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CHAPTER 20: XL4 RECHARGEABLE BACK-UP BATTERY
The following information pertains to the XL and RCC OCS units running 14.24 firmware and
later. This does NOT apply to the Prime Series. Please refer to the next chapter for
information on the Prime Series backup battery.
NOTE: For more details on the back-up battery, refer to the Battery Manual [MAN1142].
20.1 Overview
The XL4 has an advanced battery system that uses a rechargeable lithium-ion battery. The
battery powers the real time clock when power is removed, and it is needed for register data
retention. Does not include the XL4 Prime.
20.2 Storing Register Contents
The OCS controllers with rechargeable batteries write register data to high speed RAM when
connected to DC power. When this power is lost, critical circuits switch over and run on batter
power for about 1/10 of a second. During this time, register and other retentive data is saved
away to flash memory. The clock continues to run on the battery at a much lower power. The
battery is designed to last well over a year in this state. Once power is restored, the battery
recharges in eight (8) hours or less.
20.3 Battery Life
The battery is designed to last 300 full charges to 1000 partial charge cycles or 7 to 10 years.
Because typical operation does not drain the battery, the 1000 charge cycles should never be
reached and the 7 to 10-year aging of the battery would limit its useful life. The battery is
designed to be replaced.
20.4 Lithium Battery Safety
Many of the publicized battery issues are a result of using multiple batteries of flexible battery
packs. The OCS uses a small, single cell in a metal enclosure. The battery is UL recognized and
comes from quality suppliers. The OCS has safety circuitry built into the charging IC and
additional external protection including fusing. These circuits were closely evaluated by UL
and Horner engineering for use in hazardous environments.
