Am I overcharging my batteries?

[vaper1960]

I have 18650 batteries. My charger is a Nightcore Q2. Sometimes I put batteries in the charger for the day and forget (hey I'm 60) and they also sit overnight. The last time, they were in the charger for 24 hours. I'm sure it has some protection (reduces charging rate) but not sure it actually stops charging. It's a simple charger (no screen... just LED lights) so I can't check actual voltage. I also remember a video by Mooch saying it's better to only charge them to 80% (in fact, it also mentioned only letting them get down to 20%) Any thoughts on this?

 

[SupplyDaddy]

While I admit, Mooch is the last word on batteries, even I do not follow all his recomendantions.
The Nitghcore charger stops charging when the light turns green and won't overcharge your batteries. As long as it is in proper working order.

 

[UncLeJunkLe]

One way to know if your charger is overcharging your batteries is to test the battery using a digital multimeter when it's done charging. You don't need an expensive one, a $10 DMM will work for such a task. If your DMM shows more than 4.20 volts, it's time for a new charger.

 

[vaper1960]

The Nitghcore charger stops charging when the light turns green and won't overcharge your batteries. As long as it is in proper working order.

Thank you... it's in good shape and working fine. Haven't had any issues (and even after 24 hours the batteries were cold... not even warm, I assume that's a good sign) Have not had any issues at all... just wanted to know if it could be an issue.

 

[vaper1960]

UJ, I just have a an analog meter... not very accurate. I really do need a digital meter (work on cars a lot)

 

[vaper1960]

I guess my concern was if the charger just reduced he charging rate or actually stopped charging when the batteries are fully charged (wasn't sure about that)

 

[AngeNZ]

I have 18650 batteries. My charger is a Nightcore Q2. Sometimes I put batteries in the charger for the day and forget (hey I'm 60) and they also sit overnight. The last time, they were in the charger for 24 hours. I'm sure it has some protection (reduces charging rate) but not sure it actually stops charging. It's a simple charger (no screen... just LED lights) so I can't check actual voltage. I also remember a video by Mooch saying it's better to only charge them to 80% (in fact, it also mentioned only letting them get down to 20%) Any thoughts on this?

For my piece of mind, I only recharge batteries when I'm around to keep an eye on them.

As my time is limited, I often charge at 2a per battery. While that shortens their lifespan - at least I know if my charger malfunctions, I'm there to do something about it.

 

[UncLeJunkLe]

I guess my concern was if the charger just reduced he charging rate or actually stopped charging when the batteries are fully charged (wasn't sure about that)

I would find it hard to believe that a charger made by one of the better-known brands is designed to not have a proper cut-off and would just keep charging a battery. But I guess anything is possible.

 

[UncLeJunkLe]

I guess my concern was if the charger just reduced he charging rate or actually stopped charging when the batteries are fully charged (wasn't sure about that)

Well an analog meter will do to a degree just to see if you are over a certain voltage. Harbor Freight sells a DMM for $7. I have a couple. They used to give them away for free but they don't do that anymore.

7 Function Digital Multimeter

 

[DaveP]

UJ, I just have a an analog meter... not very accurate. I really do need a digital meter (work on cars a lot)

An analog meter with a needle instead of a fancy display is fine as long as it's accurate. If your charger displays voltage you can use it to compare with the the meter as you remove batteries from the charger.

 

[vaper1960]

So I'm not really worried anymore, but I will check them with my cheapo analog meter anyway.

 

[DaveOno]

You should have no worries. The Q2 is a good charger. It will stop charging when complete. It also has overcharge protection circuitry.

Q2

(see the bottom of that page)

And I found this from the Q2 user manual (available on that website under "Support)

Overtime Prevention
The Q2 has overtime prevention. It will individually monitor the elapsed charging time
for each battery slot and if a particular slot exceeds 20 hours, the Q2 will automatically
stop charging and the green LED indicators will illuminate to indicate completion of the
charging process. This feature reduces the risk caused by batteries of lower quality.​

You are not wrong to be cautious with your charging methods. Good for you.

But your Q2, and any Nitecore charger will not overcharge a battery.

 

[sonicbomb]

The main concern here is unattended charging, and that applies to any battery.
It's a really unsafe practice.

 

[vaper1960]

Thank you all for your responses. I am not really worried anymore. BTW, my batteries were cool after 24 hour charging (yes I did check) It's a simple charger (just LED lights) but seems to work great.
Sonic... no worries, I'm very careful and understand about battery safety. Of course, safety first.

 

[Rossum]

The main concern here is unattended charging, and that applies to any battery.

Yep, none of us ever charge our phones, our laptops, our tablets, our power tools, or our electric vehicles overnight, while we sleep, right?

Is there some risk associated with doing this? Yes, there is, but it's quite small, and everything we do in life comes with some risk, nothing is perfectly safe.

 

[UncLeJunkLe]

Yep, none of us ever charge our phones, our laptops, our tablets, our power tools, or our electric vehicles overnight, while we sleep, right?

Is there some risk associated with doing this? Yes, there is, but it's quite small, and everything we do in life comes with some risk, nothing is perfectly safe.

I would normally agree with this, but Chinese brands, be they vape or otherwise, are known for not being safe. I used to have an old Harbor Freight cordless drill with Ni-Cad battery packs and the charger had to be unplugged once the battery was charged or it would just heat up the batteries and render them useless in no time at all. But more importantly, one of my chargers actually melted. You can't expect this cheap junk to have the proper overcharge protection circuits or even have one at all.

 

[Rossum]

You can't expect this cheap junk to have the proper overcharge protection circuits or even have one at all.

Maybe I'm jaded because I don't buy cheap junk. The XTAR chargers I use have a voltage display and I know they stop charging when the batteries are full. If you leave cells in them for a while after they're done charging, you can actually watch them drop back a bit below 4.20. (Brand-new cells generally don't do that, or only drop to 4.19, but well used cells can drop down to around 4.15).

 

[UncLeJunkLe]

I'd never trust xtar or any other mainstream sub $100 charger with my house. I have a high deductible.

 

[vaper1960]

Just for the record... my post (question) was really about damaging the batteries but I guess UJ does make a good point. I do have a cheap USB charger for a (non-vape) device and the charger did get very warm the other day.
Side question: what is a good brand/model of USB charger?

 

[mimöschen]

index of USB equipment