Denso BTH-300BW User Manual page 45

(2) When turning the BHT on after storage without a battery cartridge loaded:
Even after the removal of the battery cartridge, the calendar clock will work with the backup power
source for a while.
If the calendar clock backup has stopped, loading the battery cartridge and turning the BHT on will
display the following message, prompting you to set the current date and time.
Set the calendar clock according to the procedure given in Section 2.3.2.
(The indication "00/01/01 00:00" will vary depending upon the calendar clock state.)
• The rechargeable battery cartridge can be recharged hundreds of times, but it will eventually wear
out. If the operation time of the fully recharged battery cartridge is noticeably shorter than normal,
replace the battery cartridge with a new one.
• Use only DENSO WAVE-authorized battery cartridges and chargers.
• Never dispose of battery cartridges into a fire.
• Battery cartridges should be recycled properly in conformity with local codes and regulations. Do
not throw them in a trash. Cover their terminal pins with vinyl tape to prevent short-circuits.
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