Testing Mike's 30AWG 0.24mm Fuse Wire

AveRageJoe

AveRageJoe

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Joined
Oct 9, 2016
Messages
119
AveRageJoe said:
Hey Mike and Peter, I was going to wait and do 1 video with both wires in it but not sure when Peters will get here. Soo Ill do a couple of follow on vids, Anywho what is you fuse length from battery to buss bar. Thanks and Ill test asap. Oh and rerouter is correct, you can test at any voltage,
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Here is the link to the video, I can retest at your actual length if you like. :)

 
Wow, that is very very... very disappointing :( Just goes to show you that you need to do through tests before using it. That doesn't mean it wouldn't help in a dead short but maybe I need to rethink what I'm using. It's a good thing I'm at a place where it still isn't too late to go back. I intend to redo the bus bars on my current packs with the 6ga wire once my next string pack is done, so at most it will take me 2 packs-worth of soldering to replace with different fuse wire for the two new ones I already completed.

Thank you very much for your time testing and putting the video together :)
 
AveRageJoe said:
mike said:
AveRageJoe said:
mike said:
AveRageJoe said:
Hey Mike and Peter, I was going to wait and do 1 video with both wires in it but not sure when Peters will get here. Soo Ill do a couple of follow on vids, Anywho what is you fuse length from battery to buss bar. Thanks and Ill test asap. Oh and rerouter is correct, you can test at any voltage,
Click to expand...

I saw your message on Facebook. I'm going to guess 1cm, but I will get an exact measurement after work and let you know.
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Just did the test and will post later today and keep you in suspense :D
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You're way too fast. LOL. Wait until I confirm the fuse length. I'll be off work in 2 hours :p
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Here is the link to the video, I can retest at your actual length if you like. :)

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I only got around to posting it yesterday sorry mate..I use 0.24 mm enamel coated winding wire. Excited to see the results - either way it goes it's a positive thing !!
 
I just reconstructed your test and pulled 28A though it outwith any issues. I can't keep it on very long to see if it melts after more than 15ish seconds since my meter says 15-30A can only be run for 30 second intervals. This is rather disappointing but I'm wondering if they still serve their purpose anyway. If there is a dead short in a pack of 120 parallel cells, it's going to burn up instantaneously. What are you guys' thoughts on this?
 
Thats why always test em and why im a bugger and keeps saying that. I use 35awg thinned fuse wire. Made for this purpose and is rated 5a. Blows fast around 8A.

:)
 
I'm looking at 38 awg, however its next to impossible to handle given the finest of the wire. 35 awg seems like the go.
 
mike said:
Wow, that is very very... very disappointing :( Just goes to show you that you need to do through tests before using it. That doesn't mean it wouldn't help in a dead short but maybe I need to rethink what I'm using. It's a good thing I'm at a place where it still isn't too late to go back. I intend to redo the bus bars on my current packs with the 6ga wire once my next string pack is done, so at most it will take me 2 packs-worth of soldering to replace with different fuse wire for the two new ones I already completed.

Thank you very much for your time testing and putting the video together :)
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No problem on the testing, glad it helped the cause. Yeah a dead short with 120p would vaporize the wire. Im gonna have to save up for the 2 amp fuse wire unless I can find it cheaper then $127 or I might end up settling for the 3 amp fuse wire for $55
 
Good work Joe - two comments ......

1 - those copper buss bars will be disapating a lot of heat - can you try to use contact points that have minimal thermal mass, or more closely replicate how the fuse is to be used in production ?

2 - have you tested that moving coil ammeter for accuracy at both bottom and FSD ?

I'm also wondering what the makeup of those wires are you've been testing - the diameter is an important factor in its ability to withstand heat, but it's composition is far more important. I'll raise that point simply because I've just tested (again) some 0.2mm tinned copper wire - 10mm long - clamped between a small pair of good quality crocodile clips, and it's gone o/c @8A after 4 seconds - it's rated at 5A continuous at 25 degree' C.

The testing environment has to mimic the actual installation exactly if you want dependable results.
 
Sean said:
Good work Joe - two comments ......

1 - those copper buss bars will be disapating a lot of heat - can you try to use contact points that have minimal thermal mass, or more closely replicate how the fuse is to be used in production ?

2 - have you tested that moving coil ammeter for accuracy at both bottom and FSD ?

I'm also wondering what the makeup of those wires are you've been testing - the diameter is an important factor in its ability to withstand heat, but it's composition is far more important. I'll raise that point simply because I've just tested (again) some 0.2mm tinned copper wire - 10mm long - clamped between a small pair of good quality crocodile clips, and it's gone o/c @8A after 4 seconds - it's rated at 5A continuous at 25 degree' C.

The testing environment has to mimic the actual installation exactly if you want dependable results.
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In the installation, one end will be soldered to a copper bus bar. The other will be soldered to the battery, so I expect heat dissipation will still be the same. I tried to replicate his tests and couldn't get the fuse to melt between two copper bus bars, but did not try it from bus bar to positive end of cell. When I tested the fuse between two alligator clips, it burnt up around 8A, the same as you noticed. I think the key here is that for the installation, it will be soldered to copper.
 
Only one end of each fuse will be connected to a large lump of copper, which has excellent thermal mass - the other will be connected to the cells thin nickel plated shell, which will conduct heat and dissipate quite differently.

To repeat my point, Joe's tests are very good indicators - but for dependable results the test has to mimic the actual "as installed".

We also need to use the same wire in production as we've tested - obviously not all 0.2mm will yeild the same results - its good to see folks have stopped saying "just use resistor legs as fuses"
 
Sean said:
Only one end of each fuse will be connected to a large lump of copper, which has excellent thermal mass - the other will be connected to the cells thin nickel plated shell, which will conduct heat and dissipate quite differently.

To repeat my point, Joe's tests are very good indicators - but for dependable results the test has to mimic the actual "as installed".

We also need to use the same wire in production as we've tested - obviously not all 0.2mm will yeild the same results - its good to see folks have stopped saying "just use resistor legs as fuses"
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Agreed, I was thinking about soldering to a junk cell and the other end to a few different copper buss bars to see what and if there is a difference. As for the wire, ya I couldnt tell you what its compositions would be. I just grabbed a few different ones mimicking what someone could have ended up doing. Ill get my other amp meters out and compare them all to each other. Vid soon
 
What's inside your homemade WTs Joe ?

treadmill or servo motors ?
 
I've got larger current sensors on order, rated to 420A, accuracy 0.1%.
Needed them for another project anyway.

Sean said:
- its good to see folks have stopped saying "just use resistor legs as fuses"
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Jehu used 1/8th watt resistor legs, but people forget the details.
As a test I put a 1/4w resistor leg across a battery that can do 70A. The cable got hotter than the resistor wire, neither blew.
 
station240 said:
I've got larger current sensors on order, rated to 420A, accuracy 0.1%.
Needed them for another project anyway.

Sean said:
- its good to see folks have stopped saying "just use resistor legs as fuses"
Click to expand...

Jehu used 1/8th watt resistor legs, but people forget the details.
As a test I put a 1/4w resistor leg across a battery that can do 70A. The cable got hotter than the resistor wire, neither blew.
Click to expand...


I did mention that he used 1/8watt resistors in one of the videos and I will test once I get to radio shack. Got the flu right now tho.
 
station240 said:
I've got larger current sensors on order, rated to 420A, accuracy 0.1%.
Needed them for another project anyway.

Sean said:
- its good to see folks have stopped saying "just use resistor legs as fuses"
Click to expand...

Jehu used 1/8th watt resistor legs, but people forget the details.
As a test I put a 1/4w resistor leg across a battery that can do 70A. The cable got hotter than the resistor wire, neither blew.
Click to expand...


Even then, you can't assume all 1/8th watt resistors have the same exact legs...
 
Sean said:
What's inside your homemade WTs Joe ?

treadmill or servo motors ?
Click to expand...

The gray one is an amtek 30, the black one is a bodine dc motor from a mail sorting machine similar to a treadmill motor but a little better, have one with a fisher paykel motor as well but took that one apart to put in an aluminum housing. Those fisher paykel motors are awesome if you ever get one. There from Australia so maybe Peter can send you one. A lot of good info on thebackshed.com. What are you using?

mike said:
station240 said:
I've got larger current sensors on order, rated to 420A, accuracy 0.1%.
Needed them for another project anyway.

Sean said:
- its good to see folks have stopped saying "just use resistor legs as fuses"
Click to expand...

Jehu used 1/8th watt resistor legs, but people forget the details.
As a test I put a 1/4w resistor leg across a battery that can do 70A. The cable got hotter than the resistor wire, neither blew.
Click to expand...


Even then, you can't assume all 1/8th watt resistors have the same exact legs...
Click to expand...

Exactly, best to use actual fuse wire. Im gonna try and get that 3 amp wire off ebay when I get some extra cash. Would like to get 2 amp but that shit is expensive. http://www.ebay.com/itm/BFW-3-Coope...697822?hash=item58bab7501e:g:aQ0AAOSwa39UvsRT
 
mike said:
AveRageJoe said:
Exactly, best to use actual fuse wire. Im gonna try and get that 3 amp wire off ebay when I get some extra cash. Would like to get 2 amp but that shit is expensive. http://www.ebay.com/itm/BFW-3-Coope...697822?hash=item58bab7501e:g:aQ0AAOSwa39UvsRT
Click to expand...

I would be interested to see some heat/resistance testing of that wire. For example, if you're pulling 1A through wire rated for 3A, how hot is the wire getting and what is the voltage drop across the wire.
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That would be a great test. Ill give it a go once I get it. I also compared the amp gauge Ive been using with my DVOM and another analog meter that has an external shunt and all three are about the same. Tested at 6-1/2amps 3.3v from the pc power supply. I did video it and I could edit the video if anyone is interested but it would probly be a boring or g-wiz type of video. Let me know
 
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