COB efficiency Spreadsheets

[JorgeGonzales]

yeah its the weekend. time for new vero vs citi vs cxb shootout. i need one of@REALSTYLES CD bin 3000K cxbs to round it out. tired of cree getting spanked.

So, for the pulsed stuff you said you were having trouble dialing in the current, but I think you just need steady current, record voltage and PPFD, work out the watts later when you chart, interpolating anything between.

Hey do you have min/max on your DMM and PAR meter? I think if you just flip the switch and record max V and PPFD that's it, since V drops with temp, as does PPFD. That's what I'm seeing here anyway with my DMM and photoresistor. Ghettolicious.

Does that sound right? @robincnn?

 

[ttystikk]

Except for the less PPfD as chip temps fall, or am I reading that wrong?

 

[robincnn]

So, for the pulsed stuff you said you were having trouble dialing in the current, but I think you just need steady current, record voltage and PPFD, work out the watts later when you chart, interpolating anything between.
Hey do you have min/max on your DMM and PAR meter? I think if you just flip the switch and record max V and PPFD that's it, since V drops with temp, as does PPFD. That's what I'm seeing here anyway with my DMM and photoresistor. Ghettolicious.
Does that sound right? @robincnn?

For pulsed, i dial in the current then turn i off for a few seconds and then get the pulsed voltage current and PPFD. Will try the max on the DMM next time.
I just try to stay consistent while comparing cobs. I do not move the lamp or the PAR meter. Also i mount the cobs on different heatsinks of same size before i start testing so that i do not have to swap cobs during experiment.

 

[JorgeGonzales]

Except for the less PPfD as chip temps fall, or am I reading that wrong?

Voltage and PPFD fall as temps rise, is what I was trying to say.

 

[Spuzzum]

Use the hlg-185h. You gain nothing from the 240h except the ability to add more cobs.

Personally, I'd go with the 240h.. running a driver or power supply at 100% load isn't the best thing for the device. Rule of thumb.. don't go over 80% load.. give yourself 20% headroom. Look at the spec sheets for the drivers.. they're life expectancy is rated at 80% load.

So.. 4 COBs at 36v = 144v. The 240h maxes at 179v. 144/179 = 80% load.

It's better to be safe.. than have to replace a driver 1/2 way through a run.

 

[BOBBY_G]

welll.. they are rated for like 100k hours or something ridiculous. i think they are a little more durable than you give them credit for. that said, a tiny cooling fan blowing on your drivers could prob double the life

 

[Spuzzum]

welll.. they are rated for like 100k hours or something ridiculous. i think they are a little more durable than you give them credit for. that said, a tiny cooling fan blowing on your drivers could prob double the life

62,000, but that's at 80% load. Durability reduces at 100%. Ask any electrician.. they'll tell you it's better to have 20% headroom. Personally, I don't care what you do.. I'm saying I'd prefer to have the 20% headroom.

Watching the diy tech talk on greenegene's youtube channel, growmau5 said he's blown a driver before.. they aren't invincible.

 

[PurpleBuz]

62,000, but that's at 80% load. Durability reduces at 100%. Ask any electrician.. they'll tell you it's better to have 20% headroom. Personally, I don't care what you do.. I'm saying I'd prefer to have the 20% headroom.

Watching the diy tech talk on greenegene's youtube channel, growmau5 said he's blown a driver before.. they aren't invincible.

understand what your saying about headroom, but how many of those general devices have a 7 year warranty ?

 

[Spuzzum]

understand what your saying about headroom, but how many of those general devices have a 7 year warranty ?

What good's the warranty when you have to wait for a new driver... 1/2 way through a run? Do you have a backup light for the week or 3 it's going to take? Unless you have a decent electronics shop in town, that carries the same or equivalent driver.. you're going to have to wait more than a day to get that light back up. Or order a new one with express delivery. That was my main point in the first place. Besides.. it's only a $15 difference per driver. You spend for the top bin COBs, get the best heatsinks you can... but then cheap out on the drivers?

cheers.

 

[PurpleBuz]

What good's the warranty when you have to wait for a new driver... 1/2 way through a run? Do you have a backup light for the week or 3 it's going to take? Unless you have a decent electronics shop in town, that carries the same or equivalent driver.. you're going to have to wait more than a day to get that light back up. Or order a new one with express delivery. That was my main point in the first place. Besides.. it's only a $15 difference per driver. You spend for the top bin COBs, get the best heatsinks you can... but then cheap out on the drivers?

cheers.

buying a top of the line driver with a very high mtf time is NOT "cheap out on the driver".

More than likely by the numbers, the cobs will poop out first regardless of 20, 10 or 5% headroom. In fact the cobs will be outdated tech wise before the drivers fail.

 

[Spuzzum]

buying a top of the line driver with a very high mtf time is NOT "cheap out on the driver".

More than likely by the numbers, the cobs will poop out first regardless of 20, 10 or 5% headroom. In fact the cobs will be outdated tech wise before the drivers fail.

I didn't mean that as an insult. I just meant spending the $15 more per driver for piece of mind is better. It doesn't matter if it's top of the line.. running at 100% load will reduce it's life expectancy, and could cause it do die 1/2 way through a crop. These things do die.. growmau5's already blown 1, and I've read it more than a few times on the reef builder forums as well. Electronic parts are finicky.. that 1 resistor in a batch 1,000, or 1 capacitor in batch 1,000 may die faster than expected. That's why there's a warranty. But like I said.. what good's a warranty, if your plant's are going to be without that light while you wait for a replacement? My main concern is the plants.. not my pocket book.

 

[PurpleBuz]

I didn't mean that as an insult. I just meant spending the $15 more per driver for piece of mind is better. It doesn't matter if it's top of the line.. running at 100% load will reduce it's life expectancy, and could cause it do die 1/2 way through a crop. These things do die.. growmau5's already blown 1, and I've read it more than a few times on the reef builder forums as well. Electronic parts are finicky.. that 1 resistor in a batch 1,000, or 1 capacitor in batch 1,000 may die faster than expected. That's why there's a warranty. But like I said.. what good's a warranty, if your plant's are going to be without that light while you wait for a replacement? My main concern is the plants.. not my pocket book.

I understand, I'm not actually advocating running at 100%, but in this case I think 20% is too conservative for the meanwells. I'm pointing out the probability of a failure. When a mfg makes a 7 year warranty I am absolutely certain that they have run the numbers.

 

[DrBlaze]

I didn't mean that as an insult. I just meant spending the $15 more per driver for piece of mind is better. It doesn't matter if it's top of the line.. running at 100% load will reduce it's life expectancy, and could cause it do die 1/2 way through a crop. These things do die.. growmau5's already blown 1, and I've read it more than a few times on the reef builder forums as well. Electronic parts are finicky.. that 1 resistor in a batch 1,000, or 1 capacitor in batch 1,000 may die faster than expected. That's why there's a warranty. But like I said.. what good's a warranty, if your plant's are going to be without that light while you wait for a replacement? My main concern is the plants.. not my pocket book.

I'm not arguing either side of this point, I would just point out that the reason for running them near 100% has absolutely nothing to do with the cost of the driver (otherwise people wouldn't be spending so much extra on more cobs just so they could run more of them at lower wattages to gain efficiency). These drivers run more efficient the closer they get to 100%, so they wouldn't want to spend hundreds of dollars extra to gain 10-15% efficiency, and then give a third or half of it back by oversizing their driver. They would probably feel it more sensible to just keep a spare driver around.

 

[BOBBY_G]

They would probably feel it more sensible to just keep a spare driver around.

if even the cheapest driver you can find just for the rare backup

 

[Spuzzum]

I'm not arguing either side of this point, I would just point out that the reason for running them near 100% has absolutely nothing to do with the cost of the driver (otherwise people wouldn't be spending so much extra on more cobs just so they could run more of them at lower wattages to gain efficiency). These drivers run more efficient the closer they get to 100%, so they wouldn't want to spend hundreds of dollars extra to gain 10-15% efficiency, and then give a third or half of it back by oversizing their driver. They would probably feel it more sensible to just keep a spare driver around.

In the old days, maybe.. but not so much with switching regulators. Just think of your pc's psu... it may be 650w, but you wouldn't want to max out your components to the exact 650w. And running it at 50% load isn't any less efficient, really. The reef builder community uses them, and they use the built in dimmer. Even some of the grows I've seen around, switching between veg and bloom simply by using a trimpot.. that wastes more energy than a switching regulator.

I'm not an electrician.. but I did have an electronics guru help me with my diy drivers back in 2011. That's the main point he stressed... that 20% headroom.

I'd rather pay the extra $15 the first time, instead of $50 for a 2nd spare driver.

 

[BOBBY_G]

id rather try to blow it up during my 7 year warranty all the while harvesting 10-20% more every 2 mos.

 

[Spuzzum]

id rather try to blow it up during my 7 year warranty all the while harvesting 10-20% more every 2 mos.

The yields would be the same. Amount of energy used for the same light fixture doesn't equate to higher yields.

Do what you want, BOBBY_G.. I like to prevent problems before they happen.

Cheers.

 

[REALSTYLES]

In the old days, maybe.. but not so much with switching regulators. Just think of your pc's psu... it may be 650w, but you wouldn't want to max out your components to the exact 650w. And running it at 50% load isn't any less efficient, really. The reef builder community uses them, and they use the built in dimmer. Even some of the grows I've seen around, switching between veg and bloom simply by using a trimpot.. that wastes more energy than a switching regulator.

I'm not an electrician.. but I did have an electronics guru help me with my diy drivers back in 2011. That's the main point he stressed... that 20% headroom.

I'd rather pay the extra $15 the first time, instead of $50 for a 2nd spare driver.

I could take it no more you obviously don't know what you are talking about. Meanwell drivers well at least the HLG185 version is 94% efficient do know what that means? The drivers don't get hot thus longer life to the driver and they are designed to handle the rated forward voltage.

 

[PSUAGRO.]

Drivers are the weakest link, 80% load is a little on the low side maxing its efficiency......,; but in the end heat is the enemy of all electronics and would agree with our old friend spuzz on not running close to max for reliability.......even on top mw, harvard , etc.

 

[PSUAGRO.]

I could take it no more you obviously don't know what you are talking about. Meanwell drivers well at least the HLG185 version is 94% efficient do know what that means? The drivers don't get hot thus longer life to the driver and they are designed to handle the rated forward voltage.

Spuzz is one of the og Riu diy guys, he knows the deal........