sorry in advance for my non-existent knowledge of English. Everything runs through the translator. I have built a battery monitor with ESP8266 and INA226. So far everything works great. I would like to get the ESP to calculate the Ah and the percentages. Unfortunately I am not so fit in ESPHome to be able to do that. Actually, the INA226 provides everything necessary for the calculation. No plan how I can implement this. I have found no examples on the net. I have really long searched.
Thank you for the answer. Should it really be that simple? I had already thought about a complicated lambda calculation
The total daily energy sensor returns me a Wh or kWh value if I understand correctly? I would then only have to convert correct?
the issue is the charge isn’t 100% efficient and i should really have a fudge factor so that current into the battery is reduced by the charging efficiency of about 80%.
as i couldn’t figure this out i made a crude hack with an automation that resets the integration when i determine the battery is fully charged
binary_sensor:
- platform: template
name: ${disp_name} Fully Charged
lambda: |-
if ((id(charge_current).state <= 0.120)
and (id(buck_pwm).state <= 65)
and (id(coulomb_counter).state >= 0)
and (abs((id(batt_voltage).state) - (id(chg_tgt_voltage).state)) <= 0.05 )
and (id(status).state == 6)
and (id(uptime_sensor).state >= 600)) {
return true;
} else {
return false;
}
this part will be very specific to my charger, basically it looks to see if the battery has reduced it current consumption, and the solar is still actually producing enough to provide that minimum consumption, the charger had reached its float charge state, the voltage is right for the current temperature and the charger has been running for at least 10min.
edit:
the automation in HA to do the reset
alias: Battery_charged
description: ""
trigger:
- platform: state
entity_id:
- binary_sensor.makerpower_mppt_fully_charged
to: "on"
for:
hours: 0
minutes: 0
seconds: 10
condition: []
action:
- service: esphome.makerpower_mppt_makerpower_mppt_reset_coulomb
data: {}
mode: single
This should help get you started with the AH and % you are looking for
now a coulomb is amps x seconds, so i update the current every second for the integrator… but make it internal so it doesnt spam your DB.
and if you want voltages but dont want to spam your db then set filters, this just throttles back to once every 60sec.
- platform: ina226
address: 0x40
shunt_resistance: 0.00148 ohm
current:
name: "INA226 Current"
id: current
accuracy_decimals: 2
power:
name: "INA226 Power"
id: power
bus_voltage:
name: "INA226 Bus Voltage"
id: voltage
shunt_voltage:
name: "INA226 Shunt Voltage"
max_current: 50A
update_interval: 2s
That’s how it looks to me. I have installed an external shunt. So this is about right. Thanks for the detailed explanation. I have to deal with it to implement it.
I’m a relative newbie to battery monitoring so more asking this out of interest.
Can’t you just do this all from the voltage (only) and some knowledge of the battery capacity? I recall discharge profiles are non-linear (so Ah would be approximated?)
Or is the idea with the suggested solutions to do it more accurately?
For my 18650 battery monitoring I just measure voltage and calibrate it to a %battery.
The voltage curve is load dependent, it is also very flat for lithium batteries, so no it is not a good choice. Integrating the current in and out gives a much better indication of the state of the battery.
