Nitecore battery charger overcharging?

Aston Senna · May 23, 2023

So I just got the Nitecore UNK2 for Nikon through B&H and have questions about operation and battery charge levels, if anyone can lend a wise voice.

I was it using it charge my OEM Nikon EN-EL15C battery, which B&H said is compatible, and also a Promaster aftermarket EN-EL15c battery.

Anyways as a test, because I just got them, I charged them using the USB on my Macbook, where it was providing over 900 ma of charge current to each. Great!

But, the charge kept lowering and lowering, which I know is normal, but I felt like I should check the batteries in camera to see where I was at since they were only down to 70% each (according to the in-camera 'battery info' menu) and it shouldn't take long to be fully charged. removed both batteries from the Nitecore charger and one showed 100% and the other 98% according to the camera battery info. This is disconcerting since they were still drawing upwards of 300 and 500 ma before removal.

I placed them back in the charger because I wanted to see when the charger would shut off, to see if I can trust it basically. It proceeded to lower the charging rate to just over 100 ma on both batteries as fullness approached, but just kept going and going, adding an additional 200 and 100 mAh on the batteries, or about 5 and 10% capacity on the batteries that the camera had already said were at 100 and 98% already.
So now I'm skeptical and not completely trusting this charger.

The charger states it has overcharge protection built in. But I feel, going off the camera's measurement at least, they were past 100% already and possibly overcharged. Just has me worried! Don't want to ruin my batteries with this thing, and then have a defective battery inside an expensive camera.

Curious if anyone else has noticed things like this with other chargers. Maybe the nikon measurement is inaccurate even and the Nitecore is doing just fine.

BertIverson · May 23, 2023

I do not have an answer to your Nitecore question. However, I have a NITECORE USN1 Digital 3-terminal Travel Camera Charger for Sony NP-FW50. I get the impression that mine undercharges Neewer NP-FW50 batteries. It quits charging and the camera indicates that the freshly charged battery is 90%. If I then put the battery in a charger which does not utilize the 3rd terminal (thermal I believe), the batteries then read 100%. Not something I worry about but I do not know whether the issue is the Nitecore charger or the Neewer batteries. The genuine SONY NP-FW50 battery charges to 100%. in the Nitecore. Who knows????

Bert

Guy Parsons · May 23, 2023

I have the NiteCore USN2 for my Sony compact batteries.

The limit there is 4.2V and the behaviour is to keep charging at an ever decreasing rate while showing that top voltage of 4.2V. The main rate is something like 620mA and at the very end it will be showing something like 40mA and a lower temperature before it indicates "End" and stops charging. So far not checked to see exactly what voltage the NiteCore ends at, is it 4.25V or 4.29V or whatever?

It's nice to go right to the End indication to get full charge, but if you have spares with you and be prepared to change them a little more often then pulling the battery from the charger before it gets to "End" will help the battery last longer.

In my M4/3 world I use the Olympus BLN-1 batteries and they charge in the OEM unit to about 8.6V or so. In a clone charger they only charge to the usual 8.4V, so my OEM batteries charged quite often in the clone charger do get a bit less charge but so far after near 10 years they still seem as good as new.

Worry less about getting "full charge" and cater for a bit of shallow charging to help make those batteries last longer.

BertIverson · May 24, 2023

Guy Parsons said:
...

Worry less about getting "full charge" and cater for a bit of shallow charging to help make those batteries last longer.

Hey Guy,

Thanks for your input. I agree better to under charge a bit than over charge.

Bert

robgendreau · May 24, 2023

I'd ask at Nitecore. The charging curve for lithium IIRC remains quite flat until the end, so constant current until full. I'm not sure that I'd consider the camera to be the best judge of full since it's perhaps not measuring or assessing full charge in the same way the charger and/or BMS is; the camera might just look at voltage.

Aston Senna · May 24, 2023

right.

So I'm purposely discharging my batteries today to get them to zero and recharge to full from zero as the screen on the nitecore does show mah added (not the current level of battery, but how much the charger adds). See how many it adds before shutoff

Guy Parsons · May 24, 2023

Aston Senna said:
right.

So I'm purposely discharging my batteries today to get them to zero and recharge to full from zero as the screen on the nitecore does show mah added (not the current level of battery, but how much the charger adds). See how many it adds before shutoff

It may depend somewhat on how you get to "flat". The camera may give the red warning of "flat" but then turn off and rest a bit and it looks good again for a few more shots. Some batteries recover significantly after a few minutes rest.

Double check the actual voltage of the battery before starting the charge. The Nitecore only shows one significant decimal point, whereas a digital voltmeter will give two or more decimal points to better judge where that "flat" battery is at before starting the charge. Try and get the two batteries to the same "flat" starting voltage. Then the NiteCore charge total will make more sense when it gets to its "End" indication.

Basically I never stress over what the camera is telling me except that I often change batteries early, well before they get to any red warnings and then as I mentioned under-charge them a little by using a clone charger with those peculiar higher voltage Olympus BLN-1 batteries.

I date the batteries when bought and label them a/b/c/d so I can cycle them regularly, they all seem to work much the same as when I bought them, low stress charge-discharge keeps those expensive little lumps living longer.

Two Olympus E-P5 bodies plus their batteries.

My only wish would be that NiteCore made one of their sweet chargers for those now probably discontinued BLN-1 batteries. Never to be made for such low sales cameras as Olympus M4/3 compared to Nikon/Canon/Sony etc.

Aston Senna · May 26, 2023

So those are still interested in this. I ran the camera flat, nothing would turn on, tried it in another camera and also dead zero power. Charged it in the Nitecore to see how much total juice it would pump and...the ma counter stops counting at 1,999 lol. The Nikon En EL15C is supposed to hold 2,280 so that doesn't really give much info. Can't believe it stops counting. However, the current slowed dramatically after 1,999 and went for about another 30 minutes before it read 'End.' I can't think that in those last thirty minutes with it slowing to 500 ma, then 400, down to like just 80 that it added more than an extra 200 ma into the battery. So, if it was an actual real zero capacity going in, I don't believe it overcharged it. Just REALLY dumb and disappointing the counter stops at 1,999.

Guy Parsons · May 26, 2023

Aston Senna said:
So those are still interested in this. I ran the camera flat, nothing would turn on, tried it in another camera and also dead zero power. Charged it in the Nitecore to see how much total juice it would pump and...the ma counter stops counting at 1,999 lol. The Nikon En EL15C is supposed to hold 2,280 so that doesn't really give much info. Can't believe it stops counting. However, the current slowed dramatically after 1,999 and went for about another 30 minutes before it read 'End.' I can't think that in those last thirty minutes with it slowing to 500 ma, then 400, down to like just 80 that it added more than an extra 200 ma into the battery. So, if it was an actual real zero capacity going in, I don't believe it overcharged it. Just REALLY dumb and disappointing the counter stops at 1,999.

Darn it! Yes, the display is limited as per the picture on their site...

So it cannot display past 1999 as it has only the "1" as the maximum digit in that position. https://photo.nitecore.com/product/unk2

Not a worry for me of course using a much smaller battery in my USN2 for Sony compact BX1 battery as it takes less to charge it.

NiteCore Australia don't even list the Nikon UKN2, in Oz they sell a much more limited range than the USA site displays.

Sadly as camera sales sail off into the sunset then NiteCore most likely will never improve or expand their range of chargers, it will shrink from now on.

Mike VanV · May 29, 2023

Another vote for...asking Nightcore to explain it to you !!!

Seems to me too be the ..."best"...place, first to ask questions !

Mike

Aston Senna · May 30, 2023

Mike VanV said:
Another vote for...asking Nightcore to explain it to you !!!

Seems to me too be the ..."best"...place, first to ask questions !

Mike

Well I did ask them, took a few days for an answer. Said it's by design to only ever display 1999 at most, since when it was first designed, there were no batteries that went to over that number in capacity lol. He assured me it will safely charge any el-15 type battery to its capacity including the 15c with its over 2,200 capacity.

I think I'll just charge these batteries until the current drops from peak to half that, if i can remember to check on them and pull them out that is.

ganthercage · Jun 5, 2023

Aston Senna said:
So I just got the Nitecore UNK2 for Nikon through B&H and have questions about operation and battery charge levels, if anyone can lend a wise voice.

I was it using it charge my OEM Nikon EN-EL15C battery, which Tutuapp 9Apps Showbox B&H said is compatible, and also a Promaster aftermarket EN-EL15c battery.

Anyways as a test, because I just got them, I charged them using the USB on my Macbook, where it was providing over 900 ma of charge current to each. Great!

But, the charge kept lowering and lowering, which I know is normal, but I felt like I should check the batteries in camera to see where I was at since they were only down to 70% each (according to the in-camera 'battery info' menu) and it shouldn't take long to be fully charged. removed both batteries from the Nitecore charger and one showed 100% and the other 98% according to the camera battery info. This is disconcerting since they were still drawing upwards of 300 and 500 ma before removal.

I placed them back in the charger because I wanted to see when the charger would shut off, to see if I can trust it basically. It proceeded to lower the charging rate to just over 100 ma on both batteries as fullness approached, but just kept going and going, adding an additional 200 and 100 mAh on the batteries, or about 5 and 10% capacity on the batteries that the camera had already said were at 100 and 98% already.
So now I'm skeptical and not completely trusting this charger.

The charger states it has overcharge protection built in. But I feel, going off the camera's measurement at least, they were past 100% already and possibly overcharged. Just has me worried! Don't want to ruin my batteries with this thing, and then have a defective battery inside an expensive camera.

Curious if anyone else has noticed things like this with other chargers. Maybe the nikon measurement is inaccurate even and the Nitecore is doing just fine.

Most reputable chargers, including the Nitecore UNK2, are designed with built-in protection mechanisms to prevent overcharging. These mechanisms monitor the charging process and automatically shut off or reduce the charging rate once the battery is fully charged. This helps protect the battery from damage.

Guy Parsons · Jun 5, 2023

ganthercage said:
Aston Senna said:

So I just got the Nitecore UNK2 for Nikon through B&H and have questions about operation and battery charge levels, if anyone can lend a wise voice.

I was it using it charge my OEM Nikon EN-EL15C battery, which Tutuapp 9Apps Showbox B&H said is compatible, and also a Promaster aftermarket EN-EL15c battery.

Anyways as a test, because I just got them, I charged them using the USB on my Macbook, where it was providing over 900 ma of charge current to each. Great!

But, the charge kept lowering and lowering, which I know is normal, but I felt like I should check the batteries in camera to see where I was at since they were only down to 70% each (according to the in-camera 'battery info' menu) and it shouldn't take long to be fully charged. removed both batteries from the Nitecore charger and one showed 100% and the other 98% according to the camera battery info. This is disconcerting since they were still drawing upwards of 300 and 500 ma before removal.

I placed them back in the charger because I wanted to see when the charger would shut off, to see if I can trust it basically. It proceeded to lower the charging rate to just over 100 ma on both batteries as fullness approached, but just kept going and going, adding an additional 200 and 100 mAh on the batteries, or about 5 and 10% capacity on the batteries that the camera had already said were at 100 and 98% already.
So now I'm skeptical and not completely trusting this charger.

The charger states it has overcharge protection built in. But I feel, going off the camera's measurement at least, they were past 100% already and possibly overcharged. Just has me worried! Don't want to ruin my batteries with this thing, and then have a defective battery inside an expensive camera.

Curious if anyone else has noticed things like this with other chargers. Maybe the nikon measurement is inaccurate even and the Nitecore is doing just fine.

Click to expand...

Most reputable chargers, including the Nitecore UNK2, are designed with built-in protection mechanisms to prevent overcharging. These mechanisms monitor the charging process and automatically shut off or reduce the charging rate once the battery is fully charged. This helps protect the battery from damage.

I would definitely trust the NiteCore charger readings as being as good as it gets, any other charger or device telling what the status is would be a bit more suspect.

The only way to check what is happening is to watch the charger and as soon as it gets to "End " then remove the battery and immediately check it with a digital volt meter, then check the voltage again an hour later and again check the voltage a day later and keep notes of what you find. Over time you get a better picture of how each battery behaves.

PhotoMac503 · Jun 5, 2023

I use OEM batteries exclusively.

As the OP said, why risk expensive gear?

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Nitecore battery charger overcharging?

Aston Senna

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