Search found 914 matches

by Matador
Feb 18 2019 5:30pm
Forum: Battery Technology
Topic: FIX for non trimmable Li-Ion charger that slightly overcharges eSkate
Replies: 20
Views: 1721

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: 20
Views: 1721

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: 20
Views: 1721

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...
by Matador
Feb 10 2019 11:22pm
Forum: Battery Technology
Topic: battery pack idea
Replies: 7
Views: 776

Re: battery pack idea

Electrolyte, I've heard is Lithium hexafluorophosphate (Li+ PF6-). When reacting with water (H2O), that stuff releases hydogen fluoride (HF). HF in it's pure form wich reacts with anything that contains calcium... Like bones. It is readily absorbed through skin. I don't know if it's that reactive in...
by Matador
Feb 06 2019 9:34pm
Forum: Items for Sale - Used
Topic: [EU] Tested 18650 cells box qty 100-500. Prismatics now avail too.
Replies: 18
Views: 3115

Re: Tested 18650 discount!

And what current rating do these cell have ?

A 3000 mAh 10A-capable 18650 cell is certainly worth much less than a 2500 mAh 30A-capable cell in my view.

Capacity alon without other info is not very usefull.... Capacity at what amp-rate ???
by Matador
Feb 06 2019 9:05pm
Forum: Stand-up E-scooters and E-skateboards
Topic: Bms voltage?
Replies: 5
Views: 727

Re: Bms voltage?

e-beach wrote:
Feb 06 2019 8:54pm
How about a 54v bms....

http://www.bestechpower.com/544v17spcmb ... tterypack/

:D :bolt:
Well then you would be talking LiFePO4 chemistry, which has quite a different nominal voltage than most other lithium-ion chemistries (such as NMC, IMN, NCA or LCO).
by Matador
Jan 27 2019 1:40pm
Forum: E-Bike Reviews & Testing
Topic: $300 Hobby King Ebike (Battery in hub!)
Replies: 16
Views: 4004

Re: $300 Hobby King Ebike (Battery in hub!)

should go around 13-17 miles with that. Samsung 35E i'm guessing. So that's max 24A in a 3P config.
I think I wouldve done the opposite. Motor in the rear and battery in front wheel
by Matador
Jan 27 2019 1:34pm
Forum: E-Bike Reviews & Testing
Topic: $300 Hobby King Ebike (Battery in hub!)
Replies: 16
Views: 4004

Re: $300 Hobby King Ebike (Battery in hub!)

How could you fit 10S3P in such a small hub and at the same time find space for copper windings, magnet and planetary gear. They don't. The motor is in the other wheel. ;) Thanks for clarifying. So for the untrained eye, it looks just like a 2WD with 2 hubs but no triangle or dowtube battery ?
by Matador
Jan 26 2019 8:23am
Forum: E-Bike General Discussion
Topic: Persecuting E-Bikes in New York City
Replies: 220
Views: 23812

Re: Persecuting E-Bikes in New York City

All NYC is able to do is (mental) masturbation with a thought for more than 10 years. It never goes anywhere... NYC politicans are wankers. They spend their times masturbating with ideas and never take action into anything. And then police officers take pictures of themselves with the conficated ebi...
by Matador
Jan 26 2019 7:57am
Forum: E-Bike Reviews & Testing
Topic: $300 Hobby King Ebike (Battery in hub!)
Replies: 16
Views: 4004

Re: $300 Hobby King Ebike (Battery in hub!)

Yep 888$ not 250. And the descriptions says the battery is built into the bicycle central frame. How could you fit 10S3P in such a small hub and at the same time find space for copper windings, magnet and planetary gear. I think this looks fishy. THe controller is also external cheap chinese clone c...
by Matador
Jan 16 2019 6:43pm
Forum: E-Bike General Discussion
Topic: I bought an E Bike for my wife but she says its to slow
Replies: 16
Views: 1279

Re: I bought an E Bike for my wife but she says its to slow

You can also just run higher voltage on the same setup (same controller and same motor). Acceleration will remain the same, but top speed would increase. For ballpark estimate, go from 36V to 48V and you speed increases to 133% of the original top speed (around 32 km/h). I have a small folding 36V e...
by Matador
Jan 06 2019 7:28pm
Forum: E-Bike General Discussion
Topic: How To, 50A BBSHD Controller Mod
Replies: 247
Views: 47662

Re: How To, 50A BBSHD Controller Mod

Saw this on youtube !! Nice!



Shunt mod at 30:00.

Matador
by Matador
Jan 04 2019 9:11pm
Forum: Battery Technology
Topic: Did the bms drain the cell group?
Replies: 8
Views: 1087

Re: Did the bms drain the cell group?

Thanks for the advice Fechter ! Will do. I did balance charge it for 12 hours the last time I fully charged it and then discharged it to 51.6V. Will rebalance everything when summer comes. I check bulk voltage every month too.

Matador
by Matador
Jan 03 2019 7:19pm
Forum: Battery Technology
Topic: Did the bms drain the cell group?
Replies: 8
Views: 1087

Re: Did the bms drain the cell group?

Since we're in the subject and I hear you guys have a lot of experience with BMS. Do you think this BMS is likely to be on that drains cells unequally (example the last 3 cells groups closer to the negative ) ? or should it be alright. I'm currently storing it at 51.6 (avraging 3.68V per cell) Here'...
by Matador
Dec 30 2018 11:39pm
Forum: Battery Technology
Topic: Cap cooling of 18650, thermal output graphs?
Replies: 10
Views: 1170

Re: Cap cooling of 18650, thermal output graphs?

How many watts of thermal energy does a 3000mah 18650 generate at 1,2,5 and 10C? We need to know the DC internal resistance of the cell you are using to answer this question. To make things even more complicated, DCIR can vary with state of charge... such as in this example for a good old Sony VTC4...
by Matador
Dec 30 2018 11:37pm
Forum: Battery Technology
Topic: Cap cooling of 18650, thermal output graphs?
Replies: 10
Views: 1170

Re: Cap cooling of 18650, thermal output graphs?

I am researching 18650 cell cooling, one source said that tab cooling prolongs cell life by reaching into all the layers of the battery, is it the same for cylindrical batteries? How many watts of thermal energy does a 3000mah 18650 generate at 1,2,5 and 10C? I found a couple of fun videos of X-ray...
by Matador
Dec 30 2018 9:24pm
Forum: Battery Technology
Topic: Samsung 40T - 35A 21700 Li-ion battery's capacity test
Replies: 13
Views: 2339

Re: Samsung 40T - 35A 21700 Li-ion battery's capacity test

If someone could make this exact 4 wire leads tester with silver plated solid copper terminal and no solder joints, that would be awesome !
by Matador
Dec 26 2018 8:25pm
Forum: E-Bike General Discussion
Topic: Hailong Case... TIGHT!! Aaagh!
Replies: 9
Views: 1434

Re: Hailong Case... TIGHT!! Aaagh!

I have plans to try and fit as much as possible into one of these. Any one reckon it would be possible to do 14s6p? Failing that maybe 15s5p? I don't need any BMS, or switch or USB, etc. and I'm not afraid to cut away some of the inside of the case if necessary. Cheers Hailong might be too small th...
by Matador
Dec 21 2018 6:15pm
Forum: Battery Technology
Topic: Building battery from MAKITA Konion PACK
Replies: 228
Views: 51020

Re: Building battery from MAKITA Konion PACK

2.8V is not dramatic, so as long as they do not ever reach below 2.5V, you're good. Learn about your VTC4 cells. CHECK THE DATASHEET which has all the specifications: Specification_US18650VTC4.pdf On that datasheet, you will see that the manufacturer (Sony), specify it's okay to discharge as low as ...
by Matador
Dec 21 2018 6:09pm
Forum: Battery Technology
Topic: Building battery from MAKITA Konion PACK
Replies: 228
Views: 51020

Re: Building battery from MAKITA Konion PACK

Both. Charge, then discharge. What you want is discharge capacity. Charge capacity is not reliable because all the cells from different packs are not necessarly in the same state of charge (some cells may be 52% charges, some 23%, some 97%). So some will need less charge time to become full. But onc...
by Matador
Dec 20 2018 10:47pm
Forum: Battery Technology
Topic: Building battery from MAKITA Konion PACK
Replies: 228
Views: 51020

Re: Building battery from MAKITA Konion PACK

Dude, just use 1000 mA (C/2)... It's much faster to test each cells. 500 mA (C/4) will take twice as long and 200 mA (C/10) will take 5 times as long. In any case, the capacity you'll get on your eBike will be slightly different from that you test, whatever the setting, because you'll very likely dr...
by Matador
Dec 16 2018 12:24pm
Forum: Battery Technology
Topic: DIY battery enclosures
Replies: 17
Views: 1015

Re: DIY battery enclosures