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I have lithium ion batteries in my cell phones, laptops, portable chargers, and all sorts of devices. Sometimes I'll keep them off for a week or two and when I turn the device on, the charge may be lower but it's not significantly lower.

But drone batteries otoh... after 5 days DJI batteries, save for the Mini 2's batteries, discharge to 60%.

Are drone batteries more prone to puffing / swelling / whatever than other types of batteries?

Drone batteries are probably discharged at a much higher rate than cell phone or laptop batteries. Maybe they're higher amperage too? Maybe those two things together make drone batteries more prone to swelling?

Maybe when other batteries say that they're at 100% they're really at 60% and they never actually let you charge the battery up fully to 100%?

In any of these cases, what about the Mini 2's batteries? The ones I have don't self discharge to 60% after 5 days, and I haven't seen any swelling either, so what gives?

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I think that puffing is generally a result of overheating, or over-discharging.

As you say, drones push their batteries hard. They can use a battery in 5 minutes and can draw very high current peaks during that flight. By comparison, a phone or laptop battery typically lasts several hours.

Similarly drones generally allow you to over-discharge. Discharging below about 15% starts to cause long-term damage, and discharging to 0% just once can kill a battery. However it's safer (and cheaper) to sacrifice some battery life rather than to have the whole drone fall out of the air - and when you have an FPV drone set up to fly for 5 minutes or less, an extra 30 seconds makes a big difference.

I believe the BMS (Battery Management System) in phones, laptops and even electric cars are designed to cut off at around 15%, for maximum battery life.

Also, DJI batteries have a built-in BMS that discharges them to 60% after 5 days.

Don't charge your batteries unless you're going to fly. The batteries are programmed to automatically discharge down to the storage level (about 60%) after left unused

Storing batteries fully charged also shortens their life, so this feature should extend their life. Normal RC batteries do not have this feature, and rely on the user to do it. Phones and laptops generally don't do this because they expect to be used daily and not left fully charged for days.

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  • $\begingroup$ "laptops generally don't do this because they expect to be used daily and not left fully charged for days". I feel like laptop's are often plugged in for days on end lol. They may be used on the go occasionally but a lot, I suspect, aren't used on the go that often $\endgroup$
    – neubert
    Aug 10, 2021 at 23:08
  • $\begingroup$ @neubert - good point! Right at the end of this (batteryuniversity.com/article/…) it says that ideally "a device should feature a “Long Life” mode that keeps the battery at 4.05V/cell" and "The question is asked, “Should I disconnect my laptop from the power grid when not in use?” Under normal circumstances this should not be necessary because charging stops when the Li-ion battery is full. A topping charge is only applied when the battery voltage drops to a certain level. Most users do not remove the AC power, and this practice is safe." $\endgroup$
    – Robin Bennett
    Aug 11, 2021 at 9:13

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