dosemeter User Manual 
Page 48
Cycle Charge of the dosemeter battery
The CHR22 Charger Unit provides a Discharge/Charge cycle that allows the 
performance of the battery to be kept at an optimum level. 
This cycle fully discharges the battery before charging. Please note that this is not the 
normal operation of the CHR22 Charger Unit. 
To carry out this charge cycle, connect the dosemeters to the CHR22 Charger and 
connect the power supply. 
Press the Discharge/Charge cycle button located on the bottom of the charger as shown 
below. 
If you press the button through the hole on the bottom of the charger, it will discharge 
all badges that are currently connected, then charge them.  This can take up to about 3 
hours depending on the battery type and initial charge state. 
The internal NiMH (Nickel-Metal Hydride) battery, like all rechargeable batteries, will 
self-discharge. When arranged into a battery the individual cells within the battery, not 
being identical, will not all discharge at the same rate. 
This means that the first cell to discharge may be forced into a 'reverse current' 
situation by the other cells and will be damaged. If the batteries are simply left 
discharged, there is no way of preventing this as the discharge is within the cell.  
Even if they are removed from the dosemeter the self-discharge will still occur. To 
prevent this, it is recommended that the dosemeter be charged monthly when not 
being used for measurements. 
If the dosemeters are left on a charger without power, the dosemeters will discharge. 
To ensure that the dosemeters do not discharge, remove them from the Charger unit 
when the Charger is not connected to the power supply.