Question about putting an M60 in different SF bodies...

[aares]

I have an M60 on the way...w00t! I know the LED is rated at 3.8-9 volts, so what will be the difference if I put it into a 6P, with two 123's, or a C3, with three 123's? Will it simply make the runtime longer? Is there any benefit with using an M60 with three batteries instead of two?

Thank you!

 

[Sgt. LED]

Just runtime.

And really who among us couldn't use more of that!

 

[Ctrain]

from what I'm told it should take the runtime from 1.5 hrs to a bit over 2!

 

[aares]

Sweet...thanks!

Any advice for rechargeables that will fit in a C3, that will be between 4-9 volts, and will last longer than 123's? Two 18500s? That would only be about 2600mAh...

 

[Bullzeyebill]

Sweet...thanks!

Any advice for rechargeables that will fit in a C3, that will be between 4-9 volts, and will last longer than 123's? Two 18500s? That would only be about 2600mAh...

That would be about 8.4 volts max at 1300mAh's, or so. You multiply voltage, not mA's when running cells in series.

Bill

 

[AzN1337c0d3r]

The correct unit of measurement for electrical capacity (and thus total work done) is Watt-hours (Whr)

The easiest way to calculate this is to calculate the Whr of each battery and multiply it by the number of batteries you have.

It doesn't matter whether the cells are in the series or parallel. They still do the same amount of work.

As for M60 and rechargables. 2x 18500s would probably be your best bet. 3x RCR Li-ion is too high a voltage for the module.

 

[mdocod]

18500s won't fit in a C3, you'll need to use a pair of 17500s, go with the AW brand protected 17500 cell, they perform right up there around their 1100mAH capacity rating and will come pretty close to the runtime of 3xCR123s.

SureFire bodies are bored to fit CR123s reasonably snug to reduce rattle, that means ~17mm, so an 18mm cell won't fit unless you bore the stock body, or replace the body with a leefbody.

Oh- and please make sure to use a good charger, or at least read up on the limitations and safety issues with cheaper chargers. I highly recommend the Pila IBC charger, it's a little pricier, but you can sleep at night knowing your cells are going to be charged in a safe manner. Li-ion is very safe when charged and discharged correctly, unfortunately, not all loose cell consumer chargers follow the rules. A mistreated li-ion cell can become a violent little fire breathing toxic gas emitting stick of doom.

Eric

 

[roymail]

A mistreated li-ion cell can become a violent little fire breathing toxic gas emitting stick of doom.

Eric... WOW! :sick2:

So is there a safe way to charge them using the WF-139?

 

[LukeA]

A mistreated li-ion cell can become a violent little fire breathing toxic gas emitting stick of doom.

Eric... WOW! :sick2:

So is there a safe way to charge them using the WF-139?

Pull them soon after they hit green. Don't leave them sitting on solid green for hours. That's how they can get overcharged.

 

[mdocod]

As LukeA said, just make sure to pull em when they're "done" and not let em sit there. This is why I prefer the IBC charger, it terminates the charge and stops charging completely, so you can leave your cells sitting there on the charger indefinitely.

It's not a bad idea to have a multi-meter handy so you can test cell voltage going on and coming off the charger so you can get a feel for how much runtime you might have used, or have left if you hadn't charged, get in the habit of charging early rather than later. (frequent top-offs is healthier for li-ion than deep cycles). 3.5V is basically dead, 4.20V is full charge, it's a semi-steady ramp of full to dead in-between those voltage readings. 4.10V is close enough to full charge to leave alone.

Eric

 

[roymail]

3.5V is basically dead, 4.20V is full charge, it's a semi-steady ramp of full to dead in-between those voltage readings. 4.10V is close enough to full charge to leave alone.
Eric

Really, 3.5v is basically dead? I did not know that. The rest I got from your battery guide thread, but somehow I must have missed this... I'll go back an read it again.

 

[mdocod]

yea.. an open circuit reading of 3.5V is basically dead, it can be brought as low as ~3.0V but this isn't very healthy for the cell, and it falls off pretty rapidly from 3.5 to ~3.0 so there isn't really much useful capacity available past 3.5V. You can pretty much figure that if a cell is reading around 3.5V open circuit, then depending on load, it was operating down around ~3V under the load anyways, plenty far discharged.

 

[OceanView]

...it falls off pretty rapidly from 3.5 to ~3.0 so there isn't really much useful capacity available past 3.5V...

I know that sometimes people can get hung up on the exact voltage that they consider "dead" or "time to recharge" but as mdocod points out, in actual use, the cell can quickly fall in voltage through this phase so hardly anyone would be able to accurately stop at exactly 3.3V vs 3.0V, for example. Personally, I recharge my lithium ion cells whenever I find them under 3.7V.

 

[roymail]

yea.. an open circuit reading of 3.5V is basically dead, it can be brought as low as ~3.0V but this isn't very healthy for the cell, and it falls off pretty rapidly from 3.5 to ~3.0 so there isn't really much useful capacity available past 3.5V. You can pretty much figure that if a cell is reading around 3.5V open circuit, then depending on load, it was operating down around ~3V under the load anyways, plenty far discharged.

I found this data in another thread and decided to post it here since this question was being discussed. Marduke says it originally came from SilverFox. Hope it helps someone else.

Li-Ion Cell Discharge
4.2 volts 100%
4.1 about 90%
4.0 about 80%
3.9 about 60%
3.8 about 40%
3.7 about 20%
3.6 empty for practical purposes<3.5 = over-discharged

 

[Bullzeyebill]

I know that sometimes people can get hung up on the exact voltage that they consider "dead" or "time to recharge" but as mdocod points out, in actual use, the cell can quickly fall in voltage through this phase so hardly anyone would be able to accurately stop at exactly 3.3V vs 3.0V, for example. Personally, I recharge my lithium ion cells whenever I find them under 3.7V.

I mostly use unprotected Li Ion's and check voltage regularly. Seems tedious but that is the fun of being a flashaholic; also a safe thing to do.

Bill