Thanks alot guys, i’m realtivley new to flashlights/chargers/batteries, i got my Panas green protected 3400 mah, (NCR18650B) having use them for around 1 year, so i always wanted to know what is the best way to prolong life, while having the max output - and optimal charge.
i now know the “best” way of doing it.
Charge to around 4-4.10V and don’t discharge lower then lets say 3.7 - 3.8V i think this is the best balance generally, i also keep my TK 75 (with batteries) in room temp not over 25-30c at most. Thanks one more time.
Edit, my incmong Efest LUC V4 (updated version) will be great in order to know when to get them of the charger, ~ 4.10V without having to check the volts, it has voltmeter on the LED screen, making life so much simple!
Check your Efest LUC V4 charge termination with a multimeter too though if that light runs in series. I notice some bays tend to terminate lower than others, 4.12-4.17, very dissappointing since I bought it to charge all evenly to 4.2V when I needed 4 at a time, as an alternative to the TR-008, which only has 3 bays and always charges all bays to 4.14V. Its kind of nice in a way, a charger imposed battery life increaser.
I also have had some Panasonic 3400mAh batteries that I have had for over a year, with heavier use than most I have heard on here, I tend to have 1+ hr/night average, sometimes up to 3hrs of usage of a light/night walking dogs. No difference in capacity that I notice yet. I do have more lights and batteries that I cycle through, so at least a couple hrs/wk usage is what they get. The only cells I’ve had a problem with (other than crappy Ultrafire in the very beginning) is a red Sony I got from someone else, they got very hot on charging, so I tossed them.
Thanks for the tips, but can’t you use the leds on the display to see the volts? or its in-accurate? i plan to remove the batteries from the charger @4.10 ±
What are the downsides of different volts (after termination)? not sure if TK 75 batteries are in parallel or serial tbh.
Also good to here about the panas doing great.
P.S. Do you have the updated version of the LUC V4?
You could also hook up the volt meter Kodachrome40 linked to a TP4056 charger board to make one of these and have a handy compact charger/volt meter in one.
You might find this information from HKJ useful too
Charge them maximum to 4.1V (90% SOC) and keep cool and recharge when resting voltage 3.8V or higher —> maximum life expectancy
charge them 4.2V and use them till empty and keep hot —> lowest life
Cycle life:
if battery has 300 cycles before capacity reduce to 70% its 100% full charge cycles.
that battery may have around 1000 cycles if you discharge 50%
I’m new to 18650 Li-ions and was wondering how it can have 0% capacity at 3.3 and 3.2. If it has no capacity left at 3.3 how can you still run the cell down to
3.2 and still have light?
BTW that’s a nice chart on capacity TY. I’m keeping a copy for reference.
I just (dis)charge my cells to 3.8v checked with a DMM and then leave them in their battery boxes.
Mine stay at 3.8v for 6 months+. Not sure how much longer because that’s the longest I’ve ever kept them in storage.
I’m no expert but as far as i understand it, about 3v is the lowest a li-ion cell is happy to go to, any lower and damage occurs so the voltage range for these cells is 2.8-3v to 4.2v
3v= fully depleted and 4.2v= fully charged. 3.7v is the nominal, average or working voltage of the cell.
This was confusing to me at first too.
They will still be able to output some power below 3v but like i said, it’s really bad for their chemistry.
Check out my signature links for more useful charts
There is a large difference in voltage, depending on when you measure it, when loaded it is significantly lower.
In some cases that difference can be more than a 0.5 volt.
In the chart below I am switching a 3A load on/off. The red line shows the voltage and it jumps up and down with load/no load:
How low a LiIon cell can go depends on the chemistry and if you measure loaded or unloaded voltage. A modern Panasonic cell can usual go down to 2.5 volt when loaded, but will recover to 3.3 volt when the load is removed.
I think that they should still hold. I have had a good experience with this. I would say a small loss is expected after a couple of years. I love the chart that was placed above. Thanks everyone
I find they either work ok or they lose their capacity to hold a charge ( cheaper nastier batteries ) for any length of time .
Twice a year I go through my rather large 18650 collection to recharge them all , ( Takes about 3 days ) and its this time I check them for voltage ..
The ones that have lost there charge in 6 months just sitting doing nothing get discarded , but the better quality 18650 hardly lose any charge at all .
I have one panasonic that if left @ 4.2v will still be 4.2v 6 months later .
And other batteries that will be close to 3v after 6 months .. ( See the trend here )
Good batteries will hold a charge , cheap batteries will self discharge , and require more frequent charging ( maintenance )
Im also leaning more towards non protected batteries , as cheap protection circuits might put a slight drain on the battery ( I have noticed this )
Removing the protection circuit stops the battery from self discharging .
If I buy more batteries , they will not be protected .
As for degradation ( ageing ) , this is highly variable and depends very much on initial quality and how much the battery is used .
Lets say your 18650 is 10 Wh (for simplicity)
500 0-100% cycles = 5000 Wh
2000 40-80% cycles = 8000 Wh
It’s not really 4x the lifetime, it’s only 1.6x… with the addition of major inconvenience.
Kodachrome is right, 40-80% is the optimum. One cycle are always 100, no matter if you use 3 times 33.3 or two times 50%.
For example the tesla always charges his battery pack to 80% to enhance his lifetime you need to select the full charge in the cars settings and even than it only lasts for few days until it switches back to 80% max…
But you have to think of the huge amount of cells and the costs in this case, that way different with a dozen cells from a flashlight fan.
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I am sure most here recharge the cells before they are empty, I do so, if I recognize a flashlight dimming I recharge this is good for cycle punt and for fun.
Batteries are so cheap so I don’t care so much about this and I always charge them fully because I want maximum current/brightness.
Hmm, it depends what cells you are using. Personally i like high quality batteries which cost like 10$ + per cell, (panas green 3400 protected) and considering i got 2x 4 cell lights, not exactly cheap.
I only have brand batteries but a pair protected panasonics costed me below 14$…so I have bought a dozen or so, I remember times were good batteries were not available or very expensive but it’s a lot better now even ten dollar is okay if you consider to get the best protection circuit and a very good cell…
Sanyo 2600 cost around 11$ per pair…
The lgD1 4.35V batteries are also not so expensive( I ordered 3 pair for 9$ each at fasttech), I recommend them because the higher voltage is a huge benefit especially if you want to use them with linear drivers like the nanjg.
Charging them to only 4.2 gives you the benefit of high cycles with the benefit of high voltage….
I have some lipo RC packs which I store at 3.6V because these are somewhat expensive and I know that I don’t need them fully charged all the time, but even in this case I know that I can toss them in few years…
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