18650 Rechargeable Li-Ion Batteries - Any reason to choose less mAH?

[ckfey2156]

Hi there,

I'm looking to buy a rechargeable Li-Ion 18650 protected cell to power a flashlight. Specifically, a Streamlight Protac HL X. Streamlight 18650 batteries have 2600 mAH. Fenix makes a 18650 battery with 3500 mAH.

Other than the extra cost, is there any disadvantage to having more mAH? Does more mAH reduce the number of times a battery can be recharged? Or, does more mAH lead to an overall shorter battery life?

Thanks!

 

[aznsx]

Hi there,

I'm looking to buy a rechargeable Li-Ion 18650 protected cell to power a flashlight. Specifically, a Streamlight Protac HL X. Streamlight 18650 batteries have 2600 mAH. Fenix makes a 18650 battery with 3500 mAH.

Other than the extra cost, is there any disadvantage to having more mAH? Does more mAH reduce the number of times a battery can be recharged? Or, does more mAH lead to an overall shorter battery life?

Thanks!

I'm going to do my best to avoid getting off into the endless technical weeds (which are considerable on this subject), which would likely also exceed my limited personal knowledge, and also likely be unnecessary for a practical answer to your question regarding suitability of the Fenix cell for use in your HL-X. I believe those Fenix cells would be a very good choice as an alternate substitute / replacement for the SL cells in this application.

The Fenix 3500mAh cells you reference are what I'm currently using in my Protac 2L-X and Stinger 2020 (and other 18650 lights), and have been using them for a good while with good results. I believe you would find them an appropriate cell for use in any SL 18650 light, and they would provide a considerable increase in available run-time vs the SL cells (which I also use and are good cells). The Fenix cells are available with or without integral USB charging.

Caveats:

I do not know the relationship between capacity and service life / charge cycles, but I doubt it would be a significant factor in my decision in this case.

At times there are tradeoffs between capacity and max output current. The Fenix cells are rated for 5.1A continuous (per Battery Junction). I don't know the (unpublished) current rating of the SL cells. I also don't know the exact current requirements of the HL-X (unpublished). I doubt that the current rating of the SL cell would exceed that of the Fenix cell, and I believe the Fenix cell would be quite adequate for powering an HL-X.

I would likely be using the Fenix cells in an HL-X right now if I had one.

EDIT: BTW, I'm familiar with the HL-X / specs / etc., almost bought one when I got my 2L-X, and it looks like a great light to me. Good choice.

 

[fivemega]

Hi there,
Other than the extra cost, is there any disadvantage to having more mAH? Does more mAH reduce the number of times a battery can be recharged? Or, does more mAH lead to an overall shorter battery life?

Thanks!

If battery is true and real high capacity:
There is advantage to have more mAh.
More mAh won't reduce the number of times a battery can be recharged.
More mAh lead to an overall longer battery life because each charge will give you longer run time so you will need to recharge less often.

 

[Monocrom]

Intentionally picking less mAh is like intentionally picking a sports car with less horsepower.

 

[iacchus]

At one time, the cells w/ higher draw ratings would not be the cells w/ the most mAh. Certain needs would decide what you went w/ there. Those would be unprotected cells, though.

These days there is more of a parity between those two specs regardless.

In your case (protected), the quality cell w/ the highest mAh rating from a trustworthy source is the best bet.

 

[KITROBASKIN]

Agree with above, in particular iacchus.

If your tool requires more amperage sustained, then check what each battery is rated. The lower capacity would be possibly brighter, longer.

Depending how bright, how long each session of use, at what level of voltage you prefer to recharge battery, you may experience very little sense of a difference in runtime.

Personally, I like to recharge at a little less than 3.8V. No way am I getting close to the stated capacity.

Seems like both your choices are more expensive than could be had. Have you looked at protected Orbtronic batteries. There are others, maybe buy more than one battery?

 

[Monocrom]

Apart from being more expensive, there seems to be no direct disadvantage of a larger capacity mah.

However, 18650 lithium batteries also have some disadvantages, such as capacity decay, difficulty in recycling, and intolerance to overcharge and over-discharge. However, these disadvantages are not directly related to the battery capacity, but are some limitations of lithium battery technology itself.

What I like about 18650 lights is that in an emergency, you can toss in two CR123A lithium primaries if your 18650 cell is depleted.

 

[fivemega]

Carrying little bigger light with more capacity / run time is big advantage
There are allways possible to use smaller cells in larger light using dummy or spacer.

 

[TIFisher]

What I like about 18650 lights is that in an emergency, you can toss in two CR123A lithium primaries if your 18650 cell is depleted.

...I would add to this statement the caveat it only applies to lights with the appropriate driver to accommodate the increased voltage of multiple CR123 cells. Many 18650 powered flashlights are unregulated and lack the required buck driver to safely allow this swap.

 

[Monocrom]

...I would add to this statement the caveat it only applies to lights with the appropriate driver to accommodate the increased voltage of multiple CR123 cells. Many 18650 powered flashlights are unregulated and lack the required buck driver to safely allow this swap.

My experience has been the opposite. I think I've encountered only two 18650 lights that couldn't reliably work with 2xCR123A lithium primaries.