Battery Musing: Can fast charging damage your battery?

[Mooch]

Yes.
But as with so many things about batteries there is no hard threshold between a charge rate that causes no damage and one that does. Any charging ages the battery. I'd go into more detail about this but most people just want a number they can use.

These numbers are my personal recommendations. There aren't any industry standards for charging rates other than "standard", which is about 1.5A and "rapid", which is about 4A for the better batteries. So here they are...

To minimize any impact charging has on the life of your battery, charge at...
26650 and 18650 = 0.5A
Smaller than 18650 = 0.25A

For a good compromise between battery life and charging speed...
26650 and 18650 = 1A
Smaller than 18650 = 0.5A

For the fastest charging without severely affecting battery life...
26650 and 18650 = 2A
Smaller than 18650 = 0.75A

If you really just don't care about battery life...
26650 and 18650 = 4A
Smaller than 18650 = 1A

There are differences between batteries that can allow some to be charged at higher rates but these numbers will work for all but the lowest current rated batteries. For them, stay at 1A or lower.

 

[Rossum]

At 0.5A, I get virtually no perceptible temperature rise from my 18650s. At 1A, they do get slightly warm to the touch. So unless I'm in a hurry (very rare), 0.5A it is.

 

[sonicbomb]

Stay organized and you don't end up in a situation where you need to fast charge a battery. Thanks for the numbers Mooch.

 

[Rossum]

Stay organized and you don't end up in a situation where you need to fast charge a battery.

Yep, I normally keep some charged ones to rotate into mods as needed, and a battery coming out goes straight into the charger, so I'm rarely in a hurry.

Thanks for the numbers Mooch.

+1

 

[DaveP]

Yep, I normally keep some charged ones to rotate into mods as needed, and a battery coming out goes straight into the charger, so I'm rarely in a hurry.


+1

Same here. I have 5 18650's for single battery mods, 3 sets of married pairs for my Smok Koopor Plus 200W, and 2 triplet sets for the RX200S. They are all in designated boxes to allow me to keep them in sets.

1A is fast enough for me to always have a freshly charged set for any of my mods. As Rossum said, I can tell a very slight warmth at 1A and virtually no perceptible heat at .5A.

I've watched people quick charge 18650 batteries in 15 minutes for model boats and airplanes. Those suckers get pretty hot.

 

[Frenchfry1942]

Soo, how do I tell my charger what setting it should be on? Or, do I look for a certain feature when I buy a charger?

 

[Mooch]

Soo, how do I tell my charger what setting it should be on? Or, do I look for a certain feature when I buy a charger?

Check the instructions for your charger and/or find the online version of the manual for the charger you're interested in buying. Some use a switch, some a button, and some use a LCD display and a menu you have to step through.

 

[xJoseph]

lol my charger is maxed out at 0.25 loll

 

[gorman]

Nitecore Intellicharger i4 here. It says it charges at 0.75A when using two slots and 0.375A when using four slots.
Seems to be on the safe side.

 

[Fozzy71]

lol my charger is maxed out at 0.25 loll

I have a eizfan 2 bay that is like that as well.

Nitecore Intellicharger i4 here. It says it charges at 0.75A when using two slots and 0.375A when using four slots.
Seems to be on the safe side.

I have the same charger but it does not get much use since I got my 6 bay efest charger for my triple battery mods. All 6 bays default to 0.5 but the 4 inner bays can be cranked up with the phone app to 1.0 if not charging more than 4 batteries and the 2 outer bays can be cranked up to 2.0 if only charging those 2 bays. That said, I am rarely in a rush and leave them on 0.5 unless I have to leave or it is late at night and I want them to charge faster.

 

[fenderstrat]

MOOCH has it been your experience that capacity plays a role??wouldn't it make sense that a 4000mah battery would take a 4amp charge much better than a 1500mah battery?? or do the li ion not react the same as li polymer?

 

[fenderstrat]

I have always looked at it this way, say at the MAX charge rate you lose 20% cycle life.and again we suppose a 200 cycle life for an average 18650(going low for worst case) so its the difference between 200 cycles charging for 6 hours(.5 A charge rate 3000mah battery)and 160 cycles charging at 3 amps for an hour.
Because its not always about planning ahead, its about my time.In almost every battery safety list I see whats the 1st rule??or whats definately in the top 3????never charge un attended.So how many of you guys are charging ATTENDED for 6 hours...lol.if I'm working in my comp/hobby room for a while I can keep an eye on things for 1-2 hours....however I can't always dedicate 6 hours of my day to watch my e-cig batts charge.and again none of us are charging un-attended,right??LOL not me(he says sarcastically)

 

[Robert Cromwell]

MOOCH has it been your experience that capacity plays a role??wouldn't it make sense that a 4000mah battery would take a 4amp charge much better than a 1500mah battery?? or do the li ion not react the same as li polymer?

I will let mooch answer but I think it is generally the other way around.
The higher the MAH the lower the charge rate for best life?

 

[Fozzy71]

I have always looked at it this way, say at the MAX charge rate you lose 20% cycle life.and again we suppose a 200 cycle life for an average 18650(going low for worst case) so its the difference between 200 cycles charging for 6 hours(.5 A charge rate 3000mah battery)and 160 cycles charging at 3 amps for an hour.
Because its not always about planning ahead, its about my time.In almost every battery safety list I see whats the 1st rule??or whats definately in the top 3????never charge un attended.So how many of you guys are charging ATTENDED for 6 hours...lol.if I'm working in my comp/hobby room for a while I can keep an eye on things for 1-2 hours....however I can't always dedicate 6 hours of my day to watch my e-cig batts charge.and again none of us are charging un-attended,right??LOL not me(he says sarcastically)

I may not be next to my charger at all times but I never leave the house with a battery on the charger. My charger goes in a lipo guard bag while charging and I use the phone app to check up on their progress

 

[fenderstrat]

what charger is that?I like the blutooth idea.I'm the same I will wander around the house doing things but not leave.but therein lies the problem,some days I am not at my house for 6 hours straight.and when I do get home its bedtime soon after and charging while sleeping is a BIG no no

 

[Fozzy71]

what charger is that?I like the blutooth idea.I'm the same I will wander around the house doing things but not leave.but therein lies the problem,some days I am not at my house for 6 hours straight.and when I do get home its bedtime soon after and charging while sleeping is a BIG no no

efest luc blu6

 

[fenderstrat]

thanks I'm gonna check that out

I just got my first 26650 mod and bought 2 of the BASEN 4500mah batts.These fat .......s take 9 hours to charge at .5 so i.m going to have to rig up a connection so I can charge them with my good charger

 

[Mooch]

MOOCH has it been your experience that capacity plays a role??wouldn't it make sense that a 4000mah battery would take a 4amp charge much better than a 1500mah battery?? or do the li ion not react the same as li polymer?

Those who like to use C ratings would have you believe that but it's not true for the battery chemistries we use, often called IMR and INR. LiPo's are Li-Ion batteries. They use a different chemistry though, often called ICR. But ICR also denotes a type of INR chemistry too so they're just really lousy ways to indicate any chemistry. They're all just manufacturer model number prefixes, not chemistries, that's why it's so confusing.

LOl, back to what I was talking about....

You can't use capacity as a direct indicator of the rated charging current. It's not always true but the higher capacity batteries often have the lowest charging current ratings due to their high internal resistance. This high resistance causes more heating so the charge current level has to be set lower.

For any battery I recommend looking up the recommended charge rates. If that's not possible then charge at 0.5A for standard charging and 1A for rapid charging (which may shorten battery life).

 

[duc916]

I charge right in front of my brick fireplace and have no qualms about leaving the house. Maybe I should just go ahead and charge it in the fireplace.