Philips V24CT User's Reference Manual page 65

2. If you are using the V24CT and V26CT and the batteries are not
already in place, insert 2 Philips 40488A 12 Volt 2.3 Amp-hour sealed
lead-acid batteries into the spring-loaded battery door in the back of
the monitor. The batteries should be inserted with the grey Philips
battery label facing upwards and the contacts pointing into the
monitor. The batteries will snap or click into place when properly
inserted.
Caution
Philips Medical Systems recommends you fully charge the batteries
before using the V24CT or V26CT for the first time. Plug the monitor into
an AC power supply (line power) for an initial charging cycle. When the
monitor is plugged in and the power is off, it takes approximately four
hours for the batteries to reach a charge of 90% capacity and nine hours
for the batteries to be fully charged. If the monitor is plugged in and the
power and external battery charger is on, it takes approximately 16 hours
to charge the batteries.
3. If using an AC power supply, plug the power cord into the power
source.
Setting up the Monitor (V24 and V26 only)
Getting Started 2-3