Search results

  1. John

    Large Portable DC Bank

    Or.... Just get a bunch of these off of ebay. I work with kids doing robotics. I got 5 of these and I filled them with 2500 mah cells. So I guess that I am at 50k mah... They are easy to charge from any USB port. And in a crunch I can just swap out flat cells for freshly recharged cells...
  2. John

    Massively parallel cell testing setup - have you seen this?

    But how does it work? Inquiring minds want to know...
  3. John

    Massively parallel cell testing setup - have you seen this?

    Really? When I click on the link it works for me. It is a short clip from 5:07 to 5:22 Here are some screen grabs to show what I am talking about. John-
  4. John

    Massively parallel cell testing setup - have you seen this?

    I don't know if this has been discussed yet, but I just ran across this 18650 cell testing setup in a YouTube video. Does anybody know about this? Thanks, -John-
  5. John

    Tp4056 reverse voltage protection

    The author states that it is too small in the video. -John-
  6. John

    Power wall location and safety question

    Korishan, It is my judgement, from all of the data that I have, that lithium batteries are a greater fire risk than lead acid batteries, by a large margin. We can debate how wide that margin is. The fact of the matter is that lead acid batteries have been around for a long time, been smashed...
  7. John

    Power wall location and safety question

    Mike, Korishan, Agreed. But to my knowledge there is nothing you can do to a lead-acid battery to cause it to burn (yeah, they generate hydrogen, but venting removes that risk). 18650s are filled with flammable substances and have the ability to self-ignite, thus must be treated accordingly...
  8. John

    Battery sizes question

    So, size doesn't matter?
  9. John

    Power wall location and safety question

    Lead acid batteries don't spontaneously ignite....
  10. John

    Battery Pack Setup-Ideas

    I understand. Thanks.
  11. John

    Battery Pack Setup-Ideas

    I understand. But your picture shows an array of 14 x 5 tubes. So if each tup has 100 cells then your total is 14s100p x 5. Am I not understanding something correctly? Or is each tube just 4x5? Thanks, -John-
  12. John

    Battery Pack Setup-Ideas

    Is this what goes in each tube? -John- So your powerwall will be 500p14s?
  13. John

    Thinking about opening an online store.....

    I am not seeing a list. Am I missing something? Thanks, -John-
  14. John

    BFC TP4056 Need Advice

    NERDville, There is a thread, "Tp4056 reverse voltage protection", that addresses this to some extent. In that thread it was advised that schottky diodes were the way to go. -John-
  15. John

    The beginning of my powerwall

    1:300 junk rate seems very low, and very good for you! What causes the battery packs to be discarded if they are in such good shape? -John-
  16. John

    Battery Pack Setup-Ideas

    MajStealth, How are the cells arranged in the tubes? How many cells per tube? This is a clever design. -John-
  17. John

    The beginning of my powerwall

    I would love to know more about your process! Given the number of cells you have processed, you must have a few tricks you have figured out. Thanks, -John-
  18. John

    Measured cell diameters? Please add your data.

    Scepterr, As an engineer that has worked in the manufacturing sector for decades, all I can say is that I wish that were true. Spec sheets frequently just parrot the relevant standards and have no direct bearing on the manufacturing process. And even if they left the factory in spec, by the...
  19. John

    Measured cell diameters? Please add your data.

    Scepterr, Yes. But "as-designed" and "as-manufactured" are frequently different in the real world. I am curious about the "as-manufactured" dimensions. We may find out that all of the cells are manufactured to a tight tolerance, and the data is boring. But we don't KNOW that until we actually...
Top