kdog said:I vidoed a test I did on a 10mm x. 2mm strip, ramped it up from 10-80amps. Unfortunately I couldn't upload it to the tube, my old phone couldn't do it. But it was bright red/yellow by 80amps and melting. I remember touching it at about 30 amps and burning my finger. I think it was just starting to glow at ~50amps. It was a while ago so I can't remember clearly. Strip was pure nickel, in open air, about 100mm long.
DjSpaceGhost said:A 7mm wide by .2mm thick strip of pure nickel can safely handle 9.5amps so I would say definitely so .
rg12 said:DjSpaceGhost said:A 7mm wide by .2mm thick strip of pure nickel can safely handle 9.5amps so I would say definitely so .
Is it 9.5A constant with no heat?
liveforphysics said:rg12 said:DjSpaceGhost said:A 7mm wide by .2mm thick strip of pure nickel can safely handle 9.5amps so I would say definitely so .
Is it 9.5A constant with no heat?
It's making heat, if it's enough to be a problem is a more complex question.
Nickel will be making ~4.1x the heat of copper of the same dimensions. The real question with setting up nickel spot welds isn't about getting the weld to work, but not causing cell damage.
DjSpaceGhost said:For some reason my response didn't post yesterday. It will not get hot enough to damage plastic cell holders at less than 7 amps.
rg12 said:I will be using a 6.75mm wide 0.2mm thick nickel for constant current of about 6.5A
Will it not go hot enough while it's sitting on the cell holder plastic?
rg12 said:Thats super useful thanks alot
btw, for how long did you "stay" on each current for the test?
Matador said:That is soo cool.
I'll add my table to this:Ampacity (Powestream extrapolation).jpg
In my table that same 0.8 mm wide x 0.15 mm thick pure nickel strip is rated 4.9A, which is about 5 degree celcius above room temp judging from your graph...
flippy said:Matador said:That is soo cool.
I'll add my table to this:Ampacity (Powestream extrapolation).jpg
In my table that same 0.8 mm wide x 0.15 mm thick pure nickel strip is rated 4.9A, which is about 5 degree celcius above room temp judging from your graph...
what is your derating factor? temperature? if so what themperature is that.
flippy said:voltage drop is not the metric one should focus on, temperature is key.
as long as the strip remains below 60ish degrees the standard aliexpress ABS cell holders and cell wrap wont lose strength or warp.
you can bump this a bit if you use that green paper rings as extra insulation.
personally i would not allow any part in my batteries get above 50c.
in the coming week i wiill be doing some temperature and high current tests with different sizes strip.