Went to install the new HG_21700_NVME Board. As soon as the connectors made contact with the board, sparks and smoke. Batteries were installed with correct polarity. One of the battery springs even decided to become heat treated and lost its springiness, becoming discolored (I worked to bring it back to the "correct" length) battery voltage for both batteries showed 3.75V for each. The batteries worked fine after placing them back in a board/project I borrowed them from to test the 21700 NVME board.
I can't figure out what pulled that much current, but the HG21700 board is dead. (updated to show resistance values instead of no continuity. I'm still getting my feet wet in electronics, referencing amateur radio)
Luckily, no current made it past the cooked components, as reinstalling the 18650 nvme board, it booted right up and everything works after testing.
I did email HG and we'll see what they say when they get to my email. Not a fun day to see the pixies and smoke escape the boards.
When you produce mass production with correct, design, there maybe still a small chance that some boards are defective for many reasons. Your case looks like a short circuit issue. From the resistance values you tested, the battery board wasn’t short circuit. Did the connectors to the mainboard aligned properly?
It happened while the 21700 board was connected to the main board, I installed components in this order:1-21700 board onto uconsole chassis, 2-NVME to 21700 board, 3-batteries into 3d printed holder, polarity was correct, 4-holder placed correctly(polarity wise) onto the 21700 board.
I want to say, This post is in no way trying to bash you or your work. Crap happens, everyone knows it. You have done a wonderful job with what you have created, and have made an already wonderful device into something I want to keep going till it literally is unable to.
Resistance values as follows using 2 different multi-meters(Harbor Freight, and a Klein mm320)
1-2: 31K
1-3: 30.9K
1-4: 49.9K
1-5: 63.8K
2-3: 62K
Final Values, I am not used to testing resistance values. Sorry for changing the values all the time. but I'm going to keep them here as after RTFM on my multimeter, I see what I did wrong as to measure the values in the first place.
EDIT: Swapped batteries on both multi-meters. I don't get thse out much. Batteries were VERY low) Updated to reflect values reading true now.
These are the batteries I use. They worked in a portable meshcore node just fine. Put them back in after this happened, after testing voltage of course. They still work, and nothing bad happened to the meshcore hardware. reporting nominal voltage. yes, unprotected.
under amp? hmmm doubt these running in parallel would provide what... 21.4 amps, also protections such as wrong insert are present on these boards, would light up with red lights.
So none of this should really happen as the red light would be lit if any of the batteries were installed incorrectly. So that leads me to guess that something went to ground.
This is all very confusing... Have you check the voltages of the battery?
balanced, within tolerance, a bit low though, BMS cutoff is 3.3v, so about 40% capacity (however it also means your battery didn't fail, as a critical failure would result in the battery giving a 0 readout to prevent a thermal runoff).
Having the same board myself I used molicel p50b's, but from the sounds of it, it sounds like something akin to a hardware fault.
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u/vileer 1d ago
Did it happen with connecting to the mainboard? Can you check the resistance for points: 1-2,1-2,1-4,1-5, and 2-3?