Sentinel V SC and RT Operation Manual
September
2017
EAR-Controlled Technology Subject to Restrictions Contained on the Cover Page.
Page 107
Replacing the Sentinel V Battery
One of the most often preformed maintenance tasks is battery replacement. The Sentinel V Series ADCP
uses battery packs, Lithium battery packs, or individual D cell batteries to provide power. The housing will
be different lengths depending on the type of batteries used (see
for dimen-
sions and weights).
When the capacity of a battery pack is 50% used, the voltage falls to approximately 14 volts. However,
keep in mind that this voltage is not an accurate predictor of remaining capacity. Batteries should be re-
placed when the voltage falls below 11 VDC.
Do not leave the battery pack inside the Sentinel V for extended periods. The battery may
leak, causing damage to the electronics.
Sentinel V battery packs are shipped inside the system but not connected.
Connect the
battery and seal the Sentinel V before deployment.
Sentinel V with D cells are shipped without batteries inside the system.
Install the batteries
and seal the Sentinel V before deployment.
Battery replacement induces both single and double cycle compass errors. The compass
should be aligned after replacing the battery pack.
Testing the Lithium Battery Pack
The optional Lithium battery pack includes a safety circuit that turns the battery off at its end of life, be-
fore the battery fully discharges. This happens when about 97% of the battery’s capacity is depleted. The
circuit also protects the battery and users against short circuits and provides users the ability to test the
pack. When the battery detects a short circuit, it waits about 300 us, and then it turns itself off. A red LED
on the circuit indicates when it detects a short. The circuit monitors the load across the battery and as
soon as the load is removed, it displays the results of its self-test.
Before installing the Lithium battery pack run the self-test by shorting the battery’s pins with a bent pa-
perclip. The LED display lasts approximately 10 seconds and indicates the battery status:
•
A continuous green LED tells you the battery is new.
•
A flashing green LED tells you the battery has been used, but can still power an ADCP.
•
A continuous red LED tells you the battery has been disconnected at its end of life and cannot be
used any more.
•
If there is no LED light at all, the circuit is defective and you should not use the battery.
You should run the self-test when you receive new lithium battery packs. This way, there is
time to replace defective batteries before you deploy. You should also run the self-test just
before installing the battery.
Instruments with high inrush currents occasionally trigger the optional Lithium battery pack
short circuit detection, which turns the battery off. If this happens, do the following:
Disconnect the battery and touch the ADCP’s touch sensor for about 45 seconds to one
minute. Connect the battery and then the ADCP should power on normally.
If the ADCP still does not power on, connect the AC adapter and wait for a minute and then
connect the battery pack. Once the ADCP is connected and ReadyV started, unplug the AC
adapter. The ADCP will work normally after that.
