Recent content by elkooo

  1. elkooo

    Opus behaviour: Normal?

    Hello folks, I just got a new OPUS BT-3100 charger. Before I had a «Liito Kala li500» but it startet behaving strange on me (didn't measure voltages correctly and repeatedly accurate (at least not lately); not all slots had the same end-voltages and thus tested cells with different results)...
  2. elkooo

    220v inverter - which one for me?

    Hello, I now have a good collection of >3ah 18650ies to start with my 14s32p battery. The closer I come to that, the more I started looking for inverters. Recently I added more Solar Panels to our Roof (6 more --> ~2.5kWp). For those and the battery I would like to have a single phase...
  3. elkooo

    DIY ATmega BMS (followup to DIY Arduino BMS)

    This is a followup for an old thread, which was blocked due to inavtivity: Here is the Link to the old thread. SO.... Another little step is done: I just testet the first Atmega328 chips. With the help of some Arduino boards (I had a Atmega2560 and a Duemilanove compatible board which is...
  4. elkooo

    Battery Fire (and probable cause)

    I think single cells loosing capacity in a large bank are not that problemathic (they will be carried through by its neighbours). The larger problem would be cells that self discharge a lot. They may eventually get hot and cause a fire if not fused. Therefore I think a thermal camera can be a...
  5. elkooo

    Battery Fire (and probable cause)

    I think the washer underneath the shrink wrap is somewhat smaller than the diameter of the cell - at least in the case of those LG-cells - may it be due to smaller fabrication or due to heat used in shrinking in the cells. Will redo the 10s5p pack but with 3D printed top covers (which get a...
  6. elkooo

    Battery Fire (and probable cause)

    The cells were genuine (they came from a 100% thrusty source). I capacity testet them all and made matching packs (divergence was only 1mAh from one 5p block to all others). The BMS was also OK (since the same pack was running well with old cells...) and is able to handle the new cells. I think...
  7. elkooo

    Battery Fire (and probable cause)

    A few more Details: On the plus-side of the cells were no paper insulatorsnor other protectorsmounted... which probably made it possible for the nickel to cut through the shrink wrap and cause theshort. The cells were conected with folded nickel strips as seen in the sketch: I think the...
  8. elkooo

    Battery Fire (and probable cause)

    So this is something that generally is not admitted with pleasure: I had a battery fire. It was probably caused by a spot welded nickel strip, that worked its way through the shrink wrap on the positive end of a cell (where the edge is already negative...). It was a 10s5p arrangement, housed in...
  9. elkooo

    DIY Arduino BMS

    So.... I did a bit of research and found, that the ATmega328P-PU chip also works with very low voltage (down to 1.8v as per spec-sheet) and is capable of running on an internal clock. Basically it can run in a similar environment as the ATtiny but has much more memory and a lot more options...
  10. elkooo

    Richie`s Modular Powerwall (Germany) 21kWh+

    Maybe I'm a little late with this... so... sorry about that. Nevertheless... I aswell thought about adding cells to a pack via a second connector but came to another solution: I will make a connector bar where every pack gets plugged in. The bar has 14 connectors in series (to get 14s...
  11. elkooo

    NighPV - Batteries to use our solar power at night

    So another process update: Love it, if a plan works out well! The plan: Basically the idea was, to have two bus-bars. I use solar bus bar (pre-tinned copper, used to lead the electricityinside a PV module to the connection box). Those are rated for 10A continuous(in a laminated...
  12. elkooo

    NighPV - Batteries to use our solar power at night

    enki, this was very helpful!! I just checked the power bill and phoned with my powergrid provider. Looks like I can run the battery on just one phase as you mentioned and the meter will becalculating if I have excess power or lack of. So as long as I don't want to go completely off-grid, I can...
  13. elkooo

    NighPV - Batteries to use our solar power at night

    @ajw22: Exactly. I had problems with slightly different cell diameters (mostly due to different shrink wrap I think..) so I decided to add a little adjustability to the cellholders. They are a little tight still but with some minor adjustments they should work pretty much as expected :) Saw...
  14. elkooo

    NighPV - Batteries to use our solar power at night

    @OffGridInTheCity: Using a heat pump is a really ambitious project, since it will draw quite some power! Wish you best of success with this! We do the heating with wood pellets (Switzerland is quite cold over winter time and our central heater does 10kWp with wood... it warms the house and...
  15. elkooo

    NighPV - Batteries to use our solar power at night

    Currently the overall average per cell is around 2640mah but I have already around 650 cells tested and have over 460 cells with >2500mah (of which I need 448 for a 14s32p). So yes, you're right - it will probbably be somewhat below 5kWh (48v x 2.6Ah x 32cells will be more like 4kWh). But I do...
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