Renfro's 760 Watt COB LED Build -> 1kW DE HPS Replacement

Nice man should be cool to watch you progress through the build and grow

I will share my learning experience as many have done before me and many will do after.

have you considered upgrading to a more efficient AC? the newer minisplits are super efficient

as i mentioned via email you'll be able to run your room at 85F with the LEDs which should reduce your load a little

CobKits said:

have you considered upgrading to a more efficient AC? the newer minisplits are super efficient

as i mentioned via email you'll be able to run your room at 85F with the LEDs which should reduce your load a little

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Well due to the municipal codes where I am I can't have any mechanical in the front of my house and where the veg room is located leaves me either a really long lineset run to locate the condenser unit in the back. I just don't feel like doing that plus I already have two big 4 ton minisplit condensers back there and a third would look really odd lol. I am also building a new place and in a year or two I don't plant to be growing here anymore. Man tearing down this grow is not something I look forward to, I may just keep the place and rent it out to someone as a turn key setup.

So today my order from cobkits.com arrived. Got 72 chips, chip holders, wagos, heat sinks, 18 drivers, potentiometers and all that jazz. Oh yeah! Now to setup a space to work on these. Got my catalog from 8020.net so I can start digging through options for a frame to use with the adjustable rig. I hope it doesn't end up too expensive as I would like to build all the lights that way. Ordered my Apogee MQ-500 today so it's on the way.

I run 16 cobs in a 4x4 at around 500 watts with 70 watts of 660nm. I can't grow worth a crap and I'm pleased. I got to watch this.

Here are some pics of the build



Popping chips in the chip holders and giving them a cleanup with 91% alcohol (heat sinks get cleaned as well).



Mounting COBs on heatsinks with Arctic MX-4 thermal compound and M3x6 screws.



Here is a project box for the DROK meter. I actually have a case of these new project boxes sitting in the garage from a salvaged freight auction 12 years ago. Perfect size boxes for these meters.

Putting paste on the chips to mount them on the heat sinks



Pigtails



A driver

Definitely fallowing this one

Let there be light!



Meter works, need to use it on the negative side though as it's reading negative when on the positive side.

12 COBs at full power, meter sums up the three feeds off the drivers. Life is good. Ordered 5 more of the meters for the other lights.

Got this cool shot of 12 cobs running with the reflectors. The lights are on in the room it's just hard to tell this is so bright. Will it replace 1150 watts of DE? umm yeah I think so. I can't wait for my Apogee MQ-500, it's shipped and on the way. Then I can measure the output. I want to throw a frame together and get it put assembled properly. I let it test run for a few hours tonite, make sure nothing decided to peach off, all good. After I turned it off I used the IR temp gun on the cobs, they were around 99 to 104f. Room is 68.



I will work on getting the meter and pots and such into the project box. Once I get a satisfactory layout I can get all the boxes cut and drilled. I will get some IEC320 C14 pigtails to wire into the drivers. If I can fit that junction, the meter and the 3 dimmers all in that project box I will be satisfied. The DC wago connections will be frame mounted, Cobby threw in some nice little clips that screw to the frame and the wagos clip securely into them so they are neatly organized and secured.

Here is a few of those clips, one with two 5 port wagos in it and the other is empty.

So my back was really hurting and I couldn't get to sleep so I worked on mounting the meter and dimming potentiometers into one of the project boxes. I have cable glands on the way and I will drill the box to feed the dimmer wires and I will also need to feed the meter. I am ordering some knobs to make it look spiffy. The project box will obviously get mounted on the frame. Once I have the perfect design and everything fits and works I will have to make 5 more like this.



I will also use some project boxes to do the AC power junction. I ordered some IEC320 C14 power sockets with switch and fuse.

I dug up my pop rivet kit with kleco clamps. I will use pop rivets when I put the frames together with 1" aluminum angle 1/8" thick.

That's a pretty cool setup. Very professionally done.

So I found some 14 gauge cable that has 7 conductors. It's actually pretty good deal too at $1.15 a foot. I intend to mount the drivers remotely and run one cable to each fixture to power three strings of cobs off three drivers. The extra 7th conductor will be used as a ground to the frame. The DC wires will be junctioned in a box on the frame and in the DC box by the controller. The dimmer knobs, meter and power switches will all be mounted with the drivers for easy access, AC in one box and DC in another.

I have trying to find some sort of plug/receptacle that would safely handle the seven 14 gauge conductors so I could make it easy to disconnect the light fixture from the drivers. If I have to hard wire it then it would be rather difficult to take the light down for service or if I wanted to run the HPS lights in the winter. I may use the trailer connectors if they will handle the 50 - 54 volts safely. Don't see why not.

Each driver can be powered on and off individually. If the driver powering the meter is turned off then the meter will turn off but the light will operate with other drivers that are on. I have DPST switches ordered to power the drivers since I will be using them at 240 volt it's best to switch both hot legs.

Each driver can be dimmed individually. The meter will be handy if you want to equalize the power on the strings and also handy for going back to previously used levels that were correct for a stage of growth or plant height.

This is gonna be fucking awesome! Stay tuned!

Nice thrrad! Thanks for the link. I will be following along.

any updates cant wait to see what they can do

ozziebud said:

any updates cant wait to see what they can do

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No I have been busy with other things mostly.

Say bro not sure if you built your frame yet but don't go to any big box stores to find your 1x1 x 1/8 aluminum. Call your local steel and metal distribution centers. I just found 25ft sticks for $18.50 a pce

oilfield bud said:

Say bro not sure if you built your frame yet but don't go to any big box stores to find your 1x1 x 1/8 aluminum. Call your local steel and metal distribution centers. I just found 25ft sticks for $18.50 a pce

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thats what i bought after pricing the t slot.