Test/review of LiitoKala Lii-S1

Batteries and Chargers Chargers
1

LiitoKala Lii-S1











LiitoKala has made a couple of small usb chargers, this model adds a voltage display to the smallest model.







The charger arrived in a nice cardboard box with specifications on it.







The pack contained the charger, usb cable and a instruction sheet.







The charger is powered from micro usb.







The charger has a LED display and some leds together with a button for user interface.







When putting a LiIon battery in the charger the 3.70V chemistry leds starts flash, presses on the button will change the selected chemistry.







Holding the button down will change the current and show the new value.







It is easy to see when the charger is done.







No battery in charger.







The charger uses the typical slider construction, it can handle batteries from 33mm to 70mm.















The charger can just about handle 70mm long batteries (The 21700 was very tight), inclusive flat top cells, this means most protected cells.







Measurements charger

  • LiIon and NiMH Batteries will be discharged with 0.1mA when power is off.

  • Default charger current is 0.5A

  • Voltmeter is within 0.02V, except at very low voltages.

  • Voltmeter will only update reading slowly and will never reduce the value.

  • Above 2 volt a battery is assumed to be LiIon.

  • Charger will not restart when battery voltage drops, but see below.

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


Charging 4.20 volt LiIon



I wonder why the current drops from the start, maybe the charger is damaged again, the 1A reverse curve looks more normal.
The termination is a bit strange, there is some sort of trickle charge going on.



A fine CC/CV charge curve, There is also trickle charge here.



This older cell has more problems with termination. The current must be fairly low, because the cell voltage do not increase after the pulse.



There is some instability problems in the internal regulation as can be seen from 165 to 180 minutes, this is not a problem for the charging.





This very old cell drops significantly in voltage when charging terminates and this means lots of restarts.





The charger can work with the cell either way around in the slot, here I charged it with + away from the display.



Adding a resistor in series with the usb power supply to simulate a long cable or weak supply did not prevent the charger from doing a good job, but it needed some more time.



M1: 32.8°C, M2: 37.5°C, M3: 39.5°C, HS1: 50.5°C



With LiIon cells the charger gives the user some time to select LiIon chemistry, before it slowly ramps the current up.



The slow ramp is also used when increasing current during charge, decreasing goes fast.



The “trickle charge”, I wonder why the charger do that. The actual current is only a few mA and will not do any damage if batteries are removed in a couple of hours after it is finished.



Charging 4.35 volt LiIon



The 4.35 volt charge works as expected.



Charging 3.60 volt LiIon




Both LiFePO4 cells is charged fine to 3.65 volt. Again the charger is pulsing, the actual pulse current is about 170mA for the 18650 cell, but only for a second or two. This is a sort of trickle charging.



Charging NiMH



The charger stops on voltage and will trickle charger with a low current. The termination looks to be slight premature.



The Pro is also terminated on voltage, here the cell has started to warm up, i.e. it is full.



The powerex cell is worn down and the termination is a bit slow.



At 0.5A the voltage termination looks fine.



The AAA is again slightly premature in termination.



This Chinese cell is terminated perfectly on -dv/dt.



With voltage termination a full cell can be detected fast.



This cell was put in the charger the other way around , this is not a problem for the charger.



HS1: 53.8°C, M1: 35.8°C, M2: 38.3°C, M3: 39.0°C



The charger starts faster with NiMH, but uses a slow ramp and measuring pulses.



Current change also uses the slow ramp when increasing current, but not when decreasing current.



Conclusion

I like the idea with a voltage display on a simple charger. The multi chemistry can also be useful and the two current means more battery sizes can be charger at a good rate.
The charger specifications says it can charger from 0V, but that is not really possible with reversible batteries, there is a risk batteries are charged backwards.
NiMH is the typical voltage termination and without any top-off charge, it means slightly undercharged batteries.
The trickle charge is low enough that it will not be a problem as long as the batteries are removed within a couple of hours.

I wonder how robust the charger is, I damaged one during some detailed test and \#2 may also be damage (See first curve).

I will rate the charger acceptable.



Notes

Here is an explanation on how I did the above charge curves: How do I test a charger
Read more about how I test USB power supplies/charger
2

Thanks for the review.

That 1A Li-Ion charge curve is quite odd, indeed. Mine is in the mail. When I get it, I’ll see if it behaves any different.

3

I should have waited for your review before I purchased one. Mine seems to be ok so far without doing any testing other than comparing the display voltage to my Fluke. That part reads a 10mv difference. Still charging my first cell.

4

Thank you for the review, HKJ.

Unfortunately, I find the implementation of the Lii-S1 to be unsatisfactory.

LiitoKala know better than to allow a trickle charge on Li-Ion cells or even on LSD NiMH. I don’t like that strange result you got where the charging current dropped from the very start, either.

I jumped the gun and bought several Lii-S1 chargers in last week’s AliExpress anniversary sale. Having seen your results, I’ve decided to break these chargers up for parts when they arrive. Fortunately, the price I paid was so low that I’m happy to do that.

It’s a shame, because I’m legally blind, and the LED voltage display would have been much easier for me to read than the usual LCD displays. Oh, well - perhaps I can assemble a TP4056 module and mini voltmeter into a Lii-S1 body and at least get a nice Li-Ion 3.7V-only charger out of it.

For now, I’ll be sticking with my trusty Lii-100 chargers, all six of which are perfect.

I’m very grateful that you do these reviews, because the wonderfully detailed information you provide is exactly what I need to make the decision that’s right for me.

Thank you again :slight_smile:

5

I did not have any complains about the voltmeter, it is fairly precise.
The problem is the trickle charge and that I damaged two chargers.

If I wanted I could probably repair the first charger (Replace Q4):

6

I measured the end voltage seconds after termination. I got 4.2246 volts with my Fluke 189

7

So is this a decent charger? If you remove the cells in time, the trickle charge should be harmless right?

8

Thanks a lot for another great review, HKJ!
I initially posted the S1 deal in the other thread and was wondering how it would perform.

This should give good insight for everyone who jumped on the deal, again, thanks so much.

9

Can't say I'm thrilled, definitively. This charger's value/price can't compare to that of the Lii-100, by a long shot. Maybe the polarity detection thing gets in the way? Shoddy implementation anyway, imho.

A Lii-100 with voltmeter and output voltage selection with no less than 0.05V granularity would have been much better.

Cheers

10

Looks like the early adopters got burned on this one. Hopefully they are up to fixing this charger in the next round of manufacturing as it has the potential to be a very nice charger.

11

Hi HKJ, I have a 1S charger, can i use this charger to charge 4 battery in parallel simultaneously, is there any downside of this method except the longer charging time? Thanks

12

That will work as long as the batteries starts at about the same charge state (i.e. voltage). You will get lower termination current, that means the final voltage will be slightly higher and higher voltage means slightly more wear on the batteries (I would not worry about it).
The charger may also have a upper charge time limit and stop before the batteries are full. Disconnecting and reconnecting the batteries will continue the charging.

If you ever connect one of the four batteries the wrong way around you will get some very hot connection in less that a second!

13

I have a 4-parallel-18650 flashlight and i dont want to take them out to charge, i want to keep them always in parallel in the flashlight and charge all at once so they are always balanced. i’m going to do a modification that can connect positive/negative polarities of charger directly to positive/negative polarities of the batteries, while they are still in the flashlight. Is there any problem with this idea? thanks

14

I have one of these chargers at work (secondary school) attached to the computer, to top up my EDC and the 18650’s in the demo-lasers (physics class) The clear and instant voltage read-out when inserting a battery is very convenient and for the rest all it takes is ignoring the negatives found in this review, really happy with it :slight_smile:

15

No, not as long as there is no risk of shorting the batteries while connecting/disconnecting.

16

I've done the in parallel charging thing many times LoL. Only drawback is it takes longer, an even longer if you don't care about optimizing cell and charger connections. In the above example the alligator clip connections (negative to the rail and positive one by pressure, which I ended up fixing with a magnet for safety reasons) displayed a high resistance which slowed down charging even further, with an early and long constant voltage phase due to all the resistances between charger output and cell can contacts.

Cheers :-)