factors, etc.

 

[tenshi]

Since we're on the topic of batteries... I accidently discharged my AW IMR below 3V (doh!), and was wondering what anyone's thoughts are about that...