Is the problem endemic to the design or is possible that it’s just a defect in the tested unit? Anyone have a v7.1 that they can test by leaving a battery in the charger after termination?
I am very surprised with the results and I am testing my unit (v7.1, purchased last November) right now.
I have carried out limited testing this evening and everything seems to work all right: it stops charging at 4.15V and the LED turns green. Left the battery inside, it slowly discharges from the voltmeter parasitic drain. Restarted several times and does the same, for now no signs of overcharging behavior.
Perhaps HKJ got a defective unit for his test? Only problem…w/o doing an in depth test on EACH unit you can’t tell if you get one that “does” cut off correctly, or will slowly over-trickle charge…NOT good because inconsistencies in production units.
Iker, with your limited testing, did you leave 5vdc input on the unit…HKJ shows that even when the light goes green, IF input voltage is left on it continues to charge at 20mA. If you disconnect power sure it acts correct but what if you left it unattended on charge for a day or two? That is what his test reveals
And its pcb is marked 7.1?
It would be great if you could leave it in the charger for several days and measure the battery’s voltage periodically. I would run a long wire from the power source to the charger and place it somewhere outdoors where if it vents nothing is adversely affected.
I left it with 5V DC input for a few hours and the battery voltage dropped slowly and it restarted (around 4.0V). Also did manual restarts by unplugging the DC input and replugging it, with the same result. Safe cutoff at around 4.2V and slow drain afterwards. Didn’t leave it unattended for a day or two, but there is no sign of trickling charge as in HJK’s tested unit.
And yes, Halo, my unit is v7.1 from FT
testing … well, the green light doesn’t mean it’s quit charging, can tell that right off:
Started with an unprotected, previously charged cell that shows 4.19v on my Radio Shack multimeter
green light immediately when put into the charger
left it for an hour
removed the cell
green light stays on even after the cell is removed
tested the cell and it’s now showing 4.20v on the meter.
back in the charger, green light continues on …
EDIT
and after another hour, it was up to 4.22v
So I stopped charging there, used the Miller to power a PDA for a while, got the cell down to 4.16v
leaving the cell overnight in the Miller unconnected to see if it drains the cell
Thanks for another excellent review HKJ. Thank you Iker for your effort to increase the sample size for the identified issue. Good call.
Iker wrote:
I left it with 5V DC input for a few hours and the battery voltage dropped slowly and it restarted (around 4.0V). Also did manual restarts by unplugging the DC input and replugging it, with the same result. Safe cutoff at around 4.2V and slow drain afterwards. Didn’t leave it unattended for a day or two, but there is no sign of trickling charge as in HJK’s tested unit.
Either your particular charger has very high parasitic drain or the cell is not very healthy for it to drop to 4v after a few hours. Maybe I missed something and there is another cause.
You are right and it is an old mediocre cell indeed and helped by the voltmeter drain (a digital LED-lighted thingie). The only unprotected cell I had by hand. Tomorrow I’ll check again with fairly new 4.35V LGs but they were charged full today and wanted to run the test ASAP
Yes, those that can assist in the test sample size kudos to you as well…not that HKJ’s tests are ever to be questioned but the test unit might have issues
I for one am firmly confident he would definitely be able to identify if there was a design issue vs a production issue.
HKJ is there any markings on the IC’s that control the charging of the Li Ion battery? Is it a firmware driven unit?
HKJ is the CC/CV charge pattern before the trickle charge good, just the slow trickle charge is bad correct?
Could it be classified as a good charger (CC/CV wise) but under NO circumstances leave it unattended once charging is complete? Is it salvageable IF people immediately remove from charging? (kinda defeats the purpose of a charger cutoff though 
)
ETA6002 IC schematic
Pinouts
WarHawk, v7.1 uses ETA6002 switching charger and M3tek MT5032A boost converter for the 5v usb output.
Even if some people find their v7.1 does terminate that just means the ETA6002 quality control is horrendous and can never be trusted. Test 100, 1000, 10,000 good chips and not one will lack termination.
I left my ml-107 charging a fully charged battery all day today (about 12 hours) it went from 4.19v to 4.23v so there might be something to the overcharging problem.
I had the battery in for about a week and it was still at 4.19v so maybe mine doesn’t discharge as fast.
I ordered three more for friends yesterday so I’ll have to pass along the warning about the OC problem.
I always tell people to take the batteries out of the charger when done charging.
Agreed
HKJ, is the resistors R6 and R8 from this image damaged or just very crappily soldered?
Looks like just some flux residue on those resistors plus a bit of glare from the lighting.
I don’t think so. “Miller” discusses the new version of the charger in a Chinese forum post from last year I found at some point. His main motivation in selecting the charger IC seems to have been the faster charging rate.
I’m checking charge termination on mine now. I’ve popped a 4.3v-termination cell in and will check voltage from time to time.
I’ve had other problems with mine though. It only supports 2A output until the cell voltage drops to ~3.75v or so, then it switches the output on and off at ~2Hz or so. Works fine if the load is cut to 1.5A. Another forum member reported similar problems with 2 out of 3 he’d purchased.
Click on the image, it links to a much larger version.
The charge curve is good enough, the "only" problem is the 20mA after it is finished charging.
They do not look that bad, check them on the larger image.
At a drain of 0.4mA you shouldn’t see a change from just leaving it overnight. 9.6mA per 24hrs. If you wanted to keep an ML-102 long term as an emergency power supply then the drain could eat the whole battery.
According to USB charge doctor my ML-102 continues to charge after green light (charge current is somewhere between 10-20 mA). It’s a 7.1 version bought in November 2014. Thanks for this review HKJ.
Is that correct?. You cannot asume that the miller drain from the power suppply (i.e., what your USB doctor reports) gets pumped into the battery, can you?. Furthermore USB doctors have about 10mA resolution so I doubt you can really know what’s going on just by that. Why don’t you just leave the cell in the charger connected and see if it raises V? .