A question about the life of the batteries

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marcosgg
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A question about the life of the batteries

Hello, I have an Imalent MS08 that I love with all my being… I use it mainly as an emergency light in case of power outages, so every time it discharges, even a little (80, 90%), I recharge it to 100%. Will that wear out the batteries more than if I let it run down to, say, 30% and then charge it to 100%?

What is the best way to take care of batteries? Always charge them to 100% no matter what happens, or let them discharge more?

I’ve only had it for a short time… the most they discharged was maybe 50% when I did several tests the other day, and then it was charging 3 hours and something.

jeff51
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Ask this over in the rechargeable batteries section and you will get way more traffic.
In general keeping the batteries topped off will shorten the life.
But just how much affects total life may not make that much difference in the long run.
It’s a trade off. Remember lith drop off the highest charge V quickly.
So you are not loosing much runtime at 4.2v. Vs a bit less.
All the Best,
Jeff

BlueSwordM
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Yes.

Your best bet to take care of cells is to not worry too much about battery life and just use your light normally.

Your light has good brightness regulation, so don’t worry too much.

Besides, most of the capacity is found around 3.6V, so no need to worry much.

My very own high current Beryllium Copper springs Gen 3:
http://budgetlightforum.com/node/67401
Liitokala Aliexpress Stores Battery Fraud: http://budgetlightforum.com/node/60547

Vegas LED Fan
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Do a Google search on “storing lithium ion batteries” and you will see almost universally that the longest life is gotten if you store them at 30 to 50% capacity and that charging them to 100% before storing them will shorten the battery lifetime. Most manufacturer websites say that you can recharge the batteries between 300 and 500 times before the capacity decreases enough to need replacement. When I go camping and use lithium ion batteries for lights I always charge them to full capacity a day or two before.

will34
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There will be tests out there that will claim storing at 100% capacity won’t affect cell life, but I found much faster self discharge from 4.2V to 4.1V than 3.8 to 3.7, and cells that are stored full will be more likely to experience earlier degradation: not holding peak current and capacity loss.

marcosgg
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Ok, I concluded to not charge them every time I know they are a bit discharged… is it ok?

BlueSwordM
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Yeah, don’t worry too much Big Smile

My very own high current Beryllium Copper springs Gen 3:
http://budgetlightforum.com/node/67401
Liitokala Aliexpress Stores Battery Fraud: http://budgetlightforum.com/node/60547

Helios azimuth
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Get a DMM and check the voltage after any long use. Even a cheap DMM is better than none. Everyone has their own methods, but my concern is not running them too low. What is too low? Ask and get a bunch of answers, but for me nothing goes below 3.2v unless I am backpacking and need the light. Often I charge at 3.5v for frequently used lights. And I tend to stop charging around 4.0v. But batteries are cheap, so you can easily replace them more often if you don’t want the hassle. Just don’t run them too low and monitor them when charging.

marcosgg
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Helios azimuth wrote:
Get a DMM and check the voltage after any long use. Even a cheap DMM is better than none. Everyone has their own methods, but my concern is not running them too low. What is too low? Ask and get a bunch of answers, but for me nothing goes below 3.2v unless I am backpacking and need the light. Often I charge at 3.5v for frequently used lights. And I tend to stop charging around 4.0v. But batteries are cheap, so you can easily replace them more often if you don’t want the hassle. Just don’t run them too low and monitor them when charging.

Good, so is this ok?

https://articulo.mercadolibre.com.ar/MLA-915281608-tester-multimetro-dig...

I can see 10A, not 35A… is that ok?

achilles' spiel
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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.

marcosgg
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achilles' spiel wrote:
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.

marcosgg
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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…

raccoon city
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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.  :FACEPALM:

alpg88
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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.  

marcosgg
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alpg88 wrote:

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!

flydiver
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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.

To Air is Human, to Respire….Divine.

BlueSwordM
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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.

My very own high current Beryllium Copper springs Gen 3:
http://budgetlightforum.com/node/67401
Liitokala Aliexpress Stores Battery Fraud: http://budgetlightforum.com/node/60547

marcosgg
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flydiver wrote:
You have a light CANON 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.

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?

flydiver
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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.

https://davestechreviews.com/2021/12/21/imalent-ms08-flashlight-review/

To Air is Human, to Respire….Divine.

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

flydiver
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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.

To Air is Human, to Respire….Divine.

marcosgg
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Got it, thanks

Helios azimuth
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marcosgg wrote:
Helios azimuth wrote:
Get a DMM and check the voltage after any long use. Even a cheap DMM is better than none. Everyone has their own methods, but my concern is not running them too low. What is too low? Ask and get a bunch of answers, but for me nothing goes below 3.2v unless I am backpacking and need the light. Often I charge at 3.5v for frequently used lights. And I tend to stop charging around 4.0v. But batteries are cheap, so you can easily replace them more often if you don’t want the hassle. Just don’t run them too low and monitor them when charging.

Good, so is this ok?

https://articulo.mercadolibre.com.ar/MLA-915281608-tester-multimetro-dig...

I can see 10A, not 35A… is that ok?

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.

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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…

Piercing The Darkness YouTube channel – https://www.youtube.com/c/PiercingTheDarkness

zoulas
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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.

marcosgg
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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

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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.

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marcosgg
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I agree.

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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.