Buying 30w COB 'high CRI' led directly from Alibaba supplier for the first time

rngwn · 2018-05-17T08:53:14.000Z

This is my ongoing experiences on buying LED cobs directly from one of the Alibaba suppliers. As of now, I have not received my goods yet (the order should be arriving soon and I will have my upgrade done after that…provided that the shipment is actually come). The one I ordered is 4x 30w COB with CCT of 5000k and 90 CRI (according to the supplier/manufacturer).

I have been infatuating with high-CRI, high-powered lighting for quite sometimes. I have a typical Chinese-made 20w floodlight lying around and I would like to upgrade it with its compatible version with high CRI. As usual, the LED inside the floodlight is the generic-looking 20w COB (as shown below) with the typical 6500k cool-white and CRI of 70. The one I look to replace with must have the CCT between 5000k and 6000k and CRI as good as it can be had, which appears to be uncommon in the same form factor used in the Chinese-made floodlights.

Before I ended up buying ones from Alibaba, I have checked out pretty much all the stores in the Aliexpress and also Yuji’s store. The issue here is of course, Yuji ones that looks like the standard COB only comes in 50w and 100w variant, which is quite expensive (~$98 ex-works for two pieces for 50w version and it is currently sold out as of writing) and the power rating is quite overkill. Aliexpress, on the other hand, appears to offer “only” 80 min. CRI in the compatible form factor as the best CRI rating available (I have never tried the non-warm white LEDs with 80 CRI before, but my gut feelings keep telling me that I should look away from those). So, I decided to take Alibaba option.

The issue of buying from Alibaba is the MOQ. Many of the listings requires you to order at least 100 pieces which I cannot afford the total price or being able to deal with the leftovers. After some time, I stumbled upon this listing which has MOQ of single piece.

https://www.alibaba.com/product-detail/Low-Light-Decay-CCT3000K-5000K-Ra90_60498337843.html?spm=a2700.9114905.0.0.yqb3Bm

I initially quoted for 4 pieces of 100w version with 5000K CCT and 90 CRI, because the listed price of 5.5$ a piece seems cheap enough. However, the quoted price is actually $9-17 a piece (depending on the chip grades used in the COB) which is actually reasonable if true to its specification, but that’s going to exceed my budget by a mile or I have to order in less quantity (and less of a spare parts for safety margins and possibility of future projects), or reduce the wattage. So I quoted again for the 30w version, which is priced $6.49 a piece and I decided to settle for this one and paid the supplier along with the shipping cost.

The shipping cost is pretty hefty of $25 (which is the reason why I bought 4 pieces) and is supposed to be shipped by Fedex. The shipment is supposed to begin at May 19, so I will probably have the chance to try them on a few days after that. Up until now, the experience is pretty okay, except for the massively understated listing price. Now I will see if the shipped product would live up to its claims.

Now there are a few more questions that I will probably cannot answer for myself, because I do not have the proper tools for testing (and I have no plans of shelling out money to obtain these tools).

The overall quality of the LED as a whole, I have seen Clive’s video about the cheap eBay LEDs suffers from parasitic shunting resistance which causes the chips inside the LED to light up unevenly at low currents/voltages.

The actual CRI value of this, including the R9-R14. The specification only claims the minimum CRI (Ra) of 90, but makes no mention of the other parameter. This one is particularly difficult for me to test for myself, because the spectrophotometer would costs me at least $1000.

As ridiculous as it might sound, I would be much appreciated if someone would actually go and buy some of these for the aforementioned tests.

Fingers crossed.

Parametrek · 2018-05-17T13:16:19.000Z

The biggest chinese producer of high CRI LEDs is Yuji. They make many COBs but they also know how much people are willing to pay for high CRI. Yuji wants $80 for a 100W COB.

$5.50 is a low price for a plain 100W COB. There is no way that Aliexpress deal is actually high CRI. Its got to be a scam.

rngwn · 2018-05-17T15:26:11.000Z

Indeed, the deal actually left me with $6.5 for 30w COBs, which is still nice, if it’s really 90 CRI (though who knows about the R9). This price is still a little above of the most expensive 30w from Aliexpress, and several times more expensive than eBay el-cheapos. In any case, some testing is required after I get my hands on these. ~~But It’s unthinkable to spend thousand of dollars just to measure these few LEDs for CRI.~~ :weary:

rngwn · 2018-05-19T08:36:07.000Z

Update:

Now the seller has shipped. It’s from DHL rather than Fedex as being told earlier. The shipment origin is from Hong Kong rather than Shenzhen where the company is actually belongs. “Interesting”. :weary:

Enderman · 2018-05-19T09:18:30.000Z

They’re not 90 CRI, they’re not 100W, and they’re not 5000k.
Buying cheap COBs is basically just throwing your money away at garbage.
You will get more output and far better quality by using something like an XHP70.2 which costs less than the $25 you paid for shipping.

rngwn · 2018-05-21T10:03:32.000Z

The shipment finally arrived and I promptly tried one of them on the flood light. The light tone is interesting, it’s seemingly colder than the throw beam and warmer than the spill beam of the Jaxman E3 with Nichia 5700k in it, while being far less ‘angry blue’ than the stock LED this floodlight came with.

This COB seems to be closer to 5500k than 5000k (almost certainly not more than 6000k) temperature wise. Once again, I don’t quite have tools to test the CRI or CCT with, so I cannot affirm or debunk the quality of this COB in this respect.

L4M4 · 2018-05-21T10:10:24.000Z

The Problem I have with these COBs (That I used to love) is the efficiency.
Nowadays we have LEDs that are above 200Lm/W - those COBs have more like 80 or 90.
The manufacturer haven’t changed anything for years, so that they can produce them cheaper.

Brand LEDs are better in every way - they don’t cost that much more, the tech. data is true and you get the same quality every time.

rngwn · 2018-05-21T10:52:43.000Z

Indeed, though if the specification of this COB is to be trusted, the spec sheet says it’s about 100-110 lm/w @ 90 CRI for this COB.

Well, the true reason I pick the COB (particularly in this shape) in the first place is that it’s easy for me to upgrade my floodlight, because I don’t want to bother too much with drilling holes into the base plates, at least for now.

edit: While the state-of-the-art LEDs is capable of 200 lm/w, that number is most likely coming from the measurement at 1w driving power under ideal cooling (Tj 25C). In practice, anything with higher than 150 lm/w efficiency rating is quite a stretch as of now.

rngwn · 2018-07-01T10:40:20.000Z

Update: I finally got myself an another floodlight of the same model. So, I can finally compare the light between the one with stock LED and the one with modded LED.

Stock LED light test

Modded LED light test