Question

Is it bad to leave a battery discharged?

Answer 1

Yes, leaving a battery discharged for a long period can be harmful, especially for certain types of batteries like lithium-ion or lead-acid batteries. Here's why:

1. Lithium-Ion Batteries (commonly used in smartphones, laptops, etc.):
   

   - If a lithium-ion battery is discharged too much, it can enter a "deep discharge" state, which may make it harder to charge later.
   - It could also shorten the battery's lifespan, as the cells inside the battery can degrade over time if left in a discharged state.
   - Typically, lithium-ion batteries are best kept at around 20-80% charge, so if you know you're not using a device for a while, it's good to store it with some charge left.

1. Lead-Acid Batteries (used in cars, UPS, etc.):
   

   - Lead-acid batteries can suffer from sulfation, where lead sulfate crystals form on the plates when the battery is left discharged for too long. This can reduce the battery’s ability to hold a charge and may even make it unusable.
   - If you know you're not going to use a lead-acid battery for a while, it's best to give it a charge every few weeks to prevent damage.

1. Other Battery Types:
   

   - Nickel-based batteries (like NiMH) also suffer if left discharged for extended periods, though they’re usually less prone to serious damage compared to lithium-ion or lead-acid.

In summary:

If you’re storing a battery, try to keep it at a moderate charge level, and if it's been discharged for a long time, it's a good idea to recharge it before using it again.