Getting the most out of your lithium battery means knowing the best time to charge it. I’ve tested lithium batteries extensively to find the optimal charging practices. In this definitive guide, as a professional lithium battery packs manufacturer, I’ll share everything you need to know about when to charge your lithium battery.
Why Proper Charging Matters
Lithium batteries are common these days. You’ll find them powering laptops, phones, power tools, electric vehicles, and more. Their high energy density delivers ample juice in a compact package.
With a lithium battery’s long lifespan, you want to care for it properly. That comes down to when and how you charge it.
Key takeaways:
- Don’t let lithium batteries discharge completely or charge to 100%.
- Allow the battery to cool before charging to prolong its lifespan.
- Charge more often for maximum daily performance.
- For long-term storage, maintain 40-50% charge.
Optimizing these practices gives you the best battery runtime day to day. It also extends the total years of useful life.
Now let’s explore the details…
How Lithium Batteries Work
To understand when to charge lithium batteries, it helps to know what’s going on inside them.
A lithium-ion battery contains positively charged lithium ions that shuttle between the anode and cathode. This flow of ions generates electric current to power your devices.
During discharge, the ions flow from anode to cathode through the electrolyte. Charging reverses the ion flow to replenish the anode.
This back and forth process slowly wears down the electrodes. With time, the battery loses its ability to hold a charge, shortening its lifespan.
The key is to charge in a way that maximizes ion flow while minimizing electrode wear. Let’s look at specific recommendations…
When to Charge Lithium Battery
Don’t Let Lithium Batteries Drain Completely
It might seem logical to squeeze out every last bit of juice before charging back up. But allowing lithium batteries to drain fully puts extra strain on the battery.
Research shows that discharging beyond 20% remaining capacity leads to accelerated loss of runtime. At 0%, permanent damage can occur.
Most lithium batteries cut off before reaching 0% to prevent complete discharge. Still, it’s best practice to begin charging around 20-40% remaining capacity. This makes for a nice sweet spot between performance and longevity.
For example, if your phone estimates 8 hours of runtime from a full charge, plug it in around the 2-3 hour mark.
Don’t Charge to 100% Either
The flip side also holds true. Fully saturating to 100% capacity adds stress in the form of elevated voltage. It also leaves the battery in a state where natural self-discharging pushes it out of the optimal zone.
Experts suggest maximum charges of 80-90% instead of 100%. Combined with the minimum of 20%, this keeps your lithium battery humming along in the productive middle zone.
Going back to our phone example, charge it to around 80-90% if possible. Configure it to pause charging at that level rather than continuing to top off.
Allow Proper Cool Down First
Here’s another scenario to avoid:
You just used a power drill to hang some shelves. The battery got hot during all that drilling. Can you plop it right onto the charger to top it back up?
No! Charging raises battery temperature on its own. Combining an already hot battery with charging creates a damaging double whammy.
It’s vital to let lithium batteries cool to ambient temperature prior to charging.
An hour or so should to the trick in most cases. But let large power tool packs cool even longer just to be safe.
Don’t leave discharged batteries sitting around for days on end. But a proper cool down prevents safety issues and preserves battery capacity.
More Often Charging Increases Daily Runtime
Frequent smaller charges make sense for devices you use daily like phones. Keeping the battery topped off ensures ample runtime to get you through the day.
Infrequent full cycles make more sense for something like a riding mower that might sit for a week or more between uses. You want maximum power when it’s time to mow.
Either approach helps maximize lifespan. It comes down to matching charge frequency to usage patterns.
Plan out charges based on your typical device runtime. Top up more often for devices used a little bit all day long. Charge fully less often for occasional prolonged use.
Maintain a 40-50% Charge for Long-Term Storage
Got an electric bike you only ride part of the year? Or a solar generator that sits idle until the next power outage?
For lithium batteries destined for long stretches of non-use, 40-50% state of charge targets the optimal resting voltage. This helps them hold a solid charge for when you eventually need it.
Before stowing them away, charge up to 50% or allow to self-discharge to 40%. Then disconnect fully to prevent any parasitic drain. Give a quick test and top-up after 6 months or so in storage.
Watch Out for Heat During Charging
Carefully monitor battery temperature whenever charging. Stop immediately if batteries become hot to the touch.
Excess heat indicates potential failure of the battery’s protection mechanisms. Left unchecked, thermal runaway could occur leading to fire or explosion.
Prolonged high temperatures also accelerate lithium battery degradation regardless of other charging practices.
Charging in hot ambient conditions makes this more likely. Or using an under-rated charger that lacks proper current and thermal controls. Stick to quality chargers rated specifically for your battery.
And keep flammables away just to be safe!
Test Out These Lithium Battery Charging Tips!
Now you know the best charging practices to maximize lithium battery life and performance:
- Maintain 20-80% state of charge
- Allow batteries to cool fully before charging
- Charge more often for daily use items
- Charge fully less often for occasional use devices
- Keep stored batteries around 40-50% charge
Adjust these lithium battery charging tips to match your specific usage patterns. And your batteries will deliver years of maximal runtime.
What questions do you have about when to charge your lithium batteries? Ask below!
