I’ve never seen it shut off while charging an 18650 because of heat. And I allowed one to go as high as 190F (88C) just to confirm. So yea. Apparently there is a software bug.
I’ve charged at 1000 milliamps in all 4 slots many, many times and never had an issue with heat. The fan does a good job keeping the temps down.
I have no doubt NeutralFan, but that’s because your batteries are good. If you pop in a battery with very high IR, no fan can stop the thermal runaway. Apparently they didn’t test that software feature, and it has a bug.
Hmm, how does it (or should it) sense the cell’s temperature? Conduction through the springy-thing?
I assumed “thermal protection” was just for the innards, not the cell itself.
You can see the cell temp sensors at the top of this pic.
The doodads wired to “TH1” through “TH4”?
Huh… interesting.
THermistors, yea.
Some poor guys have been hooking all those up, and they aren’t even fully functional.
They don’t look to have any actual physical contact with the cells, though.
Just like drivers with thermistors on the driver, vs on the LED’s board. Takes a (long) while for the driver to start heating up when the LED itself could be blue in the face and screaming for help.
The cell touches the charger in this area. And inside it is the sensor. There is no way that paper thin layer of plastic has enough R value to stop 190F from cooking the temperature sensor.
The BT-C3100 is basically the same charger as the BT-C3400. For reference, the quote below is from the BT-C3400 manual (which is more concisely and clearly written than the BT-C3100 manual):
https://images-na.ssl-images-amazon.com/images/I/51TCfcbvBaL.pdf
I do not have a method to determine if the charger always behaves this way.
Yes, the "Discharge - Refresh" mode has increased the capacity for some of my older NiMH batteries. I have never used this mode for Li-ion batteries though.
I have the BT-C2400 (aka BT-C2000) and BT-C3400 (aka BT-C3100) chargers from OPUS.
The BT-C2400 (aka BT-C2000) only supports NiMH and NiCd batteries, but I prefer it for these types of batteries because during the "Discharge - Refresh" mode, the discharge current is set to one-half of the charge current (but this may not make any appreciable difference besides making the process faster while still using a low discharge current for better conditioning and a higher charge current for more consistent full-charge termination detection). With the BT-C3400 (aka BT-C3100) the same current is used for both discharging and charging in this mode. I also prefer that the BT-C2400 (aka BT-C2000) does not have an internal cooling fan and does not use sliding rail battery contacts but I do understand why these are required for the BT-C3400 (aka BT-C3100) to charge Li-ion batteries. Also, the more secure and tight snap-in battery contacts of the BT-C2400 (aka BT-C2000) seem to provide a more consistent battery internal resistance measurement during the "Quick Test" mode.
If you want to spend a very long time conditioning and forming NiMH batteries at very low current rates check out the PowerEx MH-C9000 charger (that only supports NiMH and NiCd batteries) and read the section concerning "Break-In Mode (IEC capacity analysis)" in the instruction manual below:
https://powerex.helpdocs.com/manuals/user-manual-mh-c9000-wizardone-charger
If the electrical utility power provided to your residence is not 100% stable, be aware that if the BT-C3400 (aka BT-C3100) charger experiences a power reset due to a utility power glitch while in the "Discharge - Refresh" mode or any other mode, it will resume in "CHARGE" mode at it's default current of 500 mA, no matter which mode you were previously using. This happens to me occasionally.
I am not aware of any analyzing charger that can resume operation at the same point in the same mode after a power reset, so the above statement is not a complaint about the BT-C3400 (aka BT-C3100) specifically, but is only a warning concerning analyzing chargers in general.
Just a comment on internal resistance measurement with the slide contacts on the BT-C3100 (and presumably other similar chargers). I find that wriggling the cell a bit to make a clean contact and then maintaining firm finger pressure on the slide while the measurement is taken will make the readings much more consistent. Because the reading is quick, it is normal to do such testing one cell at a time.
On brand new authentic cells the readings are close to those reported by HKJ, who is using much better equipment.
Since i read your question about the clicking sound i paid more attention to mine and can indeed hear the fast clicks. As said above it is part of the normal charging procedure using pulses, so nothing to worry about.
That’s great - thank you. I suspected it was normal, but surprised there was so little mention of it, given the detail so many reviews go into. Maybe because it is normal.
Thanks again.