From 03fe59c2f2f262fde123d8938e49fdb434d0f39a Mon Sep 17 00:00:00 2001 From: Michel Pastor Date: Sat, 24 Feb 2018 19:09:41 +0100 Subject: [PATCH] Update docs/Battery.md --- docs/Battery.md | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/docs/Battery.md b/docs/Battery.md index 0287bf67e3..08f8a27a86 100644 --- a/docs/Battery.md +++ b/docs/Battery.md @@ -166,3 +166,15 @@ current_meter_scale = (reported_draw_mAh / charging_data_mAh) * old_current_mete = (1260 / 1158) * 400 = 435 ``` + +## Battery capacity monitoring + +For the capacity monitoring to work you need a current sensor (`CURRENT_METER` feature). For monitoring energy in milliWatt hour you also need voltage measurement (`VBAT` feature). For best results the current and voltage readings have to be calibrated. + +It is possible to display the remaining battery capacity in the OSD and also use the battery capacity thresholds (`battery_capacity_warning` and `battery_capacity_critical`) for battery alarms. + +For the remaining battery capacity to be displayed users need to set the `battery_capacity` setting (>0) and the battery to be full when plugged in. If the `battery_capacity` setting is set to 0 the remaining battery capacity item in the OSD will display `NA` and the battery gauge will use an estimation based on the battery voltage otherwise it will display the remaining battery capacity down to the `battery_capacity_critical` setting (battery considered empty) and the battery gauge will be based on the remaining capacity. For the capacity thresholds to be used for alarms the `battery_capacity_warning` and `battery_capacity_critical` settings also needs to be set (>0) and the plugged in battery to be full when plugged in. The battery capacity settings unit can be set using the `battery_capacity_unit`. MilliAmpere hour and milliWatt hour units are supported. + +For the battery to be considered full the mean cell voltage of the battery needs to be above `vbat_max_cell_voltage - 140mV` (by default 4.1V). So a 3S battery will be considered full above 12.3V and a 4S battery above 16.24V. If the battery plugged in is not considered full the remaining battery capacity OSD item will show `NF` (Not Full). + +For the remaining battery capacity and battery gauge to be the most precise (linear relative to throttle from full to empty) when using battery capacity monitoring users should use the milliWatt hour unit for the battery capacity settings.