Any safety issue leaving an 18650 in a seldom used light?

[tre]

I have been removing 18650 cells from my lights every time I am done using them because I am paranoid to leave them in an airtight waterproof light. It is a bit of a pain but I don't want a . Do you do this? Do I need to do this? I use protected AW cells.

 

[old4570]

I have been removing 18650 cells from my lights every time I am done using them because I am paranoid to leave them in an airtight waterproof light. It is a bit of a pain but I don't want a . Do you do this? Do I need to do this? I use protected AW cells.

Some lights have parasitic drain .. So when the light is off , there might still be some current used by the driver for monitoring ...
This is usually very low ...

This might be an issue if you leave the lights standing around for months with minimal use [ parasitic drain ] , I have about 20 lights with batteries in them ready to go .. Yeah , can only use one at a time , two at best .
But none have parasitic drain , so the only issue is self discharge ...
And they should be good for at least 6 months in this regard ...

 

[Ozgeardo]

I have dozens of 18650, 18500 & RCR123 batts sitting idle in numerous lights for months at a time (possible 6 months or more for some).
I leave them in tool boxes and vehicles as well as various EDC & BOB's in all weather and conditions.
I have never had any problems,
I am careful to store any spare Li-Ion batts in small plastic containers (otter, penguin or similar boxes).
I generally will check batt voltage in them every now and then (when I am motivated) and if I think they have been sitting for more than a few months I may give them a top up charge.
It is all about common sense, whilst many on this forum will be somewhat pessimistic about Li-Ion batts (too much knowledge can be a curse) I have adopted a far more optimistic view of Li-Ions.

I am pleased to say that I am finding more and more people using Li-Ion batts, many of whom have absolutely NO IDEA about batt chemistry or charging requirements.

 

[march.brown]

I have a few 18650's , 18500's and RCR123's and most of mine are in torches ... Some of the torches are hardly ever used and are "just in case" torches ... A couple are everyday users.

I too check the voltages when I remember , though it can be months before I do remember to check them ... Almost invariably , the voltages are still well over the four volt point ... I tend to top them up if they get below the four volts ... I realise that this is not good for the storage of Li-Ions but when they die I will just buy some more Ultrafires ... My couple of users have their voltages checked every few days.

I do tend to keep them at moderate temperatures (under 70F) so they are not subjected to extremes of temperatures.

I take them off the charger as soon as the light goes green so the cell voltages are rarely over the 4.2 volt point but on the very odd occasion have been known to reach 4.22 volts ... I am happier if they come off at fractionally under the 4.2 volts.

When I take the batteries out of the torch , I listen for a "hiss" after the tailcap has been turned a few revolutions just in case there is a slow vent ... I do this with all my torches though ... So far there has been no hiss ... I have considered drilling a 1.0mm hole in each of my torch bodies and filling with beeswax to act as a pressure relief valve ... At the moment , this is just a thought !

So , other than keeping my batteries fully charged , I think I treat the Li-Ions fairly well ... I will only buy protected cells in future as they give an additional "line of defence" which hopefully will never be needed ...

I guess that I almost trust the Li-Ions.

Time will tell.
.