The typical end-discharge voltage for nickel-based laptop batteries is 1V/cell. At this voltage threshold of approximately 99% of the energy is used up and the terminal voltage begins to fall off rapidly if the discharge continues. Discharge below the cutoff should be avoided, especially under heavy load.
As the battery cells can not be perfectly controlled, creates a negative voltage potential, known as cell reversal, if the discharge is continuing unchecked. The more cells are connected in series, the greater the number is likely to be reversed cells.

Nickel-cadmium may be some reversals to tolerate the typically amount to approximately 0.2 V,. During this period of time is reversed the polarity of the positive electrode. Such a situation can persist only briefly, because the development of hydrogen at the positive electrode to a positive pressure and leads to a possible gas leak from the cell. If the Sony VGP-BPS2C cell for a prolonged period of Spannungsumpolung is exposed, both polarities are reversed and the cell is electrically short-circuited. Such an error can not be undone.

Some battery analyzers use a secondary discharge (regeneration) by performing a discharge of the battery up to a very low cut-off point. This device will monitor the discharge current in order to ensure that the maximum applicable current during the regeneration phase of a safety limit. If the reversal continues to develop, the discharge would be so small that no damage can occur. That cells are destroyed during the regeneration is only possible if these cells are either weak or old.

When Sony VGP-BPS2A cells are discharged with coefficients that are higher than 1C, the end-loaded or typically lowered to 0.9 V / cell. Thus, the voltage drop is compensated, which results from the internal resistance, consisting of wiring, circuit protection and contact transitions. A lower cut-off leads to better capacity values when the battery is discharged at lower temperatures.

Among all the nickel-cadmium VGP-BPS2 battery chemistries is the least affected by repeated full discharge cycles. Several thousand charge / discharge cycles are possible. Therefore, nickel-cadmium are working so well in tools and portable radios, where they are in constant use. Nickel-metal hydride is less durable in respect to repeated Tiefentladezyklen.

Lithium-ion is typically discharged to 3.0 V / cell. The versions of "spinel" and "Coke" can be discharged to 2.5 V / cell, and thus gain a few extra percentage points. As far as the device requires no special Battery, the devices are built for a cut-off point at 3.0 V / cell.

A discharge below 2.5 V / cell can switch the Sony VGP-BPS8 battery protection circuit that is active, it prevents future load with the normal charger. Such a battery can be saved with the help of the Boost program, which is present on the battery tray by Cadex 7000 Series analyzers.

Some lithium-ion VGP-BPS9 batteries contain a specially deep Spannungsabschaltepunkt, where the battery is put permanently out of service, if the cell voltage below 1.5 V / cell falls. A very strong discharge can lead to formation of a Kupfershunts, which can cause a partial or total short-circuit. The same can happen if the cell has a negative polarity and this situation persists for some time.
The manufacturers of lithium-ion batteries recommend a discharge depth at 80%. Repeated 100% discharge reduces the specific number of charge cycles. It is therefore recommended to charge lithium-ion batteries more often, rather as they were unloaded too deep. A periodic full discharge is needed because lithium-ion batteries are not subjected to the memory effect.

The recommended end-discharge voltage for lead-acid battery is 1.75 V / cell. The discharge does not follow the mostly flat curve of the chemistries of nickel or lithium base. Instead, have lead-acid batteries have a degree of voltage drop curve, with a steep drop toward the end of the discharge.
The VGP-BPS9/B life cycle of sealed lead-acid batteries is a direct dependence on the depth of discharge. The typical number of discharge / charge cycles at 25 ° C depending on the depth of discharge is:

· 150 – 200 cycles with a 100% depth of discharge (full discharge)
· 400 – 500 cycles with a 50% depth of discharge (partial discharge)
• 1,000 or more cycles with a depth of discharge of 30% (low discharge)

The lead-acid Dell laptop battery should not be discharged below 1.75 V / cell. Nor should it be stored in a discharged state. The cells of a non-charged lead-acid battery is sulfated, a circumstance that makes the battery useless if it only a few days are left in this state. You should be concerned that the open Klemmespannung always 2.10 V or more.