Open source fuse-wire test rig

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spinningmagnets   100 GW

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Open source fuse-wire test rig

Post by spinningmagnets » Aug 29 2018 12:45pm

Enough questions have been coming in about individual cell fuses, that I thought ES should be the one place where trusted info about real-world fuse ratings could be found.

Fine strands of copper wire are sometimes used to reduce the volume of splatter when the wire blows. Common "fuse wire" is often found with a composition that is very similar to lead-free solder. Zinc / Tin.

The tiny glass-bulb based fuses contain the metallic conductive splatter for this applications where that feature is desirable.

How to test accurately? I have a Fluke meter with an amps clamp, is that accurate enough?

I don't know if using 12V instead of 4V would change the results, but since I want to end up with unrefutable and trusted data, I am set on using some type of 4V supply, possibly 30Q cells in parallel.

I'd also like a digital readout of the volts and amps, and some way to vary the amps. The highest-rated 18650's are around 30A peak, so the fuse-tester should be capable of 45A at the max.

I have a soldering iron and money to spend...any tech advice is appreciated.

Addy   100 W

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Re: Open source fuse-wire test rig

Post by Addy » Aug 29 2018 12:56pm

I don't think a clamp meter is accurate enough for this. Do you have multimeters that can measure current directly? If you can only measure voltage, you could put a shunt resistor in series with the fuse wire. Then you just need to measure the voltage across the shunt to calculate the current.

For this kind of test I found the foam-cutter mode on my Turnigy Reaktor charger (clone of iMax 106b) was very useful. If you have one of these chargers or something similar, it lets you set a DC current to output up to 10A. You can power it with a 12V supply or some batteries and tell it exactly how much current you want.

Thanks for taking the initiative to do some testing with fuse wire. I've been wanting to do some tests with fuse wire but I have too much other stuff on my plate right now.

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spinningmagnets   100 GW

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Re: Open source fuse-wire test rig

Post by spinningmagnets » Aug 29 2018 5:15pm

Thanks for the reply. If enough people come to a consensus, I will pay for the parts and perform the tests, then post data. The DIY powerwall forums use "used" cells that can often be acquired for nearly free. That price means they are willing to put in a lot of time compensating for the risk, and individual cell-fuses are popular.

Here's one youtbe that might be helpful

https://www.youtube.com/watch?v=O94_vHvKeME

markz   100 GW

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Re: Open source fuse-wire test rig

Post by markz » Nov 01 2018 7:12pm

spinningmagnets wrote:
Aug 29 2018 12:45pm

How to test accurately? I have a Fluke meter with an amps clamp, is that accurate enough?
The meter should have a wave for ac and a dashed line for dc.
I almost got suckered into buying the mc clamp on sale for $11, but it is only ac current, both voltages.
It would be nice for easy monitoring of dc amps on bike. I should really dust off my cycle analyst. :oops:

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