search

stuartpittaway / diyBMSv4ESP32

diyBMS v4 code for the ESP32 and new controller hardware
Other
187 stars 81 forks source link

Discharge also a curve for amps go down #291

Open Michi202020 opened 5 months ago

Michi202020 commented 5 months ago

Hello all,

I have a question in my charge config I have a charge curve for go down withe the Amps near the max voltage. Can I also make this near the discharge limit? My problem is that the bms say max upload and if the inverter go to max upload Amps than jump the voltage to fast down and he stop. This situation I have it a long time before it's empty.

Best Regards Michael

Michi202020 commented 5 months ago

Hello Stuart,

for better understanding i have a 70kwh battery withe 3x Deye 12kw hybrid. If i come down to 41v than he have to stop but the discharge current is to high and the voltage go to much down and the system say its to down and i load from the grid to the battery and this go over the night every hour. A Curve for emty the battery is a must to have. see movie below.

https://github.com/stuartpittaway/diyBMSv4ESP32/assets/81771598/49bf3af1-db59-462d-bac3-241390e6e533

Best Regards Michael.G

Michi202020 commented 3 months ago

Hello, No Person have a idea for this?

laserranger3000 commented 3 months ago

So what you want is a de-rating of the current at low SoC (low cell voltage). I also would like to see this being implemented. A similar logic to the high-SoC de-rating should be sufficient.

Michi202020 commented 2 weeks ago

Hello people, have you a idea for this situation? Best regards Michael.g

jetronic18s commented 1 week ago

Hello Michael,

Do I understand your problem correctly? You are discharging the batteries with a high current, in the lower SOC range the voltage is then at a value where the inverters report “low voltage”. Then no more current is drawn from the batteries, then the voltage increases again and it starts all over again?

Can you still optimize the cable sizes? Have you also measured the voltage drop of your connections?

You want a dynamic discharge current control (DCL), similar to the dynamic charging function.

Do I see that correctly?

Can you possibly reduce the voltages on the Deye depending on the current? Victron has something like this, a table with voltage depending on the discharge current.

Regards Chris