18650 Lithium Primaries?

spyderco monkey · Jul 26, 2019

Does anyone know, have there ever been any 18650 Lithium Primaries produced?

It seems like that would make for a great option - the simplicity and long shelf life / temperature resilliance of CR123's, but with increased capacity and power potential of the 18650. As it stands, 18650's don't really seem suitable for emergency lights or weapon lights that will be subject to temperature extremes and long storage without attention.

I know for 3.7V 14500 batteries (typically rechargeable) there are 3.6v lithium primaries available:
https://www.newark.com/saft/ls14500/lithium-battery-3-6v-aa/dp/23C2691

Not only is the voltage nearly the same, but capacity is greatly increased. The Orbtronic 14500 rechargeable is 840mah vs 2600mah for the lithium primary. Likewise a CR123 typically has 2x the capacity or a RCR123.

That suggests that a Lithium Primary 18650 could hold a ton of juice.

Assuming this battery doesn't exist, how hard would it be for a manufacturer of existing 18650 rechargeables to produce one? Is it simply a matter of filling a 18650 body with a different lithium battery 'paste' or is it substantially more complex then that?

HKJ · Jul 26, 2019

The Saft batteries cannot replace a LiIon battery, they are designed for much low current drain and have lower voltage.
They are often embedded in equipment that will then last 5 to 10 years before being replaced.

Producing a new battery may be simple enough, but usually there is a requirement for some approvals and they will cost money and time to get.

fivemega · Jul 31, 2019

It wouldn't be too difficult to make a plastic insulator tube size of 18650 to accommodate pair of CR123 primaries and connected in parallel.
The advantage of this will be LSD and disadvantage of less capacity and less voltage compare to rechargeable 18650
I have tested these with 2P/2S CR123 and incand P60
I estimate voltage of 2.8V per cell with capacity of 3500mAh under 1.2 Amps draw.

spyderco monkey · Jul 31, 2019

fivemega said:
It wouldn't be too difficult to make a plastic insulator tube size of 18650 to accommodate pair of CR123 primaries and connected in parallel.
The advantage of this will be LSD and disadvantage of less capacity and less voltage compare to rechargeable 18650
I have tested these with 2P/2S CR123 and incand P60
I estimate voltage of 2.8V per cell with capacity of 3500mAh under 1.2 Amps draw.

Yeah, that sounds less nice then just using CR123's as is no?

What would be cool about a 18650 lithium primary is the increase in capacity over rechargeables; it could potentially be 5-7000mah based on what we typically see in primary vs rechargeable capacities.

WalkIntoTheLight · Jul 31, 2019

spyderco monkey said:
Yeah, that sounds less nice then just using CR123's as is no?

What would be cool about a 18650 lithium primary is the increase in capacity over rechargeables; it could potentially be 5-7000mah based on what we typically see in primary vs rechargeable capacities.

CR123 has about 7.27 cm^3 of volume. 18650 has about 16.54 cm^3. That's about a 2.27x increase in volume.
CR123 has a capacity of about 1500mA.
If you scale it up to the 18650, it would have about 3405mAh.

That's about the same as what a rechargeable lithium-ion 18650 already has. Plus, a lithium-ion has a much higher working voltage, and can deliver much more current, making it a superior battery in almost every regard. Probably close to double the energy (Wh) that a primary lithium 18650 would have at modest drain. The only cases I can think of in which the primary might be better, is in very cold conditions, or extremely long storage.

spyderco monkey · Jul 31, 2019

WalkIntoTheLight said:
CR123 has about 7.27 cm^3 of volume. 18650 has about 16.54 cm^3. That's about a 2.27x increase in volume.
CR123 has a capacity of about 1500mA.
If you scale it up to the 18650, it would have about 3405mAh.

That's about the same as what a rechargeable lithium-ion 18650 already has. Plus, a lithium-ion has a much higher working voltage, and can deliver much more current, making it a superior battery in almost every regard. Probably close to double the energy (Wh) that a primary lithium 18650 would have at modest drain. The only cases I can think of in which the primary might be better, is in very cold conditions, or extremely long storage.

Ah, well thats a bummer.

But why is it that we typically see lithium primaries having higher capacities then rechargeables? ie RCR123's having 1/2 capacity of CR123's, etc.

fivemega · Aug 1, 2019

spyderco monkey said:
But why is it that we typically see lithium primaries having higher capacities then rechargeables? ie RCR123's having 1/2 capacity of CR123's, etc.

Capacity of a cell not only depends on volume but many other factors too.
A 18350 cell has about 1/2 volume of 18650 but normally with 1/3 of capacity.

WalkIntoTheLight · Aug 1, 2019

Also, 18650 (and now 21700) is a "sweet spot" of capacity. Developers have spent a lot of time maximizing capacity out of that size, since they're used in cars, power tools, and laptops. Other sizes just aren't used that much, so they don't get a lot of development.

xxo · Aug 1, 2019

spyderco monkey said:
Yeah, that sounds less nice then just using CR123's as is no?

What would be cool about a 18650 lithium primary is the increase in capacity over rechargeables; it could potentially be 5-7000mah based on what we typically see in primary vs rechargeable capacities.

I made a 3D printed adapter to run a single CR123 or 16340 in place of a 18650 - works real well. The idea was to be able to run a primaries in cold weather of for storage in a vehicle, plus I like the idea of being able to use different "fuels" in my lights.

I also printed one that went the other way to run a single 14500 in a 2X CR123 light.

18650 Lithium Primaries?

spyderco monkey

Newly Enlightened

HKJ

Flashaholic

fivemega

Flashlight Enthusiast

spyderco monkey

Newly Enlightened

WalkIntoTheLight

Flashlight Enthusiast

spyderco monkey

Newly Enlightened

fivemega

Flashlight Enthusiast

WalkIntoTheLight

Flashlight Enthusiast

xxo

Flashlight Enthusiast

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