Where to find these instant LED replacements?

[Marc]

a direct G4 CREE replacement, from a chinese manofacturer. I cannot find something similar to be purchased by unities

Please, if somebody knows something similar, I would be grateful to know



Characteristics (Google translator):

Color temperature: 4500K constant
Lighting power: 5W
Working voltage: 0 ~ 6 V AC
Life life: 20,000 hours
Lighting chip: CREE
Color rendering index:> 90%(can realize the color of the specimen color)
Light spacing: G4
Scope of application: 6V20W-6V30W halogen lamps can be replaced by microscope

Page: https://www.mayduly.com/index/product/d ... s-0-main-3

[Greg Howald]

I must admit that I have not seen that before. I hope it is up and coming.

[Sansub2]

Interested in this as well. I searched all over the place and this is the best replacement I was able to find without paying arm and leg. Light in OPs post is superior. Hope to see it in AliExpress soon.

C$ 2.43 26%OFF | AC12V LED G4 Round Spotlight Bulb 2W 3W 5730 15/24leds No Flicker Range Hood Lights Replace 20W Halogen Lamp
https://a.aliexpress.com/_mLqZBcQ

[ldflan]

These people may be selling them from China?

http://www.ningbomicroscope.com/ensite/ ... _1285.html

Skeptical, but interested.

[Scarodactyl]

I've bought from Ningbo. They took my money and sent me what I ordered promptly and were easy to deal with.

[blekenbleu]

On Alibaba:
6V 5W G4 https://www.alibaba.com/product-detail/ ... 27864.html
12V 5W G6.35 https://www.alibaba.com/product-detail/ ... 58629.html

Those are merely contact URLs for Ningbo, not click + PayPal

[AJHope]

Ahhh I hope you don'tge the crazy ETA I've been getting from alibaba *sighs* I'm too tired already from supply chain issues

[Sansub2]

I've bought from Ningbo. They took my money and sent me what I ordered promptly and were easy to deal with.

Can you please let us know how you ordered it from their site? I could not find price and buy options.

BTW, how do you guys order from Alibaba for one item?

[Scarodactyl]

I emailed Robert at the email address provided on the site.

[Sansub2]

Thanks Scarodactyl

[Marc]

thank you ldflan, Scarodactyl for that site

[imkap]

This looks great, thanks. I was just wondering about direct replacement LEDs for the Axiolab I got, would be nice to compare with halogen without too much fiddling in a same setup. Shame they are all 6v as 12V are easily found. Not sure why is that...

The Axiolab has some 'light magnifying' lens in the base, so it has more light with weaker bulbs, unlike my GFL which has a plain glass, so a lot more power is needed for the same amount of light... Halogen heat a lot, so not nice to use in the summer.

[blekenbleu]

Not to be a wet blanket, but despite increasing LED efficacy,
using one of these to replace a 20W halogen lamp at nearly full intensity
in many microscopes could be problematic without an additional heat sink.
For example, my Labophot's base has highly restricted airflow to its lamp.

[Scarodactyl]

This is a good point. I've set up a couple of stereo microscopes with cree XM-L2 LEDs, and even only running at ~6w they do warm up the chonk of aluminum I generally use as a heat sink. That said it may not be impossible to overcome with a heat sink on the back.

[Sansub2]

That is a very good point. Unless someone try it, we wouldn't know as there is not much review about it online. I converted one of the scopes with XHP 70.2. Used the heatsink from old motherboard. That thing gets hot within seconds. If we have to setup with heatsink, that will defeat the intended purpose.

BTW, FYI for others, I emailed Robert. One piece is 15$, min. 50 pieces ( if I understood MOQ correctly) and 66$ shipping for Canada. So, no go. Hope it will show up in AliExpress soon for me to try.

[blekenbleu]

it may not be impossible to overcome with a heat sink on the back.

An Optiphot 66 diascopic illuminator uses a 40mm shaft to locate its G4 lamp:

G4halogen.jpg (44.78 KiB) Viewed 830 times

A solid 20mm long half-round would kill what little convection is possible.
Perhaps cutting down a 40mm finned heatsink..

[blekenbleu]

I emailed Robert. One piece is 15$, min. 50 pieces ( if I understood MOQ correctly) and 66$ shipping for Canada.
So, no go. Hope it will show up in AliExpress soon for me to try.

Alternatives pondered involve this US$8 constant current buck regulator:

https://www.amazon.com/dp/B07J9RQ8B6
(I used this previously with hobby servos.)

... and Cree or Samsung CRI 90+ LED on DTP Copper MCPB, e.g. from kaidomain.com

LEDcopperMCPCB.jpg (10.99 KiB) Viewed 819 times

http://kaidomain.com/search&search=high%20cri
... also with finned heatsink.
Given typical microscope collector optics, LED without diffuser lens is wanted...?

[BramHuntingNematodes]

You're gonna want as small a single.die as can deliver the light. The picture looks like an array, which might benefit from a diffuser in some setups.

[imkap]

3-4w LED might be ok without a heatsink... That should be similar in brightness as a 20w halogen.
My 18v 10w CREE, warms up at max but nothing spectacular, no where near a halogen. I rarely crank it up, but did test it and still works. 'Heatsink' is an aluminium rod maybe 80mm long and 25mm diameter.

[imkap]

You're gonna want as small a single.die as can deliver the light. The picture looks like an array, which might benefit from a diffuser in some setups.

Why is a smallest die needed? Thanks

[Marc]

BTW, FYI for others, I emailed Robert. One piece is 15$, min. 50 pieces ( if I understood MOQ correctly) and 66$ shipping for Canada. So, no go. Hope it will show up in AliExpress soon for me to try.

what a pity.

I know another LED G4 at 6V, although only 1w. Far from previous model with 5w CREE.

In this model (cost 3$) the seller announces efficacy 100lm/W with the lens (who knows), and "minimal order: 10", if I understand well. However, voltage is announced "6v" instead 0-6v. I wonder if dimmable.

I will wait also for something more powerful. Anyway I leave here in case somebody is interested.



https://www.alibaba.com/product-detail/ ... 9.html?s=p

Don't know more G4 at 6V. Strange these are so difficult to find.

[blekenbleu]

You're gonna want as small a single.die as can deliver the light. The picture looks like an array, which might benefit from a diffuser in some setups.

Why is a smallest die needed? Thanks

I read that illumination source ideally fills objective back focal plane field.
That Cree is an array of 4 tightly packed chips, wired differently for 3/6/12V;
I guess it should be OK with Köhler alignment,
better than something like:

triad.jpg (9.32 KiB) Viewed 765 times

[Scarodactyl]

Light from the periphery of a larger emitter tends not to make it to the subject--it ends up scattering off. That said one of these 2x2s might be fine and I'm kins of curious to try one.

[Sansub2]

I have done the upgrade before using the following components. Even though it worked well and gave me option to have the led of my choice, it is too cluttered, unsightly and require considerable amount of work. A simple plug and play with 5w LED is more than enough for most case.

1. Light
C$ 6.03 10%OFF | CREE XHP50 XHP70 XHP50.2 XHP70.2 2 generation Cool White Neutral White Warm White LED Emitter 6V 12V with 16mm 20mm Copper PCB
https://a.aliexpress.com/_mKzOLMO

2. Controller
C$ 2.42 42%OFF | LED Dimmer Switch DC 12V 24V 8A Adjustable Brightness Lamp Bulb Strip Driver Single Color Light Power Supply Controller
https://a.aliexpress.com/_mPdS6rs

3. Holder:
C$ 1.24 7%OFF | 5-50PCS MR16 MR11 GU5.3 G4 Lamp Holder Bulb Base with Wire Ceramic Halogen Socket Pottery Connector 12V - 250V Led Light New JQ
https://a.aliexpress.com/_mKj6IqW

4. Connector (optional)
C$ 2.25 20%OFF | 5pcs Female +5 pcs Male DC Connector 2.1*5.5mm Power Jack Adapter Plug Cable Connector For 3528/5050/5730 LED Strip Light
https://a.aliexpress.com/_mtMla5y

5. Switch:

C$ 0.63 1%OFF | 5/10Pcs Push Button Switch 10x15mm SPST 2Pin 3A 250V KCD11 Snap-in on/Off Rocker Switch 10MM*15MM Black Red and White
https://a.aliexpress.com/_mLmg8rg

6. 12v power brick - used the one I already had

7. Heatsink - pulled it from old motherboard
8. Thermal paste.
Noctua NT-H1 3.5g, Pro-Grade Thermal Compound Paste (3.5g) https://a.co/d/3ri11lH

[imkap]

Light from the periphery of a larger emitter tends not to make it to the subject--it ends up scattering off. That said one of these 2x2s might be fine and I'm kins of curious to try one.

I understand thanks, I have one like this it is 9mm. 18-19V PSUs with 3A+ are easy to come by from retired laptops.
https://hr.mouser.com/ProductDetail/941-CXB1512F0BP440E

There is some halo around the iris hole when i close it down, not sure why. Although I don't remember seeing it when I first installed this LED. I have another one with a bit lesser lumens rating and 90 CRI, I'll try it next, but first I'll make another aluminium rod, so I can compare side by side...

[BramHuntingNematodes]

The theoretical ideal light source is a single point and a field lens of the right size and focal length. Filaments and arcs would approximate these. As the na of your objective increases, the amount.of surface area from your light source you can use.to collect light diminishes, even with an ideal field lens. The smaller your source is, then, the less this matters.

The three up chip is the least suitable as you will end up fixing on one of the three LEDs for the most even illumination on higher magnifications. Using a diffuser wont help the situation. In fact an advantage of LEDs is that they can be so small that diffusers can be eliminated entirely.

[blekenbleu]

one of these 2x2s might be fine and I'm kind of curious to try one.

Optiphot and Labophot lamp electronics,
which drive a halogen lamp using a power transistor,
can be repurposed to drive one of those,
since transistors are essentially current amplifiers.
Increasing resistance to the transistor's base can limit
collector current to values appropriate
for e.g. Cree 6V 3A CRI90 COB LEDs,
which should deliver over 1000 lm @ 1.5A.
Their active area appears to be about 3mm square,
roughly the same as a G4 halogen filament's long dimension.

XHP50.3.jpg (23.71 KiB) Viewed 643 times

https://cree-led.com/media/documents/XLamp-XHP50.3.pdf

[MichaelG.]

Thanks for that link, blekenbleu

I have just downloaded its 46 pages for bedtime reading.
… they look very promising indeed !

MichaelG.

[blekenbleu]

they look very promising

For some materials, appearance differences between 90 and 95 CRI are significant;
whether CRI is an appropriate metric is also arguable.
https://www.candlepowerforums.com/threa ... es.415041/
D50 (~5000K) is the traditional graphic arts color temperature;
whether photomicography color rendering is standardized seems unclear.
https://micro.magnet.fsu.edu/primer/pho ... lters.html

[BramHuntingNematodes]

3mm should be fine that disc mount must be quite small