18650 3.7v charge question

Psyxologos

Well-Known Member
I was wondering if anyone has an idea as to how long do these batteries hold their charge, provided they are not used, of course. I need them for a torch I bought and as it is an emergency torch I plan keeping in the car I want to know it will work when I need it to... So basically I am after some figures as to when to recharge them when they have been sitting in their plastic box unused, really...

thanks in advance!
 
Mine stay charge for weeks but i top them up when i go out , never leave them discharged it shags them i got my 1200 from a hobby shop for £4 each and the charger from maplins
 
Mine stay charge for weeks but i top them up when i go out , never leave them discharged it shags them i got my 1200 from a hobby shop for £4 each and the charger from maplins

Thanks. Well, I am hoping to establish a recharge cycle and I am trying to determine how long it can safely be without jeopardizing the effectiveness of the battery or risking that they will be flat when I need to use them...
 
It is a battery(LiPo) that lends itself to heavy use and recharge, they can be stored at 70% charge but you need to maintain the voltages. Drop the voltage below 20% and you may as well bin them.

You can get battery chargers that maintain the batteries then just take them when you need them at 100% charge
 
one thing i will say is buy good named batts cheap on ebay can also ruin you light or nv. best thing is to use one leave it on then see what charge rate and discharge is, tracer are the best i found.
 
It is a battery(LiPo) that lends itself to heavy use and recharge, they can be stored at 70% charge but you need to maintain the voltages. Drop the voltage below 20% and you may as well bin them.

You can get battery chargers that maintain the batteries then just take them when you need them at 100% charge

Can you please be more specific? How does the voltage drop? the batteries I bought came with a charger, but keeping them on the charger is not an option as I plan to have the batteries and torch in the car for when I need them, hence my issue with having to keep them with me but may not get used for a while....
 
I have two 18650 eagletac 3400 batteries that I use in my Olight M22 Warrior.
They hold their charge for weeks. . . I just give them a little top up every now and again before I use them.
 
If it just for emergency use can you not run the torch on a pair of lithium non-rechargable CR123's

Neil. :)
 
As you know the batteries will lose charge of their own accord. Lithium ion batteries lose about 5% in the first few weeks after charging and will have about 70% of charge left after a year.

As suggested it might be worth having some CR123s in your car if the torch will take them. Most have a very long shelf life but they will also be losing charge with time.

Your big problem might be that many of the fancy modern LED torches have something called "parasitic drain" which, basically, means that the torch draws a very low current from the battery during the time that the battery is installed in the torch. Even my relatively unsophisticated LED torch does it - I keep a battery in the torch and a spare in my pocket and the one in the torch takes much longer to recharge than the one that has just been in my pocket even if the torch has never been turned on during the period between recharges.

So, even if your battery is only going to "self discharge" to 70% in a year once you put it in a torch all bets are off until you've done some testing for yourself but over several months many modern torches will have caused a significant reduction in the energy available in any battery that is installed.
 
Most 18650 batteries have both over and under charge protection circuitry and should last a long time.
Occasionally you get a bad cell that won't take a charge for some reason, you'll see this as soon as you put the battery in the charger (most chargers are now 'intelligent' and adjust the charge rate relative to the batteries charge)
 
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As a make shift back up one of the 3AAA battery packs would see you through for a short while. 3AAA may be handier to find if your in between charges. Won't match the power output of a good 18650 though.
 
I have a small cigar lighter mini inverter that I can use in the car. Get one of these then you can plug your 240v recharger in to the car on a regular basis just to keep the batteries topped up.

Ring MP75 Mini Inverter
 
Would be worth having a read of this.....Torchy the Battery Boy: 18650 Batteries / Chargers

There's a lot of dodgy and fake batteries and chargers out there.... Some are just downright dangerous.
I've bought various batteries and more recently a nitecore i4 charger from him over the years and never had a problem.

He sells under his fleabag i/d of big_f_d_d -http://www.ebay.co.uk/itm/291125327102

's me,

Cheers,

Fizz
:cool:
 
Last edited:
Would be worth having a read of this.....Torchy the Battery Boy: 18650 Batteries / Chargers

There's a lot of dodgy and fake batteries and chargers out there.... Some are just downright dangerous.
I've bought various batteries and more recently a nitecore i4 charger from him over the years and never had a problem.

He sells under his fleabag i/d of big_f_d_d -http://www.ebay.co.uk/itm/291125327102

's me,

Cheers,

Fizz
:cool:

I use the nitecore i4 charger, it's top notch, well worth the money.
 
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