Fuse your charge ports: Ft. The smallest user serviceable fuse/holder

Fusing your charge ports is important. Fusing your mains leads is as well, but we’ll argue about that another day

I’d have to presume a large reason a lot of us aren’t/don’t want to fuse our ports (aside from not knowing about it/being a lazy fuck) is because of space constraints. Sure, you can solder directly to the fuse as @b264 does in his The Blue One build - but in the case of needing replacement, that’s a bit of a hassle.

After having found and used what I thought to be the smallest modular fuse holder in my own builds, thanks to @Jansen pulling out some tiny ass blade fuses I’d never seen before, I’ve found something even smaller (and finding the holders for these was actually fairly hard - there ain’t a lot of them made/sold)

So, here our are options.

Mini Blade Fuses/Inline Holders
For space constraints, I modify mine a bit.
Fuses specced from 7.5A-15A (depending on your charger needs) at 58V are perfect - but the 12V ones work just as well

Even smaller:
Low Profile Mini Blade Fuses/Inline holder

https://m.littelfuse.com/products/fuses/automotive-passenger-car/blade-fuses/891.aspx#

https://www.optifuse.com/inline-fuseholders-mini-low-auto.php

Actual purchasing:

https://www.hawkusa.com/manufacturers/opti/series-lps-01

https://www.brevan.com/opt/LPS-02B-18R

Fuses:

https://www.mouser.com/Circuit-Protection/Fuses/Automotive-Fuses/MINI-Low-Profile-Series/_/N-ba8b5

Pay no attention to the unconstrained wire clutter seen:

Fuse holder w/dual lock(both sides cause was drunk and derped orientation) that holds it down nicely.

Fuse it before ya lose it

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Just curious, what about these?

€ 1,44 8% Off | 10PCS 5*20MM Glass Tube Fuse Holder Screw Type Quick Blow 5X20MM Fuse with 22 AWG Wire 250V
https://a.aliexpress.com/_UlN7z

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Yup, that be a fuse holder.

Glass and tube style might not be the best thing for such a heavy vibration environment but that’s really just me guessing. I’d also be worried about it unscrewing, but loctite should fix that even tho it’s plastic.

Soldering an xt-30 to the low-profile minis is a great idea as well, but that gets into being proprietary.

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I think it will hold. I mean those kind of fuses are used in all kinds of environments.

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If there’s limited space are there any issues with using an external fuse between the charger and battery? (apart from it being something else to carry with the charger)

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Then you are not protected from a short at the port (due to e.g. water)

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Been using those for a year as well as in my friend’s boards, it still works/charges. I have never replaced the fuse. Not even once.

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You shouldn’t be replacing fuses very often or at all. And if you do need to, you’ll be glad even if it’s difficult because the alternative is much worse :crazy_face:

I have only blown out one fuse and it’s because I did something really, really, dumb. Something we’re all bound to do if you ride enough.

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Nobody ever said you have to replace a blown fuse. You can always just add another one.

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Thanks!

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Blade fuses not ideal, as they’re usually rated for 12v or 24v (arcing can maintain electrical continuity). I like Littelfuse Pico 2 series, I think the 60v version. They look like chubby resistors.

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You can buy 58V blade fuses from just about anywhere.

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https://www.mouser.com/ProductDetail/576-099707.5WXN
i got these… 10 pk for 5 bucks.

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Oops sorry struck out my error. I remember not being able to find these. Sigh lol.

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or say a dummy with a multi meter. ( not saying that was me or anything… but I melted a multimeter probe. )

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They look awesome but I had a good look at the range and can’t find any options under like 200v

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Lol, true that, I have used multimeters in sketch ways, too. Have been lucky though. Gotta always first ask yourself “what if I slip?”.

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I woke up sweating at 5A.M. wondering about whether or not the fuse should be placed before or after BMS. Obviously, in picture, I have it on ch- of BMS. I have my theories on what should be done - but @professor_shartsis or somebody else, can you chime in?

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https://www.electric-skateboard.builders/t/3d-printables-for-eskate/23199/324

In the thingiverse page I link to the fuse I used: https://www.arrow.com/en/products/0251007.mat1l/littelfuse

Here are some 10A ones, some not in the Pico series.

https://www.arrow.com/en/products/0251010.mat1l/littelfuse
https://www.arrow.com/en/products/0324010.hxp/littelfuse
https://www.arrow.com/en/products/0324010.mxp/littelfuse

I know they have high voltage ratings, but if I understand correctly, voltage ratings for fuses are for arc-breaking, so too high is fine, too low is bad. AC vs DC is very very important (AC self breaks the arc when it crosses zero volts).

I use this to hold the fuse, and allow bypass.

I’ve tested the 7a fuse to failure using a lab PSU. Nice!

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This is nice. Stilll slightly proprietary, but small enough you could store a few spare in the enclosure so it doesn’t matter as much.

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