User manual

37
8. GENERAL INFORMATION ON RECHARGEABLE
BATTERIES
Rechargeablebatteriesconsistoftwoelectrodesputintoanelectrolyte;thus,arechargeablebatteryisachemical
element.
Chemical processes are running inside this element. Since these processes are reversible it is possible to recharge
batteries.
Tochargearechargeablebattery,aso-calledchargevoltageisrequired.Itmustexceedthecellvoltage.Moreover,
the energy (mAh) supplied by charge transport for charging must be higher than the one that can be delivered
afterwards.Thisratiooftheenergydrawntoenergysuppliediscalledefciency.
Thecapacitythatcanbedeliveredmainlydependsonthedischargecurrent;itisdecisivefortheconditionofthe
battery. The supplied charge cannot be used as a measure, because a proportion of it will be lost (for example
converted into heat).
Thecapacitydatagivenbythemanufactureristhemaximumtheoreticalquantityofcurrentwhichcanbedelivered
by the battery. That means that for example a battery of 2000 mAh can theoretically deliver a current of 1000mA
(= 1 A) for two hours. This value considerably depends on many factors (condition of the battery, discharge current,
temperature, etc.).
a) Denition of „C-Rate“
This is a factor delivering the value of the permissible charge or discharge current independently of the battery capa-
city. The multiplier is the battery capacity.
Thefollowingapplies:Batterycapacity(inmAh)xC-Rate=Value(charge/dischargecurrentinmA)
Examples:Rechargeablebatteriesat1000mAhand2700mAh:
C-Rate=1C  C-Rate=2C
1000 mAh x 1 = 1000 mA 1000 mAh x 2 = 2000 mA
2700 mAh x 1 = 2700 mA 2700 mAh x 2 = 5400 mA
b) Selection of the Suitable Charge and Discharge Current
The„ChargeManager2024“automaticallyadjuststhechargecurrent.ForNiMH,NiCdbatteries,youcanalsolimit
thechargecurrentmanually.Therearesixpractice-orientedlychosenchargecurrentlimitsof500mAto3000mA
available in steps of 500 mA.
ForNiZnrechargeablebatteries,thevariablechargecurrenthasalwaysbeensetautomaticallybythe„Charge
Manager2024“andcannotbechosenfreely.
Limitation of the charge current to 500 mA is recommended for:
• Batterieswithoutinformationonchargetypeandacapacityoflessthan1000mAh
A charge current limitation to 1C is recommended for:
• Rechargeablebatterieswithacapacityof>1000mAhandtheprint„Standardcharge:12-15hoursatxxxmA“
(„Standardcharge:12-15hrs.atxxxmA“)
• Rechargeablebatterieswiththeprint„Fastcharge:4-5hoursatxxxmA“(„Fastcharge:4-5hatxxxmA“)
• Rechargeablebatterieswiththeprint„Fastrechargeable“or„Quickchargingpossible“