In
electronics
The field of electronics is a branch of physics and electrical engineering that deals with the emission, behaviour and effects of electrons using electronic devices. Electronics uses active devices to control electron flow by amplification ...
, the cut-off voltage is the voltage at which a battery is considered fully discharged, beyond which further discharge could cause harm. Some electronic devices, such as cell phones, will automatically shut down when the cut-off voltage has been reached.
Batteries
In batteries, the cut-off (final) voltage is the prescribed lower-limit voltage at which
battery
Battery most often refers to:
* Electric battery, a device that provides electrical power
* Battery (crime), a crime involving unlawful physical contact
Battery may also refer to:
Energy source
*Automotive battery, a device to provide power t ...
discharge is considered complete. The cut-off voltage is usually chosen so that the maximum useful capacity of the battery is achieved. The cut-off voltage is different from one battery to the other and it is highly dependent on the type of battery and the kind of service in which the battery is used. When testing the capacity of a
NiMH or
NiCd battery a cut-off voltage of 1.0 V per cell is normally used, whereas 0.9 V is normally used as the cut-off voltage of an
alkaline cell. Devices that have too high cut-off voltages may stop operating while the battery still has significant capacity remaining.
Voltage cut-off in portable electronics
Some
portable
Portable may refer to:
General
* Portable building, a manufactured structure that is built off site and moved in upon completion of site and utility work
* Portable classroom, a temporary building installed on the grounds of a school to provide ...
equipment does not fully use the low-end voltage spectrum of a
battery
Battery most often refers to:
* Electric battery, a device that provides electrical power
* Battery (crime), a crime involving unlawful physical contact
Battery may also refer to:
Energy source
*Automotive battery, a device to provide power t ...
. The power to the equipment cuts off before a relatively large portion of the battery life has been used.
A high cut-off voltage is more widespread than perhaps assumed. For example, a certain brand of mobile phone that is powered with a single-cell
Lithium-ion battery
A lithium-ion or Li-ion battery is a type of rechargeable battery which uses the reversible reduction of lithium ions to store energy. It is the predominant battery type used in portable consumer electronics and electric vehicles. It also s ...
cuts off at 3.3V. The Li‑ion can be discharged to 3V and lower; however, with a discharge to 3.3V (at room temperature), about 92–98% of the capacity is used.
Importantly, particularly in the case of lithium ion batteries which are used in the vast majority of portable electronics today, a voltage cut-off below 3.2V can lead to chemical instability in the cell, with the result being a reduced battery lifetime. For this reason, electronics manufacturers tend to use higher cut-off voltages, removing the need for consumers to buy battery replacements before other failure mechanisms in a device take effect {{Citation needed, date=December 2018.
See also
*
Cut-off (electronics)
External links
Samples of Low Voltage Cut-Off Relay CircuitsEffect of discharge cut off voltage on cycle life of MgNi-based electrode for rechargeable Ni-MH batteries
References
Electrical parameters