Let's talk DIY lights


Evidently they lied lol. But it really is a non issue. Just interesting is all :wink:


Ya, I’d say. So no issue at all when the driver fires and continues to run at say 50-100% power? Just when dimmed and cold?


Correct. I moved it over to my grow space and it wouldn’t shut off. I was concerned that something was wrong until it warmed up then shut off. Still runs correctly at my 50% mark, full power, and shuts off correctly but the room is never below 65°


So they may behave the same way regardless of load, you just don’t have the same conditions in different room? I don’t have a 320 here, but I’ve been messing with a 185 in my garage for about the last hour and it works fine. Was about 28f out there, I opened the door for a bit and got down to 13f. Turned it off for 10 minutes then fired back up and still no issue.

I have a buddy using 320 that should be coming over tomorrow night. I’ll ask him if he’s experienced anything like that. But it certainly doesn’t seem right.


It is weird, but all 3 drivers and all 3 dimmers work the same. They all shut off within a minute of each other once the temp got up.


reach out to meanwell yet? I would guess they would at least have an explanation, if not replace them. I’ve hooked up dozens maybe even 100 of them and never seen them act like that.

I’ve even gone as far to try sneaking a couple extra volts on the output. They still don’t turn off, the just kick out of constant current range and regulate the current lower.


It’s fine from my end, just an oddity. I have checked amp and wattage draws on my marked positions and everything is running right where it should be. With it warm now I can’t get it to duplicate (plants are in their forever home now). If I see something new or have a failure I will let you know and contact meanwell then( they will blame the pots I’m sure) lol


And they are freakin bright!!


The bright is no lie! I’ve never done more than 6 in a room over 50 Watts,

I’m sure you’re pretty good. If you had different voltage cobs, or you wired in parallel I would think you would be out of voltage range and they just wouldn’t work at all regardless of temp or dimming point. I suppose if you tried real hard you could get some sort of series/parallel configuration that could maybe do some funky stuff. But I’m sure you already looked at that stuff, so no sense in me even asking.


I did look and I think I’m at about :100: everything now and happy. I could squeeze a little more but it would cost me efficacy and longevity.


Commercial drivers probably have an overheat sensor in their heat sink. If the room was really warm then it might turn the current off when the sensor got too hot. And then back on when it cooled down, etc.I never read anything about semiconductors or LEDs having a problem with cold until you get down to liquid oxygen-type temperatures.

CFLs and long tube fluorescent are another story. Usually they won’t start in freezing temps. Warm them up with a hair driver and they will start and keep on working from their internal heat.


I was thinking the same thing. Went and checked, meanwell says -40c.

You have any other ideas?


My DIY driver has a component in the primary current path called a Negative Temperature Coefficient thermister. When it’s cold is has a resistance of 60 ohms. As current flows through it, it heats up and it’s resistance drops to 0.6 ohms. This protects the diode bridge from overcurrent when the unit starts up, since an empty capacitor looks like a short to ground. It is supposed to keep it’s self hot from the input current. Maybe they have one of these and the breeze in the room is keeping it too cold? Just a possibility.


It’s better than anything I have. I wouldn’t figure it would change much at his temps though if they’re saying the diver is good to -40c ambient.

Now if there was to be an failure in a component like that I could see. But the same failure in 3 of 3 drivers doesn’t seem likely.


But if the current was turned way down and the room was cold, at some point the NTC would cool off enough to drop the current, Which would let the NTC cool even more, which would drop the current more. etc. Negative thermal runaway!


You think a scenario like that is possible just because it was a little less than 60f? I left same series driver dimmed to 10% on in my garage with door open without issue. It’s currently -2 high today was 11f.


Probably not. I would shield my NTC a bit so fans could not cool it. But running at 10% output who knows. We tend to design for 100% output and voltage spikes, so the driver doesn’t burn up. I would talk to Mean Well. It could be a corner case they didn’t think to test. The fact that they don’t let you dim to 0% makes me suspicious.


That driver is rated for dim to zero, most are not. I have a slight thought that they are one in the same issue as well. But I also know a lot of the pots I come across don’t exactly go from 0-100k either. In fact I would say majority are high or low on one end or the other.


They don’t bother to trim pots because they assume you will do the trimming by turning the shaft! If you want a real accurate one buy a wirewound. Costs a lot more. Most standard resistors are only 5% accurate. Capacitors are even worse.

Typically circuits are designed to use negative feedback to force them to be accurate, so the precise value of a resistor or capacitor is not important.

Most of the laser-trimmed components are voltage references, A to D, or D to A converters.


Yep, have seen that plenty. It’s not really a big deal as long as you know what you’re looking for and dealing with. Doesn’t really matter if I dim to 10,15, or even 25%. But I sure as hell don’t want to be less than 100%