Introduction: NiMH Battery Over-discharge Protection Circuit When a cell is nearly empty, the voltage rapidly drops below 1.1 V. Ideally, you should stop using a NiMH cell as soon it reaches 0.8-1V. Allowing it to discharge further will lead to damage.
How do you protect battery from deep discharge?
For deep discharge protection, we need to identify the cut-off voltage of the battery. After that, we need to design a circuit in which, when the battery reaches the cut-off voltage level, a switch disconnects the load from the battery. For cut-off voltage identification, we will choose a Zener diode.
Do NiMH batteries need low voltage protection?
NiMH batteries on their own have no discharge protection circuits. A discharge protection circuit prevents the battery from discharging below a certain voltage level to prevent damage to the battery.
What happens if you overcharge a NiMH battery?
Overcharged NiMH batteries can heat up very quickly, rising to temperatures that could damage either the battery or the electronics in the charging unit. To counteract this danger, some quick chargers are designed with a fan to keep the batteries cool.
Why do NiMH batteries self discharge?
NiMH self discharge cause These can broadly be described as an oxygen cycle that occurs at high states of charge, and then ion movement that contributes to the self-discharge over longer periods of time. Therefore cells should be kept cool if it is necessary for them to hold their charge over longer periods.
What can over discharging a battery do?
Over discharge may cause difficulties in recharging the cell by increasing the battery’s internal resistance. Also, over discharging may cause lead to be precipitated in the separator and cause a short in the cell or between cells.
How do I protect my battery from overcharging?
The right charger for your battery is crucial to prevent overcharging; the charger must match the battery in terms of output voltage and Ah rating. It’s easier to avoid overcharging in lithium-ion batteries because they can receive a partial charge or be charged intermittently.
How fast can you discharge a NiMH battery?
about 1% per day
A: NiMH batteries self discharge about 1% per day so if used in a low energy consummation or stand-by device, the battery will only last about 90 days before requiring recharge.
What are the uses of NiMH batteries?
The nickel-metal hydride battery is mostly used in mobile-communication equipment, power tools, and medical equipment. NiMH batteries are divided into high-voltage and low-voltage batteries. The high-voltage NiMH battery was first developed by M.Klein and J.F. Stockel in the United States in the early 1970s.
What happens if you over discharge a battery?
Over Discharge Discharging the battery will cause the cell voltage to drop. The over-discharge protection monitors the cell voltage, turning off the output when the voltage drops below a preset “off” threshold. The output will typically turn back on once the cell voltage rises above a preset “on” threshold.
How do batteries protect against voltage changes?
The protection method varies according to cell chemistry: NiMH batteries require a circuit that detects a change in voltage or temperature, where Li-ion cells require a two-stage constant-current/constant-voltage charge method. Discharging the battery will cause the cell voltage to drop.
How does the over-discharge protection work?
The over-discharge protection monitors the cell voltage, turning off the output when the voltage drops below a preset “off” threshold. The output will typically turn back on once the cell voltage rises above a preset “on” threshold.
