Glad that there is an easy fix for it. Fan is still loud when charger at full throttle. I am going to get a notebook cooler instead.
I’m pretty sure you can stick the charger in a freezer and the fan would still blow occasionally, just the same. Or at least it seems that way.
CSgearbest please read a private message.
Hi hohol_m, I just have read it( Sorry to reply late, just because the weekends), I’m in the process to check your issue, once I have the answer, I will contact you as soon as possible. Have a nice day. 
Hey, I just noticed this in the OP:
10.27 Update
Hi guys, good news again, Opus company just lower our supply price for the V2.1, so we can do it at $39.99 with the same coupon code: OP3100 (I think this is the lowest price finally)now Laughing out loud , for those who bought it at $42 and think the $2 coupon refund is necessary, please feel free to contact our CSgearbest to get the $2 coupon refund Wink , thanks for your support as always Beer
Maybe they can send that $2 fan to those who purchased at $42.
By the time I actually get mine, it will probably be $15 and V2.7.
My last order should have actually and finally arrived today via DHL, but due to all the issues of the units and the slowness, I had to refuse the shipment. I really don’t like the fact that an eBay seller has something labeled v2.4. I hope to see my money back soon, because GearBest has a whole lot of improving to do to keep that best in their name. Now I hope to watch just how fast it makes it’s way back. I know it won’t take the same 46 days to get to me, just one day past the PayPal limit to file a dispute…grrrrrr
Hi guys,
I’ve bought the v2.1 charger at GearBest and it has arrived just yesterday. From the reviews and movie clips I knew that the fan was small, noisy and annoying. Looking at the comparison v2.1 charger should be more quiet but mine makes noise more like v1.0.
On itself the fan noise is something I could handle (I can always put it in a room where I don’t spend much time) but from day one my charger is also experiencing the issue described here. Sometimes when spinning up the fan starts to make a very loud whirring noise, like it’s blocked or vibrating a lot and then it stops. It does that a couple of times (3-5) and then finaly starts up. This is not something I would call normal and it probably won’t lead to a long life for the fan or the charger itself 
Now I’m reading that there’s some voltage issue with v2.1. I don’t understand much of it and I don’t have the skills to fix it as described. How serious is this for someone who just wants to use the charger for charging and testing Ni-MH and Li-Ion batteries?
I also read that it’s best to replace the power supply with one that has at least 6A.
This was my first order from China and I’m not sure what’s the best thing to do…
I can try to fix the fan with oil or replace it or use a cooling laptop stand. Possibly I could ask/pay someone to fix the voltage problem and I can buy a new power supply. The charger might be inexpensive but that’s quite a lot to do for something new that was only just bought.
Maybe I should contact GearBest for refund or even start a dispute on PayPal?
Best regards,
Crocodil
Crocodil - The 6A power pack is not required for the v2.1 but would improve the v2.0 model as I understand. The voltage issue is only a problem if your specific unit reads high by about or over 0.05v -- no need to do anything unless you know it's off by that.
The fan issue -- not sure. My v2.1 seems to be quieter than my v2.0, but I still have to carefully test/monitor it to see if it's working ok.
Thank you for your response. So the 6A power supply is not required but would it make the charger work better? I think I’ve read somewhere that it makes the total capacity when charging (not discharging) more accurate and also that the charger’s peak current requirements can reach 10A so a stronger PS can handle it better.
Unfortunately I have no way to check if my unit has the 0.05V problem as I lack the proper equipment and knowledge If it is however, is the only downside that the batteries will be “undercharged” by 3-4%?
As for the fan - I might have to try to use the oil trick or try to replace it (I’m awaiting a reply from GearBest). Can someone please confirm that using a laptop cooling stand (with a fan) gives any result / is worth considering?
As far as I know, all issues requiring a higher amp power pack were resolved in the v2.1 version. I believe everything you are reading pertains to v2.0, not v2.1. Hope someone can confirm this - pretty sure of this from what I read. I was one of those that bought the 6A wall pack for the v2.0 version and thought it wasn't necessary for the v2.1 -- I have both.
Only thing you need to check the accuracy of the voltage reading is a fairly decent DMM. I have a UNI-T UT-33B (http://www.fasttech.com/products/0/10002748/1487104-uni-t-ut33b-1-9-lcd-palm-size-digital-multimeter) model that costs under $14 and measured DC voltage of batteries very accurately. Highly recommend it for you - very handly in this hobby.
Getting a multimeter is a good idea, especially that I will be probably doing some shopping at FastTech soon Do you think it’s worth buying the slightly more expensive UNI-T UT33C I don’t see much difference in the specs… I might buy a soldering iron as well - that might come in handy (I first have to learn how to use it though 
).
I hope that someone can confirm what you’re saying about the power supply.
Could you please also answer my other question - what are the downsides / dangers of the charging voltage not reaching 4.2V?
Ooops, missed that Q. No dangers in under charging cells as far as I know (I'm no battery expert though). For me, charging to 4.13 or 4.14v (or as high as 4.17v) will effect my tested outputs for lumens and throw when measuring high performance lights when batteries are pushed to the max (Direct Drive single cell for example), and I'm doing 30 sec measurements. 4.18v to 4.23v is roughly good, though I prefer 4.20 to 4.22.
Under charging is probably less stress on the cells though, while over-charging supposedly will shorten battery life.
The unit I currently doesn’t even heat up to the point that I would consider an issue, and the fan comes on seemingly randomly anyways. But I’m only charging at 500-700mAh. 500mAh is the default, and no real heat is generated with my batteries. The best modification would be to replace and reduct the fan to something larger if you’re worried. But I don’t even think it needs the fan for my normal use.
I’m afraid the fan problem has gotten even worse since yesterday - the start, whirr/rattle/grate and stop cycle is now happening much more often and it takes 9-10 tries to spin up (it was 3-4 tries).
Unfortunately answer from GearBest’s Support Center wasn’t very helpful, in short: We sell the charger as provided by manufacturer, please contact us when it brakes.
This problem seems to be quite common - I have seen a couple reports in this forum and in the customer reviews at GB. I hope that maybe one of the GearBest representatives (gearbest or CSgearbest) can contact Mr. Henry Xu like with the voltage problem and ask him to investigate this.
I’ve started looking for a replacement fan. Do you have any recommendations other than http://www.tmart.com/2510-Computer-Chassis-Fan-Black_p186231.html ?
Hi Crocodil,
We are very sorry for this trouble, I will forward your problem to Henry, any update, we will let you know
10/01/2014 to 10/29/2014 from order to delivery. This is tolerable considering there was a holiday in there somewhere.
Hi CSgearbest,
My charger also showing higher voltage about 0.02 V.
I cleared the solder blob from J1 and now showing lower voltage about 0.02-0.03 V.
How to fix it?
Best regards,
hohol_m
You couldn’t expect the charger to be 100% accurate down to 0.00v difference to your DMM.
0.02v is accurate enough. The mod info on J1 above has informed that it is 0.05v compensation.
You shouldn’t have cleared the blob in the first place.
Now, it’s your call whether you want to see it –0.02v or +0.02v. In your case, I think it doesn’t matter.
Serville
My old charger BM100 100% accurate.