LEDgardener

so when i looked for the best bang for my buck constant current drivers i came across two drivers from a manufacturer called Thomas research products.
one is the:
LED50W-072-C0530-D 9$ (UPDATE: not 9$ anymore) (24-72 V @0.53A = ~50W max) https://www.digikey.com/product-detail/ ... 21-1305-ND
and the other is the:
LED75W-025-C3000-D-ND 12$ (8-25 V @3A = ~75W max) https://www.digikey.com/product-detail/ ... C3000-D-ND

the datasheets were vaguely indicating that those are dimmable drivers. however they were only specifically mentioning 0-10V dimming, but saying resistance dimming in the title (which supposedly means variable resistor / potentiometer dimming compatibility). nobody of the company replied to my email and digikey customer service didn't know anything either. but i found that their other dimmers sometimes use 50K potentiometers.
so lo and behold when i got these drivers and applied resistance between their dimming leads they were dimming indeed.
they are both reasonably efficient (rated 88%).
for larger Wattages the HLG still win but for small lighting builds these are extremely cheap solutions.
let me know what you think.

The 50w model has jumped to over 30e, but the 75w one is still cheap

for dimming you can use a A50K potentiometer, since the response curve doesn't seem to be linear. B50K will also work.
UPDATE: 50K seems too high. 10K (or 20K) seems better..

another cool idea:
i found these nifty little displays for 2$ which can be added to the driver:
Mini Digital Voltmeter Ammeter panel Meter Tester LED Display
https://www.aliexpress.com/item/Mini-Di ... 62417.html

this gives you handy instant voltage and amperage readings.
compared to my ut139c multimeter this display shows 0.02 less, for both Voltage and amperage.
you can connect it like on the picture if the voltage of your driver is between 4 and 30volt. above that it can be damaged.

Is it the same with the meanwell drivers if you wanted to dim 2 drivers at once? 25k pot, instead of 50k?

sdfoster22 wrote: ↑

Tue May 01, 2018 12:28 pm

Is it the same with the meanwell drivers if you wanted to dim 2 drivers at once? 25k pot, instead of 50k?

i don't know about that,
but i just did some tests with the 75W driver and 3x560mm VESTA strips connected it seems an A10K potentiometer is enough. i just have difficulties understanding if the two logarithmic curves (driver and potentiometer response) would cancel each other out, or if an linear potentiometer would be better.
here is the response curve (output at different Resistance values):

I saw in the datasheet that it recommends a leviton ip710 or compatible dimmer. I couldn't find enough data about that dimmer to compare.

sdfoster22 wrote: ↑

Tue May 01, 2018 9:48 pm

I saw in the datasheet that it recommends a leviton ip710 or compatible dimmer.

i know they do, but they also mention resistance dimming there.
and isn't it way cheaper and easier to just use a potentiometer?

Is there a way to dim these as a group, if I make a light using 6 TRP drivers with 9 vestas? so there would be 3 drivers for 2700k and 3 for 5000k. Each feeding 3 strips.
Could I group the dimmers by colour temperature? manage with 2 dimmers?

unkle_psycho wrote: ↑

Wed May 02, 2018 10:27 am

Is there a way to dim these as a group, if I make a light using 6 TRP drivers with 9 vestas? so there would be 3 drivers for 2700k and 3 for 5000k. Each feeding 3 strips.
Could I group the dimmers by colour temperature? manage with 2 dimmers?

I am going to run a few tests with 2 drivers this weekend. Microcenter, an electronics store near me, has 10k ohm pots. I have 2 5k ohm pots. If these drivers dim similar to the meanwell, 5k should dim 2 drivers.

sdfoster22 wrote: ↑

Wed May 02, 2018 11:44 am

unkle_psycho wrote: ↑

Wed May 02, 2018 10:27 am

Is there a way to dim these as a group, if I make a light using 6 TRP drivers with 9 vestas?

I am going to run a few tests with 2 drivers this weekend.

i reran the test with a second driver hooked up to the same potentiometer. see orange line for output measurements of 1 of the 2 drivers * each TRP 75W was connected to 2 x 560mm Vestas

so it seems the more drivers you connect to the same pot, the harder it gets to dim them accurately. 10K pot seems sufficient.
however, i am not sure if it would be different with other loads. because vesta strips could go beyond the 25V max of the drivers