What size cable braid is that boss?
I´m not the boss, but i can say it´s three layers of 0.25" tinned copper braid 
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Thanks boss #2! Is there a specific length you shoot for to achieve a specific fuse rating? @b264, @Andy87, or anyone else knowledgeable on the topic?
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Just choose diameter according to the fusing current you want. https://www.powerstream.com/wire-fusing-currents.htm
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Bookmarked
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If I wanted it to fuse, I would solder an actual fuse to it. I made that specific one rated for 135A+ continuous because I don’t want it fusing. Ever.
I’ve thought a lot about this, and everyone differs, but me personally, if the board starts severely malfunctioning while I’m at-speed in heavy traffic, I would prefer the battery stay connected as long as possible so I still might have brakes to stop while the board is burning-down. If you’d prefer the loop key fuse-out to possibly save your expensive electronics instead, that’s personal preference but I’d rather have the extra couple seconds of throttle response myself. Once it fuses, you’ve got no brakes.
Basically it’s ME > BOARD or BOARD > ME
I prefer to give the benefit of the doubt to myself over the safety of the board/battery itself.
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Thank you for the confirmation
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Dumb question, but how did you urethane it so well?
About 30 coats heh heh heh. No, I’m not exaggerating.
I mean like, did you dip it, or brush it on.
My initial thoughts would be to dip out of a larger can, your bottle just seemed like it didn’t have a large enough opening to dip it in though.
The other angle is, if something goes wrong in storage or charging, the fuse might save your house, family, and multi-unit domicile co-inhabitants. 
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That’s why I fuse the charging
For wires and loopkeys and things needing physical abrasion resistance I use
MG Chemicals Urethane Conformal Coating in the 55ml brush-on bottle
But for PCB waterproofing I prefer
MG Chemicals Silicone Mofified Conformal Coating in the 55ml brush-on bottle
except on heatsinks, then
MG Chemicals Acrylic Conformal Coating in the 55ml brush-on bottle (because it’s super-thin)
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You just put a fuse of a rating slightly higher than your charge rating on your positive charge line?
In general, fuses should be rated to protect the wires behind it.
In this specific case, I’d fuse at the amps of the lowest component. Usually this is the 5.5mm dc jack. Next is the BMS charge max, then usually the charge wires (both positive and negative – it’s a circuit).
Fuses have some built-in room over their rating. If you oversize your fuse, it won’t kick in in time to save your parts. (this may be true even if you perfectly size your fuse)
For example, for this specific mini blade fuse: https://www.littelfuse.com/products/fuses/automotive-passenger-car/blade-fuses/327.aspx
The Time-Current Charactistics table says:
- 110% of Rating: 100h Opening Time Min
- 135% of Rating: .75sec opening time min, 120sec opening time max
- 160% of Rating: .3s/50s
- 200%: .15s/5s and so on.
So a 5 amp fuse will happily pass 5.5a most likely indefinitely, and will allow 6.75amps for up to 2 minutes.
(sorry I’ve been reading about fuses again)
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No apologies. In my head I was thinking an 8 amp charger and maybe a 10 amp fuse as a reference point so good to know. You’d think chargers would just come with a fuse built in
chargers usually have a fuse, protecting the charger and the mains power. 
Ok that makes much more sense to me. @b264 you’re referring to just fusing the charging board/port side correct?
I usually put the fuse on the negative line, but yes. Either one.
Yes, just the charge jack on the board.
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Do some BMS have a built in fuse? This seems common sense for charge only ones given they already know what rate they’re charging. I imagine all battery makers would want to include this to protect their packs.