Search found 96 matches

by docware
Dec 11 2018 3:14pm
Forum: Battery Technology
Topic: 17ah Samsung 35E at 30A
Replies: 46
Views: 2757

Re: 17ah Samsung 35E at 30A

You are right, use anything what can help absorb the vibration from the ride.

13s9p LG MJ1 is best choice for you.
by docware
Dec 11 2018 12:08pm
Forum: Battery Technology
Topic: 17ah Samsung 35E at 30A
Replies: 46
Views: 2757

Re: 17ah Samsung 35E at 30A

Regarding fixing the triangle, I believe you are intelligent enough to find your way to fix the pack. You know the possibilities in shops around you, you will know the plastic battery pack details, not me, .......
by docware
Dec 11 2018 11:55am
Forum: Battery Technology
Topic: 17ah Samsung 35E at 30A
Replies: 46
Views: 2757

Re: 17ah Samsung 35E at 30A

Sorry, here is the picture :


Sanyo GA 4A disch temperature curves.jpg
by docware
Dec 11 2018 11:25am
Forum: Battery Technology
Topic: 17ah Samsung 35E at 30A
Replies: 46
Views: 2757

Re: 17ah Samsung 35E at 30A

Obviously you are able to find the way how to fix the triangle pack without damage. The capacity of Li-ion battery is going down with temperature. For example, look at the Sanyo GA cell diagram for various temperatures at 4 A discharge from 4,2 V. There is capacity 2320 mAh at 3,3 V level and 25 °C....
by docware
Dec 11 2018 2:02am
Forum: Battery Technology
Topic: 17ah Samsung 35E at 30A
Replies: 46
Views: 2757

Re: 17ah Samsung 35E at 30A

I understand of using BBSHD as a scooter. In fact, thanks to its internal reduction ratio it is only effective solution for such motor. You need to keep high rotation speed to have good effectivity of the motor. For BBSHD it is in the range 120 – 150 rpm, so definitely not for pedaling. Just hope yo...
by docware
Dec 10 2018 10:39am
Forum: Battery Technology
Topic: 17ah Samsung 35E at 30A
Replies: 46
Views: 2757

Re: 17ah Samsung 35E at 30A

On the other hand, from my calculation you probably don´t need more than 20 A (cca 1 000 W) for your required speed cca 45 km/h. Assuming really flat Netherland terrain, headwind max 10 km/h. But again, 15 Ah battery is in reality cca 10 Ah. After 30 minutes of such ride is battery nearly empty. Ple...
by docware
Dec 10 2018 9:37am
Forum: Battery Technology
Topic: 17ah Samsung 35E at 30A
Replies: 46
Views: 2757

Re: 17ah Samsung 35E at 30A

You wrote at the beginning : „The main thing I'm looking for is cycle life. I already bought a Luna smart charger for adjustable speed and a 80%-90%-100% switch. (Will probably charge at 2A and till 80% most of the time, maybe from time to time faster or more).“ That is in direct opposite of your cu...
by docware
Dec 10 2018 6:03am
Forum: Battery Technology
Topic: 17ah Samsung 35E at 30A
Replies: 46
Views: 2757

Re: 17ah Samsung 35E at 30A

"25 mph+ most of the time, using throttle."

What distance, travelling every day ? Really mph ?

Why do you assume 30 A continuous ?

Can you describe your gears ?
by docware
Nov 26 2018 6:22am
Forum: Battery Technology
Topic: Homemade Battery Packs
Replies: 1620
Views: 426644

Re: Homemade Battery Packs

DrkAngel , thank you for our yesterday´s conversation. I became interested in Li-ion cell just in summer 2017, so cells like Sanyo GA, LG MJ1, Samsung 30Q, … are for me really normal. Not realizing that in fact it is currently „state of the art“. So looking at these modern cells, I still didn´t uder...
by docware
Nov 26 2018 5:59am
Forum: Battery Technology
Topic: Seeing more 20700s in power tool batteries
Replies: 8
Views: 818

Re: Seeing more 20700s in power tool batteries

Thank you for the pictures.

Laser welding is perfect tool for mass industrial production . But copper welding is very difficult task thanks to its properties. Evidently the process is not stable at the Bosch production.
by docware
Nov 26 2018 4:04am
Forum: Battery Technology
Topic: Seeing more 20700s in power tool batteries
Replies: 8
Views: 818

Re: Seeing more 20700s in power tool batteries

Probably it´s laser welding. Can you take more detailed shot ?
by docware
Nov 25 2018 2:56pm
Forum: Battery Technology
Topic: Homemade Battery Packs
Replies: 1620
Views: 426644

Re: Homemade Battery Packs

Well, it´s my mistake that I take into account only cells like Samsung 30Q, Sanyo GA, SONY VTC6, LG MJ, ….. Cells that are on the market few years and that have suitable capacity and power for ebikes. I completely missed (for me) exotic cells like Samsung ICR18650-28A which are not adequate for ebik...
by docware
Nov 25 2018 12:24pm
Forum: Battery Technology
Topic: Homemade Battery Packs
Replies: 1620
Views: 426644

Re: Homemade Battery Packs

I hope we are speaking about cells from trustful manufacturers like LG, Panasonic, Sanyo, Samsung, Sony, with low self-discharge rate. Definitely not fake cells. From my measurement of 18650 cells from all above mentioned manufacturers, there is at least 20 % of capacity bellow 3,5 V even at 3 A dis...
by docware
Nov 25 2018 10:23am
Forum: Battery Technology
Topic: Homemade Battery Packs
Replies: 1620
Views: 426644

Re: Homemade Battery Packs

Well,
back to the merits of my question. In the light of the facts I mentioned, do you still consider 3,85 V suitable voltage for winter storage of non recycled Li-ion cells ?
by docware
Nov 25 2018 9:31am
Forum: Battery Technology
Topic: Homemade Battery Packs
Replies: 1620
Views: 426644

Re: Homemade Battery Packs

Can please shortly describe methodology of your measurement ?
by docware
Nov 25 2018 9:00am
Forum: Battery Technology
Topic: Homemade Battery Packs
Replies: 1620
Views: 426644

Re: Homemade Battery Packs

Just a few facts. 3,85 V is about 60 % SOC for most of Li-ion cells. But probably, this is not so important. Here is something more interesting : All Li-ion cells (LG, Panasonic, Sanyo,Samsung, Sony) are sent and stored for many months at 3,5 V . Here, at well known video https://www.youtube.com/wat...
by docware
Nov 25 2018 5:44am
Forum: Battery Technology
Topic: Homemade Battery Packs
Replies: 1620
Views: 426644

Re: Homemade Battery Packs

DrkAngel,

Is 3,85 V storage voltage meant for LiPo only or also for Li-ion cells ?
If yes, do you have any reason to use such high voltage for winter storage ?
by docware
Nov 04 2018 5:36pm
Forum: Battery Technology
Topic: Samsung 25R Internal Resistance
Replies: 19
Views: 994

Re: Samsung 25R Internal Resistance

I have few new cells from nkon here. Some after few cycles. Samsug 25R shows 11,5 miliohms AC and 18 miliohms DC at 4,08 V. Sanyo GA shows 20,4 (24 new) miliohms AC and 35 miliohms DC at 4,08 V. Temperature during measurement cca 25 C Sanyo GA cells in my one year old battery 10s5p are about 38 mili...
by docware
Oct 02 2018 4:59am
Forum: Battery Technology
Topic: LG M36 vs Samsung 36G capacity test - 3600mAh or just marketing?
Replies: 28
Views: 2763

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

Hi Pajda,

there is a mention of 23°C ambient temperature in your LG M36 test results.

What is ambient temperature during your cycle life testing and what is tolerance of this ambient temperature during whole testing ?

Do you measure also temperature rise of cell during the cycle life testing ?
by docware
Sep 18 2018 1:54am
Forum: Battery Technology
Topic: High drain 21700 - Samsung 30T discharge test
Replies: 60
Views: 4184

Re: High drain 21700 - Samsung 30T discharge test

Hello everybody,

you may be interested in the fact, that lygte has changed the clamp for battery testing some time ago.

https://lygte-info.dk/info/batteryTestI ... %20UK.html