Motorola TMR 2, User Manual

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19
Nickel Cadmium (NiCd)
Among rechargeable batteries, the NiCd remains a popular choice for two
way radio applications and is one of the most rugged rechargeable batteries
available. The NiCd prefers a fast charge to a slow charge. This battery is a
strong, silent worker and hard labor poses no problem BUT it should not
be left in a charger for days or be used only occasionally for brief periods.
A periodic FULL discharge is very important. If this does not occur, large
crystals form on the cell plates, thus decreasing battery capacity and
performance.
NiCd Advantages:
• Fast and simple charge – even after prolonged storage.
• High number of charge/discharge cycles – if properly maintained
over 1000 cycles are possible.
• Allows recharging at low temperatures.
• Long shelf life in any state of charge.
• Good low temperature performance.
• Economically priced.
NiCd Limitations:
• Develops memory e ff ect.
• Relatively high self-discharge rate during storage.
Nickel-Metal Hydride (NiMH)
The modern NiMH battery o ff ers up to 40% higher energy density as
compared to the NiCd. Both NiCd and NiMH batteries have high self-
discharge rates. The NiCd loses about 10% of its capacity within the
fi rst
24 hours, after which the rate settles to about 10% per month. The self-
discharge rate of the NiMH battery is about one and a half to two times
greater compared to NiCd. This type of battery is widely accepted to be the
interim step to lithium battery technology.
NiMH Advantages:
• 30-40 % higher capacity than a standard NiCd.
• Less prone to memory e ff ect than the NiCd — periodic cycles are
required less often.