2 X 16340 or 1 X 18650?

[bmcgators98]

I recently purchased a Malkoff M61W and a Surefire 6P as a host. The drop-in is rated from 3.4-9 Volts. I have been doing some research on what type of rechargable to uses. I am novice so I want to make sure I am correct in my assumptions. 2 X 16340 would provide 7.4 volts with 750 mAh vs the 18650 which would produce 3.4 volts with 2650 mAh. (AW cells). Does this result in the 2 16340 running brighter for a shorter amount of time? I realize that the 6P would have to be bored to accept the 18650, I just don't know if I want to spend the extra money. For my needs I think I would prefer the extra Lumens at the sacrifice of total run time.

Thanks for your help

 

[357mag1]

You probably meant 3.7 volts for the 18650 and not 3.4 volts. My experience with Malkoff units indicates the drop in will not be as bright on one 18650 but you would gain runtime. If long runtimes are your primary consideration then boring might be worth while. I prefer to leave the body stock and use a 17650 if a single Li-Ion is called for.
In a perfect world if your drop in pulled 580ma on two 16340 (mine does) it would have to draw 1160ma on one 18650/17650 to remain as bright. My Malkoff draws 875ma on one Li-Ion so that alone indicates it won't be as bright.
So you should have at least an hour of light using 16340 batteries. I would make my decision based on need. If you need longer runtimes either carry more batteries or have it reamed for an 18650.
By the way the light is plenty bright on one 18650.

 

[bmcgators98]

thanks

I did mean 3.7 volt. The Malkoff web site indicates that the drop-in draws 650ma at 6 volts. What is meant by "regulated or direct" As I understand it, does it mean that the light will compensate for the extra volts and hold the output constant until in drops below the 3.4 volts. Is that correct?

 

[357mag1]

What is meant by "regulated or direct" As I understand it, does it mean that the light will compensate for the extra volts and hold the output constant until in drops below the 3.4 volts. Is that correct?

You pretty much have it. There is circuity in the light that keeps it at or very close to the same brightness within a certain voltage spread. Direct drive means the LED is fed directly by the battery.

 

[etc]

18650 is the best cell to use. I use unprotected 18650 cells from quality makers like Panasonic. I also have a hundred cells taken from laptop battery packs. They usually have a lower capacity but still usable and free.

You need protected 18650 cells in multiple cell configuration, as you can overdischarge them and not notice in. In a single cell configuration, as the lite drops out of regulation and goes direct drive, you can visually see the difference as it hits below 3.7V. As the lite starts dimming, swap the cell. Have been doing this for a while with no issues.

A Malkoff module running on 1x18650 high quality cell like Panasonic around 3,000 mAh will last you a very long time, about 2 hours at least and 4-5 hours in a M60L or M61L configuration.

AW cell will suddenly cut out when the circuit is tripped, if you are in some "situation", this can be hazardous. This is the main reason I like unprotected cells, they don't leave you in the dark in an instant.
Save AW cells for 2x18650 configuration. However, if you don't want to worry about overdischarge, use AW cells, just keep in mind the added complexity of the protection circuit.

I wouldn't mess with the 6P body you have, but get an aftermarket body from FiveMega.

 

[scottshad]

18650 is the best cell to use. I use unprotected 18650 cells from quality makers like Panasonic. I also have a hundred cells taken from laptop battery packs. They usually have a lower capacity but still usable and free.

You need protected 18650 cells in multiple cell configuration, as you can overdischarge them and not notice in. In a single cell configuration, as the lite drops out of regulation and goes direct drive, you can visually see the difference as it hits below 3.7V. As the lite starts dimming, swap the cell. Have been doing this for a while with no issues.

A Malkoff module running on 1x18650 high quality cell like Panasonic around 3,000 mAh will last you a very long time, about 2 hours at least and 4-5 hours in a M60L or M61L configuration.

AW cell will suddenly cut out when the circuit is tripped, if you are in some "situation", this can be hazardous. This is the main reason I like unprotected cells, they don't leave you in the dark in an instant.
Save AW cells for 2x18650 configuration. However, if you don't want to worry about overdischarge, use AW cells, just keep in mind the added complexity of the protection circuit.

I wouldn't mess with the 6P body you have, but get an aftermarket body from FiveMega.

ETC, I see you use unprotective cells, do you do this because of cost or is because of longer run times and/or brighter output?
Are unprotective cells dangerous while in use or when being charged. I understand that unprotective cell can be used until there is no charge left, why is this bad? If they are run dry can they not be recharged?
Yes I am a newbie!
Thank you

 

[bmcgators98]

Scottshad,

The primary advantage of using unprotected cells, is that protected cells have a circuit breaker that will trip once the cell reaches a minimum voltage. In the real world means your light will unexpectedly cut out with little or no warning. If you happen doing be doing something very important, you will be out of luck. Some of the higher end lights like HDS have a built in warning system that begins to step down the light before this happens. Unprotected cells won't do this. However Unprotected cells should never be completed depleted. I think 3.2 Volts is the magic number you should not go below. Basically as I understand it is not dangerous to deplete them, however the when you first recharge them there will be added resistance causing smoke fire and explosion.

 

[Brigadier]

I recently purchased a Malkoff M61W and a Surefire 6P as a host. The drop-in is rated from 3.4-9 Volts. I have been doing some research on what type of rechargable to uses. I am novice so I want to make sure I am correct in my assumptions. 2 X 16340 would provide 7.4 volts with 750 mAh vs the 18650 which would produce 3.4 volts with 2650 mAh. (AW cells). Does this result in the 2 16340 running brighter for a shorter amount of time? I realize that the 6P would have to be bored to accept the 18650, I just don't know if I want to spend the extra money. For my needs I think I would prefer the extra Lumens at the sacrifice of total run time.

Thanks for your help

Use 2XIMR16340. You will get the voltage and brightness in a safe chemistry battery with no current limiting circuitry.

 

[bmcgators98]

Use 2XIMR16340. You will get the voltage and brightness in a safe chemistry battery with no current limiting circuitry.

That is kind of what I was thinking. Plus I don't have to spend much more money on a new host or coring.

 

[pae77]

On the other hand, getting a new host can be surprisingly inexpensive. For example Solarforce L2's which are pretty much clones of the Surefire 6P, except they are already bored to fit 18650's (or also a pair of 18350's) are usually less than $20.00 (including shipping if purchased from certain ebay dealers) for the complete flashlight body minus the lamp module. And the overall quality is much better than you might expect, considering the low cost.

 

[etc]

ETC, I see you use unprotective cells, do you do this because of cost or is because of longer run times and/or brighter output?
Are unprotective cells dangerous while in use or when being charged. I understand that unprotective cell can be used until there is no charge left, why is this bad? If they are run dry can they not be recharged?

The highest capacity protected 18650 cell is from AW, which has 2600 mAh, the highest capacity non-protected cell is 3,000 mAh. So you get better runtime.

The other reason is that non-protected cells are more reliable - no protection circuit to break.

If you overdischarge them, you damage them, not sure of the exact consequences but I would think the ability to hold charge is reduced, they get hot, etc. Overdischarging is perfectly safe for *you*, but charging them back migtht not be, monitor them during the charge cycle that they don't heat up. The cells that heat up, I throw away. I try not go go below about 3.5V. Keeping in mind 4.2V = full and 3.7V = empty. I also have a lot of semi-disposable cells that I don't care for, so if get OD'ed, just toss them. I wouldn't do that to premium and expensive cells however.

The third reason is that protected cells instantly cut out. This can be really bad in a tactical situation. Either use non-protected cells or CR123A primary cells. AW cells are useful in a limited number of situations, most of all in multiple-cell lites and in non-tactical situations. This is one reason why I like 1x18650 lites these days.

Panasonic 18650 with 2900 mAh capacity is excellent for Malkoff "Low" modules - like the Energizer bunny it keeps running and running and then running some more. I go for days without recharge.
I use Pila charger and it's great.

 

[scottshad]

ETC...thank you! I appreciate the good info!

 

[mdocod]

Use 2XIMR16340. You will get the voltage and brightness in a safe chemistry battery with no current limiting circuitry.

The LED module won't drop out of regulation until ~3.5-3.8V, that means that the cells will be discharged below 2V before there is any feedback.

LiMn cells are more abuse tolerant and all, but this is a recipe for a short cycle life.

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To the original question...

Food for thought:

2xRCR123: ~4 watt hours
1x18650: ~9 watt hours