[mntn-biker]

Here is yet another upgrade for my Marwi (new style) Nightpro bike light.

First off, thanks to all of those on the forum here whom I have gleaned information from and have provided input.

This is my parts list:

Marwi Nightpro housing (new bullet style) and switch

Aluminum insert to mount LED mounted 20mm star mcpcb heat sink (shown in the 3rd image down - message me if you are interested in 1). This acts as a mount and heat sink to disperse the led emitter heat to the outer Marwi housing.

Cree-XML LED mounted to a 20mm star mcpcb - u2-1c-tint-p-75

8xamc7135-28a selectable mode driver (jumper'd to a 2 mode low/high setting & I un-soldered the spring off the board)

Fraen FRC-N1-MCE-0R reflector

34.8mm glass lens

The reflector is actually made for a Cree MCE led but the XML U2 led is supposedly brighter. It is smaller in size (5mm x 5mm) so it actually fits the opening at the bottom of the reflector no problem.

Here is an image of my purchased parts and my original Marwi new/bullet style light (disassembled and shown without the lens retention ring).

Assembly procedure below:
Solder led leads to the driver:

Apply thermal grease/paste to both the insert and the rear of the mcpcb star (I used Arctic Silver Ceramique paste):

Insert led leads from rear of insert, screw star in place using blue loctite (you will have to countersink the star under the flat head screws so that the screws get as low as possible so as not to interfere with the reflector), and solder leads to appropriate contacts. I like having the star screwed in place so I can replace/upgrade the led later on if need be. Some choose to glue it in place but I'm not sure how difficult it would be to break that bond.

View of rear of insert/mcpcb/led assy with battery leads soldered in place (this is a good time if you want to solder/jumper your driver for a specific mode - see following image courtesy of El34)(Mine is jumpered for low/high mode - see the 4th star to the right is soldered/jumpered to the outer ring which is Battery -):

This driver image is similar to the driver I used (I removed the center spring on my driver as you may have noticed):

Apply thermal paste/grease to the outside of the insert and the inside of the light housing. Slide the insert assembly into the housing, set the reflector in place, followed by the o-ring, the lens, and then the lens cap. Prior to assembly, you will need to drill out the hole in the light housing with a 1/8" drill bit (it currently is a tapped hole), and lightly sand the inside of the housing to remove the burrs in this area. BTW - The o-ring is not the original. You will need to make a stop to your local hardware store in the plumbing department for the next size up o-ring with a thicker cross section. The final turn on the lens cap compresses the o-ring and tightens the lens and reflector in place.

When assembled, the insert assembly presses up against the rear of the reflector (the reflector is a high temp plastic so there is not an issue of shorting the led out) giving the best possible throw this combination can provide. This can be a little tricky getting the reflector centered on the led but it is doable. Also, the rear of the reflector will need to be filed down to remove the little ridges/standoffs (where arrow is pointing to in image). Depending on how well your leads are soldered to the MCPCB contacts, you may need to file some clearances on the reflector as well (circled areas).

Ready to solder the driver leads to the switch leads. I solder the leads and then heat shrink the connection.

Here is the light fully assembled. The screw that holds the switch cap in place is used to also keep the insert in place. Some choose to press fit this insert but I like to take things apart easily if I need to. Plus, the machining tolerances do not need to be as fussy for a slip fit as they do for a press fit (too tight of a press fit and you could split your housing, in theory of course).

 

[El34]

Cool beans
I'll be watching your project

 

[BrianMc]

I would advise a trial fit of the aluminum heat sink sans led or driver. I found that wood liner in a vise let me press my sinks in and if they needed some work yet, the light could sit on top of the wood jaws with tape around the threads and the shoulder of the threaded section against the top of the wood, and a deep 3/8" drive socket on an extension, socket reversed square drive down against a steel washer could punch it back out for adjustments. Once the driver is mounted it would suffer from such treatment.

I slipped a B2 Flex in the back after the sink was in place and soldered up the LED down the throat of the light. The B2Flex has temp sensing so I spaced it off the firewall/sink using a spacer. If I was doing it again, I'd run the LED leads back past the driver and solder them to separate LED leads from the driver out the back/bottom where I could work on them more easily. You design is neater. You may have smaller fingers.

Looking forward to seeing this. The Eva and IRIS lenses rock and they were MC-E items.
Though I misaimed my helmet light (also Marwi) in the ride along video you can see the twin XM-L Marwis at work here. So I think you have a very workable combination.:thumbsup:

BrianMc

 

[mntn-biker]

I have 1 of my inserts fully machined and will be posting pictures tomorrow. Everything appears as though it will work. The fit of the insert in the housing is a really nice slip fit and the 1 original screw that holds the cap and the insert works like a dream (I just needed a 2mm longer stainless steel screw to replace the original) so there is no need to "glue" the insert in place. Same goes for holding the 20mm star in place. A couple of 3mm flathead phillips screws holds it in place. Upon final assembly, I will be using blue Loctite on the screws to keep them in place so I don't over-torque the screws or they will certainly strip the threads.

 

[mntn-biker]

Pics added - see original post.

 

[El34]

Nice!

Does your front ring screw on and snug up the glass and reflector?

I have to leave a tiny 1mm gap between the back rim of my reflectors and the body or else the ring screws on all the way and does not contact the glass.
Then the glass rattles becuase there is no pressure against it.

 

[mntn-biker]

Nice!

Does your front ring screw on and snug up the glass and reflector?

I have to leave a tiny 1mm gap between the back rim of my reflectors and the body or else the ring screws on all the way and does not contact the glass.
Then the glass rattles becuase there is no pressure against it.

I will know later on this morning when my lens is delivered (from you) I just measured the original MR11 bulb and the Fraen reflector lip and knowing the advertised thickness of the lens, I'm thinking it should and if not, I can always put a bit larger o-ring in.

 

[El34]

Here's a shot showing about how much gap I have when I go to screw the front ring on. Probably about a 2mm gap

The reason is that the front ring has so many threads that it bottoms out and your glass/o-ring and reflector don't make contact.
I have taken a couple mm off the threads on the ring on a lathe and that fixes it.

 

[mntn-biker]

Here's a shot showing about how much gap I have when I go to screw the front ring on. Probably about a 2mm gap

The reason is that the front ring has so many threads that it bottoms out and your glass/o-ring and reflector don't make contact.
I have taken a couple mm off the threads on the ring on a lathe and that fixes it.

I would advise that you look for a 2mm shim that fits under the shoulder of the reflector or a large o-ring to replace the existing one so that someone that buys your kit doesn't need to have access to a lathe to fix this problem or buy a new ring. The less mods to the original light, the happier your customers will be :thumbsup: That is why I am using the original screw hole location that retains the switch cap. Granted someone will have to have a drill and an 1/8" drill bit to drill out the existing tapped hole but someone is more likely to have these items or know someone that does.

 

[El34]

I don't think I explained it properly.
The gap is there on purpose and is needed.

The front ring with the threads is so deep that you can screw it on all the way until it will screw no more.

You need some stack height so that you fill out that space and the reflector contacts the glass/o-ring.

The original halogens solved this issue by having so much wire out back that you had to compress the wires. They acted like springs that pushed the halogen bulb forward.

 

[mntn-biker]

I don't think I explained it properly.
The gap is there on purpose and is needed.

The front ring with the threads is so deep that you can screw it on all the way until it will screw no more.

You need some stack height so that you fill out that space and the reflector contacts the glass/o-ring.

The original halogens solved this issue by having so much wire out back that you had to compress the wires. They acted like springs that pushed the halogen bulb forward.

I think we are on the same page/sentence but we are reading different directions

On my other original, un-upgraded Marwi with halogen bulb, the ring screws down, the o-ring makes contact with the halogen bulb, then the shoulder/underside lip of the halogen bulb makes contact with the housing, the o-ring continues to compress and my ring eventually makes contact and bottoms out against the housing. The o-ring compresses against the lens of the halogen bulb to make it waterproof and then the ring bottoms out on the housing (the o-ring continues to compress for another .5mm to 1mm further waterproofing the seal) to keep it from coming loose riding down the trail/road. This is how my upgraded light will react.

 

[mntn-biker]

New pics replaced (better quality) and one new one added to show the cup for the driver to reside in.

 

[El34]

Pics look good!

Some of the halogen bulbs had real thick front lips when you added the bulb and the glass.

Some of the front rings had less threaded area than others.

If you find that you get some slop, all you have to do is slide your cup forward and put your threaded hole in a new place.

 

[mntn-biker]

Pics look good!

Some of the halogen bulbs had real thick front lips when you added the bulb and the glass.

Some of the front rings had less threaded area than others.

If you find that you get some slop, all you have to do is slide your cup forward and put your threaded hole in a new place.

Just got my lens. I'm within .020" of the lens cap compressing the o-ring against the lens and reflector stackup :bluefrown: So off to the local hardware store to sort thru their o-ring assortment for that perfect o-ring...

 

[El34]

yes, that is what I was afarid of.

All of that has to be calcualted when creating a heat sink and figuring out exactly how far back into the housing it should go.

I would just slide yours forward and drill and tap a new screw hole.
Can't you do that?

 

[mntn-biker]

yes, that is what I was afarid of.

All of that has to be calcualted when creating a heat sink and figuring out exactly how far back into the housing it should go.

I would just slide yours forward and drill and tap a new screw hole.
Can't you do that?

I would rather my plastic Fraen reflector not touch the heat sink for 2 reasons:

1. Would rather not have the heat transfer into the plastic reflector (directly).
2. I don't want my reflector bottoming out against my heat sink for fear of cracking the bottom of the reflector. I also have close spacing from the bottom of my reflector to the tops of the flathead screws. I haven't introduced the wire and solder yet on the top of the 20mm star.

A 25cent o-ring should fit the bill here. By doing it this way, my heat sink length and depth of cup has some tolerance built in so it does not have to be a perfect fit (think +/-.010" on tolerances).

 

[El34]

Ah ok, was not sure if the reflector sat down into the rim of the cup or not.

About the only way I can get it all straight is to do a side view CAD and then stare at it all for a few days to make sure I have thought of everything. Beer is involved also.

This is a CAD image of the Bell shaped Marwi's before I prototyped a couple heat sinks on my lathe and then had them made for real at a machine shop

 

[El34]

Ok, I looked at your CAD drawing again and still do not see why the whole assembly cannot be slid forward .02.

Everything moves forward and the relation between all the parts stays the same.

Your reflector sits on the rim of the LED just like mine does, correct.
If you silde it all forward, the reflector and the cup move at the same time and do not touch.

I guess I am not getting something?

 

[mntn-biker]

Ok, I looked at your CAD drawing again and still do not see why the whole assembly cannot be slid forward .02.

Everything moves forward and the relation between all the parts stays the same.

Your reflector sits on the rim of the LED just like mine does, correct.
If you silde it all forward, the reflector and the cup move at the same time and do not touch.

I guess I am not getting something?

Oh you're seeing it correctly - I could slide the entire assembly forward/to the left but I would need a shim/washer under the lip of the reflector which may be another option if the o-ring doesn't work out. I know hardware stores have brass shims for plumbing or something but a larger o-ring would be more forgiving and cheaper...

 

[Vancbiker]

I would rather my plastic Fraen reflector not touch the heat sink for 2 reasons:

1. Would rather not have the heat transfer into the plastic reflector (directly).
2. I don't want my reflector bottoming out against my heat sink for fear of cracking the bottom of the reflector. I also have close spacing from the bottom of my reflector to the tops of the flathead screws. I haven't introduced the wire and solder yet on the top of the 20mm star.

You may find the beam quality not as good as it could be. You won't know until you try it with the XML. The Fraen reflectors are meant to sit right on the MCE star. I have not experimented with how positioning the emitter in the Fraen reflector affects it. I have found that an axial position change of as little as .01 inch makes a noticeable difference beam quality and intensity when playing around with XPGs and a 32mm reflector.