Regarding the question of charging lithium iron phosphate batteries to 100% or 90%, from multiple perspectives, the following are detailed analysis and suggestions:
Battery Life Perspective:
Charging to 90% is more beneficial for extending the life of the battery than charging to 100%. When a lithium battery is close to full charge, especially in the final stages, more heat and voltage stresses are generated, which can accelerate the aging of the battery.
By limiting the amount of charge to 90%, these harmful effects can be reduced, thereby extending the life of the battery.
Security Perspective:
If you continue to charge after charging to 100%, it may cause the chemical reaction inside the battery to get out of control, resulting in excessive heat and gas, which can cause the battery to swell, leak, or even explode.
While modern battery management systems are often equipped with overcharge protection, charging to 90% is still a safer option.
From the perspective of practicality:
Charging to 90% is usually enough for most people’s daily needs. Unless you need to travel for long periods of time or do activities that use a lot of battery, a charge to 90% is sufficient.
Charge and discharge efficiency:
The charging and discharging efficiency of lithium iron phosphate batteries is between 85% and 90%, which means that during charging, the battery cannot completely convert electrical energy into chemical energy for storage, and when discharging, it cannot completely convert chemical energy into electrical energy for release.
Therefore, from the point of view of energy efficiency, charging to 90% can also be seen as an efficient use of electrical energy.
To sum up, for lithium iron phosphate batteries, charging to 90% is usually a better option. Doing so extends the life of the battery, improves safety, and meets the demands of everyday use. Of course, in certain situations, if the battery needs to be used for a long time, you can also consider charging it to 100%, but you should avoid doing so frequently to protect the health of the battery.