DIY COB Bulb 5W-20W under 30V - looking for COB and advice

Hi, for long time I like to make my trustworthy, efficient DIY “bulb”, FOR ME (so safety, failures, experimentation and adjustments are not concern here ;P).
For many of you know, normal bulbs/leds are over driven, companies reducing live span and electrical deficiency.

My idea is to make is to make:
COB based “bulb” that will ± fit into hole of standard MR16 bulb.
Its cheap to buy used, quality 12V or 18.5V, even 24V PSU. Its hard to get in good price 30+V. 12v3.3A cost like 1$. 24V 7.25A cost 9$.
Id like to use module like this to drive COB:
step down based on XL4015 with current limiter\_AOzFEU
(btw, does any1 know what is difference between “XL4015 module”, and “Original module” ? I cant find answer for this for quite some time, and many sellers use this two “versions”)

To make cheap cooler/radiator id like to use 1mm aluminum sheet


In some shape like this (it was made just to show concept, final version must be adjusted to used cob and its heating)
I tried this design with so called 30w cob from ali (didnt dare to drive it more than 22W), and it was cooling it to +–43*C constant.

I suppose i cant use noname COB from ali, as diodes can different like hell from diode to diode (couldnt find reliable suplier on ali, who could give data sheet, or even information about binning leds). I plan to drive from one XL4015 module like 2-3 “bulbs”, “lamps”, so diodes must take similar current, as I dont plan on using resistors i think. I also take into consideration to use like 2-3 XL4015 modules conected to one powers supply (in example 12v4a).

For now for tests I ordered 20 Cree CMA1303 0000-000C0U0A40G, but they are quite expensive if id like to buy better CRI/temperature.
Could you please advice me 5W-20W COB from solid manufacturer *that share a datasheet, basic reliable info about cobs? Where to get those cobs… Or at least model name? I suppose if i drive COB with recommended, maximum efficiency lm/W current, those DIY “bulbs” could last years, and be really power efficient.

I tried to test different cobs from like 15 sellers from ali, but its just a joke, those are damn heaters, not light source. But I have to say, those were almost random no name chips, no idea how to look for solid brands on ali. Could u guys help me to find solid cob also on ali?
For now, other parameters are not so important, but like to start from CRI (80), temperature (lower than 4k) and lm/W 100

I am sure you are way more experienced, and maybe you will find some interest in helping me.

On paper, the new Bridgelux Thrive cobs seem to fit the bill.

You’re in luck, I’ve been on a similar mission, so I’ve catalogued every super-high-CRI consumer-available COB I can find data or reviews on, and sorted them by lumen output per dollar. Hope this helps:

Edit2: NOTE that the items with built in color temp adjustability (Vesta, etc) get a 2x boost in their lumen/$ value given its value for my use cases.

EDIT: I’ve been exploring a DIY E26 socket bulb, but looking for Zigbee (or at least wifi) connectivity, 2 channel dimming for color temp control throughout the day. It’s not so simple to DIY even a single dimmable power supply in an A19 or A21 body, let alone adding support for a second channel and integrating a wireless board of some sort while still having sufficient heat sinking.

I’m curious what your use case is for 22W output? My target is a 100w A21 replacement, which means roughly 1100 lumens, or about 12W combined at today’s high-cri efficiencies.

Thank you very much, its good data for me! I was looking for quite lower cri, atm im planing to use 92 and 80.

I dont understand what is your question, could you please rephrase it? Sorry, I am not native speaker.
You mean what kind of heat sinking i was using for 22W? It was pure experiment on bench and lab/bench PowerSuplyUnit, similar to what is shown, but its too big, to replace gu10 standard size.

There are some inaccuracies in your sheet.
Look at those COBs lots under 100 lumen per wat.
$%^& mate, this topic is ultra hard. Dunno, where did you get ur data, i.e. cree cxa1304 (bin from ur sheet) typical 95cri @binning do 281 lm If = 400 mA (not 228lm)... Also @ binning diode take around 3.4W, not 10W+.
That also give very bad lm/w, but If ya would pick another bin - closely related, same cri, same 3000 K, you reach 366lmn @~3.4w (400mA), and this is more acceptable.
(general idea is higher efficiency lower cri)

But what give me a question, where do they take this values? Why do they set binning current 400ma in case of CXA1304? Lets say, I make exactly the same diode, and do binning @500mA and suddenly - if you just look at data provided @binning my diode seems to be way superior! Also CXA1304 can be feed 240% binning current (its around 300% power due to voltage increase, and relative luminous flux is around 220%), while some other diodes can be feed just 140%. I mean, just wonder how much this data is accurate, and if producers don't manipulate this values, in favor of their product.

Well... I have to take a closer look in Bridgelux data sheets. As those seems to be very price efficient.

EDIT again...


I wonder, where do you have your data from? Some prices are way higher that I can get, and some of those COBS that were very efficient for you - weren't for me.

Most all of the data is directly from the manufacturer’s data sheet. They all reference nominal and max current, and their rated lumen output is at the nominal current, so that’s how I determine lumen per watt.

Prices for most all of them are from digikey or octopart and don’t include shipping, just cost per.