Search found 907 matches

by Matador
Jun 06 2019 6:40pm
Forum: Battery Technology
Topic: BOSS LEVEL CUSTOM SPOT WELDER
Replies: 448
Views: 55934

Re: BOSS LEVEL CUSTOM SPOT WELDER

You did it for real ! 0.1 mm pure copper: hrvplvwQM7s Where a 0.1 mm x 10 mm strip of Nickel could safely pass 4.1 amps Where a 0.1 mm x 10 mm strip of Aluminium could safely pass 9.6 amps, Then a 0.1 mm x 10 mm strip of Copper can safely pass 15 amps, So imaging when you weld copper sheet instead o...
by Matador
Jun 06 2019 6:39pm
Forum: Battery Technology
Topic: BOSS LEVEL CUSTOM SPOT WELDER
Replies: 448
Views: 55934

Re: BOSS LEVEL CUSTOM SPOT WELDER

:shock: :o :twisted: Awesome !
by Matador
Jun 04 2019 6:36pm
Forum: E-Bike Technical
Topic: Proposal for soldering onto the negative end of 18650s
Replies: 4
Views: 405

Re: Proposal for soldering onto the negative end of 18650s

From what I read, cold welding uses vacuum and metal surfaces made of identical elements.
by Matador
Jun 03 2019 11:35pm
Forum: Battery Technology
Topic: New weldless battery system crowdfunfing project
Replies: 84
Views: 7258

Re: New weldless battery system crowdfunfing project

And I mean knobbling on the surface like on this picture:
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Matador
by Matador
Jun 03 2019 11:27pm
Forum: Battery Technology
Topic: New weldless battery system crowdfunfing project
Replies: 84
Views: 7258

Re: New weldless battery system crowdfunfing project

The springs I used a springsteel (tried the biggest spring gauge I could test). They litterally cooked at 4 amps per springs.... But springsteel has very high resistance... And will glow red hot and loose their recoil. Berillium copper, well 38% IACS is certainly very impressive. I see hopes in this...
by Matador
Jun 03 2019 10:20pm
Forum: E-Bike Technical
Topic: Reention POLLY DP-6C - 70 cell battery case - how fit BMS?
Replies: 17
Views: 1658

Re: Reention POLLY DP-6C - 70 cell battery case - how fit BMS?

https://endless-sphere.com/forums/viewt ... x#p1299070
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by Matador
Jun 02 2019 4:27pm
Forum: Battery Technology
Topic: Inspiration to build Solderless battery
Replies: 41
Views: 2916

Re: Inspiration to build Solderless battery

I used the vruzend kit and I do not recommend it. The connector of each module has poor spring function, often I lost connection in some cells. I suggested to them that they put copper alloy springs in place, but they ignored it. The vruzend kit is not trusted to maintain connection to cells. I mad...
by Matador
Jun 02 2019 4:10pm
Forum: Battery Technology
Topic: Esk8 battery build 12s7p
Replies: 6
Views: 714

Re: Esk8 battery build 12s7p

There is really no point putting a huge copper bus bar for the parrallel connections (which will only see milliamps of balance current at most). The whole point of high amperage conductors is for the series connection that carry all the load. Otherwise, it's just adding more weight for no benefits. ...
by Matador
May 28 2019 8:46pm
Forum: Battery Technology
Topic: mega copper battery spotwelder
Replies: 19
Views: 1589

Re: mega copper battery spotwelder

Just when you wonder if the Sphere is starting to go soft, somebody picks up the reins and goes wholly and appropriately overboard. Good luck ! Yeah, stay tuned next month for a thread asking where to procure plutonium for a home made reactor powered spot welder. 100 megawatt spotwelder... Plutoniu...
by Matador
May 28 2019 8:41pm
Forum: Battery Technology
Topic: Ezee battery fire & recall
Replies: 6
Views: 468

Re: Ezee battery fire & recall

Faulty BMS also likely ... To allow overcharging a cell group to a point of unstability. I'm thinking, at leas 4.4V... Or a puncture. Or an internal short. A little early to be deciding it's overcharge. Internal short also good possibility. But puncture ? The battery was left charging ovenight, lef...
by Matador
May 28 2019 4:56pm
Forum: Battery Technology
Topic: Ezee battery fire & recall
Replies: 6
Views: 468

Re: Ezee battery fire & recall

Faulty BMS also likely ... To allow overcharging a cell group to a point of unstability. I'm thinking, at leas 4.4V...
by Matador
May 28 2019 4:38pm
Forum: Battery Technology
Topic: end cells always fail first, why?
Replies: 15
Views: 1416

Re: end cells always fail first, why?

So, would it make a difference / be important - to keep all the BMS cell wires the same length? Yes, theoretically, it would make a difference, as longer wires have higher resistance, you get more sag on longer wires. Meaning the BMS would percieve a lower voltage than the reality for those cells t...
by Matador
May 28 2019 4:28pm
Forum: Battery Technology
Topic: Panny or Sanyo?
Replies: 44
Views: 2260

Re: Panny or Sanyo?

Comparison applys to using cells a a givent load. For a given load (in amps) power dense (High amps or high wattage) cells (aka lower internal resistance cells) generally have longer life because they heat less. But they pack less energy (Wh) density because much of the cell can volume is occupied b...
by Matador
May 28 2019 3:58pm
Forum: Battery Technology
Topic: Panny or Sanyo?
Replies: 44
Views: 2260

Re: Panny or Sanyo?

Panny PF is 8P will outlast SanyoGa in 6P biiiig time ! PF all yhr way for you.
by Matador
May 28 2019 3:47pm
Forum: Battery Technology
Topic: mega copper battery spotwelder
Replies: 19
Views: 1589

Re: mega copper battery spotwelder

Wow ! I want to see this !!! You will need extremly high power compared to nickel.... Basically you need a pulsed TIG welder like the Orion Sun Ev welder ! I don't have experience personally. Your like Niel Amstromg, the first man to walk on the moon! Haven't seen anyone get as serious as you with t...
by Matador
May 28 2019 3:41pm
Forum: Battery Technology
Topic: Spacer/Holder for 21700 cells
Replies: 11
Views: 1432

Re: Spacer/Holder for 21700 cells

What are your power density requirements (in Watts per kg of battery and Watts per liter of battery) ? What are you energy density requirements (in Wh per kg of battery and Wh per liter of battery)? In general i would go for NMC. But if you ne crazy power from a relatively small battery, if you need...
by Matador
May 28 2019 3:22pm
Forum: Battery Technology
Topic: Panasonic/Sanyo NCR20700B vs Samsung INR21700-50E
Replies: 65
Views: 4064

Re: Panasonic/Sanyo NCR20700B vs Samsung INR21700-50E

The price on 21700 will continue to decline as it becomes more and more popular... But to compare cycle life of two different cells, you need to discharge with the same ratio (ratio=cycling C-discharge rate choosen / max rated C-discharge rate of a given cell). For example discharge both different c...
by Matador
May 28 2019 3:04pm
Forum: Battery Technology
Topic: Panasonic/Sanyo NCR20700B vs Samsung INR21700-50E
Replies: 65
Views: 4064

Re: Panasonic/Sanyo NCR20700B vs Samsung INR21700-50E

nice stats, but they do show the weakness of those bigger cells, they cant handle abuse unlike the 18650... What makes you think that they are weaker than 18650 ? because 18650's generally wear out less fast then that and are cheaper per Wh. I agree that Price per Wh is higher. However I think that...
by Matador
May 24 2019 9:04pm
Forum: Battery Technology
Topic: Panasonic/Sanyo NCR20700B vs Samsung INR21700-50E
Replies: 65
Views: 4064

Re: Panasonic/Sanyo NCR20700B vs Samsung INR21700-50E

flippy wrote:
May 24 2019 4:23pm
nice stats, but they do show the weakness of those bigger cells, they cant handle abuse unlike the 18650...
What makes you think that they are weaker than 18650 ?
by Matador
May 23 2019 6:59pm
Forum: Battery Technology
Topic: Powerful inside-frame battery
Replies: 15
Views: 951

Re: Powerful inside-frame battery

The inside of your battery would most likely look like mine. Carefully review my thread on this Ancheer eBike. I posted tons of pictures for reference. Here is the link : https://endless-sphere.com/forums/viewtopic.php?f=2&t=93576 But I must say... I think a 1.5 kWh motor-controller setup on this i...
by Matador
May 22 2019 11:35pm
Forum: Battery Technology
Topic: end cells always fail first, why?
Replies: 15
Views: 1416

Re: end cells always fail first, why?

I'd say all of the above I think play a roll. Unequal current sharing if using too resistive conductors. Heat more promient at the deep core of battery (can't dissipate as easily), kind of depends on battery geometry too. Cheap BMS with unequal parasitic quiescent current drain Use of unmatched cell...
by Matador
May 22 2019 11:29pm
Forum: Battery Technology
Topic: 14s2p Minicube w/ 21700 batteries
Replies: 5
Views: 622

Re: 14s2p Minicube w/ 21700 batteries

Thanks - that was what I was thinking. Hopefully there will be a high discharge 21700 cell in the future, I love the small size of the minicube but would also like a little more capacity. This battery is close, but not suitable for a hill climber. Check out the Samsung 40T 21700 cells. Seems promiz...
by Matador
May 22 2019 11:23pm
Forum: Battery Technology
Topic: Actual Test of Pure Nickel Heat?
Replies: 24
Views: 1236

Re: Actual Test of Pure Nickel Heat?

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 wou...