Epson VR43B - User Manual

The VR43B is a solar-powered watch movement that converts light into electrical energy using a solar cell located beneath the dial. This energy is then stored in a secondary battery. This design eliminates the need for conventional battery replacement, offering a more sustainable and low-maintenance timepiece.

The movement features a power depletion warning function, indicated by the second hand moving at two-second intervals when energy is low. In this state, the watch can continue running for approximately two weeks. An overcharge prevention function is also integrated to protect the secondary battery from deterioration and breakage by stopping charging once a predetermined voltage is reached.

The chronograph function allows for precise time measurement up to 30 minutes in 1/1 second increments. Once the measurement reaches 30 minutes, the chronograph automatically stops counting. It supports standard measurement, accumulated elapsed time measurement, split time measurement, and measurement of two competitors.

Important Technical Specifications

Movement Dimensions:

Outside diameter: Ø31.20mm × 28.00mm (3-9H)
Casing diameter: Ø30.6mm
Total height: 3.97mm (including solar cell: 4.52mm)

Time Standard:

Type of quartz oscillator: Tuning fork
Frequency of quartz oscillator: 32,768 Hz
Accuracy: ±20 seconds per month (on wrist)
Operating temperature range: -5°C to +50°C
Regulation device: Nil (Pre-adjusted)

Indicator/Functions:

3 Hands: Hour, Minute, Second
Small hands: 24 hour (12H), Second chronograph (6H), Minute chronograph (9H)
Calendar: Instant setting device for date calendar
Power depletion warning function: Second hand moves at 2-second intervals when voltage is 1.2V.

Running Time:

Approx. 4 months (after fully charged)

Chronograph:

1/1 second up to 30 minutes with split time measurement
Push 4h button (more than 1 second)

Features:

Jewels: 0 Jewels
Anti-magnetism: Over 1600A/m (Direct current magnetic field)
Driving current consumption: Approx. 1.45 μA (1.4V, chronograph non-operates)
Operation stopping voltage: 1.2V (Chronograph function)
Solar cell type: Amorphous silicon solar cell

Maximum Unbalance of Hands:

Hour hand: 0.6 μN·m
Minute hand: 0.9 μN·m
Second hand: 0.09 μN·m
24 hour hand: 0.05 μN·m
Second chronograph hand: 0.05 μN·m
Minute chronograph hand: 0.05 μN·m

Moment of Inertia:

Second hand: Less than 0.25 μg·m²
Second chronograph hand: Less than 0.05 μg·m²

Secondary Battery:

Type: Lithium metal batteries
Size: Ø9.5mm x t 2.05mm
Nominal voltage: 1.5 V
Capacity: 5.5 mAh

Separated Parts (Parts code):

Hand setting stem: 0351578 or 0351177
Secondary battery unit: 302334R
Solar cell unit: 4020527
Solar cell lead terminal (2pcs): 4281516

Test of Accuracy:

Equipment to be used: SEIKO quartz tester QT-99, Greiner quartz timer-C, Witschi Q-tester 4000
Duration of measurement: 10 seconds
Microphone to be used: Electromagnetic detection type

Usage Features

The VR43B movement allows for the use of dials with a light transmittance of more than 30%, enabling a variety of dial colors while ensuring efficient charging of the solar cell.

Setting Mechanism:

Crown at normal position: Free
Crown pulled out 1st click: Instant date change
Crown pulled out 2nd click: Time setting / Reset

Chronograph Operation:

2H button: Start/Stop/Restart chronograph.
4H button: Reset chronograph, Split time measurement/release.
Battery indicator: Pressing the 4H button for more than 1 second indicates the remaining battery capacity for 2 seconds before returning to normal operation.
- High (45 seconds position): 90 days or more
- Middle (40 seconds position): 30-90 days
- Low (35 seconds position): 30 days or less

Charging Guidelines (Dial transparency rate = 30%):

Illumination (Lx)	Source of light	Environment	A (Approx. Hours for full charge)	B (Approx. Hours for steady operation)	C (Approx. Minutes to charge 1 day of power)
700	A fluorescent lamp	Inside the office	-	18	69
3,000		30W 20cm	52	4	15
10,000	Sun light	Cloudy	16	1.5	5
100,000		Fine weather	5.3	0.5	2

Maintenance Features

Solar Cell Unit:

Avoid touching or scratching the surface of the solar cell.
Ensure the dial's transparency rate is maintained above 30% (effective aperture is Ø27mm).

Secondary Battery Unit:

Only use the exclusive secondary battery unit (Lithium metal batteries).
Install the minus part of the secondary battery towards the inside of the watch.
Do not use silver oxide batteries, as accidental charging can lead to battery explosion. A safety structure is adopted to prevent charging of silver oxide batteries.
Install the secondary battery unit under the circuit block cover as illustrated in the manual, ensuring the secondary battery lead plate is securely connected to the minus terminal.

Hand Setting Stem:

To remove the setting stem, place it in the normal position and push the "setting lever" with tweezers. The setting lever cannot be pushed if the stem is not in the normal position.

Casing Part Structure:

Use the specified holding ring for the dial to prevent movement rotation inside the case and stabilize button operation.
Use a metal case to prevent movement malfunction due to static electricity.

Hand Setting:

Set each hand at the correct position according to the dial scale to ensure accurate time reading.
Do not turn the hands forcibly.
When removing hands, use exclusive fork-shaped tools. Do not remove the dial if hands are set.
Repeated setting and removal of the hour hand may reduce its fixing torque, as the hour wheel is made of plastic. It is not recommended to re-assemble the hour hand more than five times (Type M only).

Charging Caution:

Do not place the watch too close to fluorescent lamps or other light sources during charging, as high temperatures can damage internal parts.

Solar Cell Lead Terminal:

Set the two solar cell lead terminals as illustrated in the manual. There is no distinction between upper and lower for the terminal shape.

Solar Cell Unit Installation:

Push the upper part of each hook on the solar cell unit into the main plate securely.

Dial Setting:

The dial is held by four guide poles on the solar cell unit.

Button Position:

Maintain clearance between the movement and the tip of the button to prevent interference during assembly and ensure smooth casing. Using a button spring is recommended to maintain this clearance.