Test/review of Charger NiteCore UMS4

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Test/review of Charger NiteCore UMS4

Charger NiteCore UMS4
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This is a USB QC powered universal charger with adjustable current.
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The cardboard box lists lot of specifications, battery types and features.
The box contains the charger, a USB cable, manual and a warranty card.
The charger has the USB connection on the back together with a plastic heat sink.
The charger has two switches:
C: A short press will change slot and longer press will enter the charge and battery menu.
V: Step between displayed values and change settings in menu.
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When charging it will show chemistry (Li-ion), algorithm (CV), charged capacity, internal resistance, current, voltage and time.
The “Quick Charge” is present when the charger is power from a QC charger.
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The 4.35V batteries are shown as 4.3V and LiFePO4 as 3.7V and NiMH is shown as NiMH/NiCd with -dv/dt algorithm.
The yellow label has the important specifications and is easy to read.
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The slots uses the usual construction and works well. They can handle batteries from 29mm to 77.8 mm long, the new 21700 with protection will fit in the charger.
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The charger can handle 77.8 mm long batteries, inclusive flat top cells.

  • Discharges LiIon with 0.2mA and NiMH with 0.05mA when not connected to power
  • Below 0.8 volt the charger will show EEEE and charge with about 0.5mA.
  • At 0.8 volt the charger will assume NiMH and start charging.
  • The charger will assume NiMH below 1.7 volt and LiIon above 2.0 volt.
  • Will not restart if battery voltage drops.
  • Charges with 0.05mA when LiIon battery is full.
  • Voltmeter readout freezes when charging is finished
  • Voltmeter is within 0.03 volt.
  • Voltmeter has a max. readout of 4.20 volt when LiFePO4 or 4.3V is not selected.
  • Slot #1 & #3 shares a charge circuit, the same with #2 & #4, i.e. charge speed will be halved when they are used together.
  • Change between 1A and 2A for LiIon in QC mode is around 55mm long batteries.
  • Charger uses 12V in QC mode and up to 2A current.
  • Charge will restart charging after power loss or battery insertion.
  • Power consumption from USB when idle without batteries is 32mA for standard USB and 50mA from QC

LiIon charging
Current can be adjusted from 0.3A to 2 in 0.1A step. Default is 2A with long batteries and 1A with short batteries. With QC maximum is increased to 3A for long batteries.
This is a nice CC/CV charge curve with about 120mA termination current.
Display shows 3050mAh, 3:49, 157mOhm
The 3 other slots are similar, but there is a minor voltage difference.
Display shows 3221mAh, 3:53, 182mOhm for #2
Display shows 2916mAh, 4:10, 226mOhm for #3
Display shows 2997mAh, 3:45, 132mOhm for #4
The two other capacities are also charged fine.
Display shows 2493mAh, 3:13, 197mOhm and 2787mAh, 3:35, 147mOhm
Increasing charge current to 2A works without problems.
Display shows 2708mAh, 2:00, 204mOhm for SA18650
Display shows 3115mAh, 2:49, 207mOhm for SA18650
Display shows 2972mAh, 1:47, 127mOhm for SA20700
This old and worn down cell I charged at lowest setting., the charger works fine, but a lower termination current would have worked better.
Display shows 176mAh, 0:53, 500mOhm
A 14500 with 0.5A charge current works fine.
Display shows 709mAh, 1:48, 470mOhm
Boosting input voltage to the charger with QC makes it possible to charge with 3A
Display shows 2786mAh, 1:23, 133mOhm for AP18650
Display shows 3088mAh, 1:13, 130mOhm for SA20700
With four cells in the charger from normal USB the current is reduced to 0.5A for each cell.
Display shows 2949mAh, 7:27, 198mOhm for #1
Display shows 3033mAh, 6:56, 111mOhm for #2
Display shows 3258mAh, 7:11, 108mOhm for #3
Display shows 3029mAh, 6:56, 80mOhm for #4
With QC power the charge speed is faster, in this case more than two hours is saved.
Display shows 3203mAh, 5:47, 274mOhm for #1
Display shows 3158mAh, 4:22, 95mOhm for #2
Display shows 3247mAh, 4:22, 98mOhm for #3
Display shows 3230mAh, 4:22, 57mOhm for #4
Using a 0.5ohm resistor in series with the power to simulate a weak charger or long cable makes the charger real slow and it stopped before the batteries was full. It looks like a 20 hour limit on charge time.
M1: 40.4°C, M2: 41.7°C, M3: 42.0°C, M4: 40.3°C, M5: 44.9°C, HS1: 54.4°C
HS1: 57.8°C
Charge profile for NiMH and LiIon, this charger only works at selected current, there is no low current at low LiIon voltage.
The charger need some time to start a charge. The charger measured voltage with current off.
Using QC do not change it.
The charger will timeshare the charging circuit when multiple slots are used, this means average charge current is halved.
When entering the current change menu the current is turned off and first resumed when leaving the menu.
The charger has some problems with a unstable power supply.
4.35V LiIon charging
This looks fine.
Display shows 2731mAh, 3:30, 167mOhm
IFR (LiFePO4) charging
Display shows 473mAh, 1:12, 364mOhm
These batteries are also charged fine.
Display shows 1129mAh, 1:29, 139mOhm
NiMH charging
Current can be adjusted from 0.3A to 2A in 0.1A step both with USB and QC power supplies. Default is 1A
This is a -dv/dt charge curve, it looks like the charger makes a short top-off at 250mA
Display shows 1765mAh, 1:50, 214mOhm
The other slots looks similar, include the top-off.
Display shows 1831mAh, 1:53, 257mOhm on #2
Display shows 1890mAh, 1:57, 205mOhm on #3
Display shows 1806mAh, 1:52, 379mOhm on #4
The two high capacity cells are also charged nicely and also get the top-off.
Display shows 2482mAh, 2:32, 262mOhm for Pro
Display shows 2857mAh, 2:57, 452mOhm for Leise
The charger has no problem stopping with 0.5A in charge current.
Display shows 1775mAh, 3:38, 307mOhm
The AAA is also charged nicely.
Display shows 740mAh, 1:31, 311mOhm
It takes about 10 minutes to detect the full cell, this is fast for a -dv/dt charger. Here the top-off looks to be around 2 minutes.
Display shows 156mAh, 0:11, 130mOhm
The charger can charge with up to 2A on NiMH cells.
Display shows 1799mAh, 0:57, 302mOhm
With four cells the charge current is 1A.
Display shows 2065mAh, 2:06, 212mOhm on #1
Display shows 1898mAh, 2:01, 196mOhm on #2
Display shows 1898mAh, 2:01, 173mOhm on #3
Display shows 1923mAh, 2:02, 191mOhm on #4
And there is no bonus for QC.
Display shows 1932mAh, 2:04, 371mOhm
Display shows 1907mAh, 2:01, 178mOhm
Display shows 1982mAh, 2:05, 187mOhm
Display shows 1974mAh, 2:03, 165mOhm
M1: 46.5°C, M2: 47.3°C, M3: 46.6°C, M4: 47.6°C, M5: 52.6°C, HS1: 66.5°C
HS1: 64.8°C
The charger uses a low test current, probably to check for LiIon/NiMH, before it switches to the full charge current.
Using QC do not change it.
NiMH uses the same time sharing as LiIon.
The current is off when changing current.
Unstable power supply do not work with NiMH either.
Internal resistance
The internal resistance measurement is not very impressive on this charger.
This is for LiIon
And NiMH.
Some of the readings are probably correct, but there are to many sporadic readings.
Generally the charger works well, but the default LiIon current (2A) is mostly for high current batteries, it is possible to select a lower current with some button presses. There is also the detail about time sharing, this means with 3 or 4 batteries in the charger the current is halved.
The internal resistance measurement do not work very well.
I will rate the charger as fairly good.
The charger was supplied by a Nitecore for review.
Here is an explanation on how I did the above charge curves: How do I test a charger

My website with reviews of many chargers and batteries (More than 1000): https://lygte-info.dk/

Last seen: 1 month 3 days ago
Joined: 09/01/2015 - 16:16
Posts: 8

Thank you for the review!

Last seen: 20 hours 34 min ago
Joined: 03/09/2016 - 15:24
Posts: 2166
Location: Ohio

I just bought this charger. I like the fine adjustment of the charging current that this charger has.

Slot #1 & #3 shares a charge circuit, the same with #2 & #4, i.e. charge speed will be halved when they are used together.

I’m a bit confused about the charge current maximums when charging multiple cells. I’m using a 18W QC adapter. When I charge 21700 cells in slot 1 and 2 the max selectable current is 2A per slot, and it apparently delivers this current, though I didn’t verify with a second meter. The instructions don’t seem to mention which slots are on the same charge circuit. Since 3A is the max for a single slot I would expect 1.5A to be the max for each slot if the 2 slots were on the same circuit.

Then when I charge the 2 cells in slots 1 and 3 the max selectable current for each slot is 3A, the combined current is above the rated output of the charger. So I’m not sure what is going on; whether the charger output is underrated, or if the displayed current is not accurate.

Edit: I found some relevant info in the instructions:
“When charging 1 or 2 batteries, it is recommended to put them into slot 1 and slot 3, or into slot 2 and slot 4, to achieve a wider selectable range of charging current of 300mA-3,000mA. Otherwise the selectable range of charging current is 300mA-2000mA.”

This is consistent with what I’m seeing, but still does not explain the fact that 2 × 3A is above the rated output of the charger and adapter. I believe you saw similar behavior in your review of the UMS2; the ability to select currents that exceed the ratings.

Last seen: 20 hours 34 min ago
Joined: 03/09/2016 - 15:24
Posts: 2166
Location: Ohio

I looked into this more and discovered the “time sharing” issue you mentioned in your review, but it was not clear to me from your review what was actually happening.

When 2 cells are charging in slots 1 and 3 the charging current is half of the displayed value. If it displays 1000mA it will only put in 500mAh in one hour. I checked with a clamp meter and it is “time sharing”, charging with the correct current for half the time and charging with zero current for the other half. Switching between these two states every 5-10 seconds.

The instructions don’t mention this at all and seem to encourage charging in slots 1 and 3 in order to get higher currents, when in fact you get less current in that configuration. I don’t see how this is not a big flaw and misleading by nitecore. This is my first multi bay charger so maybe this sort of behavior is normal, but I’m pretty displeased.

When you use slots 1 and 4 or 2 and 3 together it seems like you can get true 2A max current for each, so it is useable as long as you are aware of this and remember the displayed currents will be wrong in some configurations.

Last seen: 7 months 4 days ago
Joined: 12/05/2020 - 10:13
Posts: 2
Location: Covilha, Portugal

Good afternoon, everyone.

I bought a Nitecore UMS4 charger to be used with a QC 2.0 mainly to charge 3 Molicel P42A 21700.
I’ve read extensively reviews and tests to many different chargers and this one seemed like the best in this price range to charge these batteries.
The only thing that I haven’t fully understood is how does the timeshare work and what are the implications of it.
I read the manual available online and as far as I understood, the charger has 4 slots for charging the batteries but in reality 2 charging circuits – one for slots 1 and 3 and another for slots 2 and 4, efectively timesharing the charging between each slot.

As far as I understood, the charger charges at 2×2A (QC) / 2×1A (USB) alternating between each slot every 10s, ie., charges slot 1 at 2A during 10s and then charges slot 3 at 2A during 10s, efectively averaging 1A in each slot, and the same happens with the other slots. Is this correct?

Is the only drawback that instead of charging at 1A constant it charges at 2A every 10s and, once the charging phase switches from CC to CV, it actually reduces the average current? After all, once the charger begins charging at constant voltage, the current that the battery can take is reduced. And since it charges at, for example, 1,5A every 10s in each slot, the average current is 0,75A when it could be charged at 1A constantly without interruptions.
So, while the charger is at the CC phase, it is no different in charging time but once it reaches the CV, the charging time is actually increased. Am I thinking correctly?

Also, if one inserts two batteries at different charge levels in slots 1 and 3, for example, they can’t be charged at the same current. How does the charge handle this situation? When it switches slots it also changes the current?

What are the drawbacks and advantages of this charging method?

I’m sorry for the long post but this is kind of complicated and I’m hoping someone could explain this to me since this charging method is new to me.


Last seen: 7 months 4 days ago
Joined: 12/05/2020 - 10:13
Posts: 2
Location: Covilha, Portugal

Another scenario I also thought of is charging different batteries in slot 1 and 2, or 3 and 4. For example, Li-on of different capacities and, therefore, different charge currents.
Or if I want slot 1 to charge at 1A and slot 2 to charge at 300mA.
Or finally, if I want to charge e Li-ion battery in slot one and a NiMh battery in slot 2.
How would the charger handle these scenarios if the charging circuit is the same, if there is timeshare?


Last seen: 6 months 2 weeks ago
Joined: 03/12/2021 - 09:33
Posts: 1
Location: Argentina

HI everyone, I am new to this and I need some advice, what should I buy, LiitoKala Lii-500 or Nitecore UMS4, I have no other choice to buy quickly here in argentina.