Perplexed Noob

I recently purchased a Sofrin Q8 and a spare set of batteries. Being new to Lithium ion battery flashlights I was not aware you do not store extras at full charge.

Lithium Ion scenario - I have a flashlight , the batteries die , and my backups are only 40% charged.

Alkaline Battery scenario - I have a flashlight , the batteries die - I chuck them and put in a fresh set and am good to go .

It seems odd to have a flashlight that you can’t keep fully charged spares for .

You can store them fully charged - but you will severely limit their lifetime.
Some store them full.
Some store them half empty.
Some store them in fridges or freezers which helps longevity as well.

Lithium ion batteries offer way better power delivery as well as somewhat better energy density. But they are typically less safe and for maximum durability should be stored half empty. It is what it is and you have to decide for yourself which tech do you prefer.
Quite a few decide that sometimes they’s rather have nimh and sometimes li-ion.

My lanterns are all kept with fully charged liion batteries in them, and have had for 3 years. What good is a dead lantern in a power outage. Not seeing any severe degradation with them, and they are inexpensive anyway

Thanks for the information. I am a bit of a slow learner , being old school.

I see batteries as consumable items. They are made to be used when necessary and will degrade over time. Sure, if you don’t need them it’s better to store them only half charged. But in the “season” most of my batteries are fully charged.

totally valid question
welcome to the forum

the 40% charge rule may be relevant when storing batteries for a year or more, but as you noted, that would not be practical for a spare battery that I plan to use as a backup.

My spare batteries get a full charge, because I use them frequently.
I do not consider them to be “in storage”, rather they are “in rotation”.

I rotate my charged batteries into my lights every few weeks. When I remove a partly depleted cell, I recharge completely.

I do not own a box of unused batteries that are stored for long periods. All my batteries are in rotation in my lights.

For me, the decision to store lithium ion cells at half charge or full charge is a matter of personality. That's why I store some at half charge and some at full charge.

As others have stated, what good is a partly charged cell if you have a power failure and need light? With that in mind I have a few sets of feither fully charged cells, or at least at 4.0 to 4.1 volts stored in little plastic cases. I also have some longer term stored cells (because I could not resist the price at the time) that are stored at about 3.6 volts. All in a place that remains cool to cold, but above freezing.

I do not worry about keeping cells that may be used at full charge. So what if their life may be shortened? They are of no value at all if unable to supply light or recharge a phone if necessary because the mains power failed.

what i would do - if i had one light - is have one main cell i use in the light
and a not-great backup

i charge them both to 100% all the time

when the main one runs down, i change to the not-great one, and charge the main one
the not-great one just has to last half a day

if i had other cells, i’d still just have one not-great one for use when the main one for each light is being charged

wle

I have a set of 4 Samsung INR18650-20R 2000mAh batteries in a flashlight that have been constant use for the last 6 years by my family that have not shown significant decrease in capacity. Actually at some point I hope they do need to be replaced since I’d rather load up the flashlight with some Samsung INR18650-30Q 3000mAh batteries, but it seems I won’t need to do that for many years to come.

I have only boughten 2 extra batteries and they are kept fully charged. One is for my wife’s flashlight so I’m able to replace the battery right away rather than her needing to wait for it to be recharged. The other is for 1 of my first flashlights when I thought it was a good idea to have a spare. The rest of my batteries are fully charged in my flashlights and I rotate through them and charge them back up when they get low.

Until the lithium ion batteries I use become a rarity, I don’t see a need to try to preserve them.

I currently have a matched pair of 26650s sitting at 3.6v for storage. They’re for my SP70, which has been in pieces for over 6 months and I don’t know when I’ll get around to modding it.

But I have more lights than cells, and the cells in my lights get out in full, and “stored” wherever they got down to, all the way until I want tk charge them again.

They’re cheap anyway. More important to store safely, than at ~50% or whatever. So, ensure no parasitic drains will drop the cells low, no chance of cells shorting on anything, no chance of them getting too hot.

I’ve got 8x Samsung 30q that 4 are in flashlights and 4 are about 4v volts
And I’ve got 6x Sony vts that 2 are in flashlights and the other are full

6 euro a pop for the Samsung’s and god know how much the Sony’s are (salvaged from Dyson)

They cost so little and if they last 2 years at how ever I charge them , then I’ll be happy
They should last a lot longer though
But imagine alkalines, I would of gone threw pack and packs buy now and wasted so much