A followup…now I get good consistency, but unrealistically high results. 18650GA doing nearly 3700 mAh?
I got independent confirmation: my C4 measures at least 10% too high compared to Lii-500. That’s after taking into account different termination voltages.
Does anyone know if I can still ask Gearbest for refund / replace long after I actually received the charger?
Also, I can’t help but wonder how many faulty C4s are there in the wild….was it a problematic batch or a single charger?
Anyone got an idea how to modify the charger to get 21700 cells in it? I really love the charger, but it’s just 0.1-0.2mm too short for these cells.
I wanted to add here that another BLFer got a C4 which measures too high:
I have tested my C4 with different brand new cells so far (protected Imalent 18650, protected Acebeam 18650, unprotected Samsung 30Qs, 35Es). Everytime I get significantly higher values on slot #2 than on the other three slots. I also have unrealistic higher capacity values. (Note: The green one left is a Sony VTC5A with only 2.600mAh nominal capacity)
I would be interested if the charger is just measuring wrong or if it really pushes more capacity into the cells which I guess is not possible. But I’d like to be sure. 
However, I’m going to contact Gearbest to find out what they think about it. To my mind, the analyzation feature of the C4 is crap if I always get wrong values. Even if Gearbest accepted an RMA I’d probably receive just another inaccurate charger in return.
See more here:
Sorry for double-posting but I thought it might be interesting to know, what Gearbest replied in terms of those high deviations/wrong numbers when doing a NOR test with the Zanflare C4.
I wrote an honest review about the Zanflare C4 on Gearbest’s website. After that, their customer service team contacted me in order to solve the issues I have with my device. I explained in detail about the high deviations concerning the capacity measurement incl. the fact that charging slot #2 always indicates much more than the other slots.
So…eventually, this is what Gearbest calls “problem solution”. Thank you very much! :person_facepalming:
———————————————————————-
Dear Thomas，
Thank you for your patiencer.
This charger comes with a volume detection function. Voltage accuracy deviation 2; Current accuracy deviation 5; Time accuracy deviation 1. The capacity is tested by charging voltage, current, and time calculations. Due to the fact that it is not a special compartment, the current market can only achieve a 10 accuracy deviation.
The use of interference Including factors: such as the ambient temperature, humidity, battery type, if the battery installed contacts are good or not and so on. For example, if use different brands of the sub-capacity tester to test, there will be some deviations.
Thank you for your understanding.
Best Regards
*
Gearbest Customer Service
http://www.gearbest.com/
That sounds very reasonable, with one exception: LiIon charge voltage must be within 1%, I would expect the voltmeter to have same precision.
So, it’s reasonable to always have 6-10% more capacity indicated than actually is in the battery? And it’s reasonable that the same slot always indicates another 75-125mAh of more capacity compared to the other ones? I know I’m right in the beginning of my learning curve but I feel it hard to believe that this kind of accuracy is useful for measuring cell capacities nor can this charger be used to find adequate pairs of cells to use them in serial connection (e.g. 4s in the new Haikelite MT07S).
Do you still think the Zanflare C4 is a “good” charger?
If you can get a IMAXb6 hobby charger. Unless you have equipment like hkj there’s always going to be some error. But 300 and 400 more mah on 30q just isn’t acceptable it’s like all your parts in that zanflare are at the worst of their tolerances all combined. With a cheap 30 to 50 dollar charger it will be off by up to 10% between my opus and my IMAX there’s never more then 100mah difference Max. Usually closer. The voltage meter on my opus is low by. .07 so it discharges to 2.73 and charges to 4.13 and I’m fine with this. I’d rather charge my batteries to 4.13 helps with cycle life and only a tiny amount of capacity missing.
Don’t expect much help from gearbest. Their customer service is either great or it’s horrible. More of the latter. The rep on here can help usually. But they’ve told you it’s within spec. I’d use my skyrc charger instead it should give you more accurate discharge values.
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That sounds very reasonable, with one exception: LiIon charge voltage must be within 1%, I would expect the voltmeter to have same precision.
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I have 2 Joinrun S4 chargers. One ends at 4.1V and the other 4.15V . Is this acceptable or should they be closer to 4.2V?
Standard chargers are not precision equipment and 125mAh is not that big a difference (Less than 5%)
As I said above, I do not like the 2% tolerance on voltage, but except for that I do not see any reason why it is not a good charger.
You probably measure after the charger has terminated, this makes it impossible to say if it is within tolerances, but it might very well be.
Try checking these two articles:
https://lygte-info.dk/info/BatteryCharge4.2V%20UK.html
https://lygte-info.dk/info/batteryChargeTerminationTest%20UK.html
Doesn’t sound reasonable to me. The figures don’t add up.
If you take their figures as accurate and assume absolute worst case to create an overestimate of capacity, the following should happen, unless I am misunderstanding something.
1) Voltage is out by 2, but that doesn’t really matter, since it will be out by the same amount at low and high, where there is very little capacity anyway, so if it terminates charge at 4.2 + 2 that is 4.284V, but it will have started charging at a 2% higher voltage as well, so the extra charge pumped in to reach that extra 0.084V was already present when it started charging at too high a cutoff, so nothing like 2% difference there.
2) Current accuracy 5, ok, so you lose up to 5 accuracy there, no getting around that.
3) Time accuracy 1% so that simply adds 1% to the error, assuming the deviation is in the same direction, ie counting the time too fast, and recording the current too high.
SO 6% is the final figure, since the voltage measurement should affect the start and finish to a similar degree, negating the effect.
6% added to 3000mAh is only 3180, your least inaccurate 30Q holding bay is recording a 22% deviation from 3000. Not acceptable at all.
If you refer to my picture with one green VTC5A in bay 1 and those purple ones in bay 2-4…well, these are Samsung 35E (nominal capacity 3.500mAh). But still, there are high deviations. So far, I still don’t get it, that bay/slot 2 always measures even more capacity, regardless what cells I put in.
Those 35 e are about 300 off with the high capacity cells you don’t get the full 3500 is pretty misleading. Around 3300 to 3400 is more what they test at
Just like with my 30qs most test around 2900. I think I’ve had a couple reach around 3000 discharging to 2.73 but it’s usually 2800 2900
A voltage different at top and bottom end do not give the same capacity difference and a 2% voltage difference may give more or less capacity difference.
Isn’t the difference negligible though?
How much more discharge would you get from a cell charged to 4.284V compared to 4.2V, and how does that compare to how much less discharge you would get if you stopped the discharge at a voltage 2% higher than spec? It is the difference between those two values that would have to be 2% of total cell capacity in order for the 2% error in voltage to give you an actual 2% error in capacity testing.
I would expect a cell at 4.284V would drop to 4.2V in just seconds on a discharge test, and behave similarly at the bottom end of the range, making both values very low and the difference between them even lower.
I posted a link about it in #44
I purchased the C4 because I have a bunch of different 18650 and 26650 cells from various sources and am curious how they are holding up.
I received it today and kind of wish I read all the comments here before I bought it…
If I choose Fast test, it discharges the cell and measures the amount of electricity it takes to fully charge it.
If I choose Normal test it fully charges it then discharges it and measures the amount of electricity needed to fully charge it.
- If I understand this correctly, the first charge on the normal test is a waste of energy because it is not measured. Should I just mostly deplete a battery with normal use then only utilize the Fast test to periodically check the capacity?
- Measuring the amount of energy released while it is being discharged is a more accurate measurement of the capacity of the battery and how much light my flashlight can produce with it. Do other budget friendly chargers operate this way?
You have not read the review properly:
*
NOR test of LiIon*
It is possible to select 300 or 500mA discharge and charge current.
The charge will first charge the battery, then discharge while measuring capacity and finally charge again.
It discharges to about 2.8V with constant current, i.e. no pwm.
IMO [Fast Charge] is not worth much.
NOR test is useful, and reasonably accurate.
For internal resistance it is better than the Opus, and MUCH better than the Lii-500, which is useless for IR.
That not only makes it a decent charger but a ‘best buy’ in that price category.
Perfect? No. But, a really good charger for the price.