Search found 86 matches

by docware
Jun 14 2019 1:28am
Forum: Battery Technology
Topic: Which cell for long lasting battery
Replies: 32
Views: 1122

Re: Which cell for long lasting battery

Dak77 wrote:
Jun 14 2019 12:57am


What kind of amp loads are you hitting that GA pack with? Ball park figure
Amp load peaks are usually about 2,2 A per cell, very seldom 3 A.
Charging amps 0,8 A per cell for the first year, now cca 0,5 A.
by docware
Jun 14 2019 12:15am
Forum: Battery Technology
Topic: Which cell for long lasting battery
Replies: 32
Views: 1122

Re: Which cell for long lasting battery

I give you an example a hard data from my measurement. Tesla Model S 85 cell is after 500 cycles (the same settings: 0.5C-1C 100% DoD) at 81% of its nominal capacity and after 1000 cycles at 71%. This is much worse result than almost all above mentioned cells. Do we heard about any significant Tesl...
by docware
Jun 13 2019 12:52am
Forum: Battery Technology
Topic: Which cell for long lasting battery
Replies: 32
Views: 1122

Re: Which cell for long lasting battery

Well, again, where did you buy the cells ? Let´s assume the cells are from trustfull source: Quick 40% loss after 170 cycles indicates that something in the conditions is not relatively mild. Despite of probably not optimal cells like MG1 (I trust to Pajda´s measurement). Something is wrong about ha...
by docware
Jun 11 2019 12:22am
Forum: Battery Technology
Topic: Which cell for long lasting battery
Replies: 32
Views: 1122

Re: Which cell for long lasting battery

Hey guys, at the moment i have a 7P13S battery consisting of 91 LG MG1 and after only about 170 cycles it lost already about 40%. I tested it multiple times and its quite disappointing. A) Can you please describe in details how did you measure battery capacity at the beginning and after 170 cycles ...
by docware
May 30 2019 4:55am
Forum: Battery Technology
Topic: Panny or Sanyo?
Replies: 44
Views: 1251

Re: Panny or Sanyo?

Yeh I see your points . Having an opening of any kind is a bad idea , I admit. Exactly. In the meantime I made small re-evaluation. In fact, we can expect that warming of the cells in real battery pack will be lesser than in my test. Moreover, both Pajda and flippy assess Panasonic PF and Samsung 2...
by docware
May 29 2019 11:23pm
Forum: Battery Technology
Topic: Panny or Sanyo?
Replies: 44
Views: 1251

Re: Panny or Sanyo?

Yes, PF has worse sag thanks to its lower capacity. Capacity does not determine voltage sag. Internal resistance determines voltage sag. Both capacity and resistance determine voltage sag. Compare GA (3,4 Ah 36 miliohm) with VTC5A ( 2,5 Ah 15 miliohm) and VTC6 (3 Ah 18 miliohm). GA v VTC5A 2A b.jpg...
by docware
May 29 2019 3:25pm
Forum: Battery Technology
Topic: Panny or Sanyo?
Replies: 44
Views: 1251

Re: Panny or Sanyo?

Do you really want to force all moisture and dust from surroundings to the cells ? Doesn´t sound well !
by docware
May 29 2019 2:10pm
Forum: Battery Technology
Topic: Panny or Sanyo?
Replies: 44
Views: 1251

Re: Panny or Sanyo?

10 % slopes is quite steep hill. Hopefully not too long. What do you mean when you say "good air circulation" ? I understand that you want to motivate your wife to excercise . Maybe after some time you can make throttle „out of order“ to get her more pedalling. 😊 If the bike will have PAS sensor, pe...
by docware
May 29 2019 10:46am
Forum: Battery Technology
Topic: Choosing battery chemistry for a light mobility scooter
Replies: 13
Views: 393

Re: Choosing battery chemistry for a light mobility scooter

Flippy is absolutely right. We use bilions phones and laptops with Lipo every day. I also appreciate his ample experiences. But, there is one factor we have to consider - producer : https://www.mpoweruk.com/china_batteries.pdf So, if you choose Lipo, try to have one from reliable production. By the ...
by docware
May 29 2019 9:10am
Forum: Battery Technology
Topic: Panny or Sanyo?
Replies: 44
Views: 1251

Re: Panny or Sanyo?

Taswegian, there are numerous degradation factors affecting the Li-ion cell during its life. Read my answer to Matador at previous page. Try to read articles at Electropaedia pages. The best way to investigate lifetime is long term cycling test, see Pajda´s testing. In real operation is cell burden ...
by docware
May 29 2019 5:33am
Forum: Battery Technology
Topic: Panny or Sanyo?
Replies: 44
Views: 1251

Re: Panny or Sanyo?

Comparison applys to using cells a a givent load. For a given load (in amps) power dense (High amps or high wattage) cells (aka lower internal resistance cells) generally have longer life because they heat less. But they pack less energy (Wh) density because much of the cell can volume is occupied ...
by docware
May 27 2019 12:45pm
Forum: Battery Technology
Topic: Panny or Sanyo?
Replies: 44
Views: 1251

Re: Panny or Sanyo?

Hmm, charge 1,3 A, discharge 6 A, some ES members consider opinion that test data are erratic and methodology is wrong.

6 A discharge is really too high, charge current is in common life also lower. Wonder that cells made such results at this torturing.
by docware
May 27 2019 12:41am
Forum: Battery Technology
Topic: Panny or Sanyo?
Replies: 44
Views: 1251

Re: Panny or Sanyo?

The controller is a cheap chinese model that all I can make out is 30A for max I assume. It has a cheap "1000w" AWT hub motor. She isn't exactly a speed demon so she will probably only lay the throttle down on steep hills and likely won't offer much pedal assistance , since the only way I was getti...
by docware
May 26 2019 1:00pm
Forum: Battery Technology
Topic: battery condition
Replies: 19
Views: 551

Re: battery condition

Yes, there is for example 850C display among others, but not sure if it is compatible with your bike. 850C.jpg Unfortunately 850C isn´t compatible with my bike. Therefore I installed this cheap chinese voltmeter. Very satisfied with the voltmeter, much better information how full battery is. Wired t...
by docware
May 26 2019 5:41am
Forum: Battery Technology
Topic: Panny or Sanyo?
Replies: 44
Views: 1251

Re: Panny or Sanyo?

Depends on the conditions. I know that my GA will persist long, long time with my slow charging, low discharging current, low DOD, low SOC, ….. But in fact, we have too vague information from Dak77 to be able to make proper advice. We would need mainly exact info about average and max current to the...
by docware
May 26 2019 1:32am
Forum: Battery Technology
Topic: Panny or Sanyo?
Replies: 44
Views: 1251

Re: Panny or Sanyo?

Dak 77, if you build 8p pack with GA, your wife will love it for next 10 years. And you also.
By the way, internal resistance GA and PF is nearly the same.
by docware
May 26 2019 1:13am
Forum: Battery Technology
Topic: battery condition
Replies: 19
Views: 551

Re: battery condition

Odessadream, installation of simple cheap voltmeter can help you with remaining capacity reading (or state of charge – SOC). And you can better decide when to recharge again. Definitely not immediately after each ride. People here are giving you good advices regarding charging. 908292-1.jpg I just r...
by docware
May 26 2019 12:29am
Forum: Battery Technology
Topic: battery condition
Replies: 19
Views: 551

Re: battery condition

Yes, regular checking of cells imbalance is in such case advisable, of course. And of course, BMS is still connected for emergency.
by docware
May 25 2019 5:14pm
Forum: Battery Technology
Topic: battery condition
Replies: 19
Views: 551

Re: battery condition

My battery 10s5p Sanyo GA is now 2 years old. Last year I started to charge to cca 40 – 41 V. So I am running this battery without balancing now for nearly 1 year. The cells are constantly within 3 mV range.
by docware
May 25 2019 4:41pm
Forum: Battery Technology
Topic: battery condition
Replies: 19
Views: 551

Re: battery condition

Balancing is practically unnecessary if you have new cells REALLY produced from LG, Samsung or Sanyo.
by docware
May 25 2019 7:52am
Forum: Battery Technology
Topic: How solar panel impact battery life for ebike?
Replies: 24
Views: 598

Re: How solar panel impact battery life for ebike?

How solar panel impact battery life for ebike ? Negatively, if you will be succesfull in your intention, as dwelling at higher SOC is negative for battery lifetime. https://www.researchgate.net/publication/328086745_Extending_Battery_Lifetime_by_Avoiding_High_SOC So you invest your money and effort ...
by docware
May 25 2019 7:38am
Forum: Battery Technology
Topic: Panasonic/Sanyo NCR20700B vs Samsung INR21700-50E
Replies: 65
Views: 2050

Re: Panasonic/Sanyo NCR20700B vs Samsung INR21700-50E

Statement from flippy about better endurance of 18650 is probably not based on trustful data, if any. Regarding the price – total 21700 battery price can be this year very close to 18650 battery, depends on the specific configuration.
by docware
May 24 2019 2:26pm
Forum: Battery Technology
Topic: Panasonic/Sanyo NCR20700B vs Samsung INR21700-50E
Replies: 65
Views: 2050

Re: Panasonic/Sanyo NCR20700B vs Samsung INR21700-50E

Hi Pajda,

thank you for sharing your data. So Samsung 50E seems to be very good cell. Can you please compare 50E with LG M50 ? Can you please compare 50E to 18650 (MJ1, M36, GA, 35E, VC7) ?

docware
by docware
May 24 2019 12:32am
Forum: Battery Technology
Topic: Panasonic/Sanyo NCR20700B vs Samsung INR21700-50E
Replies: 65
Views: 2050

Re: Panasonic/Sanyo NCR20700B vs Samsung INR21700-50E

Similar, not different :

https://endless-sphere.com/forums/viewt ... 8#p1450798

By the way, Sanyo 20700B as younger, but bigger brother of Sanyo GA is also interesting cell for ebikes with its capacity 4100 mAh and 25 miliohm DCIR at 3,8 V/25 °C.