Fenix L1P and L2P running on single cells

The L2P head seems more efficient all around than the L1P head, on all different cells I tried.

I didnt show the alkalines because they would clutter up the image too much, and were less than impressive in their power output over time.

I'm not quite sure I understand, the L2P running on a single cell and the L1P isn't? Shouldn't that be other other way around? I think we're missing some context. Are you running the L2P head on the L1P body?

PowerMatt said:

Are you running the L2P head on the L1P body?

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I'd say so.

Both lights were run with a single cell. The L1P was run stock, but the L2P head was run on the L1P body. Thus the title "running on single cells".

Okay, so that answers that. So the next question is, why is the light intensity so close? Shouldn't there be a rather dramtic difference with L2P operating under two volts? Or can the fully regulated circuit operate that low?

Interesting. Have there been any runtimes done on the L2P with a protected 14500? I would think it would be a little brighter.

Is the L2P way worse with one cell on alkalines? Perhaps thats why they don';t use the l2 guts in the l1...

Grubbster said:

Interesting. Have there been any runtimes done on the L2P with a protected 14500? I would think it would be a little brighter.

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A couple of folks tried it. I think 4sevens said he measured like 1,400 lux with the L2P head on a single 14500. Since it's that much brighter, I can't imagine the LED would last a really long time... Maybe if only used for less than a minute at a time but I'd think if you went through 20 charges or so of continuous use, the LED would be damaged from heat.

Just purely my instincts. 4sevens said he got about 45 minutes of brightness, I think. I was never brave enough to try it with my L2P head. Maybe when more folks have reported long term success.

Maybe Fenix should offer a version of the L1P using the L2P head for those who use lithium or rechargeable cells anyway.

IsaacHayes said:

Is the L2P way worse with one cell on alkalines? Perhaps thats why they don';t use the l2 guts in the l1...

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I thought I had done some L2 head single cell alkaline runtimes but I guess I hadnt. Judging by the efficiency I'd bet the L2P head is more efficient no matter what the cell.

LightObsession said:

Maybe Fenix should offer a version of the L1P using the L2P head for those who use lithium or rechargeable cells anyway.

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IsaacHayes said:

Is the L2P way worse with one cell on alkalines? Perhaps thats why they don';t use the l2 guts in the l1...

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Isaac hit the nail on the head. I asked fenix these very same questions
weeks ago - They said the L1P would slam an alkaline cell and would not be
practical - especially the poor ones. They want any off the shelf battery to
work with the L1P.

The L2P head is quite impressive in it's regulation, but it really pushes
the batteries hard. That is why I asked chevrofeak to try this with high
capacity nimh's and the lithium AA's I sent him.

Now I know what is on your flashaholic minds right now.... how about a L2P
head only sale? I've asked them about that and they astutely answered
with a no. They're busy enough trying to keep up production on premiums
only. So the only solution now is to buy a L2P and use it's head but then the L1P head is useless with the L2P body :shrug:

It's not useless - you stick a dummy battery in the tube and you have a "long" L1P. Even better - somebody invent a method of putting 2 AA cells in the L2P body but have them wired in parallel instead of series. That way, you'd get the extra run time instead of wasting the space with a dummy battery. The carrier would have to be REEEEAAL thin though. Hmmm, it's worth a try.
For now, I'm going to keep my L2 head on the L1 body and go with the L1 head on the "L2 with a dummy" body.

I did a couple more runtimes last night.




I am very unimpressed with those Energizer Max cells. :thumbsdow

@chevrofreak

outstanding!

Nice job Chevrofreak!

chevrofreak ... :thumbsup:

Can't the L1P head run on 2xAA? (Dumb question alert ) ?

bernie

its not impossible to wire batterys in the L2P in paralell instead of series, you just take 2 nimh 2500mah batterys with flat top and bottom, a very thin wire and solder between the bottom batterys + and the top one +, then you solder another wire between the top cell - and the bottom cell -, then you insulate between the batterys with a pice of rubber and cover it all in ultra-thin shrinkwrap and there you got a 1.2v 5000mah battery

Kiessling said:

chevrofreak ... :thumbsup:

Can't the L1P head run on 2xAA? (Dumb question alert ) ?

bernie

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you can https://www.candlepowerforums.com/threads/99516&highlight=r/o+l1p


--------------------------------------------
QYAJ Lux-I with Fenix L1P v2.5 circuit:
--------------------------------------------
Vin ---- Iin ---- Vout ---- Iout ---- Efficiency
--------------------------------------------
1.0 ---- 0.61 -- 3.24 ---- 0.151 --- 80.20%
1.5 ---- 1.23 -- 3.395 --- 0.294 --- 54.10%
2.0 ---- 1.57 -- 3.47 ---- 0.456 --- 50.39%
2.5 ---- 1.65 -- 3.585 --- 0.670 --- 58.23%

chevrofreak said:

The L2P head seems more efficient all around than the L1P head, on all different cells I tried.

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Can't say I am surprised, the L1P is quite inefficient.

If the converter inside was efficient, the two lines would lie on top of each other.

You can see there is quite a considerable amount of room for improvement.