Yeah generally the ESC filter capacitors charge in a couple milliseconds. You don’t want to apply throttle to the system without the key plugged in all the way. Not for any amount of time, not even for less than a second. The 5.6 ohm resistor inside the key would become part of the circuit and start dissipating huge amounts of power (more than the motors themselves) and get super-hot and fail in a very small amount of time.
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Send a photo of the pin if possible. It’s likely to be okay
At least wipe the soot off it if you can, preferably with isopropanol, if you are even able to obtain isopropanol.
I have a problem. My loopkey sometimes sparks. Not always, like 1 time out of 5 tries… And the resistor is not burnt up because I can still measure the 5.6ohm resistance… Any clue on what’s going on?
Can you show us a high-res photo of it from this angle
and also a high-res photo of the male side you plug this into. I have a suspicion the pins on the male end are slightly compressed and may need to be spread out a tiny, tiny bit.
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These are the highest res I can upload directly here (they got backscaled to 666x500, but I think it doesn’t look too bad) if you want I can also upload them to my drive in higher resolution
@Dinnye Are you able to measure the resistance between the socket and the ring? (with a multimeter)
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My multimeter probes aren’t long enough to measure that way, but I can measure the resistance between the ring and the other socket.
Btw, 20ish more times plugging it in, today, it only happen once… seems like it’s a rare occurence.
I have that part covered in both heatshrink and the end cap of an XT90. However I can get the 5.6ohm reading this way:
one probe touching the ring and one probe in the other socket.
edit: this should be the same as measuring between the ring and the socket directly below it, since the two sockets are bridged with a 10 AWG wire.
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I can’t think of anything that would cause this then, maybe try spreading the pins on the male connector VERY SLIGHTLY apart. So slight.
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Alright, thanks! I spread them very slightly apart, I hope this fixes the issue.
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I have also noticed the same and it’s due to the “no connection” zone between “just connected” and “fully connected”.
If you spend to much time in the “no contact zone”, the DC bus will start to discharge… and if you have many loads (lamps escs, etc) the bus discharge faster. So… . when you push the connectors further… the bus is actually not precharged… and you get the spark.
The trick is to first get the first stage connection where the bus is precharged… and then as quick as possible push the xt90 all the way. Minimising the time in the “no connection zone).
Here Is is an ugly illustration of what I try to say.
And here is resistance measures when just barely pushed in. Resistance is 5,7ohms
Pushed into the “no contact” zone. Resistance is infinite (dc bus will discharge at this stage)
Pushed all the way. Zero resistance.
If the male pins inside the xt90 had even thickness… this problem would not be seen… but now it’s thicker at the tip and it allows the connector to be in this “no contact” zone
If the gap between the outer ring and the inside female pin was smaller, the issue would not be seen. Probably my xt90s are fake though so maybe that’s why.
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Thanks, I think this was the problem. When I saw the last spark I was pretty slow with plugging it in, so probably that’s the reason 
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So if they don’t say Amass TM are they fake ? Is the nylon plastic different and may possibly melt?
Wow @Fatglottis that’s some great insight, thank you.
So, “don’t push it in slowly” is the correct answer it seems.
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LoL I guess but I still think epoxy works better than that.
And the cover is confusing because anytime the key is unplugged, you shouldn’t be riding and splashing stuff on the port 
Seems like perhaps a fix for a problem that doesn’t actually exist.
The charge port definitely needs ingress protection.
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Shh, dont tell them Brian. 
Its a “value add” 
(Also I have seen people asking about them so it’s a simple enough thing to add, plus it acts as a bit of a gasket around the connector)
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I was thinking of it as a gasket as well. Plus, for those that have kids and don’t want to worry about them sticking metal objects, like the tweezers from Operation around the loop key connector… I see it as an extra level of security… Kind of like a double condom for the extra paranoid
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Min height loopkey:
Channel for grip
XT-90s and normal loopkey for scale
Ground/polished by dremel
PETG cover, filled with epoxy:
Assembled. Has physical catch designed into side walls. Can’t be disassembled without damage, even before the epoxy.
Installed:
LightningLoopkey_v2.stl (1.5 MB)
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