Fenix ld10 r4 and ld20 r4 questions

ok here are the specs on fenix's website

LD10------132 lumens max for 1.5 hours
LD20------205 lumens max for 2.0 hours

im guessing the heads and tail caps are the same
if so.

LD10 runs at 1.5volts
LD20 runs at 3.0volts

ok, now here comes the questions

if i were to run the LD10 on a single 14500 rechargeable battery that would give it 3.7volts. so shouldnt the LD10 have more lumens and run longer than the LD20 on AA batteries. if this is true, why would anyone want to buy the LD20.

question about the LD20. could you use two 14500 batteries in there giving it 7.4volts. i doubt it, but thought i would ask.


thanks in advance
matt

One if form factor. The LD20 (or lights like it) is in my opinion easier to hold and easier to pocket carry than a single AA light. Also, power source. Some might wish to use alkalines or Ni-MH, or may not want to use li-ion. Also, runtime. I don't know how well a single 14500 compares to two Ni-MH AA cells, but there may not be an advantage there to using the single lithium. Brightness would be about comparable.

To answer your other question, I think you would need the PD30 head to use two li-ion batts.

as far as i understood, was that two batteries in series doubled the voltage, but kept the same amperage. so having two shouldnt make it last longer, just give it more power.

as for size. i have a tk11r2 and think that just alittle to big for EDC. i really like the size of the ld10 but want the performance of the ld20. so im hoping that the ld10 with the 14500 will give me that.

tcr03 said:

ok here are the specs on fenix's website

LD10------132 lumens max for 1.5 hours
LD20------205 lumens max for 2.0 hours

im guessing the heads and tail caps are the same
if so.

Click to expand...

if they are of the same series they tailcaps should be the same and usually from what I have heard the heads are the same but it is best to check into it.

LD10 runs at 1.5volts
LD20 runs at 3.0volts

ok, now here comes the questions

if i were to run the LD10 on a single 14500 rechargeable battery that would give it 3.7volts. so shouldnt the LD10 have more lumens and run longer than the LD20 on AA batteries. if this is true, why would anyone want to buy the LD20.

Click to expand...

more lumens = more power out of the battery source, less lumens means usually more runtime. A 14500 Lithium Ionhas less power than 2 AA nimh cells so if they were both running at equal lumens only the efficiency of the boost circuit vs ~direct drive will factor in to offset the advantage 2AA has over it.

question about the LD20. could you use two 14500 batteries in there giving it 7.4volts. i doubt it, but thought i would ask.
thanks in advance
matt

Click to expand...

no 1AA nor 2AA lights I know of are designed to take both nimh AND 2 lithium ion batteries. I am betting these lights may be "OK" with 4v but 8v would fry the drivers possibly instantly.

The LD10 with a 14500 is pretty bright. Mine made roughly 250 real out the front lumens with a 14500, although, I don't hardly use it. Also, I think I've read where others have lost the other modes with the LD10 while using a 14500. I can't remember for sure, but maybe someone will chime in. Have you looked at the 4sevens Quarks? That's what I EDC (every day carry). Search for quarks and you will find tons of info:thumbsup:. You should also consider beam shapes too. Do you prefer a light to have more spill, or do you prefer it to have a tighter beam?

tcr03 said:

as far as i understood, was that two batteries in series doubled the voltage, but kept the same amperage. so having two shouldnt make it last longer, just give it more power.

as for size. i have a tk11r2 and think that just alittle to big for EDC. i really like the size of the ld10 but want the performance of the ld20. so im hoping that the ld10 with the 14500 will give me that.

Click to expand...

the amperage from the batteries or the amperage to the emitter? You have two things going on here you have to think about. If the drive circuit tries to supply a constant current to the LED the more voltage in means less current from the batteries because power in = power to LED - driver efficiency loss. Typically the lower voltage input the lower the efficiency and with two cells vs one then the current would be half from those cells due to double the voltage. Either you get a little more than twice the runtime at the same light level or a higher light level at perhaps more runtime unless the emitter is getting about twice the current to it than off 1 cell. For reference look up Watts Law, P=IE or Power (in watts) = I (current, amps) x E(voltage)

Fenix lights tend to not work well with Li-ion batteries. They're very efficient, and work great with primary cells, like alkaline, and rechargable Ni-MH, but once you approach the 3v limit, you tend to lose the lower outputs (low and medium dissapear). People often complain of this, when using primary Lithium batteries (@ 1.7v/apiece).

When using Li-ion cells in most Fenix lights, they tend to go to "direct drive" mode, and the modes are lost.

Also, when Fenix says "3v", they mean 3v. Using a Li-ion, which is nominally 3.7v, but around 4.2v when fully charged, can increase the risk of damage to the light, because of excessive heat from the high current draw. I'm pretty sure the use of Li-ion also voids their warranty, but I'll have to check that.

Also, Li-ion 14500's have a reduced capacity (500-750mAh), compared to, say, high capacity Ni-MH(2500+mAh), or Lithium primary cells (~2000mAh). The higher voltage of the li-ion will result in less current draw, theoretically, but, because the driver loses its regulation, current draw is acutally higher, thus reducing runtime to much shorter than with Li, or Ni-MH.

Also, using 2x14500's in your LD20 will fry the driver. As I've stated before, the LD10/LD20 is a 3v MAXIMUM head. Pushing more voltage through it will damage it. You increase the risk of damage with a single 14500, but with two 14500's, you're pushing almost 3xthe voltage the driver was meant to handle. The driver in the 10/20 series is a boost converter ONLY, not a boost/buck, so it will try to boost the incoming voltage even higher. Thus, while normally that 1.2-1.7/2.4-3.4v would be boosted to approximately 3.7v (the forward voltage of the LED), when ~9v is boosted, you'll damage the driver AND the LED. Insta-POOF!!!

Instead of looking at Li-ion rechargeable systems, look at a good quality Ni-MH battery system. A smart charger and a 4pck of eneloops will probably cost less than a smart Li-ion charger, DMM, volt-meter, and 4 quality Li-ion cells would cost. And it will work better in the light in the long run.

i understand most of what you are saying. and thanks for all the input. im not to worried about all the different modes of the ld10. just trying to get the output close to the ld20 on max power.

have ppl been running there ld10 with the 14500 batteries and haveing problems with them going out. and how is the runtime on the ld10 with the 14500.

ti force said his was getting 250 lumens out of his. that would be awsome in a light that small. if the runtime was good that would sell me right there on that light.

with what i do i really only use the max power output anyway. the strobe would be cool to have, but other than that i really dont need any lower light output.

with my tk11r2 all i use is the brightest setting with my 18650 batteries. the runtime is perfect with that.

i got the tk11 with 4 batteries and a charger for around $100. i think it was a great investment.

if i were to get a ld10 i would do the same and get 4 14500 batteries and a charger.

again thanks for all your input.

I still think you should look into the Quarks. The Quark AA Tactical can run on a 14500, and you will still have all of the available modes (including strobe), plus the lumens will probably be just as high if not higher than the LD10 on 14500:thumbsup:. Plus, you can buy a 2xAA (no li-ions) body, 1xCR123 body and 1x18650 body that will all work with the AA head. Just don't use the 2xCR123 body with that head or you will fry the emitter in about 5 seconds; keep the voltage below 4.2v or . Don't ask me how I know The Tactical version and Regular version have a couple of differences, so be sure to look at both of them to see which one might fit your needs.

ok so i was looking at the quark light. i like the looks of the light. but does anyone know the specs of the light on a 14500 battery.

really just want to know about max lumens and runtime on that setting.

lumens are same as the aa^2 setup. see selfbuilts review for runtimes

the fenix will not function correctly on li-ion's.

John_Galt said:

Fenix lights tend to not work well with Li-ion batteries. ... And it will work better in the light in the long run.

Click to expand...

informative helpful post, thanks. also hi, ti-force.
ive been noticing that the Fenix LD10 and LD20 still sell strong, and on youtube people show how they drive the LD10 with a 14500 to some astonishing effect. so does anyone have long-time experience with 14500 and LD10, no damage to driver or emitter?

i am performing some runtime tests with my Xeno E03 v3 and 14500, and though it's rated 20mins for the 430 lumens OTF, i get much better runtimes on 80lumens (so-called "ultralow lol") than measured by the manufacturer and selfbuilt.

so in the end i might well come to the conclusion that the Xeno E03 is a better torch than the LD10.