SGP/EBBR/E15 - Battery Voltage Drop

From the installation of the changeout unit at E15 on 15 December 1995, the
battery exhibited a slow decline in voltage. However, after a day of the
AEM not operating, site operations restarted the AEM on 20 December 1995 and
the battery condition declined more rapidly, such that the solar panel was not
able to keep the battery voltage up (greater than 11 V DC) for nighttime
conditions, even after a cloudless day.  Battery voltage first dropped below 11
volts at 0635 GMT on 21 December.  I requested that the solar panel voltage
regulator be tested.  On 16 January 1996, site operations found that the
fuse in the solar panel voltage regulator was loose.  After the fuse was
repositioned, the battery voltage increased almost immediately to 13.5
volts and has been good since.

All data for the periods above should be considered incorrect; many sensors
require at least 11 volts DC power and the performance of the CR10 data
logger can not be trusted at less than 11 volts.

• Time offset from base_time(time_offset)
• Bottom air temperature(temp_air_bottom)
• Top vapor pressure(vapor_pressure_top)
• Top air temperature(temp_air_top)
• Bottom relative humidity (fractional)(rh_bottom_fraction)
• Wind speed arithmetic mean(wspd_arith_mean)
• Bottom vapor pressure(vapor_pressure_bottom)
• Wind direction vector mean standard deviation(wdir_vec_std)
• Top relative humidity (fractional)(rh_top_fraction)
• lon(lon)
• Reference temperature in enclosure(temp_reference)
• Bottom T/RH sensor temperature(temp_trh_bottom)
• Top T/RH sensor temperature(temp_trh_top)
• AEM position indicator(home_signal)
• Wind speed vector mean(wspd_vec_mean)
• -180.0 - +180.0(alt)
• Wind direction vector mean(wdir_vec_mean)
• Net radiation(net_radiation)
• North Latitude(lat)
• base time in epoch(base_time)
• Atmospheric pressure(atmos_pressure)

• lon(lon)
• Soil heat flow 2 (mV)(soil_heat_flow_2_mv)
• Atmospheric pressure (mV)(atmos_pressure_mv)
• Right relative humidity (mV)(rh_right_mv)
• Soil heat flow 5 (mV)(soil_heat_flow_5_mv)
• Soil temperature 5 (resistance ratio)(soil_temp_5_rr)
• Soil moisture 1 (resistance)(soil_moisture_1_r)
• Soil moisture 5 (resistance)(soil_moisture_5_r)
• Battery voltage(battery_voltage)
• Reference temperature in enclosure (resistance ratio)(temp_reference_rr)
• base time in epoch(base_time)
• Soil heat flow 3 (mV)(soil_heat_flow_3_mv)
• Net radiation (mV)(net_radiation_mv)
• Soil temperature 3 (resistance ratio)(soil_temp_3_rr)
• Soil moisture 4 (resistance)(soil_moisture_4_r)
• Left air temperature(temp_air_left)
• Soil temperature 4 (resistance ratio)(soil_temp_4_rr)
• Left relative humidity (mV)(rh_left_mv)
• Wind direction vector mean (mV)(wdir_vec_mean_mv)
• AEM position indicator(home_signal)
• Soil heat flow 1 (mV)(soil_heat_flow_1_mv)
• North Latitude(lat)
• Soil temperature 1 (resistance ratio)(soil_temp_1_rr)
• Right air temperature(temp_air_right)
• Left T/RH sensor temperature (resistance ratio)(temp_trh_left_rr)
• Soil moisture 3 (resistance)(soil_moisture_3_r)
• -180.0 - +180.0(alt)
• Soil heat flow 4 (mV)(soil_heat_flow_4_mv)
• Soil temperature 2 (resistance ratio)(soil_temp_2_rr)
• Right T/RH sensor temperature (resistance ratio)(temp_trh_right_rr)
• Wind speed arithmetic mean(wspd_arith_mean)
• Soil moisture 2 (resistance)(soil_moisture_2_r)
• Time offset from base_time(time_offset)

• Soil moisture 1, gravimetric(soil_moisture_1)
• Soil moisture 2, gravimetric(soil_moisture_2)
• Soil moisture 3, gravimetric(soil_moisture_3)
• Bottom air temperature(temp_air_bottom)
• Soil moisture 4, gravimetric(soil_moisture_4)
• Soil moisture 5, gravimetric(soil_moisture_5)
• Soil heat flow 4, corrected for soil moisture(corr_soil_heat_flow_4)
• Soil heat flow 3, corrected for soil moisture(corr_soil_heat_flow_3)
• Soil heat flow 2, corrected for soil moisture(corr_soil_heat_flow_2)
• Soil heat flow 1, corrected for soil moisture(corr_soil_heat_flow_1)
• -180.0 - +180.0(alt)
• Soil heat flow 5, corrected for soil moisture(corr_soil_heat_flow_5)
• Surface soil heat flux, average of fluxes 1-5(surface_soil_heat_flux_avg)
• Wind direction vector mean(wdir_vec_mean)
• Soil heat flow 4(soil_heat_flow_4)
• Soil heat flow 5(soil_heat_flow_5)
• Soil heat flow 2(soil_heat_flow_2)
• Soil heat flow 3(soil_heat_flow_3)
• Soil heat flow 1(soil_heat_flow_1)
• base time in epoch(base_time)
• Soil heat capacity 5(soil_heat_capacity_5)
• Soil heat capacity 4(soil_heat_capacity_4)
• Reference temperature in enclosure(temp_reference)
• AEM position indicator 0 to 15 mins(home_signal_15)
• North Latitude(lat)
• Time offset from base_time(time_offset)
• Bottom relative humidity (fractional)(rh_bottom_fraction)
• Wind speed arithmetic mean(wspd_arith_mean)
• Soil heat capacity 3(soil_heat_capacity_3)
• Soil heat capacity 2(soil_heat_capacity_2)
• Soil heat capacity 1(soil_heat_capacity_1)
• Bowen ratio(bowen_ratio)
• lon(lon)
• Wind direction vector mean standard deviation(wdir_vec_std)
• Surface latent heat flux(latent_heat_flux)
• Surface soil heat flux 5(surface_soil_heat_flux_5)
• Surface sensible heat flux(sensible_heat_flux)
• Surface soil heat flux 3(surface_soil_heat_flux_3)
• Surface soil heat flux 4(surface_soil_heat_flux_4)
• Atmospheric pressure(atmos_pressure)
• AEM position indicator 15 to 30 mins(home_signal_30)
• Top T/RH sensor temperature(temp_trh_top)
• Top vapor pressure(vapor_pressure_top)
• Surface soil heat flux 1(surface_soil_heat_flux_1)
• Surface soil heat flux 2(surface_soil_heat_flux_2)
• Net radiation(net_radiation)
• Change in energy storage 1, 0-5 cm soil layer(energy_storage_change_1)
• Half hour averaged soil temperature 4(soil_temp_4)
• Bottom vapor pressure(vapor_pressure_bottom)
• Change in energy storage 3, 0-5 cm soil layer(energy_storage_change_3)
• Soil temperature mean 3(soil_temp_3)
• Change in energy storage 2, 0-5 cm soil layer(energy_storage_change_2)
• Change in energy storage 5, 0-5 cm soil layer(energy_storage_change_5)
• Soil temperature 2(soil_temp_2)
• Change in energy storage 4, 0-5 cm soil layer(energy_storage_change_4)
• Soil temperature 1(soil_temp_1)
• Half hour averaged soil temperature 5(soil_temp_5)
• Bottom T/RH sensor temperature(temp_trh_bottom)
• Top relative humidity (fractional)(rh_top_fraction)
• Top air temperature(temp_air_top)
• Wind speed vector mean(wspd_vec_mean)