black enelope 2450 mah vs 21700 4400 mah?

[raggie33]

how many enelopes does it take to get the same runtime of a 4400 mah 21700?

 

[orbital]

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A small handful raggie.

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I'm sure you'll get some long essay on it, but it's apples to oranges with voltage ect..



.

 

[raggie33]

cool im still working on what power source to use if the world goes nuts and we lose are homes

 

[thermal guy]

Ya that's not an easy one. volts are different. Lot of maths😁 and if there series or parallel

 

[xxo]

about 5 1/2 enelloop pros or 7 standard Eneloop AA's..

 

[fivemega]

how many enelopes does it take to get the same runtime of a 4400 mah 21700?

If you consider each Eneloop as 1.2V at 2200mAh
then 3S/2P (total of 6 Eneloops) will be at 3.6V and 4400mAh which is very close to 3.7V, 4400 mAh 21700

 

[raggie33]

cool looks like ill go with 21700 plus im sure they can provide more amps

 

[3_gun]

That's one way to look at it BUT if you're worried about preparedness the redundancy of multiple lights using eneloops could be a better answer to a lighting problem.

A test I just ran with my LD12 shows me if total light out put is what I want; cheap Harbor Freight AA batteries are a better answer than Energizer L91 batteries. For the cost of 1 L91 I can get 6 HF AA batteries. 1 L91 = 8 1/2hrs, 1 HF = 2 3/4hr; so for the same cost I can have 8 1/2 or 16 1/2 hours of 70L light. Then for the same cost, if you have 4 good lights instead of 1 great light, a loss or breakage isn't as bad. Plus 4 lights spread out can light a much larger area. Also to much light just lets potentially "bad people" know where to look for supplies. Standing out in the dark is called being a target

 

[xxo]

That's one way to look at it BUT if you're worried about preparedness the redundancy of multiple lights using eneloops could be a better answer to a lighting problem.

A test I just ran with my LD12 shows me if total light out put is what I want; cheap Harbor Freight AA batteries are a better answer than Energizer L91 batteries. For the cost of 1 L91 I can get 6 HF AA batteries. 1 L91 = 8 1/2hrs, 1 HF = 2 3/4hr; so for the same cost I can have 8 1/2 or 16 1/2 hours of 70L light.

I would much rather put the $ towards eneloops and to a lesser extent L91's than alkalines - I've had way too many alkalines leak while still in the packages, years before their expiration date to waste money on them. Not to mention all of the items damaged or destroyed by leaking alkalines.

 

[bykfixer]

I stored a 2c flashlight with a pair of rechargeable c sized cells back in 2017. Also a 2c flashlight with a pair of eneloops. (same model flashlight)
A year later the c cells were dead. The eneloops were not.

Point being if they don't hold a charge, the eneloop is the way to go for long term storage.

 

[ikanode]

When trying to compare capacity at different voltages, the key is to convert amps to watts. Then the math and comparison is easy!
Watts = Amps X Volts

1.2v @ 2200 mAh = 2640 milli-Watt hours

3.6v @ 4400 mAh = 15840 mWh

15840 mWh ÷ 2640mWh = 6

So it takes 6 Eneloops to match the capacity (runtime) of one 21700.

 

[3_gun]

Four eneloop Pro batteries sell for $26, 1 Fenix 21700 sells for $28; $26 gets you 144 Harbor Freight batteries. Which gives more run time for the cost? That's only one way of looking at the problem.

I prefer 21700, 18650 & 123a batteries over AA & AAA batteries but I have all of them in supply, in redundancy. I have a way to recharge them w/o power and a way to recharge that w/o power. I also have a generator.

2 is 1, 1 is none. I have blackout curtains to block sound/light & prying eyes. I have cheap eBay lights to use around people I don't know. Being prepared when other aren't puts a target on your back. The less you stand out the better & if that means I use my cheap eBay zoomie more than my Surefires or Fenix lights so be it & if push comes to shove .. I can shove VERY hard

 

[orbital]

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cool looks like ill go with 21700 plus im sure they can provide more amps

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This is key, being able to provide more amps.

The 6 eneloops (in W/hr) will go up, if you push more Amps,, it changes the playing field.
So trying to make a reasonable 500lm, you may need 8 eneloops to hang with a 21700 ~ if eneloops even do it at all.

Just looking at W/hr, is not the full picture.

So my previous answer of a small handful was in super simple terms.

 

[Lynx_Arc]

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This is key, being able to provide more amps.

The 6 eneloops (in W/hr) will go up, if you push more Amps,, it changes the playing field.
So trying to make a reasonable 500lm, you may need 8 eneloops to hang with a 21700 ~ if eneloops even do it at all.

Just looking at W/hr, is not the full picture.

So my previous answer of a small handful was in super simple terms.

Yeah not quite the full picture as it also depends on the circuitry used and the LED too as you can have buck circuitry that essentially exchanges excess voltage for higher current and also internal resistance of batteries that under high current can either handle it or cause the batteries to heat up and have power loss and voltage drop. 18650s and 21700s can be gotten that handle high currents over 20A and with lower internal resistance lose less power doing so perhaps.
One big issue that most don't consider is cells in series that don't have circuitry protecting them from overdischarging can be damaged. I've lost over a dozen nimh cells using them in series in devices that drain them too low the weakest and lowest capacity cells can be literally driven backwards in charge (reverse charged) in some instances and require a charger that can refresh them to gain any sort of functionality and likely can lose considerable capacity and even develop higher internal resistance and lose lower self discharge also. I've gravitated towards single cell 1.5v lights and 18650 based lighting and devices. I don't have any 21700s yet as I've found 18650s a lot more common leading to cheaper solutions overall plus you can harvest discarded battery packs and power banks for cells. The main advantage 21700s have is more capacity and a little higher current capability that if not really needed just simply adds a little more volume to whatever is using it.

I guess since I've gone from C/D cells power most devices in the incan and then fluorescent days to AAs then nimh and eneloops to finally lithium ion power. To me it is the most cost effective highest performing battery platform for the time being. It is likely 21700s will more and more compete on an even basis like C vs D and AAA vs AA has been in the past but probably there will be cost difference that levels the cost/mah amount.
For quality performance lights I would say go with 18650 by default if that will easily do the job and if you need the higher performance then definitely consider 21700s for even higher performance. My concern is that they will come out with yet another "common" battery size for cars and power tools and 21700s could go the way of 20700s in the future.

 

[GaryF]

Where are you guys finding 2200 mah Eneloops?

 

[orbital]

... My concern is that they will come out with yet another "common" battery size for cars and power tools and 21700s could go the way of 20700s in the future.

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Even if there is a new '24800' or whatever, I'm not buying it.
Getting new lights, batteries & chargers to fit, becomes a lesson in economics.

If my 21700s' can't get the job done, I missed the plot.

__________
Tesla proved that the 21700 size is a top bang for the buck, in energy density.
(do you think they didn't look at every possible size, likely not)
Yes they have a new battery, it's huge..maybe for some giant light cannon 2025

 

[3_gun]

Amazon & others

 

[Lynx_Arc]

+

Even if there is a new '24800' or whatever, I'm not buying it.
Getting new lights, batteries & chargers to fit, becomes a lesson in economics.

If my 21700s' can't get the job done, I missed the plot.

__________
Tesla proved that the 21700 size is a top bang for the buck, in energy density.
(do you think they didn't look at every possible size, likely not)
Yes they have a new battery, it's huge..maybe for some giant light cannon 2025

It may be the best bang for the buck when it comes to price but energy density is pretty much the same and 18650 cells are for now cheaper per mah than 21700s I think. I believe the 5000mah 21700s are a little more density than the 3500 18650s are but it is rather negligible. Basically it comes down to size vs total capacity with consideration to higher current capability of 21700s and likely lower internal resistance. The larger size of 21700 in some cases is a drawback when you only need a few cells. If you don't need a huge amount of lumens for a long time or the max power you can get for now the 18650 still rules the market but quickly I think the two cell sizes are going to be commonplace.
Personally I would like to see improvements in smaller battery sizes like 18350, 16340, and even 14500 as if these matched the power density of the larger ones they could be for me take the place of 18650s and up. I think 14500s are about 55% the power density of 18650s they should be closer to 1600mah.

 

[Lynx_Arc]

Where are you guys finding 2200 mah Eneloops?

They could be the Chinese ones which aren't IMO worth it. There are 2000mah eneloops and eneloop pros that are about 2400 I think but 2200s remind me of the Rayovac Hybrids which preceded eneloops on the market by I think 6 months to a year or so. Most of my ROV cells have gone bad vs about 10% of my Duraloops have gone bad the majority of which are AAAs I think. I say stay away from chinese eneloops entirely

 

[GaryF]

I have Original Eneloops from 2006 and 2007 still in service and going strong, as well as 4 Duraloops from that era. I think 3 out of 16 have failed, but 2 of those were crushed a little and had physical damage. 15 years of service, it's just amazing.

In the meantime I have tried Eneloop Pros and Rayovac Hybrids, and they lasted a few years at best before internal resistance and self discharge became a problem. I've more recently tried the Amazon Basics LSD cells, and they are also beginning to fail.

That said, I also have some of the Chinese / Panasonic 2000 mah Eneloops, and they are holding up very well.