VTC6 Voltage loss-"is it Normal"?

[SubLGT]

Here is a short article about why Li-ion batteries lose capacity

http://www.electrochem.org/redcat-blog/finding-causes-battery-capacity-fade/

The capacity of a lithium-ion battery directly correlates to the amount of lithium ions that can be shuttled back and forth as the device is charged and discharged. Transition metal ions make this shuttling possible, but as the battery is cycled, some of those ions get stripped out of the cathode material and end up at the battery's anode.

 

[iamlucky13]

This is what I've thought the wisdom was- that voltage extremes and heat extremes degrade LiIon lifecycle, so for maximum lifecycle, we'd want to keep % somewhere between 40 and 70 or so, with occasional deep discharges. If we care about maximum lifecycle. Everything is a trade-off.

I wonder how the VTC6's would have held up had they been charged to say 95% capacity instead of 100%? Perhaps much better.

Right. If you can keep keep the average voltage moderate, you can see big gains in cell life for a given delivered capacity (eg: 100% SoC to 50% SoC cycles versus 75% SoC to 25% SoC cycles). It helps both with the wear that results from charging and discharge, and with the aging that occurs over time.

Reducing the charge level to 95% of nominal doesn't help the aging much, but I think it would help the cycling wear a moderate amount. It's also a non-trivial hassle for managing a battery that has an effective cost of a penny or two per charge cycle. That's assuming you get the 500 cycles they are typically rated for, which means weekly recharges for a decade, and therefore, aging is as much of a concern for a lot of us as cycling.

Those factors should affect all lithium ion cells. I didn't realize the point he was making at first, but what Capolini has clarified, is that the VTC6 seems to be more sensitive to these factors than the 30Q.

 

[ChrisGarrett]

Right. If you can keep keep the average voltage moderate, you can see big gains in cell life for a given delivered capacity (eg: 100% SoC to 50% SoC cycles versus 75% SoC to 25% SoC cycles). It helps both with the wear that results from charging and discharge, and with the aging that occurs over time.

They're lithium ion cells, costing a $4-$10 each, not a $90,000 Porsche 911.

I would have an aneurysm if I had to think of all the above, prior to using them.

Life's too short, my brothers and we have these fun things called 'women'.

Chris

 

[Tachead]

They're lithium ion cells, costing a $4-$10 each, not a $90,000 Porsche 911.

I would have an aneurysm if I had to think of all the above, prior to using them.

Life's too short, my brothers and we have these fun things called 'women'.

Chris

I have to agree. For the cost of bare premium 18650's these days, I don't worry much at all. Sometimes I even leave them full for days or weeks if I don't use as much mAh's as expected and don't get around to discharging them to storage voltage. I also discharge way below 3.75V quite a bit of the time. I still get years of use out of them at a respectable capacity. I say just use them and abuse them then recycle and replace as needed. You will still likely get years of service under most conditions equaling only pennies per cycle.

 

[ven]

:laughing: Say it how it is Chris!! I totally agree though, life is way too short. I still keep an eye on voltages, never too low or high, matched cells in multi cell lights, of good quality from reputable sellers. I never leave unattended , i had gone through a time leaving them on overnight(kind of a bad habit tbh), but not done that for well over a year. No matter how much trust/confidence i have in electrical equipment, it can fail...............1 in a 1,000,000 is still one time of a fail!

For me charging to set voltages(even pre-set so no need to watch V ), or making sure my light never gets bellow a set V and working between 2 set parameters would be a chore. Would take enjoyment out of my uses, and adding another complication to life which already has them in abundance! When my cell/s tire and dont hold V or cant power what they use to, recycle and fresh bought. Said before, but i still have cells of use that must be 7+yrs old now............

That aside, i am grateful to capo for the tests(and mooch/HKJ) which do make interesting reading

 

[Capolini]

They're lithium ion cells, costing a $4-$10 each, not a $90,000 Porsche 911.

I would have an aneurysm if I had to think of all the above, prior to using them.

Life's too short, my brothers and we have these fun things called 'women'.


Chris

So what!! lol!! I would still rather have cells that perform better,especially for the money!

 

[Capolini]

They're lithium ion cells, costing a $4-$10 each, not a $90,000 Porsche 911.

I would have an aneurysm if I had to think of all the above, prior to using them.

Life's too short, my brothers and we have these fun things called 'women'.

Chris

I forgot something! If it does not matter why don't you use some Ultrafire instead of your beloved AW'S??!!!

 

[ChrisGarrett]

I forgot something! If it does not matter why don't you use some Ultrafire instead of your beloved AW'S??!!!

All the cool kids have moved on to ASPIRE, or AWT.

AW is so 2015.

Did you not get the memo?

Chris

 

[Capolini]

Sometimes my thoughts come in Piecemeal! That is what happens when you get close to 60!

It is NOT about saving a few dollars. It IS about performance. I do not want a battery that will degrade quicker and lose that ability to perform.

I have no problem paying for the VTC5A which to this point appears to have great performance and less degradation than the VTC6.

 

[ChrisGarrett]

Sometimes my thoughts come in Piecemeal! That is what happens when you get close to 60!

It is NOT about saving a few dollars. It IS about performance. I do not want a battery that will degrade quicker and lose that ability to perform.

I have no problem paying for the VTC5A which to this point appears to have great performance and less degradation than the VTC6.

Cap, I like you and I appreciate your recent testing procedures. In no way was I disparaging your efforts. I simply replied to the fellow, who was replying to Gaus168.460's post about the various parameters of cell degradation.

My quip was meant more for the people pointing out those 'windows' where absolute longevity might be realized and commented that, for me at least, to go through that routine, might not be worth the effort, even though theoretically, it would benefit a cell's total lifespan.

I love fiddling with this stuff as much as the next guy, but at some point, to me, it's probably not worth the effort, since they're not all that expensive to replace in the long run.

I have nice target grade rifles that I take care of and don't want to abuse, but they're $1000 to rebarrel, so I get the concept.

Anyhow, keep the good tests coming.

Chris

 

[iamlucky13]

They're lithium ion cells, costing a $4-$10 each, not a $90,000 Porsche 911.

I would have an aneurysm if I had to think of all the above, prior to using them.

Life's too short, my brothers and we have these fun things called 'women'.

Chris

I agree, which is why I also pointed out we're talking about pennies per charge. I'm not suggesting maximizing cell life is some sort of absolute imperative.

Regardless, having dealt with disappointing battery life spans in the past, sometimes on $100+ dollar laptop packs, I find it both interesting and useful to know what factors affect battery life, so I can decide for my own circumstances if it's worth the effort to control that factor in some way, and choose the batteries best suited to my use.

 

[Capolini]

DUPLICATE,,,,,DELETED

 

[Capolini]

Cap, I like you and I appreciate your recent testing procedures. In no way was I disparaging your efforts. I simply replied to the fellow, who was replying to Gaus168.460's post about the various parameters of cell degradation.

My quip was meant more for the people pointing out those 'windows' where absolute longevity might be realized and commented that, for me at least, to go through that routine, might not be worth the effort, even though theoretically, it would benefit a cell's total lifespan.

I love fiddling with this stuff as much as the next guy, but at some point, to me, it's probably not worth the effort, since they're not all that expensive to replace in the long run.

I have nice target grade rifles that I take care of and don't want to abuse, but they're $1000 to rebarrel, so I get the concept.

Anyhow, keep the good tests coming.

Chris

Thanks,,,,,,,,,,,a misunderstanding on my part.

Glad to see that someone likes me on here!!!!:laughing:

 

[Gauss163]

They're lithium ion cells, costing a $4-$10 each, not a $90,000 Porsche 911....

Again, you seem to be forgetting that some of us also have very expensive battery packs (e.g. huge powerbanks, ebike batteries, etc) and/or very expensive devices with non-replaceable batteries, etc, where said optimizations may prove quite valuable for extending calendar / cycle life.

In any case, as I emphasized before, decisions on the merits of such optimizations are highly context dependent, involving motley highly subjective factors. Please try to keep that in mind when assessing such discussions.

 

[Nev]

VTC6 Voltage loss-"is it Normal"?

Oi cap,I like you too [emoji8]

 

[Nev]

I like ya dog more though [emoji190][emoji173]️[emoji190]

 

[Capolini]

Re: VTC6 Voltage loss-"is it Normal"?

Oi cap,I like you too [emoji8]

Thanks NEV,,,,Maybe I will start a fan club,,,,for CAPO!!!!

yaaa,everybody LOVES Capo!

Capo and One of his Girlfriends[in the foreground] in the Poconos.:thumbsup: