2.7 Lithium Back-up Batteries (Auxiliary Batteries)
The HHCs are equipped with lithium back-up batteries to safeguard internal memory (RAM). The
RAM is normally powered from the internal lithium-ion battery pack. These are automatically
backed up by the auxiliary batteries which act to protect stored data when the lithium-ion battery pack
The service life of the lithium backup battery varies depending on conditions such as temperature and
usage of the HHC. Under optimal use, the lithium backup battery is functional until it is charged and
discharged approximately 500 times. If the HHC is primarily used with the lithium-ion battery pack
removed for some applications, the lithium backup battery deteriorates, losing capacity due to
repeated charging and discharging. To prevent the deterioration of lithium backup batteries, take the
(1) If the message "low main Battery" is displayed or the battery status display function indicates
low charge, immediately use the CIU or the charger to charge the lithium-ion battery or replace
it with a fully charged one.
(2) Make sure that the HHC is always loaded with the lithium-ion battery pack. Do not leave the
HHC for a long time without the lithium-ion battery pack loaded.
The standard time for replacing the lithium backup battery is about two years if the above precautions
If the message "low sub Battery" is displayed a short time after the lithium backup battery is fully
charged, the lithium backup battery needs to be replaced soon.
Because the lithium -ion battery pack needs to be unloaded when the lithium backup battery is
replaced, the programs and data stored in memory are lost.
To prevent the programs and data from being lost, be sure to connect the HHC to the charger or save
the contents of memory to IC memory cards or other backup media before replacing the lithium
Batteries may explode if not installed correctly. Replace with batteries
of the same type or equivalent as recommended by the manufacturer.
Dispose of used batteries as per the manufacturer's instructions.
Only use the proper lithium auxiliary battery specified below:
Manufacturer: Fujitsu Kiden Ltd.
Drawing number: KD54003-0010
To replace the lithium back-up batteries, follow the steps below.
Tips on replacement
These HHCs require you to unload the lithium-ion battery pack before you can replace the lithium back-
up batteries. When it is necessary to back up RAM, save its data to a storage medium, such as a
PCMCIA card, before proceeding with replacement work or carry out replacement work with the
charger connected to the HHC.