I’m trying to understand what fuse I need for my 12s 7p. Oh! My charger is 8a too. What fuse holder do I need? Where should i place it at? I shocked myself yesterday.lol Damn charger failed on me.
Put a fuse between your charge port and BMS in your board, I like to use a mini blade fuse holder in the positive line, I go with a current rating of 1.5 times the charge current rounded up to the nearest 5A, so for you that’s 15A
Yes, but I don’t use a fuse holder, I just solder it to the wires, and you can epoxy the fuse to the inside of the enclosure.
It shouldn’t ever blow, but if it does, you can be thankful you’re not replacing a battery or a building, while you put another fuse in, and epoxy it to the top of the old one 
For 8A 12S charging I would use a 15A 58V fuse.
What’s wrong with a fuse holder?
Bigger and more failure points and one more part to stock or not fit correctly, and totally unnecessary.
But nothing wrong with it, it will work fine.
It could also rattle around inside. I just really like to stick the fuse to the fiberglass enclosure with epoxy, it works great.
I usually use the waterproof ones and those suckers are real secure in there
I need pliers to get them in or out, my only gripe is the aluminum low core count 16awg wire it comes with is fucking awful
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I plan on using a small cylindrical ‘buss’ fuse on mine. Simply solder the wire to each side and cover with shrink tube. I was going to fuse the negative myself. Is there a good reason to fuse the positive side instead? @ZachTetra @b264
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If you fuse the positive then the rest of the system is grounded, ditto for antisparks and loop keys
Are you talking about the glass tube ones?
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Ahhhhh makes sense. Yes. I plan on the glad ones. I see where you’re going with it haha. Glass = fragile = not ideal in a vibration factory. I was thinking of using a heavy duty shrink. I’m a sparky and I work in maintenance. I have a decent shop at work with some nice stock of things like that.
The problem with the glass fuses is not the glass. It’s the metal caps at either end, and how they connect to the fuse wire. Vibration breaks those fuses down really fast, by separating the internal wire from the metal caps at the ends. I strongly recommend you avoid them.
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I’ve also used those and soldered to the ends. I always worry about soldering to the ends, and the filament falling off inside, so I’m quick about it. They’ve worked for me.
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Don’t do this it’s sloppy
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No matter if you put it on the negative or positive of the charge port, whatever works best inside your enclosure.
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Who cares if it’s sloppy, it works really well.
Appearance of the inside of my enclosure (that’s sealed up) is not on my priority list.
Fuses should not blow anyway except in extreme cases.
Wouldn’t it be better to fuse the positive side of things though for the following reason?
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Ima see what else we got here. If I can find the autos I’ll consider it. @BenjaminF thats a fair point. Maybe a slow blow might be better suited. Way chonkier filament and a dead short will still open the circuit. I have lots of room for activities in the enclosure so space isn’t a concern. Thanks for all the weighing in bois!!
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Yep. Standard convention is to fuse the positive side. It does matter for the above stated reasons.
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Won’t those fail potentially over time due to vibration
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This is what I worry about
I was planning on using one of the ceramic ones that are the same size as the little glass ones. Those are full of sand so I think should do better about vibration. I’ve got a few dozen of 500 VDC 10 A ones at work for when the students inevitably blow them out on the multimeters so I just pocketed one. I’ve got a nice holder I can just solder in line, but they sell ones with axial leads too. We’ll see how it goes, but I feel like it should be fine. They hold up in multimeters in some pretty rough places.
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