• 3 Posts
  • 81 Comments
Joined 3 年前
cake
Cake day: 2023年6月25日

help-circle


  • A couple suggestions then:

    • I have a LabJack that I use for things like this. I’d put a sense resistor on the high side, tie that into one of the differential inputs, set up the (admittedly awful) software, and boom I’d have battery voltage and current over time. But that’s several hundred dollars.
    • Instead of that, you can homebrew a pretty similar thing.
      • Either use your Pi or a separate Arduino to read voltages. Store it in a file or send it to a host PC over serial every [1-3600] seconds
      • You could get a module like this one to capture everything digitally
      • Or you could do it the analog way
        • Probe battery voltage with an appropriate resistor divider
        • Probe current with an INA169 or similar
    • If you are using a BMS, that could give you net power flows in/out of the battery. But you won’t know from that alone whether your solar setup is functioning well or your power draw is low (for example)
    • For battery state of charge, you could worry about coulomb counting and fancy algorithms. I’d just use voltage. But know battery capacity is not linear with voltage (refer to charge/discharge curves).
    • For full understanding of inflow/outflow, you’d want a current monitor at both the solar cell side and the load side of the battery.










  • Every filament - literally 100% of them - will print better when dry. Brand new filament can be wet. PLA, sitting in my printer for a couple weeks, can get brittle enough from absorbed moisture to crack in a dozen places in the ptfe feed tube. So yeah I guess petg is moisture sensitive, but my take is that everything is. So I would recommend a filament dryer, and using it on new spools and spools that haven’t been used in a while.

    Vacuum sealing will help, but I still dry filament after storing in vacuum sealed containers.

    That said, you could also just wait until you see signs of wet filament before drying (stringing, bad surface finish, etc).


  • Petg is the best all-around choice for structural applications that is easy out of the box.

    I wouldn’t worry about chemical compatibility with laundry detergent, but if you can find the relevant ingredients there are many compatibility charts you can look for. It’s not straightforward for most common filaments though.

    For the first case, if you want to push a little deeper I’d suggest carbon-filled petg. You would need to buy a hardened nozzle for it.

    For outdoor applications, you could look into Asa.