Casio 2891 Power Supply, Start charging at Level 4, Recover Indicator, Battery Indicator, Charging Precautions, Charging Guide, Power Loss Drop during Sensor Readings

Operation Guide 2891

Power Supply

Start charging at Level 4!

Battery Level 4 indicates that remaining battery power is very low.

❚To charge the battery

Point the solar panel (face) of the watch at a light source.

The power supply of this watch uses a solar cell to generate electrical power, which is stored by a rechargeable battery. Using or storing the watch where it is not exposed to light regularly or allowing it to be blocked from light by your sleeve as you are wearing it can cause the power of the rechargeable battery to run down. To ensure stable operation, be sure to allow the watch to be exposed to light as much as possible when you are wearing or storing it.

Note that all data in memory and all settings are cleared whenever you allow the level of the rechargeable battery to drop to Level 5.

Recover Indicator

If you use the light or alarms a number of times during a short period, the RECOV indicator may appear on the display to indicate that the following operations are disabled in order to allow battery power to recover.

•Illumination

•Alarm and hourly time signal

•Timer Mode progress alert and time up alarm

•Sensor readings

Normal operation will return after the battery recovers.

Recover Indicator

Battery Indicator

Level	All functions enabled.
1
Level	All functions enabled.
2
	Illumination, alarms and other
Level	tones, sensor readings, and
3	time calibration signal
	reception disabled.
	Digital display, illumination,
Level	alarms and other tones, sensor
4	readings, and time calibration
	signal reception disabled.
Level	All functions, including
5	timekeeping, disabled.

•Exposing the watch to direct sunlight or other strong light may cause the battery level indicator to indicate a level that is momentarily higher than the actual battery level. Because of this, you should wait for a short while after charging to check the battery level indicator.

•Even if the battery level drops all the way to Level 5, you still will be able to recharge the battery and use the watch again.

•If you start charging from Level 5, the display of the watch will flash when the battery reaches Level 4. Note, however, that the watch’s functions will still remain disabled at this time, and you should continue to expose the watch to light so the battery can charge up the Level 2 or Level 1.

Be sure to expose the watch to light for recharging as soon as possible after the Level 4 indicator starts to flash. Frequent display of the recover indicator also means that the battery is low. Expose the watch to light to charge the battery.

Charging Precautions

Avoid charging the watch in the following locations, and anywhere else where the watch may become very hot.

•On the dashboard of an automobile parked in the sun

•Very close to an incandescent light source or other sources of heat

•In a location exposed to direct sunlight for long periods

Note that the display panel may become black under very high temperatures. This is temporary, and the display will appear normal again at lower temperatures.

Depending on the light source you are using, the case of the watch may become quite hot during charging. Take care to guard against burn injury after charging.

•Remember that even a partial blockage of the solar cell reduces charging efficiency.

Example: Positioning the watch

Solar Cell

•The illustration shows the resin band model.

Charging Guide

Starting from a full charge, the watch should be able to continue operating for about five months without further charging under the example conditions described below.

Example Daily Use

•Illumination: 1.5 seconds/day

•Alarms: 10 seconds/day

•Direction Reading: 10 times/week

•Altitude Readings: 10 hours/month

•Signal Reception: 6 minutes/day

•Digital Display: 18 hours/day

Making sure the watch is exposed to light regularly ensure stable operation.

Required Daily Charging Time

•The following is the daily amount of charging required each day to support the operations under “Example Daily Use”.

Exposure Level	Approximate
(Brightness)	Exposure Time
Outdoor Sunlight	5 minutes
(50,000 lux)
Sunlight Through a	24 minutes
Window (10,000 lux)
Overcast Daylight
Through a Window	48 minutes
(5,000 lux)
Indoor Fluorescent	8 hours
Lighting (500 lux)

Power Loss Drop during Sensor Readings

Regardless of whether the current battery level is Level 2 or higher, the watch may determine that the current power level is not enough to driver the sensor in the Compass, Pressure, or Altitude Mode. If this happens, the display will appear as described below.

	After Entering the Mode	During Readings
Compass	Blank	– – –
Pressure	Blank	– – –
Altitude	Blank	– – –

•Normal operation should return after battery power recovers.

•Charge Times Required to Advance to a Higher Level

Exposure Level			Approximate Exposure Time
(Brightness)	Level 5	\Level 4 \Level 3		\Level 2 \Level 1
Outdoor Sunlight			2 hours		13 hours	6 hours
(50,000 lux)
Sunlight Through a			4 hours		63 hours	29 hours
Window (10,000 lux)
Overcast Daylight
Through a Window			8 hours		128 hours	58 hours
(5,000 lux)
Indoor Fluorescent			80 hours		– – –	– – –
Lighting (500 lux)

•Note that the above charging times are for reference only. Actual charging time depends on a variety of environmental factors.

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