[2] The appropriate float voltage varies significantly with the chemistry and construction of the battery, and ambient temperature.
[citation needed] However, it should be understood that the concept of a float voltage does not apply equally to all battery chemistries.
For instance, lithium ion cells have to be float charged with extra care because if they are float charged at just a little over optimum voltage, which is generally the full output voltage of the lithium cell, the chemical system within the cell will be damaged to some extent.
Some lithium ion variants are less tolerant than others, but generally overheating, which shortens cell life, is likely, and fire and explosion are possible other outcomes.
[4] Accepted average float voltages for lead–acid batteries at 25 °C can be found in the following table:[citation needed] Compensation per cell of approximately −3.9 mV/°C (−2.17 mV/°F) of temperature rise is necessary.