Surefire L4 - E1L Combo

I am considering this combo and would like to know how interchangeable the parts are. I would like a flexible "kit" with different configuration options, and good backup options. Are the heads, bodies, and tails completely interchangeable? Assume all primary battery usage.

What are you using it for? For my uses, I'd skip the E1L and just go with the L4, and if you need a backup use a cheaper single cell like a P1D-CE. The heads/bodies/switches are interchangeable for the L4/E1L.

I've got both the E1L and the L4 and the bodies and heads are interchangeable. However please note that KL1 head (on E1L) and the KL4 head (on the L4) have different circuits and they are buck/boost and boost respectively. Both behave differently whereby KL1 head can accept 1xSF123, 1xR123a, 2xSF123, 2xR123a, 1x17670, and 2x17670 batteries. Whereas the KL4 head can only accept 1xSF123, 2xSF123, 1x17670 only.
Why use primaries only? Rechargeables are the way to go and its 'Guilt free' lumens and you will save alot in the long run. If you do decide to go the rechargeable way you need 2xR123a + 2x17670(for 2 cell body) + 1 Ultrafire WF139 charger that would set you back around $55.00

rotncore said:

I'd skip the E1L and just go with the L4, and if you need a backup use a cheaper single cell like a P1D-CE. The heads/bodies/switches are interchangeable for the L4/E1L.

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The reason I am considering this combo is becasue of the following: If all 4 parts are interchangeable (it sounds like they are,) I have much more flexibility and redundancy.

Let's say I have an L4 and a E1L. If the head fails on the E1L, I can use the L4. Oops, the switch on the L4 failed too. I can use the body and switch from the E1L.

If I have a L4 and a P1D-CE, if the head fails on the P1D and the switch fails on the L4, I'm SOL. I have 3 good batteries, one good head, one good switch, and two good bodies and I'm still in the dark.

Why use primaries only? Rechargeables are the way to go and its 'Guilt free' lumens and you will save alot in the long run. If you do decide to go the rechargeable way you need 2xR123a + 2x17670(for 2 cell body) + 1 Ultrafire WF139 charger that would set you back around $55.00

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The only reason I specified primaries was to simplify things. This would be my combo to grab when TSHTF. The most likely scenarios for me include a loss of power, where rechargeables would be of limited use. I do use rechargables, and I would get rechargeable lithiums in the L4 for general use, but I don't want to worry whether or not the rechargebles in the L4 would work with an E1L head.

aggiegrads said:

Let's say I have an L4 and a E1L. If the head fails on the E1L, I can use the L4. Oops, the switch on the L4 failed too. I can use the body and switch from the E1L.

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Just bear in mind that the KL4 head may run very dim on single primary CR123A. I know mine does.

GeorgePaul said:

Just bear in mind that the KL4 head may run very dim on single primary CR123A. I know mine does.

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Can anyone give a lumens estimate for the KL4 head on 1x 123a?

my L4 head runs great on a E1 body

all the surefire E series stuff is compatible

but

DO NOT TRY
2x 3.7v R123 with L4 head
2x 3.7v R123 with E2 lamp assembly
anything other than 1x SF123 with E1 lamp assembly

im killed my first Pila 168s a few weeks ago, my spare one is still going strong
guilt free lumens is the way to go

Another not-too-bad combination is the KL1 head with a McR-20 reflector and a UCL. Not as bright as a KL4, but with a more usable beam pattern than the KL1 (which is mostly throw). It can be a trick to get the KL1 head open though.

aggiegrads said:

Can anyone give a lumens estimate for the KL4 head on 1x 123a?

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On primaries, I did try once, about the same brightness but very short time, due to the voltage drop from fresh around 3.2 to about 2.9-3.0v, in minutes probably. Then the output drops. For single cell usage better R123a but the head gets much hotter if compared to running with 2 cells though.

Echo63 said:

all the surefire E series stuff is compatible

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Correct. Except that many find that their KL4 doesn't work right with a single CR123A. And, as you point out, you don't want to use an E1e lamp assembly (MN01) with 2 CR123As. Also, if you use an E2e lamp assembly (MN03) with 1 CR123A, it will run very dim.