Q: What causes the “Start Voltage Low Error”? The battery status seems ok in the menu.
A: On Battery (+ Solar) powered systems, the Maximum Voltage is an indicator for battery status.
This value is the “open” battery voltage, measured without any load. There is no mathematical relationship with the Average or Minimum Voltage. Minimum Voltage can be very low, while Average is ok. Problems like this can occur when the Maximum Voltage (MAXVi) is below 3.1 Volts.
T: Enable MAXVi parameter in the data logger.
Check the data log for intermittent power problems and MAXVi dropping below 3.1 Volts.
Download the Log File in ydoc format (including the system messages) and
search for “Power too low” or “PVD_DIP” or “PVD_RESET”.
PVD_DIP occurs when the Voltage drops below 2.6 Volts.
In this example, a few times, power is too low, and restored after mili seconds.
If the power fails, the data logger is going into emergency cycle.
The modem is not started and data will not be written to the log file on the SD card (preventing corruptions).
When the power level is restored, the error message is written to the log file.
The second entry ends with a number. The number is showing the amount of power low detections and restoring of the power, because the messages are written into the log file afterwards.
14:03:27.172 <14:03:28>
14:03:27.173 Power too low…
14:03:27.482 <14:03:29>
14:03:28.101 System log…PVD_DIP;Power too low;2
Even when an external DC power supply is mounted, on some occasions the power supply can suffer from intermittent power failures and cause SD card write failures or SDI12 sensor timeouts.
SD card write failures:
S;240601010012;SD_FAIL;1
SDI12 timeouts:
SDI12 WDT;timeout, followed by a data record with “<value>*T”
T: Perform a hardware check.
Check the Data Logger internal power circuit.
Remove the red and black power cable, all check white connectors on the cable and corresponding pins on the mainboard, ML-OP-524 (if mounted) for oxidation or worn-out pins.
Replace* the red and black cable(s).
Remove and reinstall the battery, check battery and holder contacts for oxidation.
Check battery status, if low replace* the battery.
If external DC power supply is used: Replace* the power supply.
Sensor power problems.
Sensors can draw a lot of inrush current during activation.
Modem or network problems.
The modem can also draw a lot of current, especially when switched to the 2G backup network.
Main fuse problems.
A main fuse with internal resistance or corrosion on the main fuse holder can also generate power problems. Replace* the Main Fuse, how to do, can be read in this FAQ.
T: From firmware version V4.8 B16, the modem driver has an extra power check.
With data logger awake and all sensors powered up, just before activating the modem, available power (MAXVi Voltage) is checked again. When the power is near the critical low voltage level (2.6 Volts), modem activity will be suspended. On a Battery /Solar or powered system, the Battery gets a chance to reload or recover to a higher voltage level.
NB The battery type and battery protection must be configured to make advantage of his option.
Download the latest firmware version here and the firmware change log can be found here.
*If new parts (red and black cable, main fuse, battery, power supply) are not available, use “known good” parts from a working data logger.