Nitecore UM2 cooked my old AA nimh as a li-on battery?

500mA is only .2C and that might just be a little low to trigger any termination, but I can’t say for sure.

Chris

So wait I’m curious now. What if i put in a brand new AA nimh eneloop inside the charger that is already 90% charged… will the charger notice the voltage rise too fast and think it is a Lio-Ion as well or am i misunderstanding this?

First of all, I’m no EE, but a well implemented charging circuit is different for NiMH and Li-ion batteries/cells. They have different charging protocols, even though your charger does both.

For NiMH, ideally it’s dV/dT, voltage and temperature and for li-ions, it CC/CV, constant current, constant voltage.

They act independently depending on the voltage of the battery/cell being inserted.

Try starting with a fresh set of Eneloop/Fujitsu set of batteries, discharge them down to say…1.20v and then charging them back up and measuring the elapsed time.

Chris

I never liked those multi chemistry chargers that recognize the cell chemistry automatically. I always felt that there is possibility for something like this to happen.
Before I got a MC3000, I used my very old MAHA C9000 for NiMH and a separate charger for LiIon only.

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I agree, two different chargers is ideal.

Not while travelling….!

That said, I do have a bunch of chargers, go-to at home is the Zanflare C4 for both NiMh and Liion, I live in a small house so all my gear packed into cupboards, accessing two seperate chargers is a PITA.

Currently travelling for work, I’ve got the Nitecore with me, I’ve only got a couple of NiMh cells to charge, I’ll do them on my desk while I work so I can watch them like a hawk…

Vapcell U2 arrived shortly before I left, I didn’t have a chance to fully test it, so I couldn’t justify bringing it with me.

For traveling, I use a Panasonic BQ-CC16 for NiMH and Xtar VC2S for LiIon. The combined volume and weight of the two is less than that of a MAHA C9000 or many 4 bay universal chargers.

I travel also. And when I do I take extra batteries with me. Its a lot easier than bringing a charger.

I’m not saying my solution is best, I only want to travel with one charger… I don’t want to carry additional weight or bulk… Charger advertised as doing both NiMh and Liion, so it’s not unreasonable to expect it to perform as advertised… :question:

As above, whatever works for you; logic for this trip: I’m out for 8 weeks, hard to predict my useage, I may only charge once, may charge 10 times… impossible to budget for that kind of use for carrying spare cells…

Plus, I hate going through airports as it is, I don’t need to be pulled aside and questioned why I’m carrying a bunch of extra liion cells…

I agree with you 100 %, these things should work as advertised and expected. Unfortunately, this is not always the case, and your case is not the first one I hear of. That is why I decided to play it safe and use two separate chargers.
The only charger I trust with multichemistry duties is SkyRC MC3000, but there, you select the chemistry manually during programming, and it’s way to bulky for traveling…

One charger for both can absolutely positively work as long as you don’t do foolish things like use dead batteries from old laptops or 10+ year old eneloops. If you are using batteries less then 5 year old, you should have no problem whatsoever.

That’s also true, but the manufacturers should state it clearly in their literature or implement safety features that wouldn’t allow such things to happen, no matter what.

Yeah but those Varta batteries worked fine whenever i used them… I mean 12$ for a smart charger is a great deal but still I’m kind of worried now. I thought smart chargers could be ‘charge and forget’ for family members but i guess it is not so.

I disagree. Manufacturers can’t prevent people from being stupid.

How is the fact that I used older batteries that still worked in my devices stupid? :person_facepalming:

At 8 years old and with batteries of questionable origin, they’re most probably toast.

Just because you can fire up a light on the lower modes, doesn’t mean the batteries are healthy.

Put a 1A drain on them, which isn’t much these days and time how long the light stays on.

Chris

I disagree with the blanket statement that batteries 5/8 years old are toast and using them is stupid. I have many Eneloops and 18650’s that are at least 10 years old and they seem to be holding up well. I test all my Eneloops every 6 months and the old ones have basically the same capacity as when I got them as well. Granted I can only discharge at 1A on my Opus 3100 but in actual usage I don’t notice any difference. I don’t test the 18650’s often but when I do they don’t seem to be much worse for wear than before (other than a couple that are toast :smiley: ).

My batteries don’t have that many cycles on them because I rotate them during usage. My 10 year old Eneloops probably only have 20 cycles on them not counting testing. Many of my non-Eneloop NiMh did go bad though after a year or 2 :rage:

Maybe it’s more accurate to say that batteries used hard and often and aren’t high quality don’t last that often?

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Batteries… both NiMH and li-ion will develop high I.R.s over time.

I have 16 Sony 18650s harvested from VAIO packs that are date coded 2002.

They still have 75% of their capacity, so with quality stuff, you’ll get longer life, but things still go bad and just wear out.

Only way to know is to test them under known loads and in an analyzing charger.

Chris

I have just bought 2 of the nitecore um2 from banggood for a ship price of $27.59. Some may be wondering why I bought 2, well I have many batteries and I have 10440 batteries which according to hkj this can charge them 0.1amps upwards.

The question is can use these power supplies? I am assuming the charge i will get for the first one is 1amp per battery and the second one I’m not to sure. Is the first one 2.1amps per USB port or 2.1amps shared?

https://www.wilko.com/en-uk/masterplug-13a-3-socket-fused-adaptor-with-2-usb-charging-points/p/0491445

https://www.wilko.com/en-uk/wilko-plug-through-usb-surge-adaptor/p/0455043

My Nitecore UM2 charger works fine with all kinds of rechargeable batteries.
HOWEVER…
The USB A/C power adapter matters. I’ve found some will cause lag or errors in the UM2 UI (display won’t change, buttons stop operating), or insufficient power to properly charge the cells. Maybe there’s a scenario where a deficient power adapter can thwart proper regulation in the charger, incurring an overcharge?