NiMh 1.2v is STILL the most underrated battery......

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nottawhackjob
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NiMh 1.2v is STILL the most underrated battery......

IMO NiMh is underrated and underutilized still to this day vs lithium. Toroid-type boost drivers with NiMH if more would be used in even today’s hi-power lights would surprise many.

What even a single AA NiMh high quality battery such as an Eneloop can do with a well-designed toroid boost driver matched to the right LED is frankly astonishing. A 14500 or 10440 lithium battery for example is overrated and over-hyped.

The bottomline point is that toroid drivers need more development attention to take advantage of the NiMh advantages
for flashlights.

Heck, even Tesla should offer a NiMh platform option instead of lithium. It sure would eliminate the inferno factor plus added longevity for what may be only a small relative drop in 0-60 mph performance.

I’d like to see some of our resident geniuses here push the envelope with NiMh to the max for one of these mambo lumen creations. IMO it hasn’t been done yet.

What do you think? Should we be torroiding more? Grad

Edited by: nottawhackjob on 06/04/2018 - 13:45
Enderman
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best nimh compared to li-ion:

3x worse wh/kg
2x worse wh/L
6x worse wh/$

nottawhackjob
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Even when torroided?

bmengineer
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Yes.

Enderman
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nottawhackjob wrote:
Even when torroided?

A boost driver just adds inefficiency and reduces the available wh.
All it does is draw more current and produce a higher voltage.
It can’t magically increase the capacity or energy density of batteries.
BlueSwordM
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Torroided? Don’t you mean boost drivers?

Also, the reason almost no higher powered lights use AA NiMH cells with a boost converter is that you need a very powerful boost converter to put out even 500 lumens, and at 1.2V nominal, pulling 5A of current results in a huge power loss in every part of the circuit, because even if there was only a 0.1V drop across the contacts at 5A, we would be losing about 0,5W alone in the contacts, which is 16% of the energy already lost in the contacts. For the same lithium ion cell at 3.6V, you lose 0,5W still, but for a 3000 mAh cell, you only lose at most 5% of the cell’s capacity in Watt Hours.

Also, boosting 1.2V at 5A to 3.2V 1.8A is very hard to do, and very expensive.

Also, even in the best of cases, NiMH has about half the energy density of lithium ion, about 1/3 of the power density, and 2-3x more expensive per Wh compared to lithium ion.

nottawhackjob
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Well in REAL life I have single AA NiMh toroid/boost lights that keep up and oft times kick butt over 14500 lights.

The Zebra SC5w for instance.

How come?

Enderman
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The values I used for li-ion are based on 18650s, not 14500.
I don’t know how the best 14500 cells compare to nimh.
Probably a lot worse than 18650s.
Also different flashlight manufacturers design their lights differently so you can’t really compare them unless it’s a 14500 zebralight vs AA zebralight.

BlueSwordM
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The price, and energy density which is lacking in 14500 cells since none of the big players are making advances in the 14500 world for good reasons.

As an example, let’s take the SC5w and compared it to a Sofirn SP10B.

One can do 550 lumens from a NiMH AA, one can do a bit more than that at 600 lumens from a 14500, although direct drive, and only 270 lumens from an AA NiMH cell.

The difference? The SC5w costs 69$, while the SP10B costs 10$ usually. I know that the difference in price is not only because of the driver, but getting a constant 500 lumens from a single AA light is very hard to do, very expensive, and requires expensive components so you don’t lose over 20% of the energy just in the contacts and traces alone.

It is also limited to doing 550 lumens for 3 mins, then drops down to 400 lumens. Well made 14500 cell lights can easily maintain that for quite a bit more than 3 mins, although runtime will be overall shorter.

nottawhackjob
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So if I understand you correctly the chemistry used in manufacturing a 14500 battery is not as good/same as a 18650.

What specifically in the 14500 chemistry is lacking vs 18650 that in the high majority of brands being made makes them relatively inferior? Could it be that a boosted AA Eneloop performs superior vs an 14500 starting out already at 4.2/3.7v no matter how you math it out?

I guess when someone uses the term “energy density” I’m having trouble figuring out that in all these years of lithiums that apparently very few manufacturers took the time to take the same superior chemistry in 18650’s and wrapped it in a smaller package. It must be really hard to do, right?

vt2nv
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Perfect.

Enderman wrote:
nottawhackjob wrote:
Even when torroided?
A boost driver just adds inefficiency and reduces the available wh. All it does is draw more current and produce a higher voltage. It can’t magically increase the capacity or energy density of batteries.
Parametrek
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Enderman wrote:
best nimh compared to li-ion:

3x worse wh/kg
2x worse wh/L
6x worse wh/$

I get slightly different numbers from my battery database. The Wh/$ is only 2x worse when considering an 8xD pack of Tenergy NiMH and 2.5x worse for the 16xAA pack.

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Enderman
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Parametrek wrote:
Enderman wrote:
best nimh compared to li-ion:

3x worse wh/kg
2x worse wh/L
6x worse wh/$

I get slightly different numbers from my battery database. The Wh/$ is only 2x worse when considering an 8xD pack of Tenergy NiMH and 2.5x worse for the 16xAA pack.


I compared eneloops/eneloop pros to the samsung 35E to get my numbers.

nottawhackjob wrote:
So if I understand you correctly the chemistry used in manufacturing a 14500 battery is not as good/same as a 18650.

What specifically in the 14500 chemistry is lacking vs 18650 that in the high majority of brands being made makes them relatively inferior? Could it be that a boosted AA Eneloop performs superior vs an 14500 starting out already at 4.2/3.7v no matter how you math it out?

I guess when someone uses the term “energy density” I’m having trouble figuring out that in all these years of lithiums that apparently very few manufacturers took the time to take the same superior chemistry in 18650’s and wrapped it in a smaller package. It must be really hard to do, right?


I don’t know, maybe chemistry since the best 18650s are NMC, not sure about 14500
If someone can tell me what the best 14500 cell is then I could calcualte and compare.
There’s a lot more research and manufacturing improvements being put into 18650 batteries because they are thousands of times more commonly used than 14500.
BlueSwordM
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@notawhackajob, it is because the best NiMH cells have 3Wh of energy, while the best 14500 cells only have 3Wh.

nottawhackjob
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Well in tangent I constantly hear that 18650 chemistry is so much more superior to other battery designs and so then I wonder if it’s really that it’s superior chemistry or only that the SIZE of 18650 has become kind of a defacto standard.

The 20700 is getting pushed more and more now. Assumably it has the same superior “energy density” of 18650. Somehow though in past and now, 14500’s never got the same degree of
design/build treatment even though a crapload of lights use them.

Enderman
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nottawhackjob wrote:
Well in tangent I constantly hear that 18650 chemistry is so much more superior to other battery designs and so then I wonder if it’s really that it’s superior chemistry or only that the SIZE of 18650 has become kind of a defacto standard.

The 20700 is getting pushed more and more now. Assumably it has the same superior “energy density” of 18650. Somehow though in past and now, 14500’s never got the same degree of
design/build treatment even though a crapload of lights use them.


There are other NMC batteries in non-18650 form factor which I have found, with similar energy density and capacity per size, however since 18650s are so much more common the Wh/$ of 18650s is superior to these other NMC cells.
WalkIntoTheLight
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My Zebralight SC5w is probably my favourite all-time light. 500+ lumens from a single AA Eneloop kicks ass.

That said, it’s not the most practical light at that output. I get 20-25 minutes of 500 lumen output (regulated) on a regular AA Eneloop out of it.

On my Zebralight SC600w Plus, which is a single 18650 light, I get almost 6 hours at 350 lumens and almost 3 hours at 700 lumens (regulated). If it had a 500 lumen setting, it would be about 4.5 hours of run time. (Sanyo GA cell.)

So, that’s well over 10x the run-time out of a 18650 than a AA Eneloop. The 18650 may only have 4x the energy of an Eneloop, but it can deliver it far more efficiently.

I do believe that NiMH, especially Eneloops, are very under-rated in the general public. But, they use alkaleaks and think that the Energizer bunny is state of the art. Eneloops are great batteries, but for sheer power you really do need to go with lithium-ion.

14500 lithium-ion I think is over-rated, though. It’s only a small step-up from NiMH. Personally, I don’t see the point of 14500’s. Either stick with Eneloops which can still provide good output, or go with 18650 which provides a lot more power and run time.

nottawhackjob
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Back to the original premise of the AA Nimh being underrated (basically being the 18650 of the world) I will still contend that a properly boosted AA Eneloop is superior to a 14500 direct driven format.

Now if Eneloop or Fuji put out a retail 18650 size version of their exquisite AA, I’d be all over it.

3 to 4 x AA Nimh in a battery carrier type stubby high performing flashlight almost gives me a Woodrow. I mean how much continuous uber-lumen runtime do you really need 99% of the practical time, especially heat dissapation wise?

Breaking records is ok. EDC practical use?

Give me a well-boosted AA NiMh or two. The boost is good. LOL

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Developing new improved chemistries cost money and you need to recoup that cost by making the most money from the batteries you sell in turn. 18650 is used everywhere and has a huge market. 14500 is a tiny market. A manufacturer only wants to make 1 size of cell to maximize the rewards from economies of scale.

There is practically no money to be made in oddball sizes. As a result many of the weird little cell sizes will use older more generic lower performance formulations.

Right now we are entering a very interesting period since Tesla is trying to push a move away from the 18650. So you’ll see 20700 and 21700 cells with the latest and greatest because someone is lining up to spend billions on these cells. But only hobbyists and solar light manufacturers care about 14500.

If you want good 14500 cells then first become an eccentric billionaire and then blow your entire fortune on a giant order Smile

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nottawhackjob
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So the 20700 and 21700 will have a different assumably superior composition while also being bigger and heavier than 18650. Seems to me outside of Tesla and maybe power tools this lithium push doesn’t do much for our little world here.

On the powertool side going brushless has been a big deal. Improvement of drivers and LEDs for lights kinda the same correlation. Going from 18650 to 20700/21700, meh, I bet not nearly.

nottawhackjob
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“….become an eccentric billionaire and….”

Yeeeeeah. I’m still working on that.

LOL
WalkIntoTheLight
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nottawhackjob wrote:
So the 20700 and 21700 will have a different assumably superior composition while also being bigger and heavier than 18650. Seems to me outside of Tesla and maybe power tools this lithium push doesn’t do much for our little world here.

Yeah, I don’t get the excitement some have for those new formats. 18650 is already on the large size for EDC or even pocket carry on walks. I don’t want something larger. Yes, it will give you more capacity and current, but an 18650 already seems plenty good enough for 99% of uses.

nottawhackjob
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You might as well go 26650. This 20700/21700 upcropping sorta reminds me of Betamax vs VHS.

And at the end of the day we all went DVD. Cool

So all the gazillion lights in 18650 tubes are basically hosed if this new size takes over.

Let’s hope not. It’s stupid.

And just becuz Tesla’s gonna do it means it makes more sense for everyone else too. Notta so much.

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I can see the 14500 cells not being much better than a high quality eneloop nimh, I’ll agree with you on that.
18650s though are still far ahead.

———————————————————

2170 cells are actually not any better than 18650s, despite all the hype.
Their chemistry is the same, energy density is the same, energy per volume is the same, the only differences are
1) it is way more expensive per Wh, since 18650s are much more common and 21700/20700 cells are rare
2) they can deliver higher currents continuously, similar to 26650s or high discharge 18650

The cells tesla is using are actually NOT the best, they opted to go for a more economical chemistry from panasonic which is not NCM.
It is very similar though, hence the similar energy density.

The claims about 5750-6000mAh per cell from that one random youtube video are actually false.
The actual capacity is closer to 4600-4800mAh, like the samsung 48G

nottawhackjob
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As I hunched, the 20700/21700 hoopla is full of poopla. LOL

And no I wasn’t inferring that a AA Nimh could go toe to toe with an 18650. Ok well maybe with an Ultrafire it can. Shocked

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nottawhackjob wrote:
You might as well go 26650. This 20700/21700 upcropping sorta reminds me of Betamax vs VHS.

And at the end of the day we all went DVD. Cool

So all the gazillion lights in 18650 tubes are basically hosed if this new size takes over.

Let’s hope not. It’s stupid.

And just becuz Tesla’s gonna do it means it makes more sense for everyone else too. Notta so much.

Why do you consider 21700’s stupid? Just because it’s larger?

I do agree however that for travel and EDC purposes 18650’s are already on the big side. I’d actually almost rather see more research go into increasing 14500 capacity.

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nottawhackjob wrote:
As I hunched, the 20700/21700 hoopla is full of poopla. LOL

Comparing a mid drain 18650 vs a 21700, you get about 40-50% more capacity with the 21700, while physically it is not that much larger than 18650, so that’s definitely something. But, a 21700 is also about 50% more expensive than an 18650, so it’s a wash. But if you need more capacity at the expense of slightly larger size, then 21700 gives it to you.

Time will tell what advancements will be made to the 21700 cells in the future.

Enderman
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21700: It’s like 40% more size and 40% more capacity, so not any better density than an 18650.
26650s are lower density but better price per wh.

Also from what I’ve look up quickly, 14500 cells are about 3wh at best, just like eneloop pros.
Seems like they have trouble delivering high currents, while nimh cells still keep most of their capacity at higher currents, and can do 10A no problem.

So yeah it definitely seems like an eneloop AA would be a better choice than 14500, only problem is that LEDs have a higher vf so a boost driver is 100% required adding inefficiency.
This can be solved by using multiple AA or AAA cells rather than a single one and a boost driver, like led lenser does. Their lights use 3-4 cells.

chadvone
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It never was

eas
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Meh. Does anyone else feel like notawackjob is getting other people to do his homework for him?

Too many streetlights, not enough flashlights.

Enderman
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Well I mean he kinda is right when comparing eneloops to current 14500 batteries.

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