# Petzl MyoBelt XP 2008 - Vivisection :)



## Szemhazai (Feb 6, 2008)

*Petzl MyoBelt / Myo XP 2008 - Vivisection *

Everything that You would like to know, bout they wont tell you in the shop.







One of the biggest outdoor makers finally wake up and put on the market refreshed version of the well known Myo XP / Myobelt XP.

Some marketing crapp : 


- *200% brighter*
- *85 lumens* output and nn the BOOST mode even 150 !
- good looking grey-black design 
- powered by „AA x 3 (1,2V-1,5V)'
- 3 color battery charge indicator (green->yellow->red)

On the leaflet inside the blister there is some strange issue : in the High mode headlamp on the dedicated 6 cell battery pack 3400mAh should work 50 hours and on the 3 Alkaline Batteries 80 hours !!!

It looks almost the same as the old one, excluding the color, but I think that any flashaholic will recognize SSC P4 emitter .





Inside, it looks the same as the old one…





In old XP’s Petzl was grudging and many times they put S-bin Luxeons instead T-bin or better. This time, inside the headlamp is original U-bin SSC P4 star – USXPI, yes they can be a bit more demanding and chose lower Vf version USXPH but this will be good too – I was worrying that they will use T-bin SSC. 





Inside almost nothing has changed… 









When U use 3 alcaline’s from the headlamp package LED will be powered as shown: 

```
USXPI            USX0H
BOOST   762,1 mA    3,73v    913,1 mA	3,82v 
HIGH    269,7 mA    3,25v    299,2 mA	3,06v 
MID     157,9 mA    3,12v    170,3 mA	2,94v
LOW      65,4 mA    2,95v     68,3 mA	2,8v
```

Now, lets test powering it up from the NiMh’s – it newer was the strong side of this headlamp, but maybe they improve something…  3 slightly used cells – 3,84V without load. In the meantime I switched the star to the USX0H .

```
I-led        V-led     V-in
HIGH    194,0 mA     2,97v    3,77v
MID     111,5 mA     2,87v    3,80v
LOW      44,0 mA     2,75v    3,82v
```
As you can see, everything goes as usual, there is not enough voltage to power the LED – so you cant use the headlamp properly.

In that case you need to use 4xAA battery pack :devil: 4 NiMH cells - 5,13V without load. 

```
I-led   V-led     I-in   V-in     Eff
BOSST   714 mA  3,40v    742 mA  3,74V   87,5%
HIGH    415 mA  3,16v    417 mA  4,16v   75,6%
MID     233 mA  3,01v    237 mA  4,57v   64,8%
LOW      90 mA  2,84v     92 mA  4,89v   56,8%
```
Let it be the light :twothumbs

*SUMMARY*
New LED, twice much light as from the earlier version, the same price, 3 year guarantee - one of the best value-for money headlamps on the market today. But it still have one weakness from the older model – it don't have good buck/boost driver. 

*OLD* Myo vs *NEW* Myo - on High




on Mid




on Low


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## HEY HEY ITS HENDO (Feb 6, 2008)

Excellent mini review Szemhazai


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## W-c.Scenario (Feb 6, 2008)

Excellent info Szemhazai,
to bad they didn't optimize it for NiMh’s,
194 mA in high mode, isn't that under 60 lumens or so? ... what where they thinking:thinking:

I was about to buy this one but I think I´ll wait and see what Zebralight and Fenix comes up with.

Many thanks


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## nzbazza (Feb 7, 2008)

Szemhazai,

Nice work and thanks for the review. :twothumbs

I agree with previous comments about the lack of performance with NiMH batteries. Also Petzl note that Lithium cells aren't supposed to be used with the H/L either, so that only leaves Alks.:green:


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## cave dave (Feb 7, 2008)

Maybe soon I can find the old one on closeout and Mod it.


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## degarb (Feb 7, 2008)

what is the price? And where is quickest way to get one?


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## Vermonter73 (Feb 8, 2008)

degarb said:


> what is the price? And where is quickest way to get one?



x2 

I loved my Tikka and Myo 5. Now they seem so dim compared to my modern lights.


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## Szemhazai (Feb 8, 2008)

In Poland it costs about 90$, the main problem is that the most of the outdoor shops still have many old MYO's XP and they need some time to sold them out. So they are keeping new myos in the stores.


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## Sarratt (Feb 8, 2008)

W-c.Scenario said:


> Excellent info Szemhazai,
> to bad they didn't optimize it for NiMh’s,
> 194 mA in high mode, isn't that under 60 lumens or so? ... what where they thinking:thinking:
> 
> ...



I don't understand all the electronic data but why do you say its not optimized for NiMh's ? 

And thank you very much for review Szemhazai


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## cave dave (Feb 8, 2008)

One of the first places to get Petzl in the US is Karst sports.

I think you can pre-order now for March delivery. $79.95
http://www.karstsports.com/pee83p2myoxp.html


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## Szemhazai (Feb 9, 2008)

Sarratt said:


> I don't understand all the electronic data but why do you say its not optimized for NiMh's ?



Because there is a big current drop when you are switching from Alkaline’s to NiMH's – if they will put there Buck/Boost converter i.e. something like Sandwich GD500 – the each light level will have the same current +/- 10% regardless power supply.


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## cave dave (Feb 9, 2008)

While peak currents and lumens might be higher on *fresh *Alkalines those values will drop like a rocket due to the unregulated nature. I bet overall performance will actually be better on NiMh.

**EDIT**
Here is the runtime graph of the original on Alks. As you can see it drops like a rock.
http://www.flashlightreviews.com/reviews/petzl_myoxp.htm

also:


de55jay said:


> ... when you put new batteries in then they look even better for the first couple off minute . With a new set of batteries the pack measures 4.8 v as it sits and 4.5 v under load . After 5 min it drops to 4.3 v and 3.9 under load...
> 
> Don



Petzl should have lowered the current to the Low beam. It was already too bright to begin with. They could have kept Lumens the same and doubled the runtime.


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## Jiffy (Feb 9, 2008)

Thanks Szemhazai! :twothumbs

I was going to mod my old Myo XP but saw the new Myo XP and bought it, thinking Petzl had put a Cree in. Now I find out I'm wrong!

So, two questions!

1) If I mod my old Myo XP with the USWOH I've got here, it'll be at least as good as the new one?

2) I use NiMh's all the time with my Myo's. How safe is it to use 4 cells?

Thanks!


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## Szemhazai (Feb 10, 2008)

Jiffy said:


> 1) If I mod my old Myo XP with the USWOH I've got here, it'll be at least as good as the new one?


Yes, but it wont have this new cool look 



Jiffy said:


> 2) I use NiMh's all the time with my Myo's. How safe is it to use 4 cells?



As safe as using 3 cells ? It is only overheating a bit .


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## Jiffy (Feb 10, 2008)

Szemhazai said:


> Yes, but it wont have this new cool look


Yeah, I do like the lime green buttons!



Szemhazai said:


> As safe as using 3 cells ? It is only overheating a bit .



I'm gonna go for it! I'm keeping the new Myo XP until I've modded the old one so I can compare the two and see how good mod is.

Thanks!


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## Sarratt (Feb 11, 2008)

Szemhazai said:


> Because there is a big current drop when you are switching from Alkaline’s to NiMH's – if they will put there Buck/Boost converter i.e. something like Sandwich GD500 – the each light level will have the same current +/- 10% regardless power supply.



| I'm sorry for my ignorance but please sometimes make it simple. What does that all mean in real life ?


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## boef800 (Feb 11, 2008)

Szemhazai,
can you tell if the new one has a new seoul dedicated optic,or would you say they even not changed to an optimized optic for the new emitter?

Alex


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## Szemhazai (Feb 11, 2008)

In my opinion it is still the same optic. The only difference in the internal design is slightly higher LED holder to compensate thinner star – but I’ve seen the same (higher) holder in 2 of old myos (’06 labeled) so I’m unable to say thet it’s new solution (my current MYO is labeled 09 ’07).

*Sarratt* - that when you will use NiMH's instead of alkalines the headlamp will burn shorter and weaker than on alkalines.


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## cave dave (Feb 11, 2008)

Szemhazai said:


> *Sarratt* - that when you will use NiMH's instead of alkalines the headlamp will burn shorter and weaker than on alkalines.



It's not as simple as that. The runtime curves will be completely different. The alkalines will start off brighter but drop much faster. The NiMh will start off dimmer but hold a higher output for longer. The Alks will have a longer "tail" of very dim light.

For all practical purposes you probably won't notice any difference.


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## degarb (Feb 11, 2008)

Again, where best place to buy for next week delivery?

And, anyone mod for 4 AA, and how did it go?


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## ToTo (Feb 15, 2008)

I have some questions about the myo xp
what is the max voltage you can drive it with?
would it be possible to run it with 2 lithium ion rechargeables and replace the 3. by a wire

is there any combination of rechargeables u get a good output using the 3battery pack?

and did they change anything of the driver?

i hope u understand what i wanted to ask
cause im from germany and dont have more than my school english

mfg ToTo


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## Szemhazai (Feb 15, 2008)

ToTo said:


> what is the max voltage you can drive it with?



Sorry but You have to test it yourself :devil: Fully loaded 4xNiMH will give 5,4V - then led will get on High 400mA it will overheat and thermal resistor will lower the current. So there is no point to increase the current witch such poor cooling.



ToTo said:


> and did they change anything of the driver?



There are no visual differences.


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## uk_caver (Feb 15, 2008)

The driver performance does seem a bit of a shame, not having any regulation. With the original USXPI LED, NiMH perforrmance would presumably be even worse.

Especially on the high and medium settings, the figures quoted earlier by Szemhazai for performance on NiMH and alkalines do look rather like what you'd expect from a resistor in series with a diode, or a resistor switched by a bipolar transistor.

The odd thing is that if there's enough smarts in the circuitry to reduce power if the LED overheats, you'd think it wouldn't have been too hard to add current regulation.


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## Ferreter5 (Feb 15, 2008)

Well, my first post here on the CandlePower forums...

After doing loads of reading for awhile and learning a whole lot from these forums I went ahead and ordered the new 2008 Petzl MYO XP (non-belt version). It's on backorder and I hope to have it sometime in March. Can't wait to try it out!

I plan to use it for night hiking and some occasional night geocaching (I do most of my geocaching when my hiking happens to take me near some). I've been enjoying treking around the NY Finger Lakes by both day and night.

Thanks for all the great info you guys have here. Not only have I learned a lot in general about the in's and out's of lights, but using the discussions here I've purchased my first headlamp and I also now have a Fenix L0D on my keychain.


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## ToTo (Feb 18, 2008)

if i use 2x 3.7V lithiumion batteries
could i replace the 3. battery by anything to reduce the voltage and to get the required input (using resistors, boards, what ever) 
is that possible?


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## Szemhazai (Feb 19, 2008)

I think, that it my be too much - at the beginning you will have 8,4V so almost twice more than the MYO XP was made for. You can put there single Li-pol tab from cell phone or photo camera and it will work fine.


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## ToTo (Feb 19, 2008)

I think you got me wrong .. i want to use the free space of the missing 3rd batterie for something like a voltage regulator ... is that possible?


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## cave dave (Feb 19, 2008)

Maybe you should buy a PT apex instead. It will handle 8.4V. Its regulated and after LED mod will be brighter too.


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## stijn (Feb 27, 2008)

As a result of Szemhazai's post, I saw “the light” and quickly knocked up the following, modest mod. Since I prefer using rechargeable, less waste and money etc., I thought to use 4x NiMh AA’s to make up the needed +/- 5v, as described earlier, Ooo and its a bit warmer too, . (I might drill out the venting holes a bit, maybe upgrade the headsink). Although Termal protect doesn't seem to have kicked in once yet.
 
I had a Petzl Tikka Xp lying around and an old neck pouch of a Petzl Zoom which I no longer use. I used the headband of the Tikka XP, to replace the Myo headband and battery pack and wired the light up as shown in the picture. The 4x NiMh AA definitely makes the Myo XP shine much brighter, as was to be expected. What I like about a neck pouch is the fact that one can’t lose the light in case it gets knocked off ones head and it reduces the weight on head.

With 4x NiMh the runtime should be better now

The overall weight including the 4x NiMh AA and pounch of the light now comes in at 272grm, which leaves it a lot lighter then the APEX extreme, for example (maybe I'm comparing apples with oranges here). 

Even though people on this forum don’t seem to favour the Myo XP, I like the floodlight lens cap a lot. It gives a great floodlight with a nice full peripheral view. And I personally prefer a none regulated light since it doesn’t suddenly just quite or start blinking, even though output obviously tails off over time.

Szemhazai, where would I be able to get hold of a SSC P4 USX0H star as a replacement for the stock one? Thanks again for your initial post!


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## hopkins (Feb 27, 2008)

Thats a nice mod Stijn! Could you post some current measurements from the
4cell battery pack with fresh out of the charger NimH please. 
Curious...

I am also a big fan of the MYO XP. Its got that ultimate feature we all
love - screws to take it apart! Thank you Petzl!!!


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## stijn (Feb 29, 2008)

Hopkins, to answer your question, (I haven't got a multi meter to measure current) but maybe voltage will tell you something.

After having charged overnight, my fairly newish but well broken in 2700Mah Ansmann AA'a in my Ansmann charger, the combined voltage of the 4xAA's was 5.79V, without load. After cooling off they where was 5.66V left. I suspect there will be a little voltage drop across the slightly longer wire which I'm now using. Accoording to Szemhazai measurements I suspect the LED will now be running at over 4.5v, which will probably shorten it's life a little. Mmmm...:thinking: What do people think?


By the way, does anybody have any recommendations on how to unscrew the big funky Petzl plastic screws on the side of the head?

Cheers,

Stijn


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## hopkins (Feb 29, 2008)

hi stijn: look here to see pictures.. He made a tool to remove the side screw things.
http://candlepowerforums.com/vb/showthread.php?t=174538
.
hopkins


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## degarb (Mar 1, 2008)

"Accoording to Szemhazai measurements I suspect the LED will now be running at over 4.5v, which will probably shorten it's life a little. Mmmm..."

I am no electrician. Only know basic laws, after looking again at the cheat sheet each time. 

From what I understand you could run a resistor per: http://www.jeffpolston.com/ledlite.htm

I don't know how much he would shorten the life. If from 50,000 hours to 10,000, no big deal. If below 2000, then I would have an issue.

How about a $3 25 ohm 3 watt rheostat they sell at walmart--erhh Radio Shack and what little real electronics they have in addition to low end/over-marked-up consumer stuff, as of 2008? Would have to eye the approx brightness, but would have a boost mode.


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## Szemhazai (Mar 3, 2008)

stijn said:


> After having charged overnight 4xAA's was 5.79V, without load. I suspect the LED will now be running at over 4.5v, which will probably shorten it's life a little.




You are wrong...  Led at this input voltage will get on "high" at the beginning about 3,3V so about 350 mA for standard _ _ _ _ I bix SSC or 500 for _ _ _ _ H and only for a short time, the current will be lowered by the thermal resistor inside the lamp.


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## Szemhazai (Apr 28, 2008)




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## hirby (May 10, 2008)

Haven't been around much since 3 kids now (1 more since the time I posted the MyoXP customization  I'm the guy who did the original 3 aa MyoXP battery pack to 4 aa Myo3 battery pack with P4 and custom heat sink back in Septemberish 2007 http://candlepowerforums.com/vb/showthread.php?t=174538
. 

My Myo XP is still running perfect after 8 months. If there has been any damage from 4 AA's to the LED or circuitry, it is not readily apparent. I've used this thing continuously on high until the batteries wore out and it runs a LONG time on 4 aa's (as in so many I dont care to measure it). It'll run even longer for general night usage on a lower level, but since It runs so long anyway, I just use high most of time. I would NOT run 4 aa's on high though for any length of period with the standard crappy heat sink.

The thermister appears to do a good job as a pseudo regulator as the light output seems damn stable for a long time. If I ever get off my butt, it would be interesting to see how much current regulation the thermister is providing. So basically is seems that instead of having a direct volt/current regulator, I now have a indirect heat-induced current regulater from the thermister. Like I mentioned though, I have a large enough custom heat sink that can absorb enough LED heat so that it isn't going to burn out before the thermister can do anything (assuming it is acting like a regulator and is not my imagination).

I mostly use 4 2500-2650 mA Duracell AA NiMh rechargeables in it (depending on which set has the charge rotation and without any noticeable diff in real-life run times). The P4 LED seems just as bright as when I put it in. With the Myo3 hard battery box, it is "very" nice to wear when under my car doing stuff. The rear of head support and comfort of the Myo3 box is MUCH better than the MyoXP battery box or concrete and the hard plastic box does not show any real wear from ground abrasion.

4 AA alkalines do "not" seem any brighter than 4 NiMh's , although with the old "3" aa battery box, alkalines "did" look much brighter at first compared to NiMh's (with much shorter run times of course).


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## moonfish (May 10, 2008)

Szemhazai, thanks for the pictures and measurements. It is interesting to the different effect of the two leds as well. I just ordered up a rebel emitter to see if the lower Vf will help out my old Icon. It looks like it is resistored so I can't see how else to make it brighter. I think the companies are really missing the boat in the headlamp market but I am odd enough to post here.


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## spyros (Aug 22, 2010)

Which rechargable batteries would you suggest for the MyoBelt?


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## Szemhazai (Aug 22, 2010)

It highly depends how often you are using it - for everyday use any good quality cells (highest capacity) will be fine (I'm using GP / Hama). If you want to use one time in a month you can use enelops - because you will not lost energy on self-discharge, but the capacity is lower.


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## spyros (Aug 22, 2010)

I plan to use it only for summer months every week or every second week. What do you think of these?
http://www.mahaenergy.com/store/viewitem.asp?idproduct=415
http://www.mahaenergy.com/store/viewitem.asp?idproduct=426


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## Szemhazai (Aug 22, 2010)

Hell knows, take cheaper


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## spyros (Aug 23, 2010)

Which one of these 2 batteries would you suggest?


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## spyros (Aug 28, 2010)

Just bought the MyobBelt, but i am not very satisfied with it. I used the alkalines supplied with the headtorch, bought the Maha 2700mah but haven't used them yet and from what i have read, the performance with these might be worse. Iam thinking of trying the Led Lenser H7 although it has the disadvantage of not having removable battery pack. I feel so light the Petzl on my head!


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## hopkins (Aug 29, 2010)

I was thinking that if the power cable was modified with snap in connectors at the battery pack and the headlamp bezel Petzl could sell long and short version replacement cables for when the wires fatigue and wear out causing the headlamp to not work. 

A happy solution rather than dealing with customer complaints and returns. 
You just buy another cable.


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## LoPan12 (Sep 20, 2010)

I didn't want to start a new post, so I thought I'd ask here. After trying to read some posts, I realized that some of this is tech talk is just over my head for now, and I don't have the spare time to...absorb it all.
I've really only got a few questions.
Is the 2008 the most recent and current incarnation of the Myo XP? If so, what's the general opinion of the LED (SSC?) inside it?
Petzl's battery chart says NO to lithium batteries. Is this a precaution or a hard fast NO? What kind of batteries would you suggest using in it?

The reason I'm curious, is that I was just at an REI garage sale, and picked one up. The return tag said "Defective...batteries overheating". Well, it looked brand spanking new (no scuffs or scratches at all), and it was priced at $19, and since I was looking for a new headlamp, I thought I'd give it a shot. 
So since I didn't want it to blow up on my head or anything, I took it home, put some new alkaline batteries in, and turned it on high for about 2 hours, and just let it sit on the table. Afterwards, I checked and the batteries didn't feel warm at all. 
What do you guys think? Should I run it for longer? Did the previous owner put the wrong kind of battery in? Put them in backwards? Any help would be great! You guys are all light gurus from what I can tell! I'm just a small time lover of pretty much anything that lights up!


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## Szemhazai (Sep 21, 2010)

Most up to date version of XP is RXP - it have regulated output. If batteries are already overheating it means that cable is broken inside and there is short-circuit - Petzl will replace the whole headlamp, most probably.


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## LoPan12 (Sep 21, 2010)

Szemhazai said:


> Most up to date version of XP is RXP - it have regulated output. If batteries are already overheating it means that cable is broken inside and there is short-circuit - Petzl will replace the whole headlamp, most probably.


 
That's what I figured. But I ran it for two hours on max power and the batteries were fine. Been sitting with the batteries for a couple days now, no overheating. So I don't think it's a short circuit. I was wondering if incorrect battery type or installation would cause they're problem, as I'm seeing none.

I know the RXP is regulated...but it wasn't $19 :duh2:


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## NoFair (Oct 18, 2010)

Anyone tried the Myo XP on a single li-ion? Considering getting one and using 2 18650s in parallel in an external pack...

Sverre


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## Szemhazai (Oct 18, 2010)

It will work - but the voltage will be a bit to low for most of the time - the same effect as for the 3xNiMH.

This headlamp needs at last 4V to work fine on high :thumbsdow


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## NoFair (Oct 19, 2010)

Szemhazai said:


> It will work - but the voltage will be a bit to low for most of the time - the same effect as for the 3xNiMH.
> 
> This headlamp needs at last 4V to work fine on high :thumbsdow



Thanks for the info. Shame about Petzl's bad electronics in this one..


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## Szemhazai (Oct 19, 2010)

Myo RXP will works fine


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## NoFair (Oct 19, 2010)

Szemhazai said:


> Myo RXP will works fine



Thinking of getting one and making a belt pack for it or getting a Hurricane: http://littlemonkeycaving.co.uk/hurricane.aspx


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