Search found 937 matches

by Matador
Nov 13 2016 9:20am
Forum: Battery Technology
Topic: Ampacity?
Replies: 35
Views: 3688

Re: Ampacity?

Hummina Shadeeba wrote:what sizes are you using for how many amps?
My take at ampacity : https://endless-sphere.com/forums/viewt ... 5#p1240322
I've done some comprehensive metal strips ampacity charts.
Ampacity (10 meter - Low temp).jpg
Ampacity (made from my own calculations... see my other post for details, forum URL link above)
Ampacity (Powestream extrapolation).jpg
Ampacity, extrapolated from PowerStream.com (they most probably overrate conductors)
Hope this helps
by Matador
Nov 13 2016 1:26am
Forum: Battery Technology
Topic: Common pack design mistakes, how to avoid?
Replies: 322
Views: 56882

Re: Common pack design mistakes, how to avoid?

When it comes to electrical conductivity, aluminum and zinc are both similar or better than nickel, and also much cheaper than nickel. I am persuaded that using 0.20mm thick nickel strips to form the paralleled sub-groups is reasonable , but for the thicker high-current series bus-bars, it seems to...
by Matador
Nov 06 2016 11:19pm
Forum: Battery Technology
Topic: Spot Welding Copper Strips to 18650 Battery Cells
Replies: 288
Views: 57533

Re: Spot Welding Copper Strips to 18650 Battery Cells

That orion welder can weld 0.0020 inch (0.508 mm thickness copper strips) ! . Errr ?..No, this time i think you mean 0.05mm thick ...unless you meant to say 0.020 inch ? Yes ! I meant 0.020 inch (0.508 mm) not 0.0020 inch. My bad :oops: . Let me correct my previous post by edditing :mrgreen: I know...
by Matador
Nov 06 2016 11:01pm
Forum: Battery Technology
Topic: Spot Welding Copper Strips to 18650 Battery Cells
Replies: 288
Views: 57533

Re: Spot Welding Copper Strips to 18650 Battery Cells

With the split, the Ni plating and tungsten electrodes, there might be a cheap and easy solution. :wink: ** That would be awesome ! I don't know if a 1500 Watt rewounded microwave oven transformer with one turn of 2/0 AWG copper wire as the secondary coil, a pair of tungsten electrodes and an Omron...
by Matador
Nov 06 2016 10:29pm
Forum: Battery Technology
Topic: Spot Welding Copper Strips to 18650 Battery Cells
Replies: 288
Views: 57533

Re: Spot Welding Copper Strips to 18650 Battery Cells

That orion welder can weld 0.020 inch (0.508 mm thickness copper strips) ! Imagine welding 10 mm width x 0.508 mm thickness copper strips. That would be 5.08 mm2 surface area --> Equivalent to around 10AWG copper wire (3.31 milliOhms per meter) ! When we weld the typical 10 mm x 0.15 mm Nickel strip...
by Matador
Nov 06 2016 9:54pm
Forum: Battery Technology
Topic: Spot Welding Copper Strips to 18650 Battery Cells
Replies: 288
Views: 57533

Re: Spot Welding Copper Strips to 18650 Battery Cells

This is intriguing. I have seen some nickel strips that had a thin slot right over the end of the cell....... Yes many of the commercial packs i have seen are also have "split end " strips ....like this one from the previous thread.. http://i1285.photobucket.com/albums/a586/ogniwa/IMG_20150915_1527...
by Matador
Nov 06 2016 9:40pm
Forum: Battery Technology
Topic: Spot Welding Copper Strips to 18650 Battery Cells
Replies: 288
Views: 57533

Re: Spot Welding Copper Strips to 18650 Battery Cells

Cheking on the net, Orion Pulse 250i EV is 12500 USD The Orion Pulse 150i EV is 7500 USD. Pretty sure somebody could reverse engeneer that thing... It probably does'nt need to be that fancy to be effective. I could use it without the microscope oculars and the robot arm and the computer... The reall...
by Matador
Nov 06 2016 9:34pm
Forum: Battery Technology
Topic: Spot Welding Copper Strips to 18650 Battery Cells
Replies: 288
Views: 57533

Re: Spot Welding Copper Strips to 18650 Battery Cells

That is an awesome machine. I'm gessing at the very least 10 000 USD, it might be more... If a reputable battery seller was building batteries with this specialized welder, guenine quality cells and thick beefy cupper-strips, I'd definitely buy from them. Well worth paying a little more extra for th...
by Matador
Nov 06 2016 6:10pm
Forum: Battery Technology
Topic: Common pack design mistakes, how to avoid?
Replies: 322
Views: 56882

Re: Common pack design mistakes, how to avoid?

Hillhater wrote:
Matador wrote: 0.007" copper thickness is equivalent to 0.18 mm thickness....
:?: :?: :?:
Yes. 1 inch is 25.4 millimeters.
So 0.007 inch is 0.1778 mm, rounded off to 0.18 mm Right ?
by Matador
Nov 06 2016 5:50pm
Forum: Battery Technology
Topic: Common pack design mistakes, how to avoid?
Replies: 322
Views: 56882

Re: Common pack design mistakes, how to avoid?

I just googled a bit "why copper is difficult to spot weld"...(look here : http://cr4.globalspec.com/thread/7404/copper-to-copper-spot-welding) I mean of course people thought of Copper instead of Nickel waaay long before me. I doesn't take a PhD to figure out that Copper is 4 times more conductive ...
by Matador
Nov 06 2016 4:49pm
Forum: Battery Technology
Topic: Common pack design mistakes, how to avoid?
Replies: 322
Views: 56882

Re: Common pack design mistakes, how to avoid?

Found this video on copper tab spot-welding :
https://www.youtube.com/watch?v=jcXInB3YMBA
https://www.youtube.com/watch?v=NaqqfzFaM7w
0.007" copper thickness is equivalent to 0.18 mm thickness...
Not bad !

The welder seem kinda different than the cheap chinese spot welders though.
by Matador
Nov 06 2016 2:59pm
Forum: Battery Technology
Topic: Common pack design mistakes, how to avoid?
Replies: 322
Views: 56882

Re: Common pack design mistakes, how to avoid?

Thanks Matador. That was my thought too. I did find a rather inexpensive source for 0.2mm Nickel foil. https://www.aliexpress.com/item/99-99-high-purity-nickel-strip-nickel-foil-thickness-0-2mm-width-200mm-length-1500mm/32475681711.html I think shearing to the width needed (10mm, 12mm, etc.) is the...
by Matador
Nov 05 2016 8:54pm
Forum: Battery Technology
Topic: Common pack design mistakes, how to avoid?
Replies: 322
Views: 56882

Re: Common pack design mistakes, how to avoid?

Just as a side note... You might have noticed from the Wikipedia's resistivity table that Gold is not as good a conductor as Copper. Why do we use it in Hi-Fidelity stereo equipement then ??? Why are most high quality Hi-Fi cable terminals/connectors Gold-plated ? We know that Nickel oxidises a lot ...
by Matador
Nov 05 2016 4:39pm
Forum: Battery Technology
Topic: Common pack design mistakes, how to avoid?
Replies: 322
Views: 56882

Re: Common pack design mistakes, how to avoid?

I would avoid plated steel. Too much resistance means lots of loss in heat and big voltage sag. The steel could turn red hot and melt at too high currents. We have an example of the possible complications here : https://endless-sphere.com/forums/viewtopic.php?f=14&t=83505&start=50#p1234386 For pure ...
by Matador
Nov 05 2016 4:35pm
Forum: Battery Technology
Topic: Announcement - Soon to be released easybuild battery box
Replies: 61
Views: 6771

Re: Announcement - Soon to be released easybuild battery box

LOL ! Seriously, vibration test ??

Eggs ? :lol:
by Matador
Nov 05 2016 10:04am
Forum: Battery Technology
Topic: 18650 battery Kit development and discussion[testing done]
Replies: 198
Views: 38001

Re: 18650 battery Kit development and discussion

Nice sturdy design. Subscribed.
by Matador
Nov 05 2016 9:40am
Forum: E-Bike Build Threads / Photos & Video
Topic: Robs bike build
Replies: 46
Views: 8887

Re: Robs bike build

Very impressive and sexy build ! Love the headlight too :D
by Matador
Nov 05 2016 9:15am
Forum: Battery Technology
Topic: Announcement - Soon to be released easybuild battery box
Replies: 61
Views: 6771

Re: Announcement - Soon to be released easybuild battery box

Any pictures of that soon to be released easybuild battery box.
At least, any pictures of the current prototype ?
I'd like to see pictures please.
by Matador
Nov 02 2016 10:00pm
Forum: Battery Technology
Topic: Common pack design mistakes, how to avoid?
Replies: 322
Views: 56882

Re: Common pack design mistakes, how to avoid?

Do anyone think that this strategy for a solderless pack could work ?
Photos here : https://endless-sphere.com/forums/viewt ... 5#p1237600
by Matador
Nov 02 2016 9:40pm
Forum: Battery Technology
Topic: Acceptable internal resistance values on 18650 cells
Replies: 43
Views: 22515

Re: Acceptable internal resistance values on 18650 cells

I suspect a 0.5 mm copper layer on that 0.9 mm spring wire may just restrict the spring action more than a little ? Have you considered using some short pieces of heavy copper braid inside the spring ? Maybe soldered each end ? My attemps to copper-plate the springs (nickel plated springtseel) have...
by Matador
Oct 30 2016 7:34pm
Forum: Battery Technology
Topic: Acceptable internal resistance values on 18650 cells
Replies: 43
Views: 22515

Re: Acceptable internal resistance values on 18650 cells

So I started the experiment of copper electroplating springs.... I'm going at very low voltage. That means low current densities (0.1211 A/dm2) since I'm using a weak acid solution of copper acetate and I want the most regular plating possible. According to calculations (ref : http://polynet.dk/ingp...
by Matador
Oct 29 2016 9:03pm
Forum: Battery Technology
Topic: Acceptable internal resistance values on 18650 cells
Replies: 43
Views: 22515

Re: Acceptable internal resistance values on 18650 cells

The Cu(OAc)2 solution in aqueous acetic acid (5% distilled vinegar) is starting to look more and more concentrated. I'll let it reduce overnignt in order to be even more concentrated. More concentration mean more ability to plate at higher amps withot risking buble formation by water decomposition (...
by Matador
Oct 29 2016 8:52pm
Forum: Battery Technology
Topic: Acceptable internal resistance values on 18650 cells
Replies: 43
Views: 22515

Re: Acceptable internal resistance values on 18650 cells

I did get lucky on a few batches of used hp laptop batteries. They were most likely unused, overstock replacement batteries. Most came with atleast 9v in a 3p config, but some were 3-6v however they took charge and held on for over a month w/o changes. The packs manufactured in 2010 though, 6 yrs d...
by Matador
Oct 29 2016 8:48pm
Forum: E-Bike Build Threads / Photos & Video
Topic: Chinese EBB Clones build
Replies: 11
Views: 5008

Re: Chinese EBB Clones build

That ride is sweet ! holy crap 260 cells !!!
by Matador
Oct 29 2016 5:53pm
Forum: Battery Technology
Topic: Common pack design mistakes, how to avoid?
Replies: 322
Views: 56882

Re: Common pack design mistakes, how to avoid?

I think a solderless pack is a viable design strategy, but I would not run current through the coil springs. I believe the spring and the current-carrying elements should be separate. Right, but the current carrying element should be quite high current rated fo my taste, the equivalent of 14 AWG co...