Xtar MC4 constantly overcharges!

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datumdatzgr
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Xtar MC4 constantly overcharges!

Hi,

I have bought an Xtar MC4 in 2020. I use it for charging unprotected 18650s. End voltage for my cells are mostly around 4.22-4.25V. The charging led remains red sometimes even at 4.27V. I have tested many old/new 18650 cells, various 5V adapters and different charging slots. I suspected it is fake. As you can see in the images, the branding style is different from packaging. But the build quality is too good to be fake. I have also MC1, it charges exactly to 4.19-4.20V. Do you have any suggestions?

https://imgur.com/a/a9y9huU

Edited by: datumdatzgr on 05/08/2021 - 13:05
RobertB
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I doubt it’s fake. It’s probably those junk garbage cells you’re trying to charge.

But ask xtar

https://budgetlightforum.com/user/6409

The least you could do is introduce yourself before posting a complaint post about some company

ChrisGarrett
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I’ll echo Robert’s comments about the cells.

Don’t return it until you put it through its paces with new/fresh NiMH/li-ion batteries/cells and then see what you see?

Chris

xtarflashlight
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Hi there, may I know where you bought it? And have you tried to charge other batteries? If you have any updates, can share it, or PM to us!

datumdatzgr
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Hi again,

Thanks for all the responses. Yes, the cells in that picture are old. But I have tried brand new LG Chem and Sanyo cells also. One of them is below.

My observations are:

0) Charger build quality is very good, no heating, compact, great for camping, I like the charger very much. That’s why i wish it didn’t have this issue.

1) Whatever combination of slots/cells I try, resulting voltages are high, MOST of the time (>4.24V).

2) If I use outer slots, (since they use a higher termination current, i think) the termination voltage is relatively low (4.22-4.25V). For inner slots, any cell may go as high as 4.28V, but they occasionally may also end up as ~4.25V. Btw, after charging, I wait half an hour, but the voltages go down 0.01V at most.

3) I have bought them from a reliable distributor of Xtar in Turkey (https://birikimpilleri.net/)

4) I have tried a 5V 3A charger, 5V 2A charger, 5V 850mA charger (for a single cell only). I have tried many high-quality USB cables. Still no change; termination voltages are always high.

5) Most probably the seller won’t accept return. So, I am thinking of getting an Xtar MC2S. I want the charger to be simple, compact, and undercharging. If you have any suggestions, i want to hear them also.

Özgür

ChrisGarrett
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Just send it back for an exchange. These chargers have about $3 worth of parts and some are bound to be dwanky coming out of the factory.

Chris

NiOOH
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Is your DMM calibrated? Can you check it against a reference voltage source or, at least against another DMM.

datumdatzgr
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Yes, my DMM is showing nice values (4.19-4.20 V) for my other chargers: MC1 and VC2S. So, I have just throwed MC4 out:( I suggest any MCx owner to be careful.

Lightbringer
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Hm? I’m curious how even crap cells would keep overcharging to 4.whateverV.

The CV phase should be a constant voltage no matter what the cell.

I had real crapcells included “free” with a light, and they charged fine. Oh, they only had like 600mAH and 800mAH capacity, but they did charge correctly.

09 F9 11 02 9D 74 E3 5B D8 41 56 C5 63 56 88 C0