Test/review of Zanflare C4

+1, all of my chargers have to use US or EU to AU adapters.

Can anyone confirm if the Zanflare C4 can charge 18350 batteries? Most sites don’t list it in the description.

Yes it can charge 18350 :+1:

Ordered one from GB for 23$. The fact that the display shows all slots at the same time and the working analyzing functions, in addition to good NiMH charging makes it an ideal replacement for my Lii-400, that I’m going to give to my father.

I am using 2 of these and have a 3rd spare (they were cheap!). Thought I should probably do a test run on the spare, and just as well: Channel 1 turned out to be dead.

4 screws below the rubber feet, so easy to open…wrong. This thing is glued shut pretty well. Finally had to punch through the glued seam with a sharpened flat-blade screwdriver and work it open from there.

Problem turned out to be the soldering for the cell+ contact plate, there was none!

Could not find any online photos of the insides, so below are some for reference. Looks decent, but the hand-soldering quality (needed for awkward components) is mediocre at best. 2 or 3 production ‘patches’ are also visible. The culprit contact plate had a bent leg, so could not insert properly into the PCB.

Separating the PCB required the springs to be de-soldered. And it is tricky to put back together, so not recommended to do this unless really necessary. Ended up with some cosmetic damage along the seam, but it is still usable (and now also serviceable).

  • No solder on those two slots bottom right:

  • Springs de-soldered:

  • UI control board, unplugged:


  • Culprit:

  • Power circuit. Four TO-220 N-channel MOSFETs, probably used as active loads for the discharge tests. Two incognito controller chips:


  • Ugly patch from 3rd inductor to sense resistor:

  • 5 V output boost circuit:

  • Floating diode patch:

My C4 normal test results are very volatile.
I tested one 35E at 3539 mAh. Couldn’t believe I was so lucky, re-tested. 3418 mAh.
Another was lower than expected, 3350 re-test OK, 3364.
A third cell that I tested twice, 18650B, a bit used, 3529 on the first test, 3438 on the next.

Also, resistance numbers are very different from one insertion to another. I can get 20 or 60 mOhm. It doesn’t depend on which slot do I insert battery to in an obvious way.

Any idea why is it so?
It’s my first analyzing charger and I don’t really know what to expect. Is it OK? Should I RMA? Something in between?

You should RMA it, my C4 is very consistent down to less than 10mAh. Even internal resistance is consistent within 5 “mR” between reinsertions.

Fellows I do not mean to be a wet blanket but bear in mind the fact that whatever cell to be internal resistance measured in the charger needs two physical connections to it, two contact resistances whose magnitude against the internal resistance of a typical cell is considerable. There's no real “fix” other than soldering or spot-welding the cells to the rail feeding contacts for this to be dismissed.

Cheers :-)

For 500mA discharge current it shouldn’t matter, the connection resistance generates negligible amounts of voltage drop at this current. 100mAh discrepancies on the discharge test are a fault and not a design issue. While 4 contacts are ideal for IR measurement, this should have no bearing on the issue the previous poster encounters, that is, completely inconsistent capacity measurements and IR readings. My own C4 operates to spec and Henrik’s review shows that IR measurement is consistent between reinsertions.

ferongr, I was not particularly referring to Agro's issue. I just wanted to point out that rail to cell contact resistances are in the same order of magnitude to that of the cell's internal resistance and, at the same time, they're not constant and predictable. To me this means that in order to get some meaningful data we should at least gather a set of measurements to average for each cell and make sure the cell's well seated for each measurement. Just in my opinion, of course.

Cheers fellows :-)

The Zanflare C4 does a lot better than expected. Even with my 20A+ cells (LG HB6) with very low internal resistance I’m getting stable and consistent readings. While the reading will obviously be offset due to the rail and contact resistance, if those two remain constant then you get usable and consistent results.

(Chart from HJK’s review )

Note that the multiple tests on all slots remain consistent, and increasing resistance also increases the reading consistently. This is a lot better than other analyzing chargers, a very usable result to see the condition of a cell and also a lot better compared to many other chargers.

Does anyone have any codes for this? Those that I could find ($19 on GB) are long dead.

While you may have received a very good sample or are extremely consistent with cell placement, I think it’s a bit much to expect that level of precision given the price point. Even a 100mah difference in capacity is only around 3% to 5% variation for a 3000+ mAh cell which I think is pretty darn good and consistent with other analyzers in the same price range.

KuoH

If the capacity measurement changed significantly between reinsertions, the loss on the contacts would be so great that would lead to localized heating. It would also lead to incorrect charging voltage, since the voltage drop would affect the CV phase. The issue with reinserstion in most 2 contact analyzers is with internal resistance measurements.

FWIW the $8 Opus BT-C100 I have is similarly consistent in current measurements (not in IR though). Since I also mostly charge pairs of married cells of 18650s from my electronic cigarettes, if inconsistent contact affected capacity measurements it would show. Since both cells are within 15mAh though, it appears you are incorrect.

For 100mah over a period of hours to perform testing, localized heating at the contacts would not be very significant. As for your measurements always being within 10’s of mAh, good for you. However if we all expected this level of precision and returned all units not meeting this criteria, there would be few analyzer chargers in the $10-$25 range like we see today.

I also have a c100, 2x c3100, 2x li 500, Zansflare c4 and a few others I can’t remember right now. Yes occasionally I can get readings that are quite close, but I’m not expecting 0.2% precision. Don’t get me wrong, I don’t mind if it’s better and certainly don’t want it to be 10% off, but I understand consumer level products are designed to certain price points and set my expectations accordingly.

KuoH

I charge a pair of batteries every day. If there was that much of a difference between capacity merasurements every time it would be obvious. I’m sorry but with two analyzing chargers and a variety of 18650s (Samsung 25Rs, Samsung 30Qs, LG HG2s) I have not encountered such great variations.

OK, it seems I found the reason for varying measurements.
Temperature swings. When I’m not home heating doesn’t work and temperature goes down by a couple of degrees. I didn’t expect this would be a problem as the cells being measured would be very warm after I return despite quite low ambient temps.
But I took the charger to my fiancee, she measured the 18650B 3 times within 30 mAh. Above 3500 mAh. So I can disregard all the measurements I did so far, but it doesn’t mean there’s a problem with the charger.

The resistance variability is not temperature dependent though…

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.