Nickel Metal Hydride battery charge
Chargers NiMH batteries are very similar to the NiCd system but the electronics is generally more complex. To begin with, the NiMH produces a very low voltage drop at full load. This NDV is almost non-existent rates of charge below 0.5C and elevated temperatures. Aging and cell mismatch works further against the already minute voltage delta. The inadequacy of the cells increases with age and number of cycles is increased, which makes use of the NDV increasingly difficult.
The NDV of a NiMH charger must respond to a voltage drop of 16mV or less. The increased sensitivity of the charger to meet the low voltage drop often fasting ends in mid-charge error in the charge cycle. voltage fluctuations and noise produced by the Apple A1039 battery and charger may mislead the NDV detection circuit if it is defined too precisely.
The popularity of the NiMH Apple PowerBook G4 battery has introduced many technical innovations load. Most NiMH Quick Charger today use a combination of NDV, plateau voltage, increased speed oftemperature (dT / dt), temperature threshold and timeout timers. The charger uses what is before closing fast charging.
NiMH batteries using the NDV or thermal control tend to offer higher capacities than those charged with less aggressive methods. The gain is around 6 percent on a good Apple iBook FireWire Series battery. This capacity increase is due to excessive memory that the Acer Aspire 3500 battery is exposed. The downside is a shorter life cycle. Instead of waiting for 350-400 cycles of service, this package can be spent in 300 cycles. methods similar to charge most NiCd, NiMH fast charger work on increasing the rate of temperature (dT / dt). A temperature increase of 1 ° C (1.8 ° F) per minute, is commonly used to terminate charging. The cutoff is absolute temperature of 60 ° C (140 ° F). A charge of 0.1 C in the header is added for about 30 minutes to maximize the load. The burden of maintenance that follows keeps the Acer Aspire 3000 battery fully charged.
The application of a rapid initial 1C charge works well. cooling-off periods of a few minutes is added when some peaks are achieved. The load is then continued at a lower current. Once you reach the next threshold load measures below. This process repeats until the Apple A1185 battery is fully charged.
Known as a "stage fee differential, this charge method works well with NiMH and NiCd Apple A1079 battery. Adjusts the charging current CTP, which allows current high early and moderate during charging late. This avoids the excessive accumulation of temperature to the end of charging when the 1G222 battery is less able to accept fees. NiMH batteries must be rapid charged rather than slow charged. The amount of the cost of maintenance applied to maintain full load is critical. Because NiMH does not absorb ' overhead and trickle charge must be less than the NiCd. The recommended charging NiMH 1691P battery maintenance is a low-0.05C. This is why the original NiCd charger can not be used to recharge NiMH batteries. The lowest rate trickle charge is acceptable for the NiCd.
And 'difficult if not impossible, to slow the charging of a NiMH Inspiron 1521 battery. A rate of C-0.1C and 0.3C, voltage and temperature profiles do not exhibit the characteristics identified to measure the state of full charge accurately and the charger must depend on a timer. Harmful overload can occur if a part or fully charged Inspiron 1525 battery is charged on a charger with a timer set.
The same thing happens when the Inspiron 6000 battery charge acceptance was lost due to age and may contain only 50 percent of the load. A timer provides a fixed load of 100 percent every time, regardless of the status of the XPS M1210 battery may apply too. Overload could occur even though the NiMH Inspiron Mini 9 battery feels cool to the touch.
Some laptop battery chargers at low prices can not be applied load is completely saturated. Economy of these chargers, detection, full load can take place immediately after a peak voltage is reached or a temperature threshold is detected. These chargers are often promoted on the merits of charging time short and moderate prices.
