Test/review of Charger Xtar MC4S

Charger Xtar MC4S











This is one of Xtars simple chargers, it can charge LiIon and NiMH. It uses a USB-C socket for power input and only needs 5V.







The charger is delivered in a white cardboard box with specifications on it.







The box contained the charger, a USB-C to USB-A cable and a instruction sheet.







The USB-C input that only requires 5V and cannot turn a USB-C charger on.







There is not much user interface, only a couple of leds. They are red while charging, green at all other times.







The specifications are on the back of the charger, in clear white print.







The charger can handle both button top and flat top batteries.

The slider moves smoothly and can hand cells from 32mm to 72.5mm long.







The charger is marked with charge current, but it is not correct.

















The charge current is on the high side for small batteries.







Measurements charger

  • Power consumption when idle without batteries is 30mA from 5V

  • From 0V to 2.8V the charger will charge with 100mA, above with full current.

  • Below 2V it will assume NiMH batteries

  • Above 2V it will assume LiIon batteries

  • When charge is finished the charger will charge with 0.7mA.

  • Charger will not restart if voltage drops.

  • Charge will restart charging after power loss, or battery insertion.

  • When not connected to power it will drain up to 8mA from a battery.

LiIon





This is a CC/CV charge, termination current is around 100mA







Slot #2 looks similar, but termination current is higher. This is a bit strange because it was supposed to charge with 0.5A, but it also uses 1A.









The last two slots are similar with 1A charge current.











There is no surprise with the other batteries.







I did the smaller cell in slot #1, to see if the 0.5A current kicked it, but not is also uses 1A on small cells.







Simulating a weak charger or long cable reduced the current significantly, but the charger terminated slightly early.







With four batteries the charger did reduce charge current to 0.5A.







M1: 30.1°C, M2: 31.3°C, M3: 31.1°C, M4: 29.9°C, M5: 33.8°C, HS1: 39.0°C







HS1: 38.9°C







The charger is very fast to start.







How much current the charger discharges batteries with when not powered. It is best to remove the batteries when the charger is done.







The charge profile for slot #2 (Marked 0.5A). It uses 1A. The NiMH only shows at 0.1A, because I do not wait 5 minutes at each step.







The charger handles the voltage dips nicely, but because it fails on NiMH i will not trust it on a small solar panel.







NiMH







This is a very fast charge, it only takes 20minutes with the first 5 minutes used at low current, but then the battery is only charged to about 10% of capacity.







This is better, the charge current is nearly 1A and it charges the battery fully.







Again a partially charged battery.







And another partially charged battery.









These two high capacity batteries gets a full charge.







But the leise fails completely to charge.







The full cell was stopped very fast.







The AAA cell is charged nicely.







Charging four cells did also fail, the one I measured on terminated very early.







M1: 30.4°C, M2: 36.2°C, M3: 37.3°C, M4: 33.4°C, HS1: 47.8°C







With NiMH the charger starts with a low current charge, this is probably to detect LiIon batteries.







After about 5 minutes it switches to full charge current and it terminates shortly after.







It is not as good with unstable voltage and NiMH as it is with LiIon, but it is not as bad as the chart shows. The problem is the pulsing of charge current (The raw data shows it do fail).







Conclusion



Xtar has completely failed with this charger. The charge currents are wrongly marked and it cannot charge NiMH reliable. It uses a USB-C connector, but do not work with a USB-C supply.



With that said it will charge LiIon nicely.







Notes



The charger was supplied by XTAR for a review.



Here is an explanation on how I did the above charge curves: How do I test a charger

Thanks for the review. I almost bought this charger.

Oh man. I bought this charger some time ago and it should reach me soon. I would like to believe that maybe your charger is defective in some way, but I will not lie to myself.
Thank you for review.

It is pretty weird that a xtar charger has bad algortihm or bad desing.

Maybe unit is faulty or something went wrong during testing….

Xtar sometimes have trouble with NiMH charging.
I was very surprised about 1A on all slots.
The fail to turn on a USB-C charger can be a production fault in the charger (A missing resistor).

Is the Xtar MC4S supposed to work with USB-C to USB-C cable? Or just USB-A to USB-C?

Based on the review, this Xtar really did fail with the NiMh charging part. I think this model will be one of the first in the “MC” series to support both Li-Ion and NiMh, but with the NiMh part failing quite miserably… (Most of the other Xtar MC series appear to support Li-Ion charging only).

I may have missed the info about the max charging rate, assuming the USB power source has sufficient current.
Is the following correct:

- when charging 4x NiMh, the charging rate is 4x 1A (and doesn’t charge at 0.5A) [to be more precise: around 0.8Amp charge rate, based on the charging graphs above]

  • when charging Li-Ion, if 1 or 2 slots, then max 1A; and when charging 3 or 4 slots, max charge current is 0.5A

It obvious only work with a USB-C to USB-A cable, I do not know what it was supposed to work with.

Xtar sometimes have problems with the NiMH algorithm. I do not know if it is due to different development teams or changes in hardware.

Correct.