Endless Sphere

Matador

But if you want high drain and very high cycle life, nothing like the A123 cells. Exactly! I'm in love with them. Do you guys mean any of their non-LFP models? If so which? Links would be appreciated. I meant the nanophosphate LFP cells. For cycle life hard to beat LFP.... But if you want the absol...

Matador

I used my 1800W hairdryer...

Matador

spinningmagnets wrote: ↑
Mar 08 2019 9:42pm
A thin and narrow nickel strip is perfect for the parallel connections.

Makita laser-welds nickel-plated copper to their 30Q/25R cells.

And also their VTC4 cells

Matador

Well flippy, this is what an 18650 going thermal can do. This is why the bunker storage and outside charging will be my only way to go in the future, regardless of chemistry. I've run through a lot of cheap ass hobby king packs, and they do have their limitations. They puff a little in a few months...

Matador

vruzend is a flawed concept with no regard for safety. that is simply the end of the story. anything less then spotwelding is a compromise in safety and reliabliity. That's almost right, except that I've not yet seen a spot welded pack that was a good example of safety or reliability. >99% of the s...

Matador

Imagine if tesla cars would run on hypergolic fuel (1,1-dimethylhydrazine and nitric oxide)... They'd burn even more...

Matador

The other thing to consider is that REAL energy density does'nt just depend on the lithium chemisty. It also strongly depends of state of charge. Store some elastic rubber bands at rest and they won't move a bit, even if you leave them unattended for ages. Store elastic bands completely stretched ou...

Matador

The Schottlky diode worked perfectly well in my case. Smaller foward voltage drop of the Schottky compared to regular diode means less heat is dissipated. You can put it on either side, so as long as the diode sits in the right direction and lets de current flow. I doesn't change anything. Schottky%...

Matador

Actually I reduced the deadzone to nearly none using resistors and a potentiometer, it still does feel much better than my old hall throttle though, although on first impressions the bike does feel a bit slower. I suspect it's because of the much less aggressive throttle. If you would be kind enoug...

Matador

Actually I reduced the deadzone to nearly none using resistors and a potentiometer, it still does feel much better than my old hall throttle though, although on first impressions the bike does feel a bit slower. I suspect it's because of the much less aggressive throttle. If you would be kind enoug...

Matador

Frozen cells will underperform during discharge in terms of capacity and discharge rate.

Charging cells that just were in the freezer is almost garanteed to completely destroy them by electropating... The freezer trick is the worst urban legend ever

Matador

Matador wrote: ↑
Mar 06 2019 6:31pm
But if you want high drain and very high cycle life, nothing like the A123 cells. This is, of course if you don't mind lower capacity and a little weight. But Li titanate would be even more heavier... To much imho

Matador

But if you want high drain and very high cycle life, nothing like the A123 cells.

Matador

999zip999 wrote: ↑
Mar 06 2019 2:43pm
Honk which high drain cell do you recommend.

Id recommend samsung 40T 21700 cells... 4000 mAh and probably more reliable max 30A.

Matador

An incendescent bulb will work... But it might be slow... Good if your pack is only good for low current. If you want to go faster, use a hait dryer instead of a light bult...

How i did it and how fast: https://endless-sphere.com/forums/viewt ... 5#p1429947

Matador

Dont go 45 or even 46 V. It,s too low. For storage, going below 3.5V is wherr you start ti be in a region of the discharge curve that rapidly drops. Not 3.4 or 3.3V, it onky takes a few tens of milliamps capacity draining and you can goa bellow 3.0V, where cells tan start to become damage

Matador

I did dicharge my 10S ebike pack, my other 14S ebike pack and my 10S eskate pack. For storage, I prefer to stay at 30-35% state of charge which is 3.63V per cells. Dont forget BMS sometimes drain parasitic current. Discharge your 14S battery to a resting voltage of 50.8V. Buy for long term, anywhere...

Matador

A further update: this evening, and yesterday evening, the charge cycle completed in the usual way, with a steady green indicator. I'm still going to investigate the battery in greater depth, but this is an encouraging development. The BMS board I used is supposed to balance the cells at the top of...

Matador

Still looking for a BMS alternative for these dyson packs.... Cells are easy to figure out... the special BMS with the relay type switch not so much

Matador

Last night, my cheap generic 48V 4A lithium ion charger started displaying a behavior I haven't observed before. After a couple days of using the bike and running through perhaps half of its battery capacity, I plugged in the charger and it began charging normally, with the red charge indicator LED...

Matador

I would manually balance each single groupe to 4.20V. Than do a discharge cycle,recharge using bulk charger. Repeat 5 times. Then take voltage readings. Maybe they just got out of balance because of leakage current that the BMS drains on certain cell groups over the years. In other words, maybe all...

Matador

I would manually balance each single groupe to 4.20V. Than do a discharge cycle,recharge using bulk charger. Repeat 5 times. Then take voltage readings. Maybe they just got out of balance because of leakage current that the BMS drains on certain cell groups over the years. In other words, maybe all ...

Matador

From EB Tester Software's Resistance test. Here is the full series of DCIR values (minimum 1 min pause between tries) measured on a fully charged cell (1hr pause) at 3.45A: 37.1, 39.4, 39.1, 38.3, 36.5, 38.0, 37.1, 38.6, 37.7, 38.0, 39.7, 38.8, 37.1 Seems like the this EB Tester produces DCIR resul...

Matador

If it was me, i would not even bother trying it. 2C cell ar le going to live a month a best before dying for good. Get some 5C or more 18650 cells for an eboard. I can garantee you you ll be disapointed otherwises. Keep these cells for future batery banks, but dont put them in a EV

Matador

List of upgrades I did. Bearing sucked right out of the factory. Changed for these : https://www.amazon.com/Zealous-Bearings-Skateboards-Longboards-Steel/dp/B00BL9VCRE/ref=sr_1_1_sspa?keywords=zealous+bearings&qid=1550985081&s=gateway&sr=8-1-spons&psc=1&smid=A26X9WNI6ZF0IL Made a gasket out of plywo...

Endless Sphere

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