diy solar

diy solar

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  1. V

    JK-BMS + Grafana in one evening.

    A perfect example of an anti-idempotent operation would be a call to an "increment counter". A more real example from real world day to day code.... using a call to get the current date and time inside the scope of the operation. No matter when you call that method/operation you will get a...
  2. V

    JK-BMS + Grafana in one evening.

    Adding... Always consider "idempotency". It's a fancy term for saying repeated requests should have no additional effect.(many caveats). If a light needs to be ON. There should be no concern sending it an ON if it already is on. The output state satisfies the requirement. If the light is...
  3. V

    JK-BMS + Grafana in one evening.

    Start with the basic "ITTT". If this then that. Subscribe to an MQTT topic of choice. Write an on_message() handler for it. Run blocking. In the on_message() send another message to a device to do something. Lights in the most simple sense are a motion sensor on MQTT. You subscribe to that...
  4. V

    JK-BMS + Grafana in one evening.

    A hypothetical synchronous operation, a REQUEST->RESPONSE call using a message bus is not 'that' difficult. Publish the request to a specific topic with a specific request ID. Store this request in the service state. Subscribe to the response topic and filter until you get a payload with your...
  5. V

    JK-BMS + Grafana in one evening.

    REST API with micro-services is a valid approach. Along with RMI (Remote method invocation). The advantages of using "middleware" like a message bus (MQTT) is that services do not need to know of each other's existence, nor do they need to "discover" them. In a traditional, non-message bus...
  6. V

    JK-BMS + Grafana in one evening.

    I think I intended the MIT license. The original messy repo is MIT I believe. The new tidier repo is unlicensed I think. I don't recall applying one in gitlab for it. So basically public domain. It's a "one man band project", just my ideas and efforts over the past 6 years or so. Many of...
  7. V

    JK-BMS + Grafana in one evening.

    Absolutely. Especially focusing on the later. In fact I tend towards only the later. When I went through some architectural design for this, I kept finding "state machines". State machines and concurrency is a recipe which will make me sit up and listen in work as it's either a bad, bad idea...
  8. V

    JK-BMS + Grafana in one evening.

    Also. Those git repos are open source, so feel free to borrow or steal. I'd prefer you fork it and pass back anything you do that's cool, but I don't mind you even copy and pasting it, just don't take credits and do try and let me know what you use it for, for my own curiosity.
  9. V

    JK-BMS + Grafana in one evening.

    Oh. Of uptmost importance with the "push" model and on_message() callbacks. With Paho, they are "in paho thread". It uses one main thread. If you spend 2 minutes in your on_message handler, then 2 minutes of all messages will cue up. If you can respond immediately you can. If you can't...
  10. V

    JK-BMS + Grafana in one evening.

    Regarding while(true) loops versus event handlers. I think you are describing what I call the "dynamics" or "cadence drivers". Basically, what invokes the code to do something? As you (?) are exploring MQTT the natural answer is... the message receive event for a topic. The "on_message"...
  11. V

    JK-BMS + Grafana in one evening.

    Sorry for late reply. Absolutely there was "prior work" in my 'core systems' which helped me alone the way. You are not far off from what I have, by the sounds of it. On Paho. If you look into my code base for the mqtt-lib you will see how I wrap it in something a bit more "fit for purpose"...
  12. V

    DIY Solar project No. 2.

    tldr; "Permanently temporary, lean-to awning, roofed with solar, is it wise? Any guides, useful references?" Last year I built my first DIY off-grid system and it has generated close to 0.5MWh of off grid power to my single office circuit. Garage roof: 3x330W panels. 3xMPPT controllers...
  13. V

    I'm not saying the weather is miserable, but...

    ... my automatic lights are coming on all day. How does this relate to solar? The interior lights determine if it's daylight or not by asking the solar power system what it thinks. The weather is so **** the solar power system isn't quite sure. LOL Some times the upstairs hallway lights come...
  14. V

    JK-BMS + Grafana in one evening.

    Fixation and low power. Mine is the 0.6Amp balancer model, which isn't enough in many cases. It also fixates on a pair of cells and will only balance that pair until it's done. Even if there is another cell approaching or even hitting LVC.
  15. V

    JK-BMS + Grafana in one evening.

    I believe the BLE protocol is just basic serial coms on top. The UART code seems identical to the BLE. https://github.com/syssi/esphome-jk-bms/blob/main/components/jk_bms/switch/__init__.py This includes the registers for the "switches". The command code for write register is static const...
  16. V

    JK-BMS + Grafana in one evening.

    So it turns out to be as simple as publishing "ON" or "OFF" to the <BMS>/switch/<switch>/state topics. https://github.com/syssi/esphome-jk-bms/blob/main/esp32-ble-v11-example.yaml Or from HA with Lovelace https://github.com/syssi/esphome-jk-bms/discussions/230
  17. V

    JK-BMS + Grafana in one evening.

    Hmm. Unfortunately not. I fell out with the JK-BMS's balancer for being rubbish and installed a Heltec balancer, which has a "switch" contact you can put a relay or smart switch (dry contact) onto. I haven't implemented that yet either, awaiting a battery upgrade, which has help the miss...
  18. V

    DC network switch question...

    It's 120W. On a 12V system it's 10 Amps. If it spikes to twice that it will be for a millisecond maybe, it'll be fine. You are correct that a AC->DC power supply will be current limited and it's output DC voltage will drop if inrush current exceeds its rating. The battery will do that same...
  19. V

    DC network switch question...

    Another consideration is DC return paths. If the PoE is not fully isolated then DC ground returns can take unexpected paths. Including, but not limited to, your house earthing circuit.
  20. V

    DC network switch question...

    A quick google suggests there are speifications surrounding PoE power delivery. If you are buying a "reputable" device which implments to this spec it should be fine. The device suggests it can be power from 24V or 48V DC and can handle 120W total. PoE is technically limited to 15.4W per...
  21. V

    Work smarter not harder. Cell pairing.

    Well, asides having to ream out a few bus bars and make the "fold series link" to join the two halves, it all went well. Luckily the old 8 were nearly flat when I swapped to the new 8. The new 8 were almost flat when I rebuilt the new combined pack. I tested each pair delta before I dropped...
  22. V

    JK-BMS + Grafana in one evening.

    The GPS port I believe is a 4 pin MicroJST. Be warned it's extremely fragile. The GPS port does not provide USB, it provides either CAN or RS845. it's not a standard protocol but a custom botch over ModBusTCP. This is why i liked that BT worked. that leaves teh GPS port free for teh battery...
  23. V

    Work smarter not harder. Cell pairing.

    Putting them in parallel is not the concern. I also bought a bunch of 3Ah shim cells to put in parallel if I need them. It's capacity matching, as best I can, the in series modules (pairs in my case). If, for an extreme example I pair cell 6 and cell 2, the total capacity of that pair might...
  24. V

    Work smarter not harder. Cell pairing.

    So I have 8 new cells. I intend to parallel them with the existing 8. Some of that 8 are lower capacity and some higher, maybe a few Ah! It would be wise to pair the lower cells with their higher counterpart. So I did this to the new cells. The peak charge was initially assisted by the...
  25. V

    Different voltages between cell case and poles for each cell

    Are you measuring with a HiZ meter ... do you have one with a LoZ mode?
  26. V

    Where are the B code EVE lifepo4 cells gone?

    As long as the price is right and they are brand new B grade cells, I'll take em.
  27. V

    “Normal” Cell Delta at Charge Voltage

    Also. The solution is not to constantly "slow charge" to top balance. The solution is to capacity balance the cells with shims or by paralleling them into equal pairs. Apart from the fact they are turning into hens teeth, I want to get a few dozen small cylindrical cells which can be used to...
  28. V

    “Normal” Cell Delta at Charge Voltage

    A technique I have seen on some BMS's (NEEEY maybe) is a secondary charge circuit. A true balance charger has the balancer and cell monitor built into the feedback loop which limits the current to keep the high cells within limits while the low cells continue to charge. It's very, very, very...
  29. V

    “Normal” Cell Delta at Charge Voltage

    While this sounds good it has a few practical issues outside of an ideal setup. 27.6V is enough to top of charge at 3.450V yes, but it's not enough to leverage the balancer and come anywhere near solving top of charge imbalances. If all cells are at 3.450V you can call them charged, but I...
  30. V

    Top Balancing "How to"

    New half of a battery. So I put them into a pack and swapped it for the old one. This is the top balance of the new 8S pack. On the left last night with the Multiplus battery charger and careful manipulation of the absorb voltage and charge current and ... on the right is the sun with my MPPT...
  31. V

    EPEver Tracer4210AN vs. Victron SmartSolar 75/15 (x2).

    Caveat: EPEver measures EPEver. Victron Measures Victron. There is no independent verification of the values done, not even correlation with battery power. So the EPever could be under-reporting and/or the vitrons over reporting. The "shape" and "trends" should still hold ground in the data though.
  32. V

    EPEver Tracer4210AN vs. Victron SmartSolar 75/15 (x2).

    Thought I'd share this. It's a cold front day with powerful down pours mixed with powerful sun and cloud reflections. "Battery Power/Panel Volts" = EPEver. MPPT2 / MPPT3 = Victron's. Panels: Craigsolar 330W 41VoC. 1 panel per MPPT. All 3 mounted in one row side by side. In the order...
  33. V

    MPPT Charge limit controller to limit current at top of charge.

    So it works. I had to make some modifications as it just wasn't responsive enough. Too slow, too blunt. Mostly the structure is as above, but instead of using a preset list of wattages, the "balancing" stage is based on "Balance Watts - CellDetlaMV". So if a cell is over 3.4V and the cell...
  34. V

    Wow is all I can say

    Tech Connections on YouTube's rant about "tablets" and "balls" being a complete scan and literally just compressed washing powder wrapped in plastic for 2 to 4 times the price. So I started buy generic powdered dishwasher and washing machine powders.
  35. V

    The end of net metering

    Call your DNO and pay for being de-energized then.
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