
Discharge Rate
A battery with 1000mAh capacity that is discharged at 500mA is discharged at
0.50C (where C stands for Capacity). A lower discharge rate reduces the discharge
current and increases service time. Maximum current is 4000mA (6000mA for the
C7400ER-C using special adapters). The discharge rate is reduced for batteries
with higher nominal voltage (for example, 2400mA for a 14.4V battery on the
C7200). For a single-cell NiCd or NiMH battery, the maximum discharge is
2500mA.
Default Charge and Discharge Rates
NiCd
: Standard NiCd batteries up to 1800mAh can be charged and discharged at
rate of 1.00C (C stands for capacity). Cadex recommends a C-rate of 0.70C or
0.50C for batteries above these mAh ratings. The default setting for NiCd is 1.00C.
For 1.2V and 2.4V batteries, the default charge rate is 0.30C to maintain normal
temperatures.
NiMH
: NiMH batteries produce heat during Charge and Discharge. The default
charge rate is 0.50C if Temperature Sensing is Disabled. In addition, due to the
very fine negative slope, the current is cut in half twice towards the end of the
charge cycle to ensure that the battery is fully charged (this current is not reduced if
the Charge rate is at 0.10C). If temperature sensing is Disabled, a rest period is
applied before the current is cut to allow for the battery to cool. This lengthens the
service time. For 1.2V and 2.4V batteries, the default rate is 0.30C to maintain
cooling. If the battery gets hot during charge, reduce the Charge rate to 1000mAh
or less.
SLA
: Battery manufacturers rate the SLA at a 20-hour discharge (0.05C). This slow
discharge is not practical when analyzing SLA batteries so the analyzer uses a
default 0.30C Charge and 0.10C (10-hour) discharge. Due to this higher discharge
rate, the battery will give a lower capacity. Refer to the manufacturers specification
for the battery rating at the 10-hour discharge and adjust the battery rating
(capacity) for the higher discharge rate.
Li-ion
: Most Li-ion (and Li-Polymer) batteries can accept a 1.00C Charge and
Discharge rate. This is the default Charge and Discharge Rate.
Cadex Electronics Inc. C7000-C Series Battery Analyzers
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