Hi,
this puzzles me over last few days. I have flushed 0.20 beta version of Flexible OpenSource (I am forever in debt to Casainho and other contributors), configured it and the battery voltage shown on LCD3 is 1.15V larger than measured at the battery terminals.
I use 13S7P Samsung 30B battery pack, which when fully charged has 54.44V on battery terminals. Yet on LCD3 shows 55.59V. This then has flow-on effect on estimates of battery charge percentage. It is off (overestimated) by mild 25-28% in comparison to battery terminal installed voltage/charge meter. I've learned hard way how much electric motor helps my legs crank the bike when system shutdown on me 20km from home.
I could "fix" it by changing:
// ADC battery voltage measurement
#define BATTERY_VOLTAGE_PER_10_BIT_ADC_STEP_X512 44
#define BATTERY_VOLTAGE_PER_10_BIT_ADC_STEP_X1000 87 // conversion value verified with a cheap power meter
in main.h but this is kind of brute force and most likely not the way to go.
Most likely I am doing something wrong in the set-up/configuration. The only two places that will affect battery voltage readout will be number of batteries connected in series (I have 13) and internal battery resistance (I have 105m Ohm after calculations based on few measurements of voltage drop). I think I set both correctly. Other that this I don't know.
If any of you has experienced similar problem could you please share the fix.
Cheers
Adam
this puzzles me over last few days. I have flushed 0.20 beta version of Flexible OpenSource (I am forever in debt to Casainho and other contributors), configured it and the battery voltage shown on LCD3 is 1.15V larger than measured at the battery terminals.
I use 13S7P Samsung 30B battery pack, which when fully charged has 54.44V on battery terminals. Yet on LCD3 shows 55.59V. This then has flow-on effect on estimates of battery charge percentage. It is off (overestimated) by mild 25-28% in comparison to battery terminal installed voltage/charge meter. I've learned hard way how much electric motor helps my legs crank the bike when system shutdown on me 20km from home.
I could "fix" it by changing:
// ADC battery voltage measurement
#define BATTERY_VOLTAGE_PER_10_BIT_ADC_STEP_X512 44
#define BATTERY_VOLTAGE_PER_10_BIT_ADC_STEP_X1000 87 // conversion value verified with a cheap power meter
in main.h but this is kind of brute force and most likely not the way to go.
Most likely I am doing something wrong in the set-up/configuration. The only two places that will affect battery voltage readout will be number of batteries connected in series (I have 13) and internal battery resistance (I have 105m Ohm after calculations based on few measurements of voltage drop). I think I set both correctly. Other that this I don't know.
If any of you has experienced similar problem could you please share the fix.
Cheers
Adam