Chapter 4: Maintenance
HOBO U30 Remote Monitoring System User’s Guide
47
If the voltage is still low after attempting to recharge the battery with an AC
adapter for 24 hours, then you may need to charge it with a current limited
variable power supply or replace it (both tasks are described below)
Important: Due to the self-discharge characteristics of this type of battery, it
is imperative that you charge the battery for at least 12 hours
every six months at minimum, even if you are not actively using
the HOBO U30 Station. Otherwise, permanent loss of battery
capacity may occur.
Charging a dead battery
In the event the battery is completely dead (less than 3.0 volts and the logger
lights do not come on when the battery is connected), you can charge the
battery externally with a current limited variable power supply (otherwise
you must replace the battery). Hold the battery across a constant voltage
source of 4.5 volts with a current limit of 2 Amps. When held at this voltage,
the battery will seek its own current level and maintain itself in a fully
charged condition. It takes up to 24 hours to fully charge a dead battery.
Important: Do not apply more than 4.6 volts absolute maximum to the
battery. Do not exceed 2 Amps of current when charging. If the
battery gets hot, immediately stop charging the battery. If the
battery will not hold charge, it must be replaced. Dispose of the
old battery per local regulations.
Chapter 4: Maintenance
48
HOBO U30 Remote Monitoring System User’s Guide
Replacing the battery
If the battery is completely dead and recharging it is not an option, then
follow these steps to replace the battery:
1.
Disconnect the AC adapter or solar panel.
2.
Disconnect the battery.
3.
Unplug all sensors, the USB cable, relay, and grounding wire.
4.
Unscrew the antenna cable with a 5/16 inch wrench.
5.
Use a Phillips-head screwdriver to remove the four screws at the
corners of the clear, inner case.
6.
Remove the clear, inner case.
7.
Use a Phillips-head screwdriver to remove the two screws that
secure the battery.
8.
Note the orientation of the battery and then remove it.
9.
Install the new battery with the same orientation and reverse the
steps to reassemble.
10.
Dispose of the old battery per local regulations.
