Search found 37 matches

by BlueSwordM
Jul 05 2019 8:54pm
Forum: Battery Technology
Topic: A123 26650 low-resistance connections
Replies: 2
Views: 247

Re: A123 26650 low-resistance connections

That's a great build actually.

Since nickel is much easier to solder vs steel, and it harms the cells way less, what you are doing is great.
by BlueSwordM
Jun 17 2019 12:48pm
Forum: Battery Technology
Topic: oups i dremeled my cel to deep damaged??
Replies: 8
Views: 478

Re: oups i dremeled my cel to deep damaged??

So, are you a Quebecker for some reason?

Because if you can speak French, you should post in French, and I'll try to translate it into more understandable English.

Hope this helps.
by BlueSwordM
Jun 14 2019 10:00am
Forum: Battery Technology
Topic: New weldless battery system crowdfunfing project
Replies: 84
Views: 5232

Re: New weldless battery system crowdfunfing project

Or if you are fancy, Titanium parts for the bolts and screws :) Absolute overkill. :) I'd like to add that I'm working on my 3rd Gen battery spring design. Since I couldn't change the material to BeCu C17500 45% IACS because of its poor mechanical properties, or use the prototype material BeCu C1755...
by BlueSwordM
Jun 13 2019 9:38pm
Forum: Battery Technology
Topic: New weldless battery system crowdfunfing project
Replies: 84
Views: 5232

Re: New weldless battery system crowdfunfing project

Wait, why would AG's design be prone to corrosion?

I mean, nickel-zinc/tin plated copper has excellent resistance to corrosion.
As he mentioned, only the steel bolts have been corroded, and that could be fixed with a zinc, then nickel, plating.
by BlueSwordM
Apr 22 2019 3:39pm
Forum: Battery Technology
Topic: Copper bus, plating with nickel for spot-welding.
Replies: 10
Views: 552

Re: Copper bus, plating with nickel for spot-welding.

Yes, I do have a Paypal address. I hope you meant 3-3,5cm rather than mm. 3-3,5mm would be awfully small, haha. No problem for 3-4 inches each. Thickness of the unplated copper if 0,2mm. I'll do the plating of the strips Wednesday, so when I'll be done Wednesday, I'll be able to send it to you. The ...
by BlueSwordM
Apr 22 2019 11:08am
Forum: Battery Technology
Topic: Copper bus, plating with nickel for spot-welding.
Replies: 10
Views: 552

Re: Copper bus, bonding nickel strip for spot-welding.

What length of copper strip would you like to have plated? I managed to do a test strip using a nickel sulfate/chloride/glycol mixture in a membrane cell, and it plated wonderfully well. Here's a pic of the test strip. https://i.postimg.cc/cJ8TcWdP/Screenshot-Gallery-20190422-120710.png Would you pr...
by BlueSwordM
Mar 24 2019 4:47pm
Forum: Battery Technology
Topic: New weldless battery system crowdfunfing project
Replies: 84
Views: 5232

Re: New weldless battery system crowdfunfing project

Also, this is quite the lengthy spring.

By making it shorter, I can easily lower the resistance of the spring.

@Matador, did you mean 100C or 1000C? Because nothing is going to resist that much heat at 1000C :)
by BlueSwordM
Mar 24 2019 2:04pm
Forum: Battery Technology
Topic: New weldless battery system crowdfunfing project
Replies: 84
Views: 5232

Re: New weldless battery system crowdfunfing project

Conductivity of BeCu C17530 is at 38% IACS. The resistance value of both the springs are 9mOhms. Technically, it's a bit less than that, but 9mOhms is a nice round number, and gives a bit of headroom. I've also planned of making the 3rd gen spring with a nickel-copper(50um)-nickel plating for additi...
by BlueSwordM
Mar 22 2019 1:57pm
Forum: Battery Technology
Topic: Copper bus, plating with nickel for spot-welding.
Replies: 10
Views: 552

Re: Copper bus, bonding nickel strip for spot-welding.

I haven't done zinc plating yet.

I'll do the nickel plating once I receive my pure nickel sheet arrives here, since, well, making my 1st electroplating solution used up all of my recycled nickel.
by BlueSwordM
Mar 22 2019 12:20pm
Forum: Battery Technology
Topic: Copper bus, plating with nickel for spot-welding.
Replies: 10
Views: 552

Re: Copper bus, bonding nickel strip for spot-welding.

Do you want someone to try it?

I've currently made copper plating using electrolysis of copper+sulfuric acid myself after a lot of experimentation.

I can easily make a nickel sulfate solution to plate a copper sheet, and then send it to you for spot welding, if I have the time of course :)
by BlueSwordM
Mar 22 2019 12:18pm
Forum: Battery Technology
Topic: New weldless battery system crowdfunfing project
Replies: 84
Views: 5232

Re: New weldless battery system crowdfunfing project

Silver would get very worn out for an electrical contact. In the industry they have fairly precise micron widths and alloys for the best plating there are probably ASTM grades that you can have if you invest in equipment for it. Nickel micron astm search gives this page https://advancedplatingtech....
by BlueSwordM
Mar 20 2019 10:43pm
Forum: Battery Technology
Topic: New weldless battery system crowdfunfing project
Replies: 84
Views: 5232

Re: New weldless battery system crowdfunfing project

Well, contact resistance would actually be slightly lower in a real build since I tested their resistance via a 4-wire setup at the top of the spring, and the whole surface of the spring could be used as a contact. The 1st gen used a nickel plating, which is inexpensive and has good contact resistan...
by BlueSwordM
Mar 19 2019 3:59pm
Forum: Battery Technology
Topic: New weldless battery system crowdfunfing project
Replies: 84
Views: 5232

Re: New weldless battery system crowdfunfing project

Current and resistance measurement of the springs were done uncompressed, as compressing them could lead to something akin to a spring bypass. Spring force? Way too much if the spring is uncut, since its nominal height is 13mm, and since the spring doesn't have much of a conical shape, it is limited...
by BlueSwordM
Mar 19 2019 11:39am
Forum: Battery Technology
Topic: New weldless battery system crowdfunfing project
Replies: 84
Views: 5232

Re: New weldless battery system crowdfunfing project

What do you mean current capability is too low? That's why I've made my own BeCu spring design :) https://i.imgur.com/kpeexiS.jpg Nickel plated BeCu C17530 springs. In a dual spring setup, they are absolute monsters, and have no problem handling 20A+ currents. https://i.postimg.cc/t4VKjmPq/IMG_20181...
by BlueSwordM
Mar 17 2019 6:38pm
Forum: Battery Technology
Topic: New weldless battery system crowdfunfing project
Replies: 84
Views: 5232

Re: New weldless battery system crowdfunfing project

So, any updates from the OP?

Seems like it lost traction.
by BlueSwordM
Mar 09 2019 9:42pm
Forum: Battery Technology
Topic: New weldless battery system crowdfunfing project
Replies: 84
Views: 5232

Re: New weldless battery system crowdfunfing project

So, would you like to have some help for the spring contacts?
I've gathered quite a bit of experience regarding very high current springs, and I can put in a hand if you want.
by BlueSwordM
Feb 15 2019 11:40pm
Forum: Battery Technology
Topic: Samsung 33J - a 21700 Li-ion battery designed for Tesla
Replies: 7
Views: 638

Re: Samsung 33J - a 21700 Li-ion battery designed for Tesla

Guys, as I've said somewhere else, this is actually a cell that's used in the Tesla PowerWalls 2.

They want to meet max production capacity for the Tesla cars, so they turn to other battery manufacturers for the PowerWalls 2s.
by BlueSwordM
Jan 31 2019 11:32pm
Forum: Battery Technology
Topic: The "thermal management of LiPo" thread!
Replies: 102
Views: 9143

Re: The "thermal management of LiPo" thread!

One thing you can actually use is paraffin wax in conjunction with aluminium heatsinks.
by BlueSwordM
Jan 24 2019 10:30pm
Forum: Battery Technology
Topic: DeWalt DCB546 - What cell capability (amp draw) could they provide
Replies: 1
Views: 215

Re: DeWalt DCB546 - What cell capability (amp draw) could they provide

The cells inside of the Flexvolt 6Ah packs, from what I've seen and tore down one that got destroyed, are a 2P5S arrangement of NCR20700As. These can output up to 30A each continuously, so I would expect 50-60A out of a 2P pack. Which isn't the case here. They are using 2Ah cells, which isn't all th...
by BlueSwordM
Jan 24 2019 10:27pm
Forum: Battery Technology
Topic: Importance of matched cell resistance in pack?
Replies: 7
Views: 343

Re: Importance of matched cell resistance in pack?

What battery tester charger do you have?

Most ones that can do this don't really have accurate internal resistance measurements.
by BlueSwordM
Jan 23 2019 10:31pm
Forum: Battery Technology
Topic: Looking for Authentic Lg HG2 Cells
Replies: 3
Views: 275

Re: Looking for Authentic Lg HG2 Cells

Well hello maarkmohamed. There is Liion Wholesale selling 400+ cells at 3,97$US/cell: https://liionwholesale.com/collections/batteries/products/samsung-inr18650-30q-battery-15a-3000mah-flat-top-wholesale-discount-genuine-and-tested They are also selling Samsung 25Rs for 3,35$US/cell for 400+ cells: ...
by BlueSwordM
Jan 23 2019 9:52pm
Forum: Battery Technology
Topic: Does capacity degradation affect max safe charge/discharge current?
Replies: 9
Views: 416

Re: Does capacity degradation affect max safe charge/discharge current?

Modern cells aren't affected in the internal resistance department much by capacity degradation.

What mostly affects internal resistance is charge rate.

Faster charging stresses the cell more, and over a long period of time, can affect a cell's internal resistance significantly.
by BlueSwordM
Jan 22 2019 11:25pm
Forum: Battery Technology
Topic: Charging with a coil (Adaptto)?
Replies: 14
Views: 1578

Re: Charging with a coil (Adaptto)?

In your case, your best bet would be to limit the SOC to 20-80% to allow for maximum cycle life along with fast charging capability.
by BlueSwordM
Jan 22 2019 10:08pm
Forum: Battery Technology
Topic: Queen Battery QB26800 6800mAh 20A - the big guy!
Replies: 12
Views: 1311

Re: Queen Battery QB26800 6800mAh 20A - the big guy!

It's also because this is such a massive cell which can handle the heat.

A smaller cell with the same capacity and power output would not fare so well.
by BlueSwordM
Jan 04 2019 6:55pm
Forum: Battery Technology
Topic: A sure way to check for fake cells
Replies: 8
Views: 1433

Re: A sure way to check for fake cells

How many legs does the positive terminal have?

If it's not 3, then you've got for sure a fake cell.