Search found 886 matches

by Matador
Mar 06 2019 6:31pm
Forum: Battery Technology
Topic: Sony VTC6 - a 3000mAh/30A monster in 18650 size
Replies: 19
Views: 1300

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: 1300

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: 409

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: 409

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: 409

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: 20
Views: 1388

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: 1965

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: 20
Views: 1388

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: 27
Views: 1061

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: 27
Views: 1061

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: 867

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: 543

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: 19
Views: 1221

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...
by Matador
Feb 23 2019 2:59pm
Forum: E-Bike Technical
Topic: Nickel Strip ratings
Replies: 14
Views: 789

Re: Nickel Strip ratings

Right, 27 mm strips is less typical of a width. Most use width of up to 10 mm. Your is almost 3 times wider (which is good). But what matters is the conducting cross sectionnal surface area (in mm2)... In your case, 27 mm width x 0.15 mm thickness is 4.05 mm^2 CSA. In terms of gauge, 4.05 mm^2 is eq...
by Matador
Feb 23 2019 12:24pm
Forum: E-Bike Technical
Topic: Nickel Strip ratings
Replies: 14
Views: 789

Re: Nickel Strip ratings

Matador's Conductor Strips Ampacity Charts:
(ratings are relatively conservative)
Ampacity (Powestream extrapolation).jpg
Ampacity (10 meter - Low temp).jpg
Enjoy,

Matador
by Matador
Feb 23 2019 11:43am
Forum: Battery Technology
Topic: Panasonic NCR18650G - the mysterious 3600mAh battery's capacity test
Replies: 8
Views: 867

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

Also look at how DCIR varies with State of Charge(SoC)/State of Discharge (SoD) and temperature. You have to account for that. An ES member already showed that in the past, quite nicely too: https://endless-sphere.com/forums/viewtopic.php?f=14&t=73701 I must say all your efforts are really appreciat...
by Matador
Feb 23 2019 11:36am
Forum: Battery Technology
Topic: LG M36 vs Samsung 36G capacity test - 3600mAh or just marketing?
Replies: 28
Views: 3090

Re: LG M36 vs Samsung 36G capacity test - 3600mAh or just marketing?

DC IR test results done with EBC-A20 (5 iterations with 15-30s pause @3600mA) M36: 28.6, 29.7, 31.1, 30.0, 28.9mOhm 36G: 31.4, 31.9, 30.8, 33.3, 30.8mOhm :warn: That must be AC internal impedance you're measuring not DCIR... You can see from the discharge curves that the DCIR values are way more th...
by Matador
Feb 23 2019 11:21am
Forum: Battery Technology
Topic: Panasonic NCR18650G - the mysterious 3600mAh battery's capacity test
Replies: 8
Views: 867

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

Something like this, but with copper and no soldered bottleneck: tester.JPG tester2.JPG Source: https://www.arbin.com/store/battery-holders/high-current-battery-holder/ Holder explained more here: https://www.arbin.com/news/page/2/ See the massive brass nuts and bolts on top... that's where you atta...
by Matador
Feb 23 2019 10:51am
Forum: Battery Technology
Topic: Panasonic NCR18650G - the mysterious 3600mAh battery's capacity test
Replies: 8
Views: 867

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

The measured DC IR of fully charged cell at 3.45A was 38±1.5mΩ My cell's weight was 46.39g From your discharge graph, at around mid-capacity, going from 0.69A discharge to 5.00A, you can see the voltage drops from 3.60V to 3.26V with the added current. That would be a DC IR more in the range of 79 ...
by Matador
Feb 18 2019 8:41pm
Forum: Battery Technology
Topic: FIX for non trimmable Li-Ion charger that slightly overcharges eSkate
Replies: 19
Views: 1221

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

Alright, It works ! Terminal voltage is 29.35V hot (still) on the charger still plugged in but the LED did turn back to green. Took from 18h54 to 20h04 to charge from 26.6V (3.800V) to 29.35V (4.192V). So that was 1h10 minutes. LED did change back to green. So I went from 26.65V (4.236V) without the...
by Matador
Feb 18 2019 7:29pm
Forum: Battery Technology
Topic: FIX for non trimmable Li-Ion charger that slightly overcharges eSkate
Replies: 19
Views: 1221

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

Sunder, I went ahead: Schottky diode1.jpg Schottky diode2.jpg Plugged it into the wall. LED green with no load (as normally expected). No load voltage measured at 29.4V with newly installed schottky diode instead of 29.6V without. Plugged the battery on. LED turned red (as normally expected when cha...
by Matador
Feb 18 2019 5:54pm
Forum: Battery Technology
Topic: FIX for non trimmable Li-Ion charger that slightly overcharges eSkate
Replies: 19
Views: 1221

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

I'll solder the diode after dinner. Forgot to mention... this e-Skateboard cost me 145 USD shipped. I invested in more decent bearings though (Zealous bearings x 8 = 20 bucks) and a light system (25 bucks... the Koowheel lights). This new battery I made was essentially free. I knew the original woul...
by Matador
Feb 18 2019 5:30pm
Forum: Battery Technology
Topic: FIX for non trimmable Li-Ion charger that slightly overcharges eSkate
Replies: 19
Views: 1221

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

With that "Cocktail" of mixed cells, i would be more worried about getting an even charge on each 2p pair when charging. Im guessing the charger is not a balancing charger ? Might i suggest you invest $25 in a cheap RC balance charger that you can easily adjust the settings on , and ensure those mi...
by Matador
Feb 18 2019 5:24pm
Forum: Battery Technology
Topic: FIX for non trimmable Li-Ion charger that slightly overcharges eSkate
Replies: 19
Views: 1221

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

Thanks for the reply Sunder. I think I'll go ahead and try it. I actually have two identical diodes.... Will start using one and see the result, but I could end up trying two diodes in series at the output. Cycle life is a bit of a concern, but not soo much, but 4.24V really seem to not give any adv...
by Matador
Feb 18 2019 3:56pm
Forum: Battery Technology
Topic: FIX for non trimmable Li-Ion charger that slightly overcharges eSkate
Replies: 19
Views: 1221

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

Hey there. Quick question for you folks. I have a cheap e-skateboard called the "Small Fish Plate" (mono hub motor 250W). It runs on a 7S1P Lithium cobalt oxide battery (cells are cheap chinese BFN 2000 mAh). The fun kicktail skateboard weights only 9 pounds, is easy to carry to work and tops out at...