Running 2x14500 in Fenix LD20

I know the LD20 can support alkalines, NiMHs & lithium so I would like to find out if it can support 2 x 14500 Li-Ion cells.

Searching CPF only revealed info mostly about the LD10 & 14500 but little about the LD20. So far, I'm aware of the fact that by running 14500 in the LD10 will result in losing both the low & medium modes.

So will the same thing happen with the LD20?

Can someone enlighten me? Thank you!

I think when they refer to Li-ion compatibility they mean with the LD10 battery tube. At ~8.2 volts off the charger, two 14500's will fry the driver. Best bet is to stick with rechargeable Ni-MH's, so you don't lose low and medium in your light (when using Li-ion's, and even two L91's, the light is in direct drive, mewaning no low or medium mode).

Or get the LD10 battery tube and use a single 14500.

Thanks John for the quick reply!

Another question, what's the max voltage the driver can tolerate? nothing beyond 4/5V?

~3.3v

2x14500 is a bad idea. Even 1x14500 is pretty borderline as it can overdrive and cause a loss of low modes.

John_Galt said:

...or get the LD10 battery tube and use a single 14500.

Click to expand...

That's what I use for my EDC.

With the 2-cell tube and 2 Eneloops, it's good for 180 lumens.
Dropping down to the single tube and one Eneloop gives you 120 lumens.
Using a single 14500 lifts the output to around 220 lumens.

It's over the specified voltage for the light, but I've had no problems, and know there are others on the forum getting the same results.

Since it's over 3V, only turbo mode is available, but that's what I want. When it drops below 3V, the other modes return, but it's not long before the battery protection kicks in. (You can still limp home on the lower modes though)

For me, this is the perfect pocket light, and it goes with me everywhere. If I need longer runtime, I revert back to the twin Eneloops.

Update:

I had reason to use a single Eneloop in my L2D recently and noticed a darkening of the centre of the beam.

This is after 6+ months of running the 14500.

So there you have it - overdriving the LED will eventually cause a problem.

collo said:

Update:

I had reason to use a single Eneloop in my L2D recently and noticed a darkening of the centre of the beam.

This is after 6+ months of running the 14500.

So there you have it - overdriving the LED will eventually cause a problem.

Click to expand...

i hope you were not running 2x14500 in your l2d

a single Eneloop in my L2D

Click to expand...

a single Ni-Mh is no overdriving of the light!

must have been something else that caused the problem.
PS: Did it go away when using 2 Eneloops, a cell setup the light is made for?

I think he means he noticed a difference in the beam after going back to normal cells that was presumably unnoticeable with the 14500.

RtOaNn said:

I know the LD20 can support alkalines, NiMHs & lithium so I would like to find out if it can support 2 x 14500 Li-Ion cells.

Click to expand...

The LD20 is boost-only (i.e. no buck circuit), so 2x14500 would fry it. Don't try it.

1x14500 works, but you are over-driving the light which can have potential long-term consequences (not to mention loosing all the lower modes in this case).

Wiggle said:

I think he means he noticed a difference in the beam after going back to normal cells that was presumably unnoticeable with the 14500.

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That is correct. Running the shorter tube allows it to fit in the pocket nicely. Was running a single 14500 for great output. There was obviously some damage occuring that wasn't visible till dropping back to the lower voltage of the single eneloop.
The damage is also visible with the longer tube and 2 * eneloops.
Now that I know it is there, I can see it with the single 14500 too.

Just wanted to let others know because everything I had read up till now suggested that there likely would not be a problem.

Just wanted to let others know because everything I had read up till now suggested that there likely would not be a problem.

Click to expand...

to be correct:
* 14500 (single!) never has been officially allowed,
* letting the light run on turbo for some time never has been allowed

the not allowed 14500, as it shifts the driver to direct drive - which is, in fact, turbo the whole time - is nothing that has ever been advised. Whoever does it (me included) knowed that it is totally on own risk, with the chance of damaging the light.

... dont remember having read anything sounding different.
:thinking:


PS: my quarkAA on 14500 runs nicely, so far.