Based on the markings, this is a
lead battery identification tag (or a lead plate from a battery case) dating back to
October 1942.
During World War II, these types of heavy-duty batteries were used for industrial, military, and telecommunications backup systems.
Breakdown of the Markings:
- TYPE DMCO-9A: This is the specific model or "type" designation. "DMCO" likely refers to the manufacturer or a specific design series.
- 72 HOUR CAP 116 AMP HR: This indicates the battery's capacity. It was designed to deliver a total of 116 Ampere-hours when discharged slowly over a 72-hour period. This "long-rate" discharge is typical for standby power, such as for railroad signals, telegraph systems, or emergency lighting.
- 1170 SP. GR.: This stands for Specific Gravity. It tells the user that when the battery is fully charged, the electrolyte (sulfuric acid) should have a density of 1.170. This is a relatively "low" specific gravity compared to modern car batteries (usually ~1.265), which was common for stationary batteries to ensure a longer life.
- DATE 10 42: This confirms the manufacturing or installation date: October 1942.
Historical Context
In 1942, most lead and rubber production was diverted to the war effort. Industrial batteries like this one were critical for maintaining communication lines and infrastructure. Because the tag itself is made of lead, it was likely part of the battery's internal structure or a plate embedded into the side of a glass or hard-rubber battery jar.
