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  1. L

    advice on DC relais

    Hello, my e-scooter is based on 20s 40AH LiFePO4 prismatic cells and I charge it at 5A. I have an overcharging protection which I designed which is based on a relais between the battery and the charger which disconnects as soon as 1 cell reaches 3.6V. Unfortunately the relais contact kind of...
  2. L

    long charging cables

    my e-scooter is based on 20s 40AH LiFePO4 prismatic cells. Currently I charge it in the garage and so the external charger is very close with ~50cm cord. But I am moving to a new place with not possibility to have electricity in the garage, so I am thinking to keep the charger in the house and...
  3. L

    Connector for battery main leads

    I have a e-scooter fed on 20S LiFePO4 40Ah battery pack. I am thinking to use such power as a backup in case my house suffers from power outage from the grid. To do that I need: - a safe and easily accessible connector on the scooter connected to the battery main lead for 72V - a converter from...
  4. L

    charge as you go

    Today I experienced an interesting phenomenon.... My e-scooter is powered by a mix of Winston 40ah and Wina 50ah LiFePO4 cells in a 20s configuration. I had a ~15km ride then I parked the scooter for the night at close to freezing temperature; then today I picked up the scooter and checked cell...
  5. L

    overdischarged wina LiFePO4 50ah cell

    Today I badly screwed up.... No BMS and overestimated my pack charge! On the way home I was noticing lack of thrust in my scooter powered by 20s LiFePO4. As soon as I reached home, I measured that one cell was 0 Volt, this is a cell I knew it was the weakest link. Immediately I put the pack on...
  6. L

    SuperCapacitor

    Experts, on my e-scooter I have connected a cell-checker on every battery which give me real-time voltage reading. At times during acceleration, but also deceleration, they give very low reading, kind of unrealistic such as 2.6V, but only for one sample and then go back to normal. I suspect this...
  7. L

    greasy orange dirt

    Experts, it has been one year since I put version 2 of my Elettra2500 e-scooter on the road and now I have decided to open it for a thorough check-up. All looks good apart from a greasy orange dirt on the top of one of the Winston 40ah cell. Do you have any idea of what it can be? And above all...
  8. L

    voltage surge after vacation

    I had a nasty surprise coming back from holiday..... My scooter is based on 20x winston 40ah LIFeYPO4 prismatic cells in series; before leaving for holiday I left the battery at roughly half charge, in pretty much balanced state and disconnected the main leads. After roughly 5 weeks I...
  9. L

    cell checker draw

    Experts, I am using three of these cell-meters to keep my 20S 50Ah LiFePO4 always under control. It has a ground pin and 7 cables to connect to a series of 7 cells to provide individual voltage reading: It works pretty well indeed. Considering a current draw of 35ma on the ground pin, I...
  10. L

    hellp with high-voltage-cut-off

    need help 'cause I am stuck with something I really cannot understand!! Last year I built a balancing system based on TL431 low voltage regulator for my 20S lifepo4 pack, so I bought 25x TL431 from mouser and all went well. Now I am building a high-voltage-cut-off also based on TL431 and very...
  11. L

    advise for opto-coupler

    I want to build an over-voltage-cut-off for my bulk charger for my 20S LiFePo4 pack. I am thinking of using TLV431 voltage reference for every cell: the TLV will drive the optocoupler. The first optocoupler to fire will switch a flip-flop which will disconnect the charger. I need advise on...
  12. L

    under-rated charger: is this a scam?

    Experts, I recently bought this charger which is rated of output current of 1 Amp, but today I connected it to a LiFePo4 Wina 50ah cell and all that I can see is a miserable 0.6Amp :-( http://www.ebay.it/itm/221876225877 As you can see from the attached photo I just connected the charger to the...
  13. L

    concurrent/independent charging

    Experts, I don't know if concurrent or independent charging is the right term for what I am going to described, the fact is that neither serial nor parallel applies.... My new electric scooter will be based on a 20S LiFePo4 battery pack with following cells: - 8 winston 40ah brand new cells - 4...
  14. L

    pressure or not?

    Experts, after ending up with 12 badly swollen cells out of my 20 pack of Wina 50Ah LiFePo4 I have learned the hard way that this type of cell must be mechanically contained in order to put a uniform pressure to avoid swelling. I wonder if I should do the same for winston 40 AH or Sinopoly 40AH...
  15. L

    Bad BMS

    Happy to be back on the community! I have been very busy till recently with work and study, so I had to park my Electra project for a while...... Today I tested the BMS that I bought a couple of years ago because I was in fear that the overcharge function is not working...
  16. L

    Silicon or hot glue or what to fix connectors

    In the previous build of my electric scooter I used hot-glue to insulate and firmly hold together cables welded to cells and connectors. But thinking over it, now that I want to rebuild the scooter from scratch, I realize that it was a bad idea, because if a cables warm up they can melt the...
  17. L

    melsen 72v40ah battery pack

    I just recently found this product from Melsen: http://melsen.en.made-in-china.com/product/SBvJMzXEaxUR/China-Melsen-LiFePO4-Battery-72V-40Ah-Rechargeable-with-BMS.html In essence it is a 20s 40ah LiFePO4 battery pack 200x200x253 mm size, 16 kg weight inclusive of BMS. Considering that I am...
  18. L

    What is this current?

    This is a Wina 50Ah cell. I noticed that the aluminium cage is at ~+3.2 Volt with respect to the anode. So I wanted to measure how much current can flow from the case to the anode getting to figures between 0.2 to 4 mA. What is this current? Can be somehow be related to self discharge? If there...
  19. L

    cell containment

    I learned the hard way that if there is no pressure on the side of the battery this can easily swell; it is even worse if the pressure is not uniform: https://endless-sphere.com/forums/viewtopic.php?f=14&t=84399 In my case the battery are held is a metal box we reach to lower half of the...
  20. L

    lodging Wina50ah

    Roughly one and half year ago I upgraded my electric scooter to lithium using 20s Wina 50AH cells. Now I am dissecting the battery because range went down to one fifth of original range; I am measuring capacity of on cell in the neighbourhood of 12 AH. Inspecting all the cells I can draw a very...
  21. L

    winston WB-LYP40AHA vs sinopoly SP-LFP40AHA

    on the paper they look identical; I also red on this same forum that people swapped one for the other. I wonder if you have any experience to share to help me with this choice
  22. L

    is 3xe-electric-cars.com in business ?

    I placed an order at this site one week ago but no feedback. I called them, nobody picks up. I wrote them, no answer. Shall I assume it is out-of-business?
  23. L

    Aluminium case

    I see some LiFePO4 batteries like Wina and ZG-LFP with aluminium case. This makes me very afraid of the following. On the wina the case is electrically connected to the anode, I have got a confirmation from GWL technical support team after measuring it myself. The case is isolated with a thin...
  24. L

    ZG-LFP

    experts, I have seen this morning on ev-power these (new?) batteries: - https://beta.ev-power.eu/LiFePO4-special-cells/LiFePO4-High-Power-Cell-3-2V-60Ah-Alu-case-CE.html I am planning to replace the un-impressive Wina 50ah on my electric scooter: ZG-LFP060AHA are really a good option on the...
  25. L

    wina exit strategy

    I had a lousy experience with Wina 50ah in 20S configuration on my electric scooter as from my previous post: https://endless-sphere.com/forums/viewtopic.php?f=14&t=83669 Given also other negative feedback collected on the net, I have decided to abandon this brand and replace it with Winston...
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