Leaving my batteries in a smart charger? Safe or not?

[simonpink]

Hey all,

I generally put one of my two 18650 batteries in my efest luc 4 bay charger before I go to bed each night.
So each battery spends 24 hours in the charger before getting swapped out. I started with a kanger evod and was aware that the usb charger had basically no protection, so leaving it unattended was a recipe for disaster. Does the efest's overcharge protection mean it's safe to leave them in there?
I guess my confusion comes from information on sites selling them.
They list the features

FEATURES:

1. 4 kinds of protection - over-discharging, over-voltage, short-circuit and reverse polarity protection.
2. Automatically stops when fully charged.

But a warning about unattended charging can almost always be found further down the page.
If it stops charging once it's done, shouldn't that mean there is no risk of my house going up in flames?

 

[Susan~S]

Not a good idea to charge batteries unattended. You can't count on your charger to NOT malfunction.

 

[cope]

there is never NO risk.. care should be given case some what if should happen while your sleeping.

 

[Rickajho]

Hey all,

I generally put one of my two 18650 batteries in my efest luc 4 bay charger before I go to bed each night.
So each battery spends 24 hours in the charger before getting swapped out. I started with a kanger evod and was aware that the usb charger had basically no protection, so leaving it unattended was a recipe for disaster. Does the efest's overcharge protection mean it's safe to leave them in there?
I guess my confusion comes from information on sites selling them.
They list the features

FEATURES:

1. 4 kinds of protection - over-discharging, over-voltage, short-circuit and reverse polarity protection.
2. Automatically stops when fully charged.

But a warning about unattended charging can almost always be found further down the page.
If it stops charging once it's done, shouldn't that mean there is no risk of my house going up in flames?

In theory - yes. In practice the first version of the Luc 4 was put in the market with a circuit that was charging batteries over voltage. Would I trust any charger from this company now? Hell no.

Make sure you test your batteries coming off that thing with a meter to make sure you didn't buy a 1st generation version.

 

[simonpink]

Thanks for the replies.
The charge is done by the morning, so I should just get into the habit of pulling it out before I leave for work.
I've got a decent multimeter so I can do that. What tests should I be doing?

 

[SunshinePete]

I, a fearer of fiery death, turn off the power to everything but the central heating and refrigerator before going to bed. A fault in the charger, with or without batteries inserted, could all too easily result in catastrophe. Pull the plug out before you go to bed or leave the house, you know it makes sense.

 

[Kanthal]

It's never a good idea to leave batteries on the charger long after they are fully charged.

If you're like me and often forget to take batteries off the charger once they are full charged, just be sure you have a good battery charger that will stop all current flowing through it once the battery has fully charged. If you bought a cheap battery charger then you should definitely not leave the batteries in it long after it's fully charged .

Never trust what the colored LEDs do on your charger.Even if you have a top grade battery charger there's still a small chance that it will not work properly. I have so many 18650s that sometimes I forget to take out batteries that I put on the charger 2 days ago. I've never had any problems with leaving batteries on the charger for 2 or 3 days at a time but,I have a battery charger that I have a bond with. I always use a multi meter to check the batteries if I leave them in the charger longer than they should. So far nothing has gone wrong.

 

[Kanthal]

Thanks for the replies.
The charge is done by the morning, so I should just get into the habit of pulling it out before I leave for work.
I've got a decent multimeter so I can do that. What tests should I be doing?

you should be doing voltage test. A fully charged 18650 should read around 4.15 to 4.25 V depending on what battery it is.

 

[Baditude]

Statistically, most battery incidents occur while charging. This is when a battery is most likely to be vulnerable and get into trouble.

Think about it. Charging batteries involves pumping lost electrons back into an empty battery. This process can involve producing heat, and batteries don't like heat. Batteries and heat make batteries go "BOOM" !

Manufacturers attempt to design safeguards built into chargers and batteries, but any mechanical or electrical device is bound to fail at some point, and when that happens to something with all of the potential energy in a battery, then you've got a big problem on your hands. Even if your charger has built-in safeguards, conventional wisdom says to still remove charged batteries from the charger.

There is some evidence to show that if a charger provides a "trickle charge" to the battery after a full charge, that this routine can decrease the overall life expectancy of the battery.

 

[nostradadus]

Thanks Baditude. Always nice to have photo evidence of why you should not leave your batteries in the charger. Always remove batteries after they have been charged AND charge them on a non-flammable surface.