Search found 798 matches

by Matador
Mar 18 2019 7:30pm
Forum: Battery Technology
Topic: Sony VTC6 - a 3000mAh/30A monster in 18650 size
Replies: 19
Views: 703

Re: Sony VTC6 - a 3000mAh/30A monster in 18650 size

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...
by Matador
Mar 14 2019 6:55pm
Forum: General Discussion
Topic: Discharge unbalanced battery
Replies: 7
Views: 187

Re: Discharge unbalanced battery

I used my 1800W hairdryer...
by Matador
Mar 10 2019 10:10pm
Forum: Battery Technology
Topic: Welding busbars to Nickel Strip?
Replies: 2
Views: 149

Re: Welding busbars to Nickel Strip?

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
by Matador
Mar 10 2019 10:06pm
Forum: Battery Technology
Topic: What battery to choose after your last one burned your house.
Replies: 43
Views: 1348

Re: What battery to choose after your last one burned your house.

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...
by Matador
Mar 10 2019 9:45pm
Forum: Battery Technology
Topic: New weldless battery system crowdfunfing project
Replies: 63
Views: 1721

Re: New weldless battery system crowdfunfing project

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...
by Matador
Mar 10 2019 9:32pm
Forum: Battery Technology
Topic: What battery to choose after your last one burned your house.
Replies: 43
Views: 1348

Re: What battery to choose after your last one burned your house.

Imagine if tesla cars would run on hypergolic fuel (1,1-dimethylhydrazine and nitric oxide)... They'd burn even more...
by Matador
Mar 10 2019 9:25pm
Forum: Battery Technology
Topic: What battery to choose after your last one burned your house.
Replies: 43
Views: 1348

Re: What battery to choose after your last one burned your house.

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...
by Matador
Mar 10 2019 8:49pm
Forum: E-Bike Technical
Topic: Reducing 55V charger down to 54.6V
Replies: 14
Views: 351

Re: Reducing 55V charger down to 54.6V

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%...
by Matador
Mar 07 2019 6:32pm
Forum: E-Bike General Discussion
Topic: Sensitive throttle vs the sensation of power
Replies: 38
Views: 852

Re: Sensitive throttle vs the sensation of power

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...
by Matador
Mar 07 2019 6:31pm
Forum: E-Bike General Discussion
Topic: Sensitive throttle vs the sensation of power
Replies: 38
Views: 852

Re: Sensitive throttle vs the sensation of power

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...
by Matador
Mar 07 2019 6:10pm
Forum: Battery Technology
Topic: jump starting caveat - Warning!
Replies: 16
Views: 434

Re: jump starting caveat - Warning!

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
by Matador
Mar 06 2019 6:32pm
Forum: Battery Technology
Topic: Sony VTC6 - a 3000mAh/30A monster in 18650 size
Replies: 19
Views: 703

Re: Sony VTC6 - a 3000mAh/30A monster in 18650 size

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
by Matador
Mar 06 2019 6:31pm
Forum: Battery Technology
Topic: Sony VTC6 - a 3000mAh/30A monster in 18650 size
Replies: 19
Views: 703

Re: Sony VTC6 - a 3000mAh/30A monster in 18650 size

But if you want high drain and very high cycle life, nothing like the A123 cells.
by Matador
Mar 06 2019 6:29pm
Forum: Battery Technology
Topic: Sony VTC6 - a 3000mAh/30A monster in 18650 size
Replies: 19
Views: 703

Re: Sony VTC6 - a 3000mAh/30A monster in 18650 size

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.
by Matador
Mar 05 2019 10:39pm
Forum: E-Bike General Discussion
Topic: Discharging a 52 volt battery pack
Replies: 7
Views: 173

Re: Discharging a 52 volt battery pack

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
by Matador
Mar 05 2019 10:37pm
Forum: E-Bike General Discussion
Topic: Discharging a 52 volt battery pack
Replies: 7
Views: 173

Re: Discharging a 52 volt battery pack

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
by Matador
Mar 05 2019 10:33pm
Forum: E-Bike General Discussion
Topic: Discharging a 52 volt battery pack
Replies: 7
Views: 173

Re: Discharging a 52 volt battery pack

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...
by Matador
Mar 05 2019 8:33pm
Forum: E-Vehicles General Discussion
Topic: What does this charger behavior indicate?
Replies: 12
Views: 354

Re: What does this charger behavior indicate?

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...
by Matador
Mar 03 2019 7:24pm
Forum: General Discussion
Topic: Dyson battery BMS?
Replies: 6
Views: 1285

Re: Dyson battery BMS?

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
by Matador
Mar 02 2019 7:44pm
Forum: E-Vehicles General Discussion
Topic: What does this charger behavior indicate?
Replies: 12
Views: 354

Re: What does this charger behavior indicate?

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...
by Matador
Feb 27 2019 6:42pm
Forum: E-Bike General Discussion
Topic: BMS defect or unbalanced cells
Replies: 18
Views: 318

Re: BMS defect or unbalanced cells

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...
by Matador
Feb 26 2019 7:20pm
Forum: E-Bike General Discussion
Topic: BMS defect or unbalanced cells
Replies: 18
Views: 318

Re: BMS defect or unbalanced cells

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 ...
by Matador
Feb 25 2019 7:43pm
Forum: Battery Technology
Topic: Panasonic NCR18650G - the mysterious 3600mAh battery's capacity test
Replies: 8
Views: 486

Re: Panasonic NCR18650G - the mysterious 3600mAh battery's capacity test

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...
by Matador
Feb 24 2019 11:38pm
Forum: Battery Technology
Topic: Could you rate these 18650 cells for me?
Replies: 10
Views: 256

Re: Could you rate these 18650 cells for me?

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
by Matador
Feb 24 2019 12:22am
Forum: Battery Technology
Topic: FIX for non trimmable Li-Ion charger that slightly overcharges eSkate
Replies: 8
Views: 261

Re: FIX for non trimmable Li-Ion charger that slightly overcharges eSkate

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...