Search results

Announcement - Help us fight the BOTS! Please report all spam including stuff in your inbox!
  1. Generic

    My experience buying already checked and selected cells

    What do you mean by explosions? Like sparks? Make sure one electrode is only touching the fuse wire, and the other electrode is not. And use the lowest setting on your spotwelder. When I started, 3 out of 4 welds were sparking and I had no idea what I was doing wrong, and now I never get a...
  2. Generic

    Results of Capacity Testing 18650s for 1,600+ Cycles

    I came back just in time to see your first pack's 1000th cycle, congrats! The LG cell was warmer than the others for the last 1,000 cycles or so, but nothing extreme. Out of the 4, the LG had the highest IR (probably, I have no means to test that) and for the longest time had the biggest voltage...
  3. Generic

    How bad is this?

    Thank you! Now I have to see if I can find a replacement before I do any more damage.
  4. Generic

    First build questions

    I tried that with explosive results. Twice. Did I do it wrong?
  5. Generic

    How bad is this?

    I can't find any information on the internet about a transformer with a broken outer core. Lots of info about windings shorting, but nothing about bad cores. How do I even test this? This is from an Aims 6000W 24v split phase inverter. The inverter works when I have AC connected on startup and...
  6. Generic

    Kobalt 40v battery packs BMS

    Depends. Do you have any Kobalt chargers or equipment? When I was making my ebike battery, I already had a bunch of Ryobi 40V BMS's, chargers, and connectors, so I just picked one out and ran with it. Worked with my 36V ebike and it could handle the 750 Watt motor without a problem. And I didn't...
  7. Generic

    Results of Capacity Testing 18650s for 1,600+ Cycles

    First off, I want to apologize to everyone for not posting sooner. I meant to log in to post so many times, and I didn't. Today I'm making an effort to post this, so here it goes. Originally I was going to quit at 2,130 cycles when the ASO cell kicked the bucket, but I kept going because I was...
  8. Generic

    18650 best soldering technique part2

    The lawn-tool brand "Ego" made by Chervon (not Chevron), uses double wrapped cells with a phase change wax-like material that will melt when a cell gets too hot. It's not exactly high-temperature wrap, but it's another solution. Gauss163, I took a 240 watt soldering iron and held it on 30 high...
  9. Generic

    Cell Database Submissions and Updates

    I have a bunch of non-translucent green SGs that perform well and have the same positive cap and sticker under the wrap as these translucent blues, so I'm thinking the translucent blues are rejected greens and not re-wraps of major brand cells.
  10. Generic

    Cell Database Submissions and Updates

    You got the date code backwards, it's March of 2011. It's funny, I just took apart 3 packs of these. One pack was "recycled" and had dremel marks on the caps. One pack was all 0V, and 1 pack had cells between 1V and 2V. I believe these are re-wraps of used cells, but I don't have proof.
  11. Generic

    Cell Level Fusing w/ 24AWG TCW

    It's been a few months since I did this, but I too was initially getting the sparks like you mentioned. There's two things you can try and let me know if they work, as they did for me: 1) be very careful to make sure that your electrode tip is only touching the wire, and absolutely not touching...
  12. Generic

    Results of Capacity Testing 18650s for 1,600+ Cycles

    Korishan - As far as I know, cobalt is the single most expensive part of an 18650. Which is why I posted the theory above, to get generic cells cheaper, they have to lower the cobalt content. It's not like these things are handmade and they save on labor. Also, it's not me trying to be...
  13. Generic

    Results of Capacity Testing 18650s for 1,600+ Cycles

    First off, I made a mistake. I write down every result on a notepad, and then do data entry into excel when I hit a milestone and am ready to report an update. Well, for some reason, I wrote Cycle 1528 twice (...1527, 1528, 1528, 1529...). What I decided to do is average the results of the 2...
  14. Generic

    Behaviour of cells in parallel take 2

    Thank you Wolf!! During the discharge, right around 3.6V, cell 1 and 3 (3.6V cells) started to contribute more current than cells 2 and 4 (3.7V cells). However, the increase in current was not as dramatic as I expected. The 3.7V cells were around 0.9 Amps and the 3.6V cells were around 1.15...
  15. Generic

    2 3s 16650 in parallel

    Inductive loads need more current to start than to run. If you have a clamp meter that works with DC and can give you an inrush current reading, test the circuit without the BMS and find out the maximum amps the motor draws at initial startup. Make sure the reading is less than the number of...
  16. Generic

    Behaviour of cells in parallel take 2

    I actually picked those two at random from the cell database, but I was looking for 2 fairly common cells with similar capacity and different nominal voltages. I have no idea if they have similar IR ratings from the factory, so hopefully they do. I'm looking forward to your test results!
  17. Generic

    EBL charger to recover batteries

    I didn't mean an SMD resistor, I just meant the pads on most SMD parts are so close together, that I usually end up creating an unwanted solder bridge. I love the idea of using a potentiometer and being able to change the resistance value infinitely. I was just letting people know that there was...
  18. Generic

    Behaviour of cells in parallel take 2

    Nominal voltages. Like the Panasonic CGR18650E is a 3.6V nominal cell vs. a Samsung ICR18650-26D is a 3.7V cell. Chemistry could be the same, but the 3.6V cell has the bulk of its energy at 3.5-3.6V and the 3.7V cell has the bulk of its energy at 3.7-3.8V. I always theorized that at 3.5V, the...
  19. Generic

    Results of Capacity Testing 18650s for 1,600+ Cycles

    I skipped the update at 1300 cycles, but here I am at 1400! Here's the graph: And where we are at SoH: I also set out to see if degradation is linear or exponential. The CJ and THLD were clearly exponential. The ASO and LG cells, I'm not sure. Here is a chart showing the rate of...
  20. Generic

    Behaviour of cells in parallel take 2

    Everyone assumes that if you have 4 cells at 4 Amps, that each cell has a 1 Amp load on it. Thanks for proving otherwise! Without looking back, did you test two 3.7V cells in parallel with two 3.6V cells, all with equal capacities and IR? Just curious to see if the 3.6/3.7V makes a difference...
Top