Chinese 40W 365nm compact E27 lamps legit?

[dabateman]

Depends on how you define best.

 

If you want the most 365nm light to exit your bulb than yes ZWB2 is best.

 

If you want absolutely no visible light leakage (greater than 400nm) and reduced IR for bulbs that aren't efficient and leak IR, like many Chinese leds do, than ZWB1 is best. 

 

Look for 2mm or 3mm of either.  Thats not uncommon. 

[Avalon]

ZWB2 seems like more reasonable option. ZWB1 is just too expensive and I will need 24pcs to cover each lens. I can tolerate little purple light leakage, strong fluorescence should compensate for this. I wish there were 365nm LED's with already built in filters.

 

Do chinese filters and 365nm LED's loose UV transparency over time? I noticed 3W LED's are composed of two shells - one inside is silicone and outer hard plastic.

[ulf]

1 hour ago, Avalon said:

ZWB2 2mm seems to be best and cheapest option. ZWB1 gets really expensive so I'm glad to hear it's not the best choice.

 

That 36W lamp seems to be made of 3W LED's. There are 12 LED's so at least input power might correct. Question is how much UV they really output. Obviously energy is

No! I do not think so. 

 

Please supply a link to the lam you think are a 35W lamp.

 

Even if they use leds that are specified to handle  a 3W input the power supplied will be less.

 

The main problem with LEDs is heat. 

 

They have an efficiency of around 30% or slightly more for the very best rather expensive ones.

This means that the rest of the supplied power will be generating heat for 36W in that means 25W heat.

 

Compare an old style incandescent lamp of of 25W. Those bulbs get very hot to touch.

 

The problem is that it is the LED chips in the core of the components that cannot reach more than say 100°C before they start degrading and gradually gets destroyed.

This means that the component itself must have a lower temperature and the special metal circuit board must be even less hot. To achieve that you need big heat sinks with a lot of surface, normally with fins oe some fan cooling.

 

The 8W (15W) lamp I showed above has a reasonable thermal design. 

Unless your 36W??? lamp has at least four times as much cooling area it will not work properly.

 

It is possible to design high power UV-LED light sources, but they need really good cooling to survive.

UV-light is used all the time in the industry for curing different laquers and resins, but those light sources are properly cooled.

[ulf]

29 minutes ago, Avalon said:

ZWB2 seems like more reasonable option. ZWB1 is just too expensive and I will need 24pcs to cover each lens. I can tolerate little purple light leakage, strong fluorescence should compensate for this. I wish there were 365nm LED's with already built in filters.

 

Do chinese filters and 365nm LED's loose UV transparency over time? I noticed 3W LED's are composed of two shells - one inside is silicone and outer hard plastic.

The quality UV-LEDs I know about do not have any silicone, but a lens made of quartz. 

Really cheap Chinese "3W" UV LEDs have plastic bodies shines due to  fluoresensce 

[Avalon]

24 minutes ago, ulf said:

No! I do not think so. 

 

Please supply a link to the lam you think are a 35W lamp.

 

Even if they use leds that are specified to handle  a 3W input the power supplied will be less.

 

The main problem with LEDs is heat. 

 

They have an efficiency of around 30% or slightly more for the very best rather expensive ones.

This means that the rest of the supplied power will be generating heat for 36W in that means 25W heat.

 

Compare an old style incandescent lamp of of 25W. Those bulbs get very hot to touch.

 

The problem is that it is the LED chips in the core of the components that cannot reach more than say 100°C before they start degrading and gradually gets destroyed.

This means that the component itself must have a lower temperature and the special metal circuit board must be even less hot. To achieve that you need big heat sinks with a lot of surface, normally with fins oe some fan cooling.

 

The 8W (15W) lamp I showed above has a reasonable thermal design. 

Unless your 36W??? lamp has at least four times as much cooling area it will not work properly.

 

It is possible to design high power UV-LED light sources, but they need really good cooling to survive.

UV-light is used all the time in the industry for curing different laquers and resins, but those light sources are properly cooled.

Here is the link: https://www.ebay.com/itm/254156528488?hash=item3b2ce8db68:g:T34AAOSwyAVc2Yj9&amdata=enc%3AAQAHAAAA4ADJWDVW3XaXVopI2VoaGB1CWTM5Fbg5%2FkKvxFYxrg6qwgxDR5GPf%2FRZcnlh0fM1qDMz58XZk0SuD5CCB4jnn2vk1PYYBfXZnVzQTNOF3XlAnjv1OTv7HeJmu1XvHQku5RX08unEUVMijp7qGUoQ%2BDBpa8L0y1O4oPax9uL7Kz0soqu05L7R0BmiLF60P3EmaDjtbyHukR2XBbBBQPVpTPYtLO2Zhpss5rhO6N%2BFkLwnOsoafj%2Fx5mV8yuaPp%2FeY8dA7U%2Bx7mUGRHMmvw9RqHL4hNnnsPDdAQnePoDeQ2W4P|tkp%3ABk9SR_zsp4nVYQ

 

I'm not talking here about output wattage, this information is not listed. That can be tested. Input voltage should be about 4.3V and current 700mA for a 3W LED. 1W LED's looks similar but uses lower current. I have built 365nm LED and it generates lots of heat. So yes very ineficient UV production.

 

So over 100C UV LED's start degrading and these lamps may have short life? Lamp cooler is pretty big, 122mm in diameter and has lot's surface area but indoors without fan it will get hot after a while. Taking photo shouldn't take more than few minutes.

[ulf]

The lamp you show is a typical lamp that is adopted for UV.

In it's original design I think it was intended for white LEDs, and the 36W is likely an "equivalent" value for a 36W incandescent spotlight.

For white light an intensity equivalent to a 36W old style lamp is reasonable.

The finned structure is rather big, but the conversion from the high voltage line AC is also generating heat.

 

Normally the data sheets for LEDs recommend an even lower temperature.

Look at the derating diagram in the data sheet below. 

It is for a LED in the range of 3-4W input, but they indicate a radiant flux of 0.7-1W instead.

That is the essential parameter, not the input power or some "equivalent" marketing number.  

https://www.mouser.se/datasheet/2/445/15335337AA350-3085117.pdf

They recommend 80° ambient with a rather good cooling to keep the actual chip temperature low enough.

 

At the first page:

The Absolute Maximum Ratings (Ambient Temperature 25°C): Junction Temperature  125 °C

This is the inner point in the chip where the light is generated.

The Absolute Maximum Ratings is a value you must design to avoid at all cost, with quite a bit of margin.

The surrounding structures MUST be quite a lot cooler and I cannot see any possibility  that the "36W" lamp can do that for an input to the LEDs of 36W.

 

 

 

[dabateman]

17 hours ago, Avalon said:

Here is the link: https://www.ebay.com/itm/254156528488?hash=item3b2ce8db68:g:T34AAOSwyAVc2Yj9&amdata=enc%3AAQAHAAAA4ADJWDVW3XaXVopI2VoaGB1CWTM5Fbg5%2FkKvxFYxrg6qwgxDR5GPf%2FRZcnlh0fM1qDMz58XZk0SuD5CCB4jnn2vk1PYYBfXZnVzQTNOF3XlAnjv1OTv7HeJmu1XvHQku5RX08unEUVMijp7qGUoQ%2BDBpa8L0y1O4oPax9uL7Kz0soqu05L7R0BmiLF60P3EmaDjtbyHukR2XBbBBQPVpTPYtLO2Zhpss5rhO6N%2BFkLwnOsoafj%2Fx5mV8yuaPp%2FeY8dA7U%2Bx7mUGRHMmvw9RqHL4hNnnsPDdAQnePoDeQ2W4P|tkp%3ABk9SR_zsp4nVYQ

 

I'm not talking here about output wattage, this information is not listed. That can be tested. Input voltage should be about 4.3V and current 700mA for a 3W LED. 1W LED's looks similar but uses lower current. I have built 365nm LED and it generates lots of heat. So yes very ineficient UV production.

 

So over 100C UV LED's start degrading and these lamps may have short life? Lamp cooler is pretty big, 122mm in diameter and has lot's surface area but indoors without fan it will get hot after a while. Taking photo shouldn't take more than few minutes.

I bought 2 large leds like that in the past. It at first output no UV and you could burn your hand on the cooling fins in seconds.  Then I pulled off the front plastic lens group and found it to be a polycarbonate that absorbs all uv. So you may need to pull off the front focusing lens. 

The seller wasn't helpful at all and wanted me to smash the bulbs with a hammer and send them a photo for a refund.  I still think that to be insane. I like to work through problems,  not smash them.

 

[Avalon]

1 hour ago, dabateman said:

I bought 2 large leds like that in the past. It at first output no UV and you could burn your hand on the cooling fins in seconds.  Then I pulled off the front plastic lens group and found it to be a polycarbonate that absorbs all uv. So you may need to pull off the front focusing lens. 

The seller wasn't helpful at all and wanted me to smash the bulbs with a hammer and send them a photo for a refund.  I still think that to be insane. I like to work through problems,  not smash them.

 

Polycarbonate lens wouldn't make sense for UV lamp since it absorbs strongly UV. They might be made of PMMA which trasmits UV. Did lens looks like this? https://www.ebay.com/itm/153542681713?hash=item23bfdb6471:g:XhAAAOSwlm5dEZJS&amdata=enc%3AAQAHAAAAoB%2BZqUcdlA8EOr0LJ59uNn3RG54yN2lp71yp1l0HeAIRT3gZrDHiOchWzskLi9k7y1stsBtbPMSeqeZ3IctPsd0KYMDYV4sEQihVabPdkZntutOyhoOKCoiCgomRS8wnGfvWjQ0bXTLavMAWr1Kik3no3VjeYK6WtS0gLLOWSA1TkXWSYZWcg%2BFutLu8ClThn9e41%2Bu6l1KpLT5vyU1knz4%3D|tkp%3ABk9SR_D5lcvVYQ

[dabateman]

The lens they place over the leds is one solid piece of plastic, with focusing points molded in for each led.

Hopefully they have corrected the problem with the newer ones. I bought mine september 2020 from here:

https://rover.ebay.com/rover/0/e11400.m43.l5919/7?euid=f58e0d9214554f78bbfe740b0eae0fd5&bu=43538101403&segname=11400&crd=20200927004859&osub=-1~1&ch=osgood&loc=https%3A%2F%2Fwww.ebay.com%2Fulk%2Fvod%3Fitemid%3D253953321012%26transid%3D2680653714015&sojTags=bu=bu,ch=ch,segname=segname,crd=crd,url=loc,osub=osub

[Avalon]

I see that Ebay seller refuses to sell 365nm lamp and explained PMMA lens indeed partially block UV.

 

Since I can't order it I need to build my own lamp but it's going to be more work and research. Are 3W UV LED's with quartz glass lens worth using over cheaper 3W? I mean these LED's as in  the link: https://vi.aliexpress.com/item/1005004128889352.html?spm=a2g0o.productlist.main.25.4b1c68fei7tpGp&algo_pvid=6aef0fb4-c45a-46b1-b387-d8f079d7386b&algo_exp_id=6aef0fb4-c45a-46b1-b387-d8f079d7386b-12&pdp_ext_f={"sku_id"%3A"12000028137217647"}&pdp_npi=3%40dis!EUR!16.34!13.89!!!!!%402122443916783803858225311d06e0!12000028137217647!sea!LV!924777360&curPageLogUid=QbbQ5NMF2JAS

[ulf]

Do your lamp have to be mains driven?

What will you use it for, fluorescence photography or illumination to help focussing at 365nm or something else?

[Avalon]

I'll try to build for each LED aluminum metal tape reflector and build second lamp with 3W LED's packed as close as possible - for this I will use 44mm glass lens.

[ulf]

Again,

Do your lamp have to be mains driven?

What will you use it for, fluorescence photography or illumination to help focussing at 365nm or something else?

 

There are many aspects that must be right when building UV-LED illumination to get it efficient and still survive without any overheating.

Even the LEDs you linked to will not survive long without being mounted on a heatsink or bigger reasonably thick aluminium or copper plate.

You can see that those are mounted on 20mm carrier circuit boards made of copper. That is to spread the heat and make it easier to transfer to a heatsink.

 

To make multiple lamps each with its on filter and reflector will be expensive.

 

I have been down this path a few times making my own UV-lamp design from the beginning and tried a few tings and made a lot of calculations. 

 

The first one was a 50W LED array based design supplied from a 24V power supply module. It is operational.

I have two projects on hold due to lack of time and because I do not think I will need them.

 

They are also based on LED arrays, one 90W and one 150W.

All three will/would naturally be fan cooled and can take one filter like a ZWB2, 52mm, if I remember correctly.

 

[Avalon]

Of course I will use big heatsink and will use 48V 700mA driver, these things get hot fast. I thought of using single 50W LED but after oing calculations 3W LED's seem to offer best price per watt. Besides I have spare 3W 365nm LED's so I want to pair them with better LED's.

[ulf]

9 hours ago, Avalon said:

Of course I will use big heatsink and will use 48V 700mA driver, these things get hot fast. I thought of using single 50W LED but after oing calculations 3W LED's seem to offer best price per watt. Besides I have spare 3W 365nm LED's so I want to pair them with better LED's.

Good, then you seam to be well aware of the need for good cooling off the LEDs and are not restricted by a design that can work away from external power like mains power.

Then everything in the design becomes so much easier.

With a big/efficient enough heat sink you might not even need a fan for forced cooling, even if the lamp would be on for a long time.

The LEDs you linked to looks like they can be OK for your needs. It is ambitious to use copper based PCB material and might hint about a better quality of LED. Copper PCBs are more often used for higher power LED arrays with more difficult cooling needs. 

 

My 90W and 150W projects have been aimed to a compact  battery driven design as hand held lamps to be used in the field for fluorescence photography.

That adds several more design challenges.

[colinbm]

@Avalon Beware that Chinese suppliers are always dodgy.
You are advised to know the product & to be able to test what you purchase when it arrived.
I have been ripped off a few times & it was only the intervention of Aliexpress that I got any satisfaction.
The biggest rip-of was from a supplier I had been dealing with for two years, satisfactorily, spending a few thousand with them.
Then the last order for over $1000 went sour, they sold me LEDs that were only half the power they specified, but they wouldn't admit that they had dudded me.
It was Aliexpress that got them to replace them with the correct LEDs.
Of course I have stopped dealing with them.

PS. The copper heat sinks are light-years better then the aluminium ones.
The UV 365 LEDs get very hot.