Are You Charging Correctly?
8th December, 2023

If you’re plugging in your mobile computer, tablet or wearable whenever it’s convenient, or constantly topping off the battery to keep a full charge “just in case” you can’t charge it later, you’re killing your battery and draining your bank account. 

That’s because a battery is only built to last a certain number of charge cycles.

Does that mean that if you’re plugging your device in three times a day, completing only partial charges each time, that your battery could die in approximately four months (~166 days) if it’s built for a 500-cycle lifespan? 

Not necessarily, but your battery life could be cut in half.  It all depends on your charging habits. So, let’s talk about what can either extend or shorten the life of your battery and device by asking and answering a few questions:

Q: Is every battery charging event considered a “charge cycle”? Or does the battery have to go to zero and then fully recharge for it to be considered a full cycle?

A cycle is defined as 100% of the battery’s capacity, but it does not have to be discharged in one go to be considered a “charge cycle.” Two days of using 50% capacity or four days of using 25% capacity are both equivalent to one full cycle. It doesn’t matter if you charge back to full each day between those 25-50% discharges or not. 

Q: So, if I only discharge a battery 70% today (and have 30% remaining when I plug it in to recharge), that would be equivalent to using 70% of a cycle, right?

Correct. The battery would only be depleted a full cycle once the battery is discharged (or used) another 30%.

Q: If I only let the battery drop to 30% before recharging (because I don’t want to get stuck somewhere without a fully charged device), but I always charge to 100%, is that helping or hurting the battery’s health?

There are certain extreme charging behaviours/methods that will negatively impact battery health and deplete its usable life faster. For example, charging to a higher voltage/percentage (such as charging all the way to 100%), charging faster, or keeping the battery on the charger longer (trickle charging) can all harm the battery and shorten its lifespan.

That said, there are three variables in particular that contribute to battery swelling and capacity fade (the things that shorten battery life):

1, State of Charge

2. Temperature

3. Time Duration

If any two of these variables are high, then the third needs to be low.   

Therefore, it’s ok to charge a battery to 100% full *if* the temperature isn’t extreme and the amount of time the battery will be kept at 100% is less than a few weeks.   


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