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Carbon steel strip VS. Stainless steel strip VS. Pure nickel strip. Fake nickel strips tested! Practical performance test results

battery
wires

#1

UPDATE, Corrosion tests show that neither of these strips are what I thought them to be. The results are posted in this thread HERE, so let’s see if we can figure what these strips are actually made out of.

2nd UPDATE, both strips seem to be steel based off of resistivity of the metals. Thread name updated to mirror this.


I was planning on redoing my board wiring and decided to test the performance difference of my ebay sourced 0.1 mm and 0.15 mm nickel strips. But it turns out the other strip wasn’t pure nickel strip, but rather nickel plated steel strip, so I decided to test them both and declare the results here. Even though the test procedure was quite simple, I took pictures for you guys, so it’ll be clear how it was done.




Both strips were also 8 mm wider. Our two strips to be tested with relevant information presented. Sorry, I don’t know why the last picture got it’s orientation changed.


Testing will be done with a nifty DC-DC buck converter with a display for setting voltage and current limits and it will also show the output power. Power will be supplied via 3S Li-Po.

The strip under test will be attached to the output of the buck converter and then tested by supplying a constant 5 amp current through it.


1st test: Pure Nickel Strip (Actually carbon steel) (8 x 0,10 mm)

Power loss: 1,35 W
Voltage drop: 0,27 V
Strip resistance: 54 mOhm
Material resistivity: 1.2 e-7 (Carbon steel listed in at 1.47 e-7)
Strip felt just a bit warm to the touch


2nd test: Nickel Plated Steel Strip (Actually stainless steel) (8 x 0,15 mm)

Power loss: 4,80 W
Voltage drop: 0,96 V
Strip resistance: 192 mOhm
Material resistivity: 6.6 e-7 (Stainless steel listed in at 6.90 e-7)
Strip felt burning hot for a moment before fingers sucked up the heat.


3rd test: Real Pure Nickel Strip (8 x 0,15 mm)

Power loss: 0.60 W
Voltage drop: 0,12V
Strip resistance: 24 mOhm
Material resistivity: 8.2 e-8 (Nickel listed in at 6.99 e-8)
No noticeable increase in strips temperature.

Conclusion:
Nickel Plated Steel Strip is S*#T. Even in this test with it being thicker at 0,15 mm then the pure nickel strip at 0,1 mm, it still had almost 4 times resistance. When taking into account the thickness and resistance and then converting them to a 0,1 mm thickness equivalent. The resistance would be around 290 mOhms for that 350 mm strip. With that kind of resistance if you were to pull a measly 10 Amps through it you would generate 29 Watts of power loss via heat and at that power you will start adding unnecessary heat to your Lithium cells and might even risk a fire at higher currents.(old conclusion)

All three strips mirror pretty well their natural resistivity and is also directly linked to their performance. Pure nickel strip is absolutely dominating the other steel based strips, with stainless steel being particularly s**t. Copper would on the other hand still absolute trash even the pure nickel strip, but comes with the oxidation problem, unless further protected from exposure. So now I know that all three materials are in the circulation and will from now on probably by my strip in bulk from aliexpress, so I can avoid the possibility of getting scammed.

This doesn’t actually make things easier as I was trying to source some thicker strip from ebay, but it seemed that almost all the results were steel core, but that only became evident after looking at the item description. Closer look at the descriptions turned out “Nickel Plated Steel Strip” or “99.6% Pure Nickel Plated Steel”. Also, always double check the item description if the item name has “pure Ni/nickel plate/plated”, as that might be your earliest warning that you’re buying nickel plated steel

UPDATE
Genuine pure nickel strip tested and results added to the first post

2nd UPDATE
Pure nickel strip tested in an identical setup as the fake strips so results can now be compared to each other. Also calculated the resistivity of the metal the strip and also added the closest sensible result from https://en.wikipedia.org/wiki/Electrical_resistivity_and_conductivity that it compares to in a table of different metals/materials. Results are pretty darn close to what the strips have been concluded to be made out of.


#2

@SimosMCmuffin this is a much needed test, thank you for conducting it! We’ve had lots of discussion about this topic in the past so it is great to see some useful exploration with real-world tests!

I’ve given up relying on vendors’ claims of purity on ebay… I test every spool of stripping that comes to me to by scuffing it and giving it a salt-water bath for a few days. Any Corrosion = steel plated. None - pure nickel.


#3

Thanks for sharing. Definitely info everyone needed to know.


#4

I’m doing corrosion testing on both of the strips to validate that they are what I claimed them to be and will post a picture of them later.


#5

neato. in your test i was looking for the time period with the current on and what voltage the test was done at. i guess theres the math way to figure the voltage

how much of a battery pack’s voltage drop while riding can be attributed to the connections between the cells?
where’d you get that awesome converter with the screen?


#6

The voltage is irrelevant as the power loss is I^2*R.
R is a constant based on the strip, and he is setting I.
He could be running 11V or 50V, the result would be the same.


#7

there is a voltage drop posted but no context of a supplied voltage. with ohms equation and the resistance and voltage drop given and the current I think you could get the voltage suppled


#8

as @PXSS said:

Supplied voltage doesn’t really change anything, as this test shows just how current causes voltage drop in the test strips, so regardless if you were running 16 Volts or 44 Volts, if you were pulling 5 Amps through that kind of strip. You would get the noted voltage drop.


#9

Corrosion test results:
After scuffing up the two strips and leaving them in a 1:1 salt & vinegar bath to induce corrosion. I really can’t say I expected the results.

I now have to say, I am not sure what either of these strips are made of.

So the no. 1 strip, which I thought to be pure nickel strip, has rust on it. I don’t think this should happen if it’s 99,97 % nickel.
Meanwhile no. 2 strip has absolutely nothing done to it, which in my mind removes any possibility of it being ferrous metal.

I have updated the 1st post to guide them here so maybe we can sherlock holmes the metals these strips are made out of.


#10

The voltage drops as you try to draw more power. Same as with your battery voltage dropping under bigger load e.g. at a hill because the source is not strong enough to hold the voltage constant while delivering the amount of current.


#11

Been doing some math to figure out the metals in the strips by calculating the resistivity of the metal.

Math based on experience and http://resources.schoolscience.co.uk/CDA/16plus/copelech2pg1.html

Once resistivity was calculated the values were compared to a table of other metals resistivities from https://en.wikipedia.org/wiki/Electrical_resistivity_and_conductivity

1st strip had a resistivity of 1,27 e-7 Ohm*Meters, placing it between tin and carbon steel, so it’s not pure nickel by any means, but if it’s something like carbon steel that would explain why it would rust.

2nd strip had a resistivity of 6,78 e-7 Ohm*Meters, placing it pretty much spot on with stainless steel. This might also explain why it did not rust in the test, as it probably has nickel and chromium alloyed with it.

TLDR; Neither strip is nickel, but rather steel based disappointments. I’ll update this threads name to mirror this discovery.

Based of these results, a real pure nickel strip of 0,1 mm thickness, 8 mm width and 350 mm length should have a resistance of about 26 mOhm,


#12

PM me. I’m interested in sending you a test strip from the stuff I have. It’s sunstone brand (they make really expensive spot welders). Let me know what length the test strips are and I’ll send you one through usps (if you’re in the us)


#13

Appreciate the offer, but due to being located in Finland. I’m not going ask you to send over here.


#14

I’ve done similar test in the past (not in vinegar /salt bath, but just salt and water), and the pure nickel strip was the only one without any sort of corrosion.


#15

I put them both back in a salt and water solution and I intend to let them sit there for couple of days and post new pics then. Let’s see what they look like then.


#16

@PXSS and @SimosMCmuffin supply voltage doesnt change anything? you will get a different voltage drop with the different supply voltage as ohm’s law states. you determined the power loss using the 5amps and the resistance and that reveals a lot but if you’re talking about voltage drop its something else and depends on the supply voltage and reveals different info: maybe you’re riding at 12s with 50 volts and you’d like to know what voltage you’re actually supplying the esc with. This would include all the bad connectors and also the sag of the battery cells themselves. you could look at the voltage drop in the connectors and then isolate it from voltage sag of the actual cells that way

its a great test you did. I’m trying to be constructively critical here so we all know more


#17

@Stefan youre adding voltage sag which depends on the cell’s ability and also the drop due to connections.


#18

Hey @Hummie that converter is the DPS5015 and you can get it for around $35 on Banggood. I’m planning on getting one because there awesome and super useful. (5015 means 50V and 15A)


#19

Ah, yes I forgot to mention what the module was, and yes you’re correct. I first tested the 30 V 5 A module to see if they were any good and after confirming that “Hey! this thing is pretty neat” it also seemed to be pretty accurate with it’s displayed info. I then ordered 2 of the DP5015 modules to build a bench power supply combined with a chinese 48 V PSU.


#20

I guess you’re referring to the Ohm’s law with the higher voltage -> lower current for the same power?

What I meant that this voltage drop happens in the strips in relation to the current, so for example if you used the worse tested stainless steel strip you would always get about 1 Volt drop if you are pulling 5 amps through it. So magic battery without cell voltage droop at 12 Volts would provide 11 Volts to the ESC with 5 amp pull and 40 Volt battery would provide 39 Volts to the ESC with the same 5 Amp current. Of course you can get a lot more power transfer with 40 Volt battery due it producing more power with less current.

EDIT: read your replied post again and in that case if you know the resistance of your strips, then you can calculate how much voltage drop they would cause with X current and then figure out the real battery voltage