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  1. E

    kWeld - "Next level" DIY battery spot welder

    I've had the kweld for a while and used it with a car battery and now got the ksupply and kcap somewhat recently and tried to assemble everything but have ran into trouble. I'm not getting any voltage on the output from the ksupply. I'm using the DPS-800GB PSU. I do get 12.25v on the input...
  2. E

    Strange BMS issue

    The connector was glued on top which was difficult to break so i don't think it could slide back. So my theory now is that the pins were not crimped correctly. Thanks.
  3. E

    What makes a cell group just die?

    Many thanks for the response. I do not know if it was gradual. But the other cells were indeed fully charged and the battery was sitting unused for about 3 months. Why can a fully charged battery, sitting idle, have a cell group killed? I will not take the risk and change the BMS.
  4. E

    What makes a cell group just die?

    I have a 14s6p battery pack and one p cell group is totally dead =0v. What makes a cell group die like this while the rest is totally fine?
  5. E

    Strange BMS issue

    Turns out it was a bad balancing cable. Unbelievable, I tested the cable a million times. Check continuity, resistance, voltage. Etc. Don't understand what's bad with it.
  6. E

    Strange BMS issue

    I have a strange BMS issue. I change a bad BMS with a new one. The bad BMS outputs correct voltage, but as soon as it is loaded, it drops the voltage. The new one outputs 0.45v so something is bad with it. I change to another new BMS. I test the new one before soldering it and it outputs...
  7. E

    How do i solder this tab?

    I know I must be careful not to apply to much heat so I don't damage the cells. But I could attach something to cool the cell while soldering.
  8. E

    Strange issue. Changed BMS but didn't solve the issue.

    The pack was folded as you can see on the picture and I didn't unfold it to check. I just presumed the BMS was bad so I will unfold it and check the connections. However, you would think the groups would've gone unbalanced after me charging and discharging it a few times.
  9. E

    Strange issue. Changed BMS but didn't solve the issue.

    So i got a battery pack which would cut under load after 1-30 minutes randomly and even stop charging randomly. So i changed BMS and didn't do any good. I tried another charger and it didn't do any good. I even balanced the cells using the balance wires. All cells were quiet balanced but i...
  10. E

    20s battery pack reads very low voltage (20v)

    Great, thanks, will check. I could understand if the BMS itself drains the battery pack. But not when the load comes from before the BMS. Then you would think the BMS kicks in and cuts everything.
  11. E

    20s battery pack reads very low voltage (20v)

    Ok. Got it. It will also not take charge.
  12. E

    20s battery pack reads very low voltage (20v)

    A friend has a 20s battery pack with BMS which he connected to some LED lamps. He forgot to turn off the lamps and ran the battery low, but not for a long time (like a few hours). Now it reads 20v. Wouldn't you think the BMS would cut-off of the voltage before something like this happens? I...
  13. E

    Ebike Battery pack got unbalanced. Reasons?

    Well, turn out i was wrong. My BMS does balance so it actually might be a faulty BMS. I got two suspects now :) My balancer is working hard now.. haha
  14. E

    Ebike Battery pack got unbalanced. Reasons?

    Thanks all. I'm suspecting frequent full discharges or a bad BMS as this type of battery pack is quiet common, so the design shouldn't be a problem. Just wondering, how can a broken BMS without balancing function unbalance the pack? :wink: I'm getting my Active balancer this week, a year...
  15. E

    Ebike Battery pack got unbalanced. Reasons?

    Yes it has a BMS. But i don't think it's a balancing BMS.
  16. E

    Ebike Battery pack got unbalanced. Reasons?

    I got an ebike battery with brand cells (MJ1) and after about 1000km of usage, the pack is heavily unbalanced. How can a battery pack all of a sudden get this unbalanced? I know it's a difficult question, but it could give me some hints :) The cell groups measure voltage: 3.13 (+) 3.12 3.06...
  17. E

    Discharge from the charge port

    It takes me a fair amount of work and disassembly to reach the discharge port. I wanted to make it easy by discharging from the charging port. Sounds like it's a bad idea. I don't want to risk the bms.
  18. E

    Discharge from the charge port

    I would like to discharge a battery pack to storage voltage from the charging port. I'm respecting the cable max current so I won't exceed the charge current rating when discharging. I think it's a BMS with separate C and P. So I guess I'm missing out the low voltage threshold shutdown but I...
  19. E

    DC Load test large battery packs. Rheostat?

    Oh man, I'm so glad i asked all of you guys. DogDipstick, what ohms are your heater loads?
  20. E

    DC Load test large battery packs. Rheostat?

    Thanks, but the rheostat is variable up to say 10 ohms so i should be able to set the resistance to 1.2 ohms :D I will check the video. Thanks!!
  21. E

    DC Load test large battery packs. Rheostat?

    Bump anyone?
  22. E

    DC Load test large battery packs. Rheostat?

    I have large battery packs, up to 60v@36Ah and output around 2000-3000w, which i would like to troubleshoot by loading them. I'm thinking a variable rheostat + Battery Coulometer...
  23. E

    JST-SM Crimp Tool

    Wonderful. I need a JST-SM crimper. I got the SN-01BM but it doesn't work at all it seems. Thanks
  24. E

    JST-SM Crimp Tool

    So, how did it go with the SN-28B and JST-SM compared to the PA-09 5 years later :lol: I'm curious to know. :pancake:
  25. E

    Help me troubleshoot this pack please. How are these voltages?

    They are in many ebikes and scooters and have been around for many years and they don't try to hide their brand like other fake chinese factories. But yes, i haven't seen any proper tests on those cells.
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