A question about the life of the batteries

Always topping up to 100% can shorten the life of li-ion, but deep discharging does this also.

In general, I’d say to preserve a proprietary battery (or one fixed in place for a device), frequent re charging to keep the battery within 40-60% is a good idea. IMO cylindrical lithium ions are so cheap and ubiquitous, though, that it’s not worth it to worry.

I would agree with you but in my country it is just almost impossible to get those batteries locally… so I have to import them and this is a problem… waiting 45 days …

So when I buy something I have to study it… so dramatically funny….

BTW: good ideas, I will do as you say.

Hello again… I got a Nitecore UMS4 charger, it works fine

I charged all my batteries and they look good

Would you give me some advice on how to take advantage of the charger? (can the flashlight work better somehow?) The flashlight works perfectly fine, I’m just curious.

on the other hand: the performance of the batteries is exactly the same if they are charged by the flashlight’s internal system or the charger?

what I know is that if you always charge at 3A fast charge, in theory the life of the batteries will be shorter than charging at 2A or 1A…

I chose the Nitecore UM4 because it'll accept cells up to 79mm long.

I think the UMS4 only accepts cells up to 77mm long.

Now that I think about it, the extra 2mm probably won't make a difference as I don't even plan on getting protected 21700 cells.

I should have gotten the UMS4 because it charges more quickly.

Emergency light needs to be ALWAYS ready, And yes it will come at the cost of battery performance, but how much, i have no idea, will you lose 5% -10% more capacity over time? or will it lose a dozen of cycles, few dozens? does not really matter, the purpose of the light requires it always to be fully charged.

I agree!

You have a light CANNON there!
What emergency requires that? Blinding a pack of coyotes at 200 meters? You can’t use that thing in the house for reading, or damn near anything ‘normal’.

You are asking how to take care of the batteries, but it seems ultimately battery longevity is not your primary goal, as you agree with the statement to always have it fully charged. What is your ‘average’ use time? What would be your maximum use time?
Batteries have a lifespan. You can increase it a little by keeping them in the 20-80% charge. It’s more hassle then ‘charge and use’. You have to decide if it’s worth it.

I agree, but the MS08 is far from what I would call an emergency light.

An emergency light would be something with decent high capacity, a simple UI, no e-switch driver drain, etc.

Still, alpg88 is correct. Don’t be really scared though: you have a lot of battery capacity, so no need to constantly charge it.

The problem is that I live in Argentina and batteries are NOT easy to get… it’s a hassle to import them, so you have to worry about their durability. I have it prepared for power outages at home and at the club where we practice table tennis and/or to help a family member and also for tourism/adventure and for summer nights at a club.
It is good to know that keeping them between 20 and 80% will last longer, that is enough knowledge for me.
How would you know what your 50% is for example? How does the Nitecore UMS4 charger report it to me? would you say they are at 50% when the voltage is at, say, 3.8? Or how is that measured?

Anything between 3.4-3.8v, even 3.2-4.0v (no load) is fine with me. I rest/store around 3.5-3.7v.
In general if I fully charge an ‘important’ lithium (my car, phone, and watch-expensive or hard to replace), I try to keep it in that range unless I’m really going to need it soon. If you NEED it, use it.
Battery research has shown it works. My experience has shown it works for me enough to put up with that level of hassle.

It does look like you can change the output significantly. At lower settings it’s pretty reasonable, and it would last a VERY long time. There’s a use/time chart in this review. You have to decide how long you need it, and how long you are likely to use it in a real emergency at required output.
As suggested, you can measure the voltage with a voltmeter. Some lights have a crude % indicator, but this one does not seem to. With time you’ll can get a rough sense of what you are using if you use it fairly routinely.

What does it means this? “You have a light CANON there!”

Spelling error, should be cannon, as in huge gun. (corrected now).
I don’t carry anything like that for scuba, and divers use big lights for scuba. Some do, of course, but they are quite expensive.
My car lights aren’t that powerful.

Got it, thanks

I do not read Spanish, but it looks like there is a 20 volt DC selection. That is what you would use to measure the voltage of your battery. At that price, get two to see if they are accurate. “You tube” has videos showing you how to use a DMM, because the instructions for cheap stuff are often wrong or misleading.

Someone asked Elon Musk on Twitter what he recommends, his response was 30 - 80% will almost double the battery’s life cycles before needing replacement.

Always charging to 100% is wearing your battery at a faster rate. My Samsung S21 has a feature that stops it charging at 85%.

When it comes to most flashlights, max brightness can only be achieved by charging to 100%, so you need to decide how important battery life is or whether max output is…

There is an optimal way to store batteries but AFAIK, that entails keeping the cell at about a 50% charge. Doing this would defeat your goal of having an emergency light. Add the parasitic drain factor and the battery may be completely dead by the time you actually need it.

Best advice, keep it fully charged and replace as needed. Also, keep a backup light as well if you really want to be prepared.

Well, it is good to know it! anyway I will have backup lights and most of my batteries I could let them between 50 and 80%…. good idea, cheers

Look, if you’re going camping in the middle of nowhere and your life may depend on a few minutes more light, charge everything to 100%.

If you have frequent power outages, invest in a few big-ass powerbanks so that you can charge lights, phones, etc., when needed. And worst case, portable solar panels can trickle-charge those powerbanks when not actively needed.

But especially knowing Li cells are hard to get, treat them nicely. There’s nothing wrong with letting a light run down to 3.3V or so. My GTmicro is at about 3.5V now, and I figure I’ll wait a little bit more before topping off. Most of my other lights are around 4.0V or so, unless I use the built-in charger and let it top off on its own. But I do generaly “run them down” a bit to minimise the number of cycles.

If a storm’s coming and there’s a possibility of a power glitch (almost never happens here in NYC unless it’s a local event like a tree keeling over and knocking out powerlines), then sure, I’ll top ’em all off Just In Case.

Just don’t worry or be obsessed with that “100%” day to day.

I agree.

I keep my lithium cells around 3.7V for storage. But I keep my lead acid (for my solar system) fully charged. So in a power cut if I need to charge them, I can easily do so without worrying about wearing them all out prematurely.

The cells that I use daily get fully charged, but I don’t care about longevity on those as I can just buy new ones when I feel the capacity has decreased too much for my liking, or I put them in lower drain lights instead. Even when pushed really hard on a regular basis I still get at least 2 years from a cell.