Xtar MC4 constantly overcharges!

Batteries and Chargers Chargers
1

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?

[Album] imgur.com
2

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

3

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

4

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!

5

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

6

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

7

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

8

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.

9

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.