^
Thank you Robert…… :+1: . 
EDIT: Like you Robert, I have never had an issue of protection circuit being tripped with 2.8 V discharge. No problem at all.
What if anything did you need to do in order for a 25x25x10mm axial to fit in the charger?
Mine overheated again last night discharging 4 18650’s at 1000mah. I kind of think of the unit now as a max 2000mah discharger.
Thanks
One more favor Robert. If you still have the original 5V ADDA fan, would you verify the size as 25 x 25 x 9 mm please?
I am still wondering if that 25 x 25 x 6 mm ADDA fan I listed a couple of pages back would fit…. with maybe a bit of silicon caulk holding it in place?
Thank you……. . :+1:
Honestly I’d love to see the discharge go down to 2.5 volt but u don’t see that happening. The lower the better. Protection circuits trip below that. And would be very accurate capacity results. I’ve popped protections and they were below 2.5 when I got them reset. 2.7 would be great.
Maybe we can get henry to add 2 amp discharging like the sky rc 3000? Can that be asked. Since there building from scratch may as well ask for good features. Since it maybe another 7-8 years before another version is made
I have no doubt what you just said gauss makes perfect sense…. :+1: But it never will to me… :person_facepalming: … 
My only hope/wish it that the new charger will give discharge values that match reasonably well specific battery to specific battery.
In other words, simply put. If I do a discharge test on a LiitoKala 26650 in my OPUS BT C-3100 v2.2 and it comes out at 5000mAh…. I would hope I could put the exact same battery in the “New OPUS” and do a discharge test and the results come back extremely close to the same 5000 mAh.
.
IF post #719[Gauss] is in reference to me you are MISTAKEN. I NEVER requested anything. I SUGGESTED keeping it @ 2.8v, if they choose not to I would prefer 2.7v over 3.1v. There is a big difference between a suggestion and a request. 
@ Teacher -The ADDA fan that is in my Opus is 25mm x 25mm x 9mm
/\\\\\\
Thank you for verifying that Wolfdog.
@gauss,
Do you even own an Opus? How about a flashlight or Lithium Ion batteries?
I have yet to read a post of yours[Here or CPF] that is based on your personal experiences with these.
Your posts are primarily data based and are NOT real life testing experiences. No mentioning of your application of the said items AFAIK.
Makes me wonder.
Your welcome.
/\\\\\\
Or suggestions either.
My experience is that most flashlight/battery/charger companies have no competent electrical engineer on staff who can evaluate suggestions.
They may assume a suggestion from someone at BLF is a reliable guide to development.
I went through this a while back trying to explain passive drain to a fairly large flashlight seller with their PR/sales/review person as intermediary.
It took considerable citation to published sources before their engineers quit telling her there was no such problem. Then they fixed it.
Hi there, I’ve read through the forum and it seem the provided power supply will reset once the 4x1A charging spike. Anyone here have check the v2.2 incoming capacitor been removed, anyone try to add back the cap and try it?
V1.0 No incoming capacitor
V2.0 & V2.1 do have a capacitor rated 1000uF 16V
V2.2 Can anyone add/replace a bigger capacitor like 2200uF 16V and check the stability?
I guess gauss 163 for your benefit my 3400 has the APD PS and if you can guess my 3100 has a KYT PS
I’m with Wolfdog on this one—Do you even own a OPUS charger—-I’m really tired of every time I post something that I’m actually experiencing —you come behind me and second guess what I have to say—-That’s as down home old BLF as I can get
Since you are so Tech Savy—why don’t you enlighten all of us Not So Smart people as to what you use to test your cells
This thread has been derailed for a very long time—- it originally was for differences between the 2 chargers 3400/3100
— I personally own a 3400 and a 3100—so I stated my Real Life experiences with them
You know what I don’t need this S—————T — I’ll just PM the members who are like me Technically challenged HaHaHa —we can help each other out
Lets look at the history:
The first 3100 charger had very high current pulses (9A) and the supplied power supply could not handle it, this made the charger show wrong values when charging batteries.
After some emails with me the designed found out that the batteries he used for testing did not represent what was available and he did an adjustment to a intermediate voltage in the charger, this reduced the peaks to 6A, this was within what the supplied power supply could handle.
It looks like a new power supply was selected, but it could not handle the 6A peak (I doubt that the above adjustment was reversed) and the overload protection shuts down the power supply for a short time (The first power supply did not shut down), this makes the charger reset.
In all cases the charger do not use more than 3A in average.
The other point is the discharge voltage.
Most protected batteries will have a cut-off at 2.5V or lower, but because the charger is pulsing the current, it may go below that voltage in pulses, even when the average current is adjusted to 0.1A (Peak current is still 3A).
There is no easy solution to this, either the charger can do:
Test voltage when current is on, this means that batteries with higher Ri (Including small cells) will not be discharged fully.
Test voltage when current is off, this means that batteries with higher Ri may trip the protection.
The best solution is, of course, to use a constant current draw, but this requires a controlled transistor with a heatsink (SkyRC MC3000), not only a on/off circuit with a resistor to dump the heat.
I prefer the controlled transistor, but it makes the charger more expensive when higher power levels is required (Liitokala do it, but at fairly low currents).
Yeah this thread has been derailed a few times, I agree…… BUT, it has seemed to get back on track sooner rather than later.
I freely admit I am one of “The Technically Challenged Brethren”…. …
I’m sure no one would have guess that. :person_facepalming: . 
. Baaa-haaaa
BUT, I have learned a lot from this discussion; and that is a fact Jack. .
Even though I don’t understand a lot of the technical stuff gauss posts, I read more about it later & a bit is actually sinking in from time to time. Let me be clear, there is nothing wrong at all with how gauss posts his technical stuff; it is I just am not smart enough or informed enough to understand it without further research most of the time. And even then I may not get it, but so what…. I am getting some of it, therefore I am learning a bit more. :+1:
Thank you gauss……… :+1:
Usually HKJ “dumbs down” what he says enough that I can understand it a bit easier. :+1:
And, just to be crystal clear here also; when I use the phrase “dumbs down” that is in no way a derogatory statement toward HKJ.
It is a compliment of the highest degree. If he wanted to he could describe something in a way that I personally would not have any idea at all what he was talking about. Thank goodness he does not do that.
Thank you HKJ!!! :+1:
And wolfdog, God Bless him; through dogged determination, many hours, & blood-sweat-tears he has spearheaded this journey of the quest to find out what in the heck is wrong with the OPUS.
There have been successes and failures, but each one has brought us closer to the answer or answers as it may very well be.
I don’t think wolfdog is a technical genius, but so what; he has plowed forward and I for one have learned a lot from the vast amount of info he has dug up and brought to the table. :+1:
And ALL of it is bringing/has brought us closer to the answers. 
Good job wolfdog………. :+1:
And what I said several posts back, about us being friendlier towards each other; I meant it. Sure, I said it in a semi-comical way… but I meant it. Of course there have been a few bumps in that road, but so what. I honestly do think we as a group, on & in this thread; we have become a bit more understanding and friendlier toward each other. YMMV, but that is my assessment.
We might not be able to sit around a campfire and sing Kumbaya just yet without a few of us punching each other out………. BUT, on this particular thread, we have done much better than when it started. :+1:
Wolfdog mentioned this first a few hundred posts ago & for the most part, it has gotten even better since then.
Chops has had a whole lot of good input also as have several others that will go unnamed because of time constraints
In other words, from my simple perspective; this whole journey has been & is, a learning experience; in more way than one. :+1: …
The End…….
That is something I tries very hard to do. Not that I will write stuff in a non-technical way, but I try to limit the technical jargon a bit.
And sorry about the links in my last mail, I used the wrong syntax, it is fixed now. I give up on links in answers, spaces do not work (I am too lazy to do my answers in raw html, anybody that want to see where my links leads to simply replace %2520 with a space in the link).
The general problem is that spaces in links do not work and when posting links from the browser where spaces is replaced with 20 the board replaces that with an escape for the sign (%25), instead of accepting it as a code for space.
Then you could just as easily use html code, it will also work.
I personally think you do a great job and I am one “dummy” that appreciates it greatly. .
No apology necessary, but thank you for the explanation of how to “fix it”. :+1:
Amen gauss, I totally agree. Thank you. :+1: