Jump to content


  • Posts

  • Joined

  • Last visited

  • Days Won


JustinSchoeman last won the day on August 13 2020

JustinSchoeman had the most liked content!


Recent Profile Visitors

821 profile views

JustinSchoeman's Achievements

  1. The only way to properly balance cells is to charge them. The best once-off balance is to connect the cells in parallel and charge them. The only way to actually maintain any real balance is to permanently use a balancer board.
  2. Correct - but it will be a lot quicker and more accurate than using a balancer board.
  3. These balancers only work to equalize the voltage across each cell. The resistive ones just discharge the cell with highest voltage. The capacitive ones transfer charge from the cells with highest voltage to lowest voltage. Most can achieve <10mV difference between the cells, some as low as 5mV. But none will actually perfectly match the voltage. If you disassemble the battery and connect the cells in parallel, then they will eventually settle to perfectly matched voltages. As others have pointed out above, at nominal cell voltages, charge level is very insensitive to voltage, so a 5-10mV difference would generally be quite a large charge imbalance (perfectly matched voltages will still have some imbalance, but less). The easiest way to actually balance the cells is to charge them. When they are close to maximum voltage, then small charge differences lead to large voltage differences, and balancing the voltages will give you well balanced charge levels.
  4. They are available locally at lbsa.co.za . But they will do a worse job than just connecting the cells in parallel.
  5. Deye is the OEM. I am not sure to what extent they allow others to develop firmware, or if they update the firmware to other's specifications. Either way, I think the main board firmware is likely shared - the changes I have seen seem only to be related to the UI (which is a separate board).
  6. Not sure what display that is, but if 52.1Hz if the gen frequency, then it is above 'Grid Hz High' on the Deye, and it will not be accepted.
  7. Almost certainly frequency related. Try bump Grid Hz high to max and Grid Hz Low to min, and see if it helps.
  8. For arduino, yes, but you only need the calculation to go from voltage to temperature, and you should easily be able to do that in any language/reporting platform of your choice. The calculation is: // Thermistor [email protected] #define TEMP_R 10000.0 // Thermistor B val #define TEMP_B 4200.0 // Kelvin offset #define TEMP_K 273.15 // 25C in Kelvin #define TEMP_REF (TEMP_K + 25.0) // to current through 3k resistor double i = (5.0 - v) / 3000.0; // resistance double r = v/i; // calculate temp from r double c = (TEMP_B * TEMP_REF); c /= TEMP_B + (TEMP_REF * log(r / TEMP_R)); c -= TEMP_K; if(c <= 0) { mb_temp = 0; } else if(c >= 999.0) { mb_temp = 999; } else { mb_temp = c; } Thermistor constants are defined above, then the basic calculations to go from the voltage across the sensor (v) to the temperature (mb_temp). NOTE: This calculation is slightly different from that in my code. My code is based on the voltage between the sensor and ground, so I have swapped it around in the above sample to work with the voltage across the sensor.
  9. If you tee the temperature sensor on the Geyserwize, you can connect it to any HA device with 5V analog input. You can then use the calculations from my code above to convert this voltage to a temperature.
  10. He only replaced the sensor (inside the brass tube), not the whole thermostat. If you are using a D1, you can probably use the existing sensor (10k NTC) as-is. My hardware + code for interfacing is here: https://github.com/justinschoeman/ModbusThermostat/blob/master/temp_geyserwise.h If you use that code, you will need to adjust the 'to voltage' calculation according to the power supply voltage and ADC resolution. /* * Geyserwise input/conditioning: * * ------- 5V (PIN 5 MCU) * | * / * \ 10k NTC * / * \ * | 1k 5% * + ----/\/\/\-----+ ---------> PIN 32 (MCU) * | | * / ----- * \ ----- * / 3k 1% | 10uF ? * \ | * | | * --------------------------- 0V (PIN 1 MCU) */
  11. I believe https://lithiumbatteriessa.co.za have a Daly Smart BMS with customised firmware that can communicate with Deye/Sunsynk. Not sure if they can parallel though. Maybe contact them and find out?
  12. Correct. But one thing I forgot - you must check 'Use Timer' as well. If not checked, then battery is only used when grid is not available (and charging is according to the battery configuration pages only). No need to restart the inverter - settings are applied immediately.
  13. 1) Check 'Priority Load' - this will direct solar energy to first power the load, with any excess used to charge the battery. 2) Set time of use settings (you can make them all the same). Set SOC/V to your minimum acceptable battery charge. If battery charge is above this, additional load will come from batteries. When battery charge is lower than SOC, then load will be powered by grid. If you check 'Grid' for a time slot, then the battery will also charge to that SOC from grid in that time window.
  14. There are a number of BMSs which are compatible - but they are not generally sold on the DIY market. Mostly wholesale to manufacturers. The ones that are available separately tend to be ludicrously expensive. The 'cheapies' generally used on the DIY market are intended for electric bikes/scooters/other vehicles, so they don't really bother with inverter comms.
  15. There is a guy on the other forum who did something similar, except he heats the 'old' geyser with excess solar once his battery is charged. I am not sure how much ambient heating will get you, as geysers tend to be fairly well insulated.
  • Create New...