4Sevens Preon 1 (1xAAA) Comparison Review

[UnknownVT]

It might be current regulated, but not to a constant level. The brightness off Preon is directly proportional to the battery voltage. This makes a Preon much more friendly for alkalines than a constant brightness light.

If the LED was on direct drive I would agree....

The Preon head can accommodate 1x or 2x AAA batteries the total voltages are below the typical Vf - so the circuit is a boost circuit.

Since the boost circuit boosts the voltage up to Vf - which remains the same for the emitter regardless of the battery used. Then the brightness of the light is dependent on the amount of energy (so current) that the batteries can deliver to the circuit/LED combination.

Does the difference between a nominal 1.5V of the alkaline (which sags much more quickly) and the nominal 1.2V of the NiMH make much of a difference? Since they both have to be boosted to Vf and therefore the brightness is dependent on the ability to deliver enough energy (so current) to drive the LED?

 

[HKJ]

If the LED was on direct drive I would agree....

It is not anything to agree with or not, I have measured it. As you can see on the green curve the brightness increase with increasing battery voltage.

From my Danish review:

The Preon head can accommodate 1x or 2x AAA batteries the total voltages are below the typical Vf - so the circuit is a boost circuit.

Since the boost circuit boosts the voltage up to Vf - which remains the same for the emitter regardless of the battery used. Then the brightness of the light is dependent on the amount of energy (so current) that the batteries can deliver to the circuit/LED combination.

Does the difference between a nominal 1.5V of the alkaline (which sags much more quickly) and the nominal 1.2V of the NiMH make much of a difference? Since they both have to be boosted to Vf and therefore the brightness is dependent on the ability to deliver enough energy (so current) to drive the LED?

Some AAA lights are stabilized (Eagletac PN20A, Ray S20) and some are not (ITP A3, MaraTac AAA and Titanium Innovations IlluminaTi). They are all using a boost converter, but with different design.
The stabilized lights works best with NiMH, because they increase the current draw, when the battery voltage goes down, this is not smart with alkaline!

 

[UnknownVT]

It is not anything to agree with or not, I have measured it. As you can see on the green curve the brightness increase with increasing battery voltage.

From my Danish review:

Thanks for the graph - I looked at your review (using Google Translate from Danish to English) -

Using 1.2V nominal for NiMH/eneloop - your graph shows that the lumen output to be less than 60 lumens whereas the 1.5V nominal of the alkaline would be at about 80 lumens - was there really that much of a difference some 33% brighter than on an eneloop?

Do you have a version with the actual plot points for eneloop and alkaline or just the measurements of actual lumens readings were please?

This is a revelation and educational to me - thank you.

Some AAA lights are stabilized (Eagletac PN20A, Ray S20) and some are not (ITP A3, MaraTac AAA and Titanium Innovations IlluminaTi). They are all using a boost converter, but with different design.
The stabilized lights works best with NiMH, because they increase the current draw, when the battery voltage goes down, this is not smart with alkaline!

Is the Preon then a non-stabilized circuit - ie: non-constant current - therefore does not increase current draw to compensate for sagging battery voltage?

Thanks

 

[HKJ]

Thanks for the graph - I looked at your review (using Google Translate from Danish to English) -

Using 1.2V nominal for NiMH/eneloop - your graph shows that the lumen output to be less than 60 lumens whereas the 1.5V nominal of the alkaline would be at about 80 lumens - was there really that much of a difference some 33% brighter than on an eneloop?

The plot is made with a bench power supply and the lumen are calculated from measured brightness and the specified lumen output value (This will be correct, as long as the specified value is correct ).

Alkaline might start at 1.5 volt, but will not stay that high for long, NiMH will start at 1.4 and will keep above 1.2 for most of the run.

Do you have a version with the actual plot points for eneloop and alkaline or just the measurements of actual lumens readings were please?

For actual performance with batteries, you have to look for runtime curves. The above voltage scan is useful to see how the driver works, but can not include how batteries works under load (But a driver that tries to draw 1.5A from a AAA battery, does not work well with alkaline (S20), this is also confirmed with the runtime curve).

Is the Preon then a non-stabilized circuit - ie: non-constant current - therefore does not increase current draw to compensate for sagging battery voltage?

Yes, Preon, ITP A3, MaraTac AAA and Illuminati are all based around a similar (maybe same) circuit, but with different program in the controlling microprocessor.

 

[UnknownVT]

Alkaline might start at 1.5 volt, but will not stay that high for long, NiMH will start at 1.4 and will keep above 1.2 for most of the run.
Yes, Preon, ITP A3, MaraTac AAA and Illuminati are all based around a similar (maybe same) circuit, but with different program in the controlling microprocessor.

Thank you for that -
so on high using alkaline one can probably see the light dimming fairly quickly due to voltafe sag of the alkaline
- whereas on NiMH (where the voltage does not sag as quickly) one kind of see a relatively constant output -
this is due to the battery characteristic rather than any regulation by the circuit?

 

[HKJ]

Thank you for that -
so on high using alkaline one can probably see the light dimming fairly quickly due to voltafe sag of the alkaline
- whereas on NiMH (where the voltage does not sag as quickly) one kind of see a relatively constant output -
this is due to the battery characteristic rather than any regulation by the circuit?

Exactly, except you will have problems seeing it (A "small" brightness change over time is very difficult to see), but it can easily be measured.

 

[UnknownVT]

For actual performance with batteries, you have to look for runtime curves.

Using that hint I found a runtime graph from selfbuilt's excellent review - 4Sevens Preon Review (1xAAA & 2xAAA): RUNTIMES, BEAMSHOTS, and more!

Note: this is selfbuilt's runtime for the Preon 1 and 2.

It doesn't look like that alkaline is brighter than using NiMH in 1xAAA (except right at the start) or 2xAAA at anytime?

In fact the 2xAAA runtime was kind of what I was expecting NiMH in comparison to alkalines - which do not seem to be able to sustain the current delivery required.

 

[tokerblue]

I originally bought a black Preon 1 and love it. I'm a huge fan of it and it's my EDC. It's just so simple to put in my back pocket as I would a pen. I ended up buying a Preon 2 (black + titanium) and a red Preon 1 body for my wife. I kept the Preon 2 body in the event I need a brighter light. The clicky interface from the Preon 2 is great for her and she has a nice red+titanium combo Preon 1 with clicky.

 

[pee10755]

Thank you for the information. Is there an lio rechargeable option for this light or would the voltage be too high and fry the light?

 

[selfbuilt]

Some AAA lights are stabilized (Eagletac PN20A, Ray S20) and some are not (ITP A3, MaraTac AAA and Titanium Innovations IlluminaTi). They are all using a boost converter, but with different design.
The stabilized lights works best with NiMH, because they increase the current draw, when the battery voltage goes down, this is not smart with alkaline!

As always, thanks for the detailed circuit analysis HKJ.

For those of you curious about the difference in alkaline runtime, here is a comparison of the Med/Lo modes of the Preon 2 and Eagletac PN20a2 that I reviewed recently:

Note that the PN20a (and to a lesser extent PN20a2) suffer from a relative lack of efficiency on Hi. But the Med mode (shown above) is very impressive.

 

[Tolip]

It looks like the neutral white only comes in black.
Has anyone taken apart the heads to see how easy it may be to change out the exteriors? I'm wondering if it will be worth my time to buy a titanium head and swap out the guts.

 

[HKJ]

An interesting detail:
The high output at the start of the PN20a2 is because it goes into direct drive. The Vf of the led, in low mode, is lower than 2xalkaline.

 

[UnknownVT]

Thank you for the information. Is there an lio rechargeable option for this light or would the voltage be too high and fry the light?

The Preon head is rated/spec'd Operating Voltage Range: 0.9V-3.0V -
so Li-Ion 10440 is out of range/spec and is not advised.

 

[red02]

Any idea if the Warm white preons will lego with parts from the regular ones?

 

[UnknownVT]

Any idea if the Warm white preons will lego with parts from the regular ones?

Oh absolutely - the Preon head(s) are interchangeable on the 1xAAA and 2xAAA bodies.

So the Warm White Preon 2 head will fit and work on a Preon 1 body with clicky or plain end as a twisty.

4Sevens Preon 2 Warm White Comparison Review

 

[Hiro Protagonist]

Thank you for this excellent review and amazing beam shots! I stumbled onto CPF while trying to find a light to replace my lost arc-AAA .

I read about the Ti Preon1 on CPF and very recently got it. I love the light, although I scratched the body with the clip while trying to install the battery... I didn't know about the posts warning about breech loading the battery. How can I polish out the scratches?

Keep up the good work! lovecpf

 

[UnknownVT]

although I scratched the body with the clip while trying to install the battery... I didn't know about the posts warning about breech loading the battery. How can I polish out the scratches?

Thank you for your kind words.

Have you tried metal polish?
Depending on the depth of the scratches -
you may have to go from coarser (which can make the scratches look even worse initially) to finer polishes.

I just came across Cape Cod Polish Cloths that seems promising
(hint: look in the "23 new from $2.99" section for $0.00 shipping)

 

[Hiro Protagonist]

I'll look into trying metal polish. Thanks from a CPF newbie!

 

[was.lost.but.now.found]

My experience with Ti is a lot less than my experience with stainless but sometimes you have to restore a full polish before you then can add a nice brushed finish.

 

[UnknownVT]

My experience with Ti is a lot less than my experience with stainless but sometimes you have to restore a full polish before you then can add a nice brushed finish.

I don't think that is right - satin or brush stainless steel finishes require much less work than mirror polished.

What you seem to be saying is that one needs to get a high polish before being able to restore a brushed finish - that just doesn't sound right.

You may need to work a bit more to remove a deeper scratch which might result in getting to a higher polish - but that is probably because one is using too fine a grade polish/rubbing compound - ie: the wrong grit - too fine polishes out the undamaged brushed finish.

here's a link to removing scratches on brushed stainless steel - among the many answers - no one suggests getting to a high polished state.

Anyway the Ti Preon is mirror polished titanium -
so it is originally at a high state of polish......