SGP/EBBR/E26 - Battery Voltage Drop

Shortly after the PM visit on September 26, 1995 the EBBR battery voltage at
E26, Cement, OK declined to lower than acceptable levels.  During the October
13, 1995 PM visit the battery was replaced.  I do not know the specifics of why
the battery voltage declined so suddenly, but failure of one or more of the
battery cells is a possibility.  I have not received the site operations log of
the PM visit yet.  The voltage dropped to 10 volts at night.  At various times,
soil temperature, soil heat flux plate output, and atmospheric pressure (at
least) were not reported correctly by the CR10 datalogger.

Amazingly, the AEM continued to work and reported millivolt outputs that
did not fall below the acceptable ranges.

All data between 2100 GMT on September 26, 1995 and 1230 GMT on October 13,
1995 should be considered suspect, particularly when the battery voltage
fell below 11 volts (every nighttime).  This general caution is issued
because incorrect reporting of data also took place during times when the
battery voltage was reported as 12 Volts, a normally acceptable level;
the reason for this behavior is unknown.

• Atmospheric pressure(atmos_pressure)

• Soil temperature 5 (resistance ratio)(soil_temp_5_rr)
• Soil temperature 3 (resistance ratio)(soil_temp_3_rr)
• Soil temperature 1 (resistance ratio)(soil_temp_1_rr)
• Soil temperature 4 (resistance ratio)(soil_temp_4_rr)
• Atmospheric pressure (mV)(atmos_pressure_mv)
• Soil temperature 2 (resistance ratio)(soil_temp_2_rr)

• Soil heat flow 5, corrected for soil moisture(corr_soil_heat_flow_5)
• Soil heat flow 2, corrected for soil moisture(corr_soil_heat_flow_2)
• Atmospheric pressure(atmos_pressure)
• Soil heat flow 1, corrected for soil moisture(corr_soil_heat_flow_1)
• 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)
• Top vapor pressure(vapor_pressure_top)
• Half hour averaged soil temperature 5(soil_temp_5)
• Half hour averaged soil temperature 4(soil_temp_4)
• Soil heat flow 4(soil_heat_flow_4)
• Soil temperature mean 3(soil_temp_3)
• Soil heat flow 5(soil_heat_flow_5)
• Soil temperature 2(soil_temp_2)
• Soil temperature 1(soil_temp_1)
• Soil heat flow 1(soil_heat_flow_1)
• Soil heat flow 2(soil_heat_flow_2)
• Bottom vapor pressure(vapor_pressure_bottom)
• Soil heat flow 3(soil_heat_flow_3)