Nickel Strip vs Fuse Wire

M

Milanbeh

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Apr 14, 2019
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Hi All

Just something that's been bugging me. Does nickel strip have a fuse rating?

Ie. These are direct replacement for fusing wires? If not what protection exists as an alternate?
 
Fuses have fuse ratings.

Anything that is being used as a fuse which isnt actually a fuse, is basically a use at your own risk type thing. You have to test it yourself to find the rating. Even if you are using thin wire or resistor legs, the length of the wire matters from fuse to fuse. This is why in real fuses you see an enclosed and pre-determined blow area.

Just my opinion, but if you want a fuse, use a real fuse. I also agree with what was said above.


Even a wrench can be considered a fuse just have to test it to see what its rated at.

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Thanks to the second part of my question. Given the cross sectional area of generic designs which employ nickel strips I doubt the function includes fusing but merely a conducting surface which can be rapidly deployed by a spot welding. In this case where is the fusing within the system. How would one stop the battery bank being overloaded beside a potential trip switch inline which is governed by the rated design amperage.
 
I would venture to guess that an extremely large amount (probably 95%+) of battery packs built dont employ cell level fusing. That concept appears to have been made popular by Tesla, but their cells from what I understand dont have a CID for safety either.

Cell level fusing isnt even something I concern myself with most of the industry doesnt use it.

If you want to stop your battery bank from being overloaded, just do what the rest of the industry does, and just add a PACK LEVEL FUSE.

There is also so much cell level using does not protect from, and also adds so much additional complexity, that it becomes somewhat fragile in its own right. I also feel this has a lot to do with how a pack might be constructed, but its a design consideration which you can make yourself depending on what you are trying to accomplish.
 
With respect, i have a slightly different opinion about what can be used.
Imho you dont need a exact ratio of the fuse, you just need a fuse which open on the case of several Cells concentrate their current on one shorted cell.
The range is just so that it should hold the max current you draw per cell, and should burn above that as long as the shortened/damaged cell can take it.

What i use is Teflon wire like
https://yiweike.en.alibaba.com/product/344027275-209490464/Teflon_isolated_wire.html (not the correct diamater ! Just the type)
where i have an old version which is silver coated. It opens on 5-7 Amps, which is 2C for a cell, i load far below that.
 
Hi everyone. I found this thread while searching for cell level fusing.

I've purchased the 5A small glass fuses, but I'm curious about the nickel strip fuse. So I decided to purchase the 2mm wide, 0.12mm nickel strip to see if it could be used for cell level fuses.

First, I tested the glass fuse. I use a single 18650 cell, LXD 18650-20P3 cell, fully charged. With the DC clamp multimeter set to DC current, in the max monitoring setting, I connect the glass fuse, and it trips really fast—less than 1 second. The max current recorded in the multimeter is 4.6A. I accept this as the limitation of the clamp ammeter.
Then I cut the 2mm nickel strip, around 2 cm, and tested it. It glows and finally breaks apart. But takes around 2 seconds. The max current recorded is 26A.

So, my conclusion for this experiment is:
1. If you need a fast acting fuse, use the fuse with the well known rating, and test a sample of it to make sure it can trip.
2. If you just need another safety layer, a fuse that could be spot welded easily, then a thin, 2mm wide nickel strip could become a slow acting fuse. Just make sure to use a lot of kapton / heat resistant tape, since the glowing nickel strip will produce a lot of heat until it trips.
 
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dk135 said:
2mm wide nickel strip could become a slow acting fuse
Click to expand...
Uhm, I wouldn't use a nickel strip as a fuse, simply because there's components which are expressly made to be fuses and do the job better: they are enclosed in a small container so you're sure you'll have no hot residuals falling around (which could be a serious problem).

What if the fuse is crossed by more than 5A, lets say 20A or more at once (this could happen in my setup if 3 of the 4 batteries in parallel would disconnect). Can we be sure the 2mm wide strip will melt in the same way, with a nice clean one point break? Or could it become a dangerous red hot metal strip ready to drop and melt anything around it?

I wouldn't risk it by using proper fuses.
 
Nickel strips vaporize just fine, just like having classic copper ones (like old fuses had). So yes, you can fuse-rate them.
The only secret is correct calibration. One strip of 0.15 x 80 mm will be practically vaporized in a power tool like a chainsaw using 12Ah batteries.
So do the math, calibrate for what you need. Here's a start table to work with.
 

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Boron said:
one guy is making Ni fuse strips with built in fuse links https://batteryhookup.com/collectio...uous-roll-by-the-foot-18650-cell-level-fusing - seems neat to me
Click to expand...
Yeah, that style is pretty common as well. They are available on various different supply chains.
The biggest thing with these is they need to be connected on the Positive end to make sure when it pops, it actually disconnects from the cell. And you also really should use those felt washers to make sure no metal bits drop down below the Pos cap, though this should be done anyways regardless of the connecting type
 
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