Recent content by ed209

  1. ed209

    4s4p LiFePO4 Build Log

    Spec I found online is 1.96 kg, or 4.32 lbs.
  2. ed209

    4s4p LiFePO4 Build Log

    Awesome! I like the way you did your bus bars, lots of flexibility. I’m in the middle of moving so my project is on hold for a while :(
  3. ed209

    4s4p LiFePO4 Build Log

    Everyone: LiFePO4 batteries have a very flat voltage curve Me: Yep, sounds good. My batteries are pretty close to full so I'll just top balance with this dinky charger instead of wasting time reassembling the pack. 6 days later.... finally starting to get near 3.5 volts. Adding an open...
  4. ed209

    4s4p LiFePO4 Build Log

    They make battery disconnect switches that are pretty compact and enclosed. If you use it a lot that might be a more durable option. Search for "mini battery cutoff switch"
  5. ed209

    4s4p LiFePO4 Build Log

    You're welcome -- it's also to keep me motivated between project time (day jobs are such a drag :)) The batteries are gorgeous but they aren't as easy to work with as prismatics, where the leads are on the same side. I'll have more details of my box in a few weeks as I start the fitment...
  6. ed209

    Variable Power Supply and MPPT for charging LifePO4 bank

    @Baserati How did it end up working? I have a similar situation where I want to feed a 12v cigarette port through a constant current voltage booster to an MPPT controller. I'm building a battery that has alternator and solar charging. In my vehicle I have alternator charging set up. When I...
  7. ed209

    4s4p LiFePO4 Build Log

    Fun fact: my charger's time and mAh readings top out at 65535 (2^16 including 0) Time gets stuck at 92:15 which is 1000 minutes (rollover) + 92 minutes + 15 seconds = 65535 seconds
  8. ed209

    4s4p LiFePO4 Build Log

    Top balancing cells with my little hobby charger. I can't get it to push more than 3 amps so this is going to take a while (I forgot to fully charge it while assembled). Since it's an actual charger and not a power supply, I do feel comfortable letting it run all night unattended... famous...
  9. ed209

    New Bolt EV Batteries and no BMS, one year observations.

    Good luck with that. Hopefully it’s just their BMS setup and not the cells themselves, since they specifically mention not discharging them low.
  10. ed209

    New Bolt EV Batteries and no BMS, one year observations.

    FYI: https://media.gm.com/media/us/en/gm/home.detail.html/content/Pages/news/us/en/2021/aug/0820-bolt.html All Bolts are up for recall.
  11. ed209

    4s4p LiFePO4 Build Log

    Yep, got it on a whim, while my other breaker is the recommended "T Tocas". New one is on order!
  12. ed209

    4s4p LiFePO4 Build Log

    I will add a note. The particular brand I got kept tripping at <50 amps, and would randomly disconnect while the switch was still engaged. On inspection I noticed some play in the connection barrels as well. Caused me a lot of grief while troubleshooting in a hot garage. Thanks for the info...
  13. ed209

    4s4p LiFePO4 Build Log

    Tangent. Here's where my scrap aluminum came from. Around 8 years ago I made a computer case based on a micro ATX form factor. It was completely impractical and the cooling sucked, but it worked and I was proud of it. I figured I'd share since only a few people have ever seen it. Some day...
  14. ed209

    4s4p LiFePO4 Build Log

    Lesson of the day: do NOT buy this kind of breaker! During charge testing, this mf-er caused such a headache. EDIT: your mileage may vary but my experience was not good. Sketchy connection and breaks way under rated amps. I'm replacing it with a standard breaker from a recommended seller...
  15. ed209

    4s4p LiFePO4 Build Log

    Test fitting bus bars ...we have 12 volts! Need to make a bunch of tweaks, though I wish it were feasable to remake them. Main fix is they are too high by a few millimeters because I failed to notice the lid has a part that's much lower than the rest. Also quickly coming to a design...
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