It seems to me that the 25x25x9mm size fan is a real odd ball.
I checked Mouser, Jamco, digi-key and Newark none of them sell a 25x25x9mm 12v axial fan. They all have lots of 25x25x10mm fans.
Papst has a 25x25x8mm in their catalog that I’m sure you could shim to fit but because it’s Papst I’m sure the price will be the 25 dollar range if not higher.
I would hate to can my charger because the fan died and I can find a replacement.
Hi welcome to BLF. :sunglasses:
I have plenty of fans that fit this charger. They just do not have the CFM[air movement] to do the job. That is most of the problem because my Lite-on SMPS is superior to the SMPS Opus gives!
Last night I ruined the best charger and it was the only one[out of 4] that could discharge from start to finish without stopping.I still have the fan. It is the exact same as the one in the charger I just got today….never know it may be better. that is my next step becuase this discharge test is @ 3h 10 minites and the batteries are only @ 3.40v. Same batteries in my now dead charger completed the discharge[2.8v] NON STOP in 2h48m!
I still have 2 delta fans,they will do the job and the charger will have no problem keeping the Opus cool.
,sorry for rambling!
Instead of Modding the board or the new case—try modifying the old lower case so where the fan fits—I don’t understand all these problems you’re having—my 2 chargers never give me these problems—-I only do charge/discharge test when the cells are new and when they are older—-most of the time I charge only with an older Xtar and if I feel like working backwards the Littokala
+1 to that! Above & beyond. 
. Very impressive. :+1:
Just so I am sure I am understanding correctly.
With the OPUS you just got from Liion W’sale to replace the “killed” one… we are back to square one? Except this time it is happening when using the LiteOn power supply?
Oh my…… :person_facepalming:
I’m sorry your having issues with the brand new opus, as chops said I’ve never had issues, I test new batteries, and lots of pack pulls. Then as cells age I’ll retest them.
Bad luck you have I guess never heard of a unit reach thermal cutoff from regular operation. Only the reset when charging 4 cells all around low three volts. Maybe you put the old fan you kept in. Or get a small deskfan to blow on it.
You know what your orbtronics normally test as capacity wise. Compare it with the new ones. I have a feeling they won’t be far off. When a load is removed the voltages increases. When reapplied it will drop back where it was. The energy was used out of the batteries. It shouldn’t change the results much if any. Run a light down to the 2.8 cutoff it jumps back around 3 volts but that energy density is used up. Turning the light back on will shut it back off shortly
Not the same issues of power cycling, its reaching thermal cut off tempature inside the unit suspending the discharge or charge until the temp decreases
I will try to answer all the questions in this post.
I ruined my charger last night,Jon did not replace it, he gave me a very good deal on a new one.
Every Opus[had four] I owned or tried worked. They have variances. The Best one which I ruined last night was the ONLY one that never stopped[because of heat] during the discharge cycle,Therefore it was MORE accurate because it did not measure mAh again after stoppage.I actually watched these chargers once the mA read”0”. sometimes they stop for 2 minutes or more until the batteries cool. The voltage goes up b/w 0.03v and 0.06v during stoppage. That is measured again,hence the inaccuracy.This happened every 7 to 8 minutes with this new charger.
Basically the longer it takes to discharge the higher the mAh reading and more Inaccurate those readings are.This is after using the same batteries and comparing time of discharge and capacity results.
Before I forget. My Orbtronic comparisons were in a post earlier today.New charger was around 45 minutes longer and was ~175mAh higher.[Four slot median]
What I have simply determined in the last few hours is this. A fan like the delta would eliminate this problem. also, the variance in the charger also plays a role because this new charger has the Lite-on as did yesterdays catastrophe. So I put old chargers fan in new charger and it STILL has stoppages. That tells me something is a little different electronically,i have no idea what it may be.
I will admit I am more picky than most. I also am a great observer and write these stats down and also watch the charger when it is stopping. So I am not imagining the inconsistencies, I may be bothered by them more.
I am driven to get this or another charger to work like the deceased one! Like HKJ said, more air flow should solve your problem. I believe that. sometimes you have to improvise in order to eliminate an imperfection.
I have 6 X 4BAY quality chargers. the ONLY reason I got the Opus is for relatively accurate Capacity tests. The One I have now[after two tests] seems to be the most inaccurate of the Four.
I know I did not say exactly everything I wanted to. Those thought have escaped me. It bothered me a lot that I ruined the Opus becuase i knew that it would be difficult to find one as accurate.
I may drive you nuts along w/ myself,but I am determined to get this one or the next one to be as accurate as the deceased Mr. opus.
I emailed someone to splice/rewire/mod my remaining Two Delta fans,THAT IS THE SOLUTION FOR THIS CHARGER,I AM CONVINCED,MORE AIRFLOW! :+1:
If I fogrot anything I am sorry,I am a bit delirious today,actuall 4 days in a row w/ not enogh sleep,good night,good weekend,Capolini/wolfodg/Camilli/Volpini!!!
EDIT:I THOUGHT I POSTED THE CHARGE/TEST RESULTS EARLIER…HERE THEY ARE:
This is with the same 4 x 18650 Orbtronic batteries and discharged @1amp.These batteries were cycled 470 times bought on 12.21.2012.
Old charger:Time:2h48m Four slot median:2784mAh Done last week.
New charger: Time:3h34m. Four slot median:2955mAh
Diff: 46 minutes/171mAh. I do not mind the extra time but it correlates with the Inaccurate capacities.
My final test in the KP 4 X 18650. I will have those results before I go to bed,I would guess at least 150Mah off and an additional[minimal] 50 minutes more time. I will EDIT and post that tonight.
In order to get a better comparison of these tests and how accurate Mr. Deceased Opus was.This is a good barometer.
30 Q Brand new-
HKJ-2884mah…………….Opus Four slot median:2910mAh
Good question,I do not think I WOULD have the patience to watch it for 3.5/4.0hours!
I would bet at least 15 times. I estimate every 7 or 8 minutes w/ 2 minutes rest. Add that up and we will Say every 10 minutes[including rest]…6 times/Hour times 3.5 hours plus.,that is 21 times. It slows down a little around 3.3v. FINAL ANSWER IS 18……….I bet I would be within 3!
You ask me a question,It can be a long winded answer.
These KP are only @ 3.56v after 2h 33m!! .
EDIT: This is my experience with Four BT-C3100.
They either STOP/REST/RECOVER for the entire discharge OR they do not do it at all[KING OPUS].
I have Two announcements:
1. I am determined, obsessed and possessed to get this or my final attempt Opus charger to Run like “KING OPUS”. That will be its new name!
2. Jon[owner L.ION] and Dominic his main man both told me that they will only use 3 X 18650 when doing discharge tests. Primarily because of the RESET problem right near transition of Discharge/Charge. That happened w/ two of mine.
Secondarily most likely because STOP/REST/RECOVER issue that we have been talking about on/off for 6 weeks or so!
……
I’m doing a discharge test right now with 4 VTC5 —so far it’s been cranking hard 1:02 with a reading of 1022 no resets
I’ve never had that problem with this 3400 my 3100 is at the camp—
So I’d say my 3400 is King Opus——JK—-the damm thing will most likely break now—-LOL
VTC5 are only 2600 mAh not 3400mAh 
My solution[s] are in my next post
what are you saying—that it will only fail with a 3400mah cell—- Ive done 100s of cells without any kind of failure that you’re talking about—just recently tested and matched 26/ 30Qs not one interruption—that’s with the stock(better PS)
Opus Solutions-"Utilizing my ideas along with others"
"TRIPLE COMBO"
1.Cut some vents in the bottom of the Opus.
2.***Elevate Mr. Opus entirely with "Mr. Slab Of Steel"
3. Use an external fan to blow on Mr. Opus!
Try this until "The Delta Destroyers" are back in commission.
***Mr. "SLAB OF STEEL" reduced the external temperature of my FENIX ARE-C2 From 132F down to 90F
LINK BELOW FOR SLAB OF STEEL...Groundbreaking discovery implemented by "Your average Joe Hobbyist",,"Wolfdog"!
https://budgetlightforum.com/t/-/45250
For the most part YES. I have to do more testing to see how this one will fare,I would think the same results as the other 2 that did this: As long as it is NOT 4 X 3400mAh it can usually handle it, although Jon had ones reset w/ 4 X 3000mAh.
I will bet when I discharge 2 or 3 of the same batteries the results will be more accurate.
Two Issues with these chargers.That have been determined with a lot of help from others and my vigorous testing and stats!
1.Resetting near the transition from discharge to charge[this has prompted Jon NOT to discharge 4 x 18650]SOLUTION: My LITE-ON SMPS 12V/5.5A/66W.
2. The charger STOPPING because it is too hot and only resumes when the temp. is below 40C/104F. SOLUTIONS: a fan with excellent CFM[Ability to move air],Delta 12v/0.12a/1.44watts!
I have experienced that with 3 out of the 4 Opus.chargers I have had
To start off with your charger is stopping it’s discharge way before the end(heat) and restarting— so cell size has nothing to do with it
All I know is I have two of them and they work perfect—good luck with all your testing
I’ll admit I am a bit confused… not terminally confused mind you, just a bit confused. 
1. The initial problem mentioned was a “reset” shortly after the discharge cycle had ended & the charge cycle had begun. This problem was identified as happening when 4 x 18650 cells were being tested.
This is what my charger was doing also, nothing more.
The solution to this was replacing the inadequate power supply with an adequate SMPS.
As far as I can recall, no mention was made by anyone at the time of their charger stopping during discharge because of “heat” related issues.
Sooooooo….
2. Is this a newly discovered issue?
Mine has not & does not do that. When was this issue first discovered?
Just attempting to keep up.
I think the problem started when a fan was replaced —I’m not sure though
It is the total mAh CAPACITY! More capacity/More work/more heat!
4 x VTC5[2600mAh] = 10,400mAh
4 X K’power 3400mAh= 13,600mAH Additional 3200mah!
That is like an extra battery. That is why w/ 3 x 18650 3400Mah the charger does NOT have problems.
If you read the manual it will tell you about “WHY” the charger stops/starts again during Discharge or when the batteries get above 40C/104F.
You’re still not explaining why the heat is building up and shutting the charger off early in the Discharge cycle—at that point the charger has no idea what size the cell is—I usually don’t read manuals(I don’t have those problems—why would I)—when something gives me too much trouble —I toss them
That is all well and good. But none of it answers the questions I asked.
In addition mine does not do it with 4 x Sanyo NCR18650GA’s…. 3500mAh each.
4 x Sanyo GA’s [3500mAh ea.] = 14,000mAh … Additional 400mAh from the K’powers
What I am asking is quoted again below……