Fuse wire welder prototype

TinkerGear

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Aug 4, 2020
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Hi guys, I normally post on various Facebook groups but I was asked by several users to post on here. I have been prototyping a fuse wire welding attachment that I wanted to share. It's a concentric pin design, intended to make welding fuse wires to 18650 cells or nickel strip as easy as possible. My latest prototype is V1.4 and I'm finally happy enough with it to send out a few prototypes for testing. Questions, comments, criticism, and suggestions welcome. To be clear this is a prototype in development, and is NOT FOR SALE.



image_qejnqa.jpg
 

Wolf

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Sep 25, 2018
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TinkerGear said:
Hi guys, I normally post on various Facebook groups but I was asked by several users to post on here. I have been prototyping a fuse wire welding attachment that I wanted to share. It's a concentric pin design, intended to make welding fuse wires to 18650 cells or nickel strip as easy as possible. My latest prototype is V1.4 and I'm finally happy enough with it to send out a few prototypes for testing. Questions, comments, criticism, and suggestions welcome. To be clear this is a prototype in development, and is NOT FOR SALE.
Like it!
Very cool will it work with a GrapheneTurnigy 6.0 battery?
Also can't wait for the Kweld attachment.......
Wolf
 

TinkerGear

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Aug 4, 2020
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Wolf said:
TinkerGear said:
Hi guys, I normally post on various Facebook groups but I was asked by several users to post on here. I have been prototyping a fuse wire welding attachment that I wanted to share. It's a concentric pin design, intended to make welding fuse wires to 18650 cells or nickel strip as easy as possible. My latest prototype is V1.4 and I'm finally happy enough with it to send out a few prototypes for testing. Questions, comments, criticism, and suggestions welcome. To be clear this is a prototype in development, and is NOT FOR SALE.
Like it!
Very cool will it work with a GrapheneTurnigy 6.0 battery?
Also can't wait for the Kweld attachment.......
Wolf


The Nano welder is a separate project than the fuse wire attachment. I haven't pushed the V1.4 attachment to the limits yet but it should work with that battery. The main concern would be duty cycle. As far as the Nano spot welder goes, you should be able to plug pretty much any 2S-3S battery to the XT60 port. I know an early tester hooked it up to a 12V car battery.
 

rev0

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Does it work with the glass axial fuses? I had no luck manually spot welding these with a Kweld, the thicker copper wire either blew up or didn't get hot enough to stick. I prefer glass fuses now for soldering cell packs, but they are more work than fuse wire, I also prefer them since you can get much lower ratings; even the 30ga fuse wire you show I've tested only to blow at ~20A.
 

Wolf

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TinkerGear said:
The Nano welder is a separate project than the fuse wire attachment. I haven't pushed the V1.4 attachment to the limits yet but it should work with that battery. The main concern would be duty cycle. As far as the Nano spot welder goes, you should be able to plug pretty much any 2S-3S battery to the XT60 port. I know an early tester hooked it up to a 12V car battery.
Ah XT60 No biggie I can make a XT90 (Battery connector) to XT60 easy enough.
Wolf
 

TinkerGear

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rev0 said:
Does it work with the glass axial fuses? I had no luck manually spot welding these with a Kweld, the thicker copper wire either blew up or didn't get hot enough to stick. I prefer glass fuses now for soldering cell packs, but they are more work than fuse wire, I also prefer them since you can get much lower ratings; even the 30ga fuse wire you show I've tested only to blow at ~20A.
Are they bare copper or tinned? I have tested with 1/8 and 1/4w resistor legs and 34, 30, 28 and 26awg tinned copper wire. I have some glass fuses on the way but I'm 99% sure it will work great on them.
 

hbpowerwall

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Can't wait to see how this evolves
 

rev0

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TinkerGear said:
rev0 said:
Does it work with the glass axial fuses? I had no luck manually spot welding these with a Kweld, the thicker copper wire either blew up or didn't get hot enough to stick. I prefer glass fuses now for soldering cell packs, but they are more work than fuse wire, I also prefer them since you can get much lower ratings; even the 30ga fuse wire you show I've tested only to blow at ~20A.
Are they bare copper or tinned? I have tested with 1/8 and 1/4w resistor legs and 34, 30, 28 and 26awg tinned copper wire. I have some glass fuses on the way but I'm 99% sure it will work great on them.

Hmm nevermind, turns out they're nickel coated steel most likely. Some info I found from Googling:

"Most resistor leads are steel, plated in nickel, and then solder or tin coated.

Some component leads are copper, plated with tin or tin-lead."

I confirmed my fuse leads are magnetic, here's a cross section look also from a freshly clipped bit:

image_vjrdlj.jpg
 

TinkerGear

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rev0 said:
TinkerGear said:
rev0 said:
Does it work with the glass axial fuses? I had no luck manually spot welding these with a Kweld, the thicker copper wire either blew up or didn't get hot enough to stick. I prefer glass fuses now for soldering cell packs, but they are more work than fuse wire, I also prefer them since you can get much lower ratings; even the 30ga fuse wire you show I've tested only to blow at ~20A.
Are they bare copper or tinned? I have tested with 1/8 and 1/4w resistor legs and 34, 30, 28 and 26awg tinned copper wire. I have some glass fuses on the way but I'm 99% sure it will work great on them.

Hmm nevermind, turns out they're nickel coated steel most likely. Some info I found from Googling:

"Most resistor leads are steel, plated in nickel, and then solder or tin coated.

Some component leads are copper, plated with tin or tin-lead."

I confirmed my fuse leads are magnetic, here's a cross section look also from a freshly clipped bit:

image_vjrdlj.jpg
If that's the case they're identical to the resistor legs I tested. I can confirm it works perfectly on them
 

SKILIS777

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Aug 7, 2020
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Hi all
Im new to all of this and i going to start a project to make a 6s 6p battery pack for my ups.
I what do do a fuse wires method but im stuck on the calculating the wire to use.
How do i calculate it?
Remember im new and need the normal person calculation. Lol
Thanks
 

rev0

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There's no way to calculate it :)

I have tested the 30ga Remington tinned copper wire you see in the OP's video, and it blows around 20A, for around a 1" length. Shorter length will blow at slightly higher current, since the wire is closer to the cell/bus bar to wick away the heat. It's a complicated matter. Best bet is to buy some wire sizes you think might work or be close, then test it yourself with a power supply in constant current mode, dialing up the current until it blows.
 

SKILIS777

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Thanks will do that but i mean what amp must it blow on the battery pack.
Is 5 amp right for a big battery park and for a small one.
Or is it calculator on the device and how must amp it pulls on Max.
 

rev0

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The fuse wire can be no bigger than the maximum spec for your cells (typically, around 4-6A for a laptop cell), otherwise it's not protecting anything. It can be lower, depending on what your end application is, but really it should be sized to protect the cells, and protect your system with a pack level fuse sized appropriately. I use 3A glass fuses, which blow at around 5-6A, but can operate continuously at 3A. It's a decent compromise size for cell level fusing, any lower rating and the fuse resistance starts getting pretty high and would affect pack performance under load.
 

gauss163

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Re: fusing: be careful that inconsistencies in fuse resistance doesn't destroy any careful cell IR matching during pack construction. It is known that a small IR mismatch can lead to a much larger lifetime loss(due to positive feedback processes), e.g. see the paper i cited here where they show that a 20% IR mismatch can lead to a 40% reduction in life.
 

daromer

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6s. 24v system? I think 7s suits better to be honest. Then you dont overcharge. Also note tha amount of cells in parallel if that can handle the current.

Secondly do you use new cells? If so i would use nickle strips and no internal fusing. Not for that small battery.

3rdly. Lithium batteries in a standard UPS made to use LA is not optimal and you need to have a deep understanding of how it charge, what voltages and all that. Dont forget a BMS to protect the battery and the unit if something happens....
 

SKILIS777

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Thanks everyone this help a lot.
Daromer, yes im going to add a BMS and it is laptop batteries. I was going to do nickel strip but because of the laptop batteries i what to do fuse wire. I still need to get a decent charger so I can get the capacity of the batteries.
Thanks again for all the information.


And I'm from South Africa so it's very hard to get all the stuff cuz the people do not do this in South Africa or not what I know
 
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