Surefire L4: efficient and economical battery solution?

[Dinan]

Just got my first "real" flashlight, the Surefire L4 Lumamax. I have never owned a flashlight that used 123A lithium batteries before so I was trying to research which ones would give me the best runtime while maintaining the brightness, yet be affordable.

I've read lots of threads on 3.7v batteries vs. the 3v ones. Rechargable vs. non-recharagble and I'm not sure which to go with (what brand as well).

Also I was just reading about an exploding flashlight so that got me a bit wary... but I don't plan on mixing brands of batteries!

 

[bouncer]

either order your 123's through surefire($1.79 ea) or on ebay (price and quality varies) or my recommendation and what I plan on donig shortly is go to www.lighthound.com and order a 17670 protected lithium ion cell and charger (actually I'll be buying a couple cells) DO NOT USE 2 R123 CELLS FOR THE L4 ALL REPORTS SAY YOUR LIGHT WILL NOT HANDLE THE VOLTAGE

 

[Randy Shackleford]

Agreed, the KL4 will probably magic smoke with two rechargable 123's.

A 17670, if your L4 body accepts it, is way to go.

.

 

[Dinan]

I don't quite understand... the website says the 17670 is 4.2v max and 3.6-3.7 nominal. Aren't the rechargable 123's also 3.7v?

What's with all these long numbers for batteries heh...

Will the 17670 give as much runtime as 2 regular non rechargable 123a's?

 

[NotRegulated]

Dinan,
The rechargable 123's and the 17670's are both 3.7 volt. The difference is you need two 3.7v 123's which is 7.4 volts. Too much for the L4. It will blow the LED. Get one 3.7 volt li-on 17670 (which is the same size as two 123's) and it will power the L4 just fine. I am using this setup. The one 17670 should give equal to more runtime than two 123's. I am using AW's 17670 cells. You can run the L4 on these rechargables and be very happy. Use primary 123's for backup.

 

[Fenris]

17mm = diameter 67mm = length 0 = cylindrical

 

[asdalton]

I don't quite understand... the website says the 17670 is 4.2v max and 3.6-3.7 nominal. Aren't the rechargable 123's also 3.7v?

What's with all these long numbers for batteries heh...

Will the 17670 give as much runtime as 2 regular non rechargable 123a's?

Lithium ion rechargeable cells run at about 3.6 volts. (They're 4.2 volts coming hot off the charger.) The difference between a rechargeable 123A cell and a 17670 cell is the size and capacity of the cell; in each case, the battery is one Li-ion cell.

For the Surefire L4 or L5, you want to go with the 17670 cell, which has the physical size of two 123A primary cells. The L4's boost converter will run the LED at full brightness even with the reduced voltage. The run time will be less than when using two primary 123A cells, but that is a minor inconvenience if you keep two rechargeable cells and just swap in a fresh one when one is used up.

Don't use two R123A cells, because the voltage will be too high.

 

[Dinan]

Thanks for the info guys.

I've been doing some poking around on the forums and I've read a few posts saying that since the 17670 is less than the normal 6volts, the flashlight will run hotter?

I can already feel the light getting pretty warm using the batteries it came with... will the 17670 make it too hot to hold when using it for more than a few minutes?

 

[Xygen]

I'm using 2 3.0V rechargeable cells for some month now. No problems. They have exact 3.0V when under load. But when it comes to runtime, the 17670 is the winner.
But protected rechargeable cells have one negative quirk. They shut down suddenly when flat... No warning... :sigh:

 

[bagman]

But protected rechargeable cells have one negative quirk. They shut down suddenly when flat... No warning... :sigh:

I run my L4 on the old PILA 168S cells and have never had this happen, it always steps down to a much lower light level for a few minutes to warn you you need to swap it out?

 

[Dinan]

So I guess the 17670 looks like the best choice for rechargable... but any word on temperature difference with a lower voltage battery?

 

[Outdoors Fanatic]

Run a Pila in it. They seem to the best li-ion batteries out there.

 

[ROK]

IMHO 17670 is best solution.
But you have to check first whether 17670 is compatible with your L4 body in hole dimension.

So I guess the 17670 looks like the best choice for rechargable... but any word on temperature difference with a lower voltage battery?

 

[jumpstat]

I run mine with AW's Protected 17670. Runtime great, but more operational heat than running 2xprimaries. Probably the circuits also contributes to the heat, but great light non the less.

 

[Bullzeyebill]

Using 17650,17670, or 18650's (for example a TB body) the circuit will have to work a little harder to supply the required 6+ volts to the led. There may be a little added heat, but the KL4 is known to get hot anyway. I ran my two KL4's with a 17650, or 18650, and enjoyed the economical runtime.

Bill

 

[thospress]

IMHO 17670 is best solution.
But you have to check first whether 17670 is compatible with your L4 body in hole dimension.

My AW 17670s would not fit the L4 but found another home in a Streamlight ProTac 2L, where all is well.

 

[shane45_1911]

Holy thread resurrection, Batman!!
(Yes, 17670 is the way to go if it fits)

 

[Illum]

Actually, the 17670 would only apply to the Surefire L4s made before 2009. The new ones that uses a SSC P4[?] LED as opposed to the conventional Lumileds Luxeon V uses a buck [step-down] circuit as opposed to a buck/boost circuit to power the LED. With the new "Updated" L4, 17670s operate under essentially no regulation, simply because input voltage is too close to the LED's forward voltage.

info here, note the graphs: http://www.candlepowerforums.com/vb/showthread.php?228070

I have two of these "new" Surefire L4s, and my opinion is that for its output, price, runtime, etc. There are WAY more cheaper and better lights than to stick with surefire. Thusfar the outputs of my old L4s have not be replaced by anything modern yet

 

[cland72]

You can run two AW LifePO4 3.0v cells. Delivers optimum voltage, and unlike the 17670 you won't have fitment issues.

 

[novice]

Illum,
Most older SF lights are like vintage wines, with their own separate qualities to be appreciated. I have a possible lead on an older 5-watt L4 for $149, which seems a bit steep for a on-paper-spec 65-lumen light with a runtime of 1.5 hours. You mention that your older L4 lights have an output that can't be replaced. I know that I am missing something here. Could you elaborate on why you appreciate them so much? Thank you!