TheGreatSouthern
Well-Known Member
Hey there folks, couple pics attached of my QB22a build. It's 15 strips all in parallel. Running my own home brew drivers
I've built 4 of these, and just wondering how the driver efficiency compares to that of meanwell drivers which everyone seems to be using.
So I'm running my strips at 11.05A , making 737mA per strip. binning current is 450mA so I'm running at 163% of binning current which if I understand correctly is just fine and dandy as rated current is 200% of binning current. You'll note they are well and truly over engineered as far as thermal management is concerned, each strip dissipates it's heat into a 1200mm length of 25x25x1.5mm aluminium extrusion - so compared to a quantum board it's running lower current per chip (I think, just going off the QB specs) with vastly better heat dissipation, which should equal significantly better photon efficacy (not sure how much better, please chime in if you know). The extrusions have a fan blowing across them and barely get warm to the touch, maybe 30 degrees C.
The driver consists of a 20A constant voltage power supply tuned up to about 55-ish volts which supplies two constant voltage/constant current DC to DC converters to smooth that voltage. those two converters are boost only and are set to constant voltage mode to supply a stable and clean 55 volts to the output stage.
You'll note a ferrite toroid hanging off the side, just to keep the noise down and keep the microprocessor in the output stage from freaking out. The output stage is a programmable CC buck converter good for 60 volts at 20A, so theoretically could run at 1200 watts, but there's no way I'd run it that hot. Never over 600w anyway as the output is only 45-48 volts or so. The key to efficiency here is not to boost voltages too much - DC to DC converters lose a lot of efficiency the greater the increase in voltage across them, so 53-55 volts in and 55-56 volts out and we're golden. You'll note they are hung up - that's to keep the weight off the lighting rack and for thermal management. all the heatsinks on the driver arrangement are fan forced.
The driver shows 501 watts, that's reading though the output and I'm showing 520 watts on the 220V AC side, so about 96% driver efficiency if my crappy math skills are holding up. Sound right? The driver efficiency drops off dramatically if I turn the output up to 600 watts, down to about 80%, but since I don't really need the extra light I keep them running low.
So if anyone's running similar power levels through a meanwell driver do you know the driver efficiency? I'd love to know how mine stacks up.
Also, if anyone knows, just how in the fuck do you tell which flux bin the chips in a QB22a are in? seriously this has baked my noodle something fierce. All I can tell from the data sheets is that the bin data is on the bottom left hand side of the information sticker on the PCB, immediately left of the QR code. All it says is S04 which doesn't match up with any of the LM301b bins at all. Confused.
Considering there is something like a 10% difference between the lowest SL bin output and the highest SM bin output you'd be quite reasonable to want to know which bin the chips on your expensive strip came out of.
Some things to note:
Photo quality is a bit poor, sorry about that. the room is packed so full of gear it's hard to get in there and get decent photos and my phone camera is a POS. but you get the idea.
The quality of my wiring work is poor. I'm aware of that. Hard to believe I've been wiring stuff my whole life for a job looking at that, but it's basically a prototype. If it works out I'll do it proper but as long as it doesn't catch fire in the mean time there's not much point being meticulous with it.
Please let me know your thoughts, all criticism is welcome and appreciated.
Kind regards
TGS
I've built 4 of these, and just wondering how the driver efficiency compares to that of meanwell drivers which everyone seems to be using.
So I'm running my strips at 11.05A , making 737mA per strip. binning current is 450mA so I'm running at 163% of binning current which if I understand correctly is just fine and dandy as rated current is 200% of binning current. You'll note they are well and truly over engineered as far as thermal management is concerned, each strip dissipates it's heat into a 1200mm length of 25x25x1.5mm aluminium extrusion - so compared to a quantum board it's running lower current per chip (I think, just going off the QB specs) with vastly better heat dissipation, which should equal significantly better photon efficacy (not sure how much better, please chime in if you know). The extrusions have a fan blowing across them and barely get warm to the touch, maybe 30 degrees C.
The driver consists of a 20A constant voltage power supply tuned up to about 55-ish volts which supplies two constant voltage/constant current DC to DC converters to smooth that voltage. those two converters are boost only and are set to constant voltage mode to supply a stable and clean 55 volts to the output stage.
You'll note a ferrite toroid hanging off the side, just to keep the noise down and keep the microprocessor in the output stage from freaking out. The output stage is a programmable CC buck converter good for 60 volts at 20A, so theoretically could run at 1200 watts, but there's no way I'd run it that hot. Never over 600w anyway as the output is only 45-48 volts or so. The key to efficiency here is not to boost voltages too much - DC to DC converters lose a lot of efficiency the greater the increase in voltage across them, so 53-55 volts in and 55-56 volts out and we're golden. You'll note they are hung up - that's to keep the weight off the lighting rack and for thermal management. all the heatsinks on the driver arrangement are fan forced.
The driver shows 501 watts, that's reading though the output and I'm showing 520 watts on the 220V AC side, so about 96% driver efficiency if my crappy math skills are holding up. Sound right? The driver efficiency drops off dramatically if I turn the output up to 600 watts, down to about 80%, but since I don't really need the extra light I keep them running low.
So if anyone's running similar power levels through a meanwell driver do you know the driver efficiency? I'd love to know how mine stacks up.
Also, if anyone knows, just how in the fuck do you tell which flux bin the chips in a QB22a are in? seriously this has baked my noodle something fierce. All I can tell from the data sheets is that the bin data is on the bottom left hand side of the information sticker on the PCB, immediately left of the QR code. All it says is S04 which doesn't match up with any of the LM301b bins at all. Confused.
Considering there is something like a 10% difference between the lowest SL bin output and the highest SM bin output you'd be quite reasonable to want to know which bin the chips on your expensive strip came out of.
Some things to note:
Photo quality is a bit poor, sorry about that. the room is packed so full of gear it's hard to get in there and get decent photos and my phone camera is a POS. but you get the idea.
The quality of my wiring work is poor. I'm aware of that. Hard to believe I've been wiring stuff my whole life for a job looking at that, but it's basically a prototype. If it works out I'll do it proper but as long as it doesn't catch fire in the mean time there's not much point being meticulous with it.
Please let me know your thoughts, all criticism is welcome and appreciated.
Kind regards
TGS
