Lathem Sonachron Battery – Replacement Backup Battery for DWA-S Program Timer

The Lathem Sonachron battery is the internal backup battery used in the Lathem DWA-S Sonachron program timer. This battery maintains time and stored programming during power interruptions, allowing the system to continue keeping time and retain scheduled events until power is restored. When the battery reaches the end of its service life, common symptoms include a dim display, loss of programming, or incorrect time after power outages.

The Sonachron system relies on this internal battery to preserve memory and timing accuracy for extended periods. According to manufacturer documentation, the backup battery allows the unit to maintain time and data for several days during power loss, automatically recharging once AC power returns. :contentReference[oaicite:2]{index=2} Replacing the battery is often the first and most effective step when troubleshooting Sonachron timing or display problems.

When to Replace the Sonachron Battery

• Display becomes difficult to read or appears dim
• Programmed events are lost after power interruption
• Clock resets or loses time unexpectedly
• Battery is more than 4–5 years old

EmployeeTimeClocks.com supports legacy Lathem equipment with replacement parts and technical guidance so existing systems can remain in service without unnecessary replacement costs.

FAQ

How long does a Sonachron battery last?
Typical service life is approximately five years depending on operating conditions and power stability.

Do I need to unplug the unit to replace the battery?
No. The unit should remain plugged in during replacement so programming is retained.

Will replacing the battery fix most Sonachron problems? Yes.
In many cases yes, especially when symptoms include dim displays or lost programming.

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Common Battery Failure Symptoms

Backup batteries are a normal maintenance item in electronic time clocks and timers…

Backup batteries in time clocks and program timers gradually lose capacity over time. When the battery can no longer hold a charge, the equipment may continue to operate while plugged in but fail to retain time or programming during power interruptions. Recognizing these symptoms early helps prevent unexpected resets and lost schedules.

• Clock or timer loses time after power outages
• Stored schedules or programmed events disappear
• Display becomes dim or difficult to read
• Unit resets to default settings
• Programming must be re-entered after unplugging

In many cases, replacing the internal backup battery restores normal operation and extends the life of otherwise reliable equipment. Preventive battery replacement every few years helps avoid downtime and unnecessary service calls.