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  • Post in thread: Hacking the new Growatt WiFi-F modules

    Hi all, just sharing my recent experience working with a Growatt SPF 3500 ES and the included WiFi-F module. I have a few other solar systems already feeding their data into InfluxDB and Grafana, and wanted the new Growatt unit to do the same. Otti’s project on GitHub provided some inspiration...
  • Post in thread: Toyota Announces EV Battery Breakthrough

    As with all alleged battery breakthroughs, I'll have to see it to believe it. So many broken promises over the years has me irreversibly cynical. :LOL:
  • Post in thread: Not grounding panels

    Not true. Some inverters float the panels at very high voltages with respect to ground. An unlucky person who touched a faulty panel frame or rack could have a nasty surprise/early death. This is why proper earthing of mounting systems is considered mandatory by practically all panel, racking...
  • Post in thread: Hacking the new Growatt WiFi-F modules

    Here's the list of working registers: Name Address Offset (from 0x1000) Type Multiplier Unit System Status 0 uint16_t 1 0: Standby; 1; (No Use); 2: Discharge; 3: Fault; 4: Flash; 5: PV charge; 6: AC charge; 7: Combine charge; 8: Combine charge and bypass; 9: PV charge and bypass...
  • Post in thread: Active balancer, make it smart!?

    I've taken a bit of a different approach to this issue and addressed most of it in software. I have a JK BMS, and have been using the amazing esphome-jk-bms software by syssi to monitor and send all the BMS statistics to MQTT. With a small modification, I've configured this to switch a relay on...
  • Post in thread: Blocking Diode Question please:

    I completed the testing this morning: Conditions were ideal with a clear blue sky and 24°C temperature. After some experimenting with positions, I ended up using an east-west facing setup as this aligned the panels best with the sun. One panel was fully illuminated while the other was only...
  • Post in thread: Battery isolator between battery and inverter

    Here you go. The switch in series with the 20R resistor is a momentary swtich for pre-charging the capacitors, the other is your high-current toggle switch. The momentary switch wouldn't need to be high current type, 5A would be sufficient.
  • Post in thread: JBD BMS JST plug type

    For anyone else who ends up here looking for answers, after a lot of searching and bit of trial and error, I've found that the plug type on the JBD BMS (for both the balance wires and the 4-pin UART/NTC connectors) is actually HY2.0. Molex PicoBlade, JST-PA, JST PH 2.0 and the others mentioned...
  • Post in thread: Keeping LiFePO4 Battery Banks cool in Australia

    Just an update on this - I think it's important to discuss our successes as well as failures, and this one was definitely a fail. I bought an old office style water cooler for spare change and stripped the compressor and refrigeration loop out of it. On its own it was able to cool the 2L water...
  • Post in thread: Taicopower server-style LiFeP04 batteries, buyer beware... Pics included of inside of the battery.

    The information is relevant because competition within this market, especially in China, is brutal. Vendors will do just about anything to increase their margins or produce a product that is cheaper and more attractive than their counterparts. This includes ripping off and cheating their...
  • Post in thread: Blocking Diode Question please:

    They'd be fine, they'll just produce a bit more heat. 0.75v @ 10.2A = 7.65W heat/wasted energy. 0.22v @ 10.2A = 2.24W heat/wasted energy. Worst case it's a 0.4% difference in the total maximum output of your array. Not worth worrying about.
  • Post in thread: Active balancer, make it smart!?

    In my setup the ESP queries the BMS for all its running statistics every few seconds, and then uploads the data to InfluxDB. It also operates the balancer relay if the necessary cell voltage conditions are met. While this was coded to work online/while connected to WiFi, it'd be trivial to...
  • Post in thread: Growatt BMS Emulator

    A quick update: I've successfully programmed an ESP8266 to retreive data from my BMS (JBD/Overkill) and translate it into emulated Pylon CAN bus messages. The output looks identical to what the inverter would expect when configured with Option 5 - Li and Option 36 - L52. When I have a moment...
  • Post in thread: open source mppt's

    I've always wanted to try this approach. Anyone who monitors their MPPT closely will see that the voltage it determines to be the maximum power point doesn't vary much throughout the day - about 10% even with changing angle of the sun, cloud cover, etc. So the approach of holding a fixed array...
  • Post in thread: Extention cord as Pv wire. Is it unsafe?

    It depends on a few things: - Will it be used outside for extended periods? The extension cord probably isn't manufactured to withstand the rigours of daily exposure to high levels of UV, moisture, heat and cold for years on end, as they're usually intended for short term, temporary use. PV...
  • Post in thread: Battery isolator between battery and inverter

    You'd place the resistor in parallel with the disconnect switch, with its own momentary switch. That way while the big disconnect switch is in the "off" position, you can hold the momentary switch for a few seconds, completing the circuit through the resistor to pre-charge the inverter's...
  • Post in thread: Battery isolator between battery and inverter

    No, it's in parallel with the disconnect switch, so it'd do nothing. I'll upload a circuit diagram a bit later to make it a bit more clear.
  • Post in thread: Growatt - Odd behavior

    Just wanted to express my appreciation for those in this thread who put the miles in to diagnose and understand the issue of Growatt inverters ceasing solar production/charging. I was stuck on this same issue until coming across this thread. I made the recommended adjustments and now it's all...
  • Post in thread: Unable to modify temperature delay on JBD/Overkill BMS

    After a bit more fiddling around I managed to resolve this - the latest version of JBDTools (V3.7-20220415) was able to write the settings successfully. This software is somewhat hidden on the Jiabaida website, so here's the link for anyone else experiencing this issue...
  • Post in thread: Taicopower server-style LiFeP04 batteries, buyer beware... Pics included of inside of the battery.

    It's hard to tell from the photos if you have the necessary space, but you could wrap some damp cloth around the cell terminals to try to avoid heat conduction through them towards the cell, and use a metal or fiber cement heat shied to protect against the hot air stream. Check your insurance...
  • Post in thread: Blocking Diode Question please:

    Extreme indeed, I'm amazed you didn't see a difference in that scenario. A great example of the value of real-world testing.
  • Post in thread: Blocking Diode Question please:

    It seemed unanimous earlier in the thread that blocking diodes are unnecessary and generally a waste of time and energy. We then moved on to series vs parallel connections for panels facing different directions.
  • Post in thread: Water pump run-time limiter

    I had an unusual problem to solve recently - I have a cabin that's completely off grid and not connected to any public water supply, running on stored tank water only. This is in a fairly arid area, so water is precious and can't be wasted. One risk that's been sitting in the back of my mind is...
  • Post in thread: Growatt SPF very high idle power

    While this is true, I've managed to find peace with my Growatt AIO. Yes, the support is awful and the standby power can be high. But the unit does work really well once properly set up. I have mine running some heavy equipment in a workshop and it's never missed a beat. When I don't need AC...
  • Post in thread: Confused About Epever Controller Specs on Max Wattage

    I don't think you'll have any problems, the 390w figure just indicates how much power the Tracer can deliver according to the maximum current it can handle at a given voltage. Its firmware will self regulate and prevent an overcurrent situation. The total maximum PV power for the 3210AN at 12v...
  • Post in thread: Is a FET-based BMS much use?

    This has been an interesting read and a failure mode I've not considered before. It would be trivial to make an independent device consisting of a voltage divider, micro controller and solenoid/relay to monitor voltage and force a disconnect if battery voltage exceeded a specific set point...
  • Post in thread: Hacking the new Growatt WiFi-F modules

    Yes, I dumped the stock firmware before I started experimenting with my own, I've attached it for whoever might want a copy. I can also post all the MODBUS registers if it'd be helpful, through trial and error I found that the documentation for these systems has a couple mistakes and many...
  • Post in thread: Blocking Diode Question please:

    You only need to care about the voltage drop across the diode, which is where the inefficiency and heat comes from. The total voltage of the system doesn't really have any effect on this.
  • Post in thread: Growatt SPF5000ES Low voltage cut off can not be set higher than 45,9

    Try adjusting setting 12 (B2AC) to something above 48v. It doesn't have any functional effect in your configuration, but it might then allow changing 21 to your preferred value as the two are related. If you have no grid, you should probably also change 14 (charger source priority) to OSO...
  • Post in thread: Active balancer, make it smart!?

    That's correct, however my ESP32 connects to the BMS using Bluetooth. This is preferred as it has complete electrical isolation. The buck converter powering the ESP32 is currently downstream of the BMS power MOSFETs. This means monitoring will stop in the event of the BMS cutting off discharge...
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