High capacity cylindrical

 Main specifications are:

• They are economic devices because of long life, with more than 500 cycles of charging / discharging.
• Excelent discharging rate owing to low internal resistance. Voltage level is stable during this process.
• Charging cycles are accepted even after long storage period.
• 1-2 hours fast charging cycle is allowed.
• Wide working temperature range. Some specific series are suitable for 70ºC conditions.

Charge

• Current, time, temperature and so, can change Ni-Cd batteries charging curve.
• These batteries must be charged from 0ºC to 45ºC temperature conditions but 0ºC - 30 ºC range is more efficient.
• Inversing polarity is not allowed during charging process.
• Do not overcharge battery because efficiency will be affected.
• Unlimited charging time is allowed if current is less than 0,05C. This charging method is named “Trickle charge” and usual current limits are from 0,03C to 0,05 C.
• If fast charging is used, it is absolutely necessary to detect negative voltage increasing (-DV). This value is an indicator of charging process is finished. Battery negative voltage (-DV) increasing, is a special Ni-Mh batteries feature to detect battery is full. Let’s explain this characteristic:If current is applied to empty battery, voltage is increasing value slowly during charging process. However, when battery reaches full condition, voltage starts to be lower and temperature is higher. This is right point to stop charging current.

Discharge

• Charging temperature range is from 20ºC to 65ºC.
• Discharging current level could affect to battery capacity. Best capacity results are reached with 0,1C to 0,5C discharging currents. High discharging current will increase battery heating.
• Overdischarging will damage battery. Do not forget battery connected to system if it is discharged.
• Once battery reaches voltage value below 1,0 Volts, it is fully discharged.

Other Specifications

• These batteries can be long storaged in dry conditions with 20ºC - 45ºC temperature.
• After long storaging, first chargings will reach lower capacity than nominal value specified.
• Battery life is more than 500 cycles if charging - discharging is arranged under right conditions. Different processing conditions will atempt battery life, losing cycles life.
• Do not solder directly on battery contacts, heating excess will damage checmical and mechanical internal parts of the battery. Nickel or silver-nickel tags, are suitable to be soldered on battery contacts with electric soldering process.
• Avoid shortcircuit in Ni-Cd batteries because extreme pressure will produce high heating.

Packing Batteries

When higher voltage is required, packing several battery cells is necessary. Cells assembling is arranged with electric soldering of Nickel tags. Also, it is usual to introduce protection devices as follows:

• Polyswitch. This device is rated at specificed nominal currency. Over this currency, internal resistor is increased to stop currency passing. When device gets colder, internal resistor is close to 0.
• NTC. Electronic component with variable resistor depending on temperature rate. It is used to check battery temperature.
• Thermostate. This device cuts off voltage sourcing when temperature excess is higher than value rated. When device gets colder, it resets itself.
• Thermo - fuse. Safety device which cuts off voltage but without resettable function.