Put a Piece of foil between the contact point—- better yet a strip of copper or brass —- but foil does work— fold a piece about 4-5 layers thick about 1/2 ” wide x 1- 2 ” long so you can hold it in place until the battery clamps it in
Hey WolfDog!! How goes it??
It’s been a bit over a year since this thread got started & we had all that fun last summer figuring things out.
Good to see your post. Sorry about the problem & hopefully Henry will also get you that new charger he promised you…. if they ever finish them.
Take care my friend…… 
Thanks Chops & Teacher!
I tried the aluminum foil before I used the magnets. It did not work.
Here is the deal. It is a pain in the a but usually I can get contact[unstable and precarious] if I manipulate the battery by twisting it and lifting the positive end UP a bit. The key is when I see that it is connected I have to stop. This can 10 to 30 seconds to accomplish.Any small bump or movement and ALL the data from a capacity test is gone! :person_facepalming: If it happens during charging,no big deal as I have a half dozen other chargers I can use instead.
Also to note, I had solder blobs put on before I got the magnets. Since it was not flat anymore that may have hampered the connection. I sold those Two Orbtronic to my soldering technician and hiking buddy Bob.
I ordered Another FT Orbtronic and One BT Orbtronic 26650. If they do not work properly[to be expected] I will try the magnets on those.I wanted Two BT’S but they only had one left,in fact they only had One FT left also!
The Ijoy 26650 4200mAh has the most recessed FT of any 26650 I ever had. When a small solder blob was put on that, basically making the top level w/ the wrapper and can,I got it to work very well,just like the 18650’s ect.
Here is the Ijoy w/ My CATvn V6 NW 5000K awesome torch!
P.S I see that all of my photos are gone from when I started the thread. I use postimage.org. That sucks,that was a lot of hard work and time consuming!
They work now but I think they had a glitch or change in format? I can not remember.
BTW the Delta Fan and Liteon SMPS are still working SUPERBLY!!! No Hiccups! :+1:
I use magnets 6x1 millimeters. The plus and minus the battery. At Ali I bought them 100 pieces for about $ 2. If they are low, buy higher. Maybe 6x2 millimeters.
^
Thanks,Mine are 3mm X 12mm. I think Home depot has your size. I will get them if they do when my new batteries[sold the others] come in next week. First I will see if these 3mm X 12mm work.I would only be able to use 1 because of their size. 2 of your size seems better!
@ Peter J.
Just got some 6mm X 1mm Neodymium magnets on Ebay….3X the money but will get here 3X faster than coming from China! :+1:
Thanks for your help, I am sure they will work after posting your pictures.
Did you try just using 1 magnet?
Are you using 2 to make it even?
,thanks,
I use two. On plus and minus. I bought them 100 pieces. The price was very low - US $ 1.51. The price is really fun. 100 pcs!! The shipping cost was US $ 0.63.
I bought them here:
https://www.aliexpress.com/item/Cylinder-Rare-Earth-Mass-Neodymium-6mm-x-1mm-Magnet-100-Pcs-Mini-Small-Disc-Magnetic-Materials/32849096796.html
Yes, I saw that. Great deal. I just did not want to wait 2,3 4 weeks for it. I paid $7.64 including shipping for 100 pieces! I only need 10 at the most. I will have them next Wednesday or Thursday.
Judging from my own experience, the only way to keep the OPUS BT-C3100 from overheating and also from heating the batteries, is to stick a big ass fan under it, there is no other option. 
Here is mine abomination, works great so far! xD I also put a step down converter, so I can control the fan speed.
hmmm…….I’ve got an extra Corsair liquid CPU cooler around here somewhere………
Nice custom fan A_M_K. :+1:
Now you just need a better power supply so you do not have stoppages and Resets where you lose all data during discharge tests like me and many others had from the original power supply.
My 12V/5.5A/66W Liteon SMPS
/\ :+1: That is a nice fan set up A_M_K. Good job.
Yep WolfDog, the ‘LiteOn’ power supply was a great find by you; as well as a lifesaver for our chargers with the crappy power supplies!! :+1:
Mine is still going strong……
A job well done by you!
We have to give Professor Gauss some credit for suggesting it!
My Delta fan and Liteon power supply are still working like a charm,15 months later! :+1:
Yep…. your right, “Professor Gauss” had slipped my mind. . :+1:
SUCCESS! Thanks Petr J. :+1:
Those same magnets doing something incredible!!
So what resistor was used to get the 12V down to 5V?
Excuse me being clueless 
Heat protection no longer works, but it’s noisy.
^
Heat protection no longer works The Delta fan REDUCES the heat!!
Sure it is a little louder but that is well worth the results. I turn my off when i go to bed,sometimes I have left it on and slept w/ no issues!
Looks like you modified it a bit more by removing some material.
Here is mine,It protrudes by 1mm,that is how much more depth it has then stock fan.
