I have the C3100 since somw years, warranty time is over.
It still works but since some weeks the display freaks out, sometimes for all cells, sometimes not.
The values runs crazy, extremely fast changing, unreadable.
It´s in original state, no modding like changed fan or something.
What´s your experience with this charger?
I’ve been using a BT-C3100 V.2 exclusively for 4 years or so. So far no issues with the exception that mine terminates li-ion a little higher than the generally accepted 4.20V, taking most of my cells to 4.22V. I think the voltage calibration is off by .02v because the unit shows 4.20, but my DMM’s consistently return the extra .02. Not a big deal in the grand scheme of things. I babysit my charging sessions and usually pull cells when they hit the 4.16V (+) mark on the display. It does a great job on my AA/AAA Eneloops as well.
This being said, I dont work it hard and all my charging is done in the house in a controlled environment, and the unit is stored in an airtight container with desiccant in between uses. It does everything I need it to do, and I trust it as far as I can throw it (as I would for any other Chyna made charger).
It’s my go-to charger when I don’t just charge in situ, or if I’m charging pairs of NiMH and such.
Buzzes like an angry bumblebee when the fan starts up, but other than that, it’s fine, and I had mine since the Nixon administration, or so it seems.
I Use most of time for charge/discharge lithium and test internal resistence of Ni-Mh battery.
Someone said that pulse charging (with peak ~3A) can cook AAA Ni-Mh even at low current settings. It’s a right thing?
That’s why I use another one with constant current for them.
Thank you for the answers.
It looks like I had just bad luck with my BT-C3100.
Like I said, it still works but it´s impossible to see the state on the display, which makes it almost useless for me.
Didn´t use it often last time because I´m annoyed by the fan, even if I charge 4x 500mA with NiMH
If it’s legit numbers going crazy, it’s most likely something in the “brains” that’s going mental. Nothing much to do in that case.
If it’s gibberish numbers and indicators (“V”, “discharge”, “test”, etc.), it’s likely the display connection/-or coming loose. Try gently pushing on/near the display edges/corners to see what happens.
Video would help.
Will make a video of the display and post it here, maybe next week.
I´m curious about what does it next, the behavior of the display is not stable, even not with the unstable behavior 
I’ve had mine since 2014 and it’s been flawless. The fan has always been quiet and I’ve never had to lubed it.
I use a different charger for my NiMH batteries, only because that charger can’t charge Li-ion and it’s a good charger, but I use the Opus to jump start the low voltage ones that it can’t recognize.
Sorry to hear that yours is giving you problems. I’m not sure which charger I would get today if I needed a new one, but it would definitely have a built in fan to keep the temps down. Unless you have a fan, like I do, to help which I’ll turn on when I’m charging numerous batteries at a time.
Huh, that sounds totally different to my Opus. Even with charge NiMH with 0,5A in a not so warm room it turns often on; OK, it´s not so noisy but other cahrger can do same without fan
If I compare to the Vapcell S4+ the cells in the Opus getting warmer at same charge current, the Opus itself stays cooler than the Vapcell. But the Vapcell shows that for charging with my used currents no fan is required.
Discharging is different, especially with LiIon, but discharging NiMH with 0,5A needs no fan IMHO
I’ve seen numerous examples of chargers taken apart to show burnt circuit boards since they got too hot and stop working. One that I recall was with the La Crosse BC700 charger that I use for my NiMH batteries.
That’s why I like to keep things nice and cool with an extra fan just in case.
Do you talk more about LiIon or NiMH, charging or discharging?
Expect the half-dead/crazy going slot on my Dlyfull A4 I had never such problems. OK, now maybe my C3100 have also some problems but except the display it should work.
The BC700 which is a Dlyfull and sold with many different names have often heat problems like almost all compact chargers. That´s why I prefer only charge small cells with low current or don´t use all slots at same time.
To avoid failure with these multichannel chargers better don’t use them above half of their max output current
This is based on??
They overheat
I bought mine in July 2018. One channel, 2nd from left, stopped working correctly so I put a heat shrink piece on the negative terminal so it’s not used. In that regard, it’s no the more reliable charger I have.
I like that the default is 500 mAh. The Miboxer I have will usually adjust the current and many times, it’s to high if I’m not in a rush to use them. I also like that the Opus will top out the NiMh to 1.5V as the Miboxer doesn’t push them that high.
Posting videos not allowed, any hints where I can upload the video and link it to here?
Upload to UZube and share link. Usually works well
Just throw it on yootoob and c&p the link here. Eg:
Good a tipp from someone for Imgur 
