Test/Review of Charger Klarus CH4s

Batteries and Chargers Chargers
1

Charger Klarus CH4s





Klarus is mostly known for their flashlights, but they do also sell some chargers. Here I am looking at a 4 channel universal charger that shows how much capacity that is charged into the batteries.



I got the charger in a retail box from a gearbest.



The box contained the charger, a mains cable and a instruction sheet.



The charger has both a mains power input socket and a micro usb power input socket.
During my test the micro usb socket broke loose.



During power on the charger will show all segments on the display.



Here I have loaded the charger with some batteries, the charger will automatic select NiMH/LiIon chemistry, but LiFePo4/3.7V/3.8V must be selected manually with the mode button. Default is 4.2 volt LiIon (3.7V on display).
The mAh display shows how many mAh is charged into the battery.



There is two buttons, one to select battery chemistry (MODE) and one to select slot.
When the charger is loaded with batteries the MODE button will select chemistry for all batteries at once. To select chemistry for individual batteries press the SLOT button (Very good functionality).
When the charger starts charging the selection is locked for that battery, to change it the battery must be removed and inserted again.



The charge uses the typical slider construction with a metal rail and it works very well from about 30mm to 71mm, i.e. the charger can handle just about any protected 18650 and 26650 cell.








The charger can handle 71 mm long batteries, including flat top cells.
The minimum charge current is 0.5A, this is on the high side for 10440 cells.



Measurements

  • Power consumption when idle is 0.56 watt, it drops to 0.38 watt when the display reduces brightness.
  • The display will reduce brightness after two minutes without any button presses.
  • When only using slot #1 and #4 the charge current is 1A
  • When using slot #2 or #3 the charge current for all slots will drop to 0.5A
  • Current will change between 0.5A and 1A as batteries are inserted and removed.
  • A full cell in slot #2 or #3 will still reduce current in slot #1 and #4
  • Mode button is used to select LiIon chemistry
  • Slot button is used to select slot when selecting chemistry.
  • Charger will start charging from about 0V
  • Above 2.0 volt the charger assumes LiIon batteries.
  • From about 1 volt the voltmeter will be precise (Within +/-0.03 volt).
  • When the battery is full the voltmeter will stop updating.
  • The charger will not restart if battery voltage drops.
  • Charge will restart charging after power loss, or battery insertion.
  • When not connected to power it will drain about 2.2mA from a LiIon and 0.7mA from a NiMH battery.



Charging LiIon 4.2V



This is a nice CC/CV charge curve with 100mA termination.
Display shows 2924mAh



The second slot only charges with 0.5A and uses the same 100mA termination. The lower charge current will make it slower, but also useful for smaller batteries.
Display shows 2816mAh





The two last slots looks like the two first.
Display shows 2757mAh and 2880mAh




2600 and 3400mAh cells also looks fine.
Display shows 2578mAh and 3120mAh



This older 2600mAh cell do not look as perfect, the voltage is a bit high during the charge and the termination is a bit early. This is nothing serious, but could be better.
Display shows 2297mAh



Another old cell, again the charger curve is imperfect.
Display shows 611mAh



This cell is newer and the charge curve looks much better.
Display shows 717mAh



Using the usb power input was rather slow. The problem is voltage drop in the cables, this charger needs 5V or a bit more.



Increasing my power supply to 5.2 volt did help, but I did not reach full charge speed. It do even reduce charge rate when battery voltage increase and the charger needs more power.
Display shows 2916mAh, 2883mAh, 2872mAh, 2644mAh



Using mains voltage is much better, but current is a bit lower than for a single cell.
Display shows 3057mAh, 3021mAh, 3086mAh, 2946mAh




M1: 34,8°C, M2: 37,6°C, M3: 38,6°C, M4: 36,6°C, M5: 49,0°C, M6: 48,5°C, M7: 51,4°C, HS1: 61,4°C
Batteries are not heated much during charge.



M1: 34,7°C, M2: 37,5°C, M3: 38,2°C, M4: 36,4°C, M5: 48,6°C, M6: 52,8°C, HS1: 63,9°C






The charger is fairly slow to start because it waits for user input.



Charging LiIon 3.6V (LiFePo4)



A good LiFePo4 charging.
Display shows 1190mAh


Charging LiIon 4.35V






Charging NiMH



This looks like a nice -dv/dt charging.
Display shows 1654, this is significantly lower than my curve shows.



With the lower charge current the -dv/dt charging can be slower to terminate.
Display shows 1753



This time it terminated perfectly.
Display shows 1517



The last channel did also terminate perfectly.
Display shows 1774




Higher capacity with 1A charge current, the termination works perfectly.
Display shows 2239 and 2169



It looks like the charger stops slightly premature on this AAA cell.
Display shows 502




Detecting a full cell depends on charge current, it is faster with 1A than with 0.5A



NiMH needs less power and less voltage than LiIon, but it is not possible to see the charge current on the above chart.



Same as above, put with the input current removed. The charge current is about 0.5A for all four batteries, there are no problems with voltage drop from the usb power supply.
Display shows 2093, 1955, 1787,2713 (Oops, the last one did not terminate).



There is not much difference between mains power and usb power when charging NiMH.
When a cell is finished there is a bit more current to the other cells.



M1: 34,4°C, M2: 35,7°C, M3: 35,8°C, M4: 34,7°C, M5: 39,9°C, M6: 38,9°C, M7: 43,8°C, HS1: 50,4°C
The batteries are not heated much during charge.



M1: 33,7°C, M2: 34,8°C, M3: 35,5°C, M4: 34,0°C, M5: 41,9°C, HS1: 49,5°C




The charger is fairly slow to start because it waits for user input.



With NiMH the charger stops at regular intervals to measure voltage.


Testing the mains transformer with 2500 volt and 5000 volt between mains and low volt side, did not show any safety problems.



Conclusion

When the charger is turned off it looks like something I have seen before, but display and functions are significantly different.
I like the capacity display, but it is on the low side for NiMH.
The support for 3 different LiIon types is also very nice and the selection function is good to use.
LiIon has a good charge curve, except on old cells.
NiMH works fine at 1A, but need better termination on 0.5A, I am a bit worried it might miss termination on some cell when using 0.5A.

There is a lot to like about this charger, but due to the above issues, it is just below what I will call good, i.e. acceptable.



Notes

The charger was supplied by Gearbest for a review.

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

2

I was waiting for this!

Thank you for another great review HKJ :star:

3

I’m glad you got this from a retailer — that avoids the risk being sent a specially prepared sample. (No offense to Klarus, that is a worldwide problem and has always been)

Do you have any idea whether Klarus will respond to your evaluation by improving this device?
If so I’ll hold out for an improved version rather than cross it off my list of possibles.

4

It do probably happen once in a while, but if you check my reviews you will see that I have got duds, even from manufacturers.

The termination is very difficult to adjust for a review, the only thing you could do was selecting a charger with very precise voltage levels.

I have no idea. Klarus do now about me, but I do not know if they are going to listen to me.

5

Thank you very much for the review!

6

I had high expectations of this one. The report show it still performs well.

Thanks for the review HKJ

7

[quote=Rolz]
The report show it still performs well.

[quote]

It does, I was very close to calling it good. I do like the user interface and the way it works.

8

Thank you for the review hkj. So often there are minor flaws that devalue a product, and you have to wonder, do they really know what they are doing? If so, why didn’t the manufacturers run these tests with the prototypes and iron out the problems?

9

I do often wonder about that. Once we had a charger designer showing his surprise about the charge curve of Panasonic LiIon cells (He is very good at making NiMH chargers). It took him a few iterations of the charger to mostly fix it (And some of my tests).

10

Without wanting to be rude about anyone, i can only think the people working on these products, producing them for the price they do, are at the limit of their abilities! For the record, i wouldn’t know where to begin :smiley:

11

Depends on the company, it can also be lack of time to study what is required. I.e. they now how to make the electronic, but if they do not know exactly what is required, they may get it wrong.

12

Thanks for the review HKJ. I was looking at this one before deciding on the simpler i4. I like how the mAh readings are pretty solid within actual ratings too.

13

I was really expecting at least a good on this charger :~ , would be nice if next one comes with discharge capabilities, thank you so much for the review HKJ you are truly my only reliable source for final opinion in regards to batteries and chargers, I ended up buying this charger :wink:

14

It’s such an awesome charger… it could almost be everything… so close. I’m gutted about the termination issues on NiMH with low current, I’ve been procrastinating about a new charger for a while and I really wanted this one to be great. Also, isn’t 500 mA a little high for AAA, is that likely to reduce cell lifetime? Almost forgot, Great review! Thanks

15

No, it is perfect, but it is too low for AA when using -dv/dt termination (You need some extra tricks for reliable termination at that current).

16

This looks like a nice charger. I have some questions though:

1. Does the voltage display update with a full battery as the battery’s voltage drops?

2. Is capacity measurement during charge good enough to tell how worn out is a battery or do you need an analyzing charger that measures capacity during discharge for that?

3. Is the capacity measurement for NiMh completely wrong/random or is it still usable to tell if a NiMh is worn out?

17

No, most chargers disables the voltage readout when they stop charging.

It is good enough.

It is not random at least when charging with 1A, it does just show a lower value. You just have to accept that everybody else got 2000mAh cells and you only got 1700mAh cells, even if they are the same cells (The actual value will probably vary between different copies of the charger).

Generally the calibration is not important to show if a cell is worn down or not, as long as you can compare the values to a new cell.

18

Thanks. FWIW my Xtar VP1 shows voltage drop after the charge is complete.

19

The meter on VP1 only locks up when voltage is above 4.20 volt. This is not perfect, but better than always freezing the reading.

20

At some point during the charge with the older cells the voltage overshoots the 4.2V mark. Is this reflected on the display?