I ordered a Liitokala Lii-202 recently to include in a modded L-6 package that I am selling to a local guy. Upon testing I discovered uneven charging between charging slots. One slot charges to 4.19 and the other charges to 4.13. I checked this a couple of times with new 26650’s. The charger does this on both the 500ma and 1amp settings. I ordered a few more before I discovered this, and need to find a fix before I can sell this package.
With a little hand-holding I could probably change the component responsible if I knew what it was. Any ideas?
Hey mate there is a thread with a fix for this some where in blf. Maybe some one can chime in and help?
I think it was a wrong resistor value.
You know, I thought I remembered reading that somewhere. A search did not find it. Seems like that may have been on the 100 series though.
Yea mate it could have been. but it would be the same fix I am guessing.
Hi scotlarock,
you might look here, very good thread for adapting charging current and termination voltage on the lii-100.
202 is very similar, only R5/R6 (and the second pair) are not 150k but 51k.
I experienced the same uneven on some - not all - of my lii-202s (but at least only down to 4.168V…).
I suspect either tolerance of the resistors or bad adjustment in the firmware.
Which pcb revision of the 202 do you have?
Harley, thanks for the response. I will do some more research and report tomorrow.
Here is my report:
R-5 is labeled 513
R-6 is labeled 513
PCB board is labeled V7 and dated 2016-10-28
Since this charger will be exclusively used for charging the 2x 26650 cells for the L-6 I don’t think it really matters if the termination point is the lower or higher of the two. Reminder- bank 1 terminates around 4.14, and bank 2 is around 4.19.
I have quite a few SMD resistors in different values in the size needed (0805). Anyone have an idea as to which value to add to the existing resistor, and is R-5 the left, or right bank?
I guess I’m wondering why you are even concerned with 0.05v difference. That’s gone 30 seconds after you turn the light on. Both channels are easily within spec, they aren’t overcharging, and the spread is minuscule.
I just got one in an order and it does the same thing.
In practical terms I agree with you, but he’s selling them on and I assume he really doesn’t want to have to explain all this to the customers, especially when it’s something he isn’t completely comfortable with himself.
I’d be more interested in what an accurate voltmeter showed the cells were charging to.
My Opus 3100 says it charges to 4.20 volts but a couple of good voltmeters say that’s 4.17 volts. I’m cool with that. I wouldn’t like them to say it was much over 4.20.
And my Li-500 always ‘says’ it charges to 4.22-4.23v. It’s more like 4.17v by DVM. I haven’t seen any issues with my 202 or 100 myself, but I’m obviously not overly concerned about a few hundredths of a volt as long as they aren’t overcharge.
Incorrect on what you said about the Lii-500. That is the final CV part of the charge cycle…… not the battery termination voltage.
Yes, I know. Some may not.
Well, Peardrop was correct. I’m selling the L-6’s as a package. Including 2 new 26650 unprotected cells, along with the 202 charger. Since the cells are running in series I would like to keep the risk level as low as possible, by keeping everything matched.
The voltages I reported are measured on my DMM. This charger does not have a voltage display.
Understood. But at 0.05v difference, used in series that amount will be totally shadowed by discharge differences in the individual cells.
Ok, so if I understand you correctly your opinion is to “not worry about it”. Thanks for the input. Not sure however, if I will leave it as is.
Hey mate did you check the value of the resistor is it correct?
In HKJ’s test/review thread I posted some pics of my 202.
R5 and R6 are the voltage divider for the left channel, R15 and R16 for the right.
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I desoldered both of one channel and measured a slight difference. R15 lower than 51k, R16 higher. Out of coriousity I swapped them and that changed the termination voltage from 4,168V to 4,189V. So adapting the resistors works, you just need to find the right values…
If the concern is risk level through the cells being seriously mismatched because of the difference in voltage fresh off the charger, I have to agree with flydiver again. The charger isn’t over-charging. The cells are unlikely to be perfectly matched anyway and the slight difference in voltage fresh off the charger will quickly lessen as they discharge.
Have you tried charging the cells fully, running the light until they are discharged to whatever voltage you are suggesting the customer shouldn’t let them drop below, and seeing how well they track? That’s the real test and the one the customer will put them to.
Harley, after reading your last post I tried a couple of things.
1. Added a 10ohm resister to each of the existing in the R-5, and R-6 spot. This did nothing except maybe “confuse” the charger into keeping all led indicators lit, with no cell in the slot.
2. Removed the existing R-5 and R-6 resistors. I then re-soldered both of them back in place (the resistors are the very small 0603 package and no fun to work with).
After the re-solder job the termination voltage on the right bank raised to 4.16. I can’t explain why the change occurred, after all I just reattached the factory components.
Thank you Harley, for taking the time to answer my question. Members like you are what make this forum great!