Lighting Mars Reflector 96 COB conversion

[Terra Firma]

Hi everyone,

I've decided to convert a Mars Reflector 96 to use COB LEDs.
I've opened up the light to check what type of drivers it uses (see the pictures).

I decided to connect 2 x 36V COBs in series per driver putting out 0.65A.
I bought the items below on Ebay and they should arrive beginning of next week.
6 x Citizen CLU048-1212C4-353H6M3-F1 Version 6 (90CRI) 3500K COBs.
6 x BJB CLU048 holders.

I then looked into getting new quieter fans, and got confused about connecting 0.3A fans to a 0.65A driver. Each fan is connected to separate wires (than the LEDs) coming out of a driver. Would the current output of these wires be less than 0.65A? I don't have a multimeter so can't check.

After reading through the LedGardener website tonight I sketched a plan for building 2 completely new COB lights instead of converting the Mars light. My idea was to attach 4 COB's to a heatsink and connect them in series to a 1050mA or 1400mA Mean Well driver (if dimmable to a lower current for veg). I got carried away and calculated the thermal resistance of 4 x 36V cobs running @ 1050mA attached to 1 heatsink: 0.4C/W I couldn't find a website in Europe that sells heatsinks large enough to space out 4 cobs on (app. 400x400mm) so I gave up for now. Does anyone know a good company?

I'm still not quite sure whether I should build 2 new lights or modify my Mars light. I need the light to cover two plants on a 1 x 0.75m area. 2 separate lights would give better coverage and flexibility, but would cost quite a but more. The Mars conversion would be cheaper but won't cover the required area very well. What are your thoughts?

 

[BigSm0]

While conversions are inexpensive it’s best to leave them as just that. Inexpensive as possible. I’d say it’s how most get started in cobs and trust me it’s addictive. I would run the 4 cobs, keep the fans and drivers for now and benefit from the more efficient light. Efficiency is very important but you may end up chasing it, and usually much further than you will ever be repaid in energy savings.

 

[orrganic]

My Cob journey began with a Mars reflector 48 and some citizens and imo its not even worth paying for the piece of aluminium to fix cobs on, especially if youre worried about the fans noise. If I could go back I would definitely have just bought a ready made unit like Bigsm0s auto cob or something of the likes... You want that sweet spot of amperage x voltage for optimum lighting, the 650ma likely won't achieve that.

 

[Terra Firma]

While conversions are inexpensive it’s best to leave them as just that. Inexpensive as possible. I’d say it’s how most get started in cobs and trust me it’s addictive. I would run the 4 cobs, keep the fans and drivers for now and benefit from the more efficient light. Efficiency is very important but you may end up chasing it, and usually much further than you will ever be repaid in energy savings.

You mention running 4 cobs? My initial plan was to run 6 cobs @ 650mA (app. 22W per cob @ 33.5V) in the Mars with active cooling from the fans. The noise of the fans isn't really an issue, but I might replace them anyway because new fans are cheap and quieter.

The other option I am contemplating is to replace the 3 drivers with a single Mean Well driver to run the cobs, and add a small dedicated driver to run both fans. I could run the cobs at either 1050mA (6 x 36W = 220w) or 1400mA (6 x 50W = 300W). The fans are 3.6W each.

@BigSm0 : what are your suggestions?

My space is 1.5x1.5m and I'm doing a perpetual auto grow of 3 veg and 3 flower. The converted Mars light would hang above the center flowering plant, with a HS1 on either side of it for the other 2 flowering plants.

 

[orrganic]

I have a feeling these drivers won't support 6 let alone four 36v cobs. I have the same driver and was only ever able to run a citi 1212 and one of the smaller max 55w citizen cobs but never two 36v citi 1212s. So if that applies to these drivers you'll have max 22wx3 66w out which will be under powered... Imo.

With a 1050ma driver at 36.5wx3 for 109.5 or 50w x 3 for the best bet of 150w out. Also where are you planning on mounting the cobs? On the old aluminium plate once cleared of old diodes, a new plate or single heatsinks?

 

[Terra Firma]

I have a feeling these drivers won't support 6 let alone four 36v cobs. I have the same driver and was only ever able to run a citi 1212 and one of the smaller max 55w citizen cobs but never two 36v citi 1212s. So if that applies to these drivers you'll have max 22wx3 66w out which will be under powered... Imo.

With a 1050ma driver at 36.5wx3 for 109.5 or 50w x 3 for the best bet of 150w out. Also where are you planning on mounting the cobs? On the old aluminium plate once cleared of old diodes, a new plate or single heatsinks?

Hmmmm. Sounds dissapointing.

I'm either going to buy a new aluminium plate or reuse the one from the light. A new plate would be less work. I might buy bigger heatsinks to mount on the aluminium plate though. Depends on the cost and if it's required.

Could I buy a 1400A driver and reduce it to 1050mA so I still have the option of doing 50W per cob?

 

[MickJ]

These guys do them up to a meter long.
https://rover.ebay.com/rover/0/0/0?mpre=https://www.ebay.co.uk/ulk/itm/131535356625

Sent from my comfy chair.
[emoji16][emoji41] [emoji43][emoji848]

 

[Terra Firma]

I received my 6 COBs + BJB holders today but haven't opened the package yet.

I've decided to make 2 completely new lights and just placed an order for 2 drivers and 6 heatsinks (www.elpro.org).
It hurts now but the pain should go away when I bask in the light of my new COB lights

Each light will be a triangular formation of 3 COB LEDs on circular heatsinks (ModuLED Mega 13450-B-HBG) connected with some kind of frame. The driver will be a Mean Well HLG-185H-C1400A, which I can run at 1400mA or dim to 1050mA if required. It also gives me the option of adding a 4th cob at a later stage and running it more efficiently at 1050mA.

I think I will convert my Mars Reflector to a dedicated veg light with 2 - 4 cobs somewhere later this year.
For now I'll leave it be.

 

[Terra Firma]

These guys do them up to a meter long.
https://rover.ebay.com/rover/0/0/0?mpre=https://www.ebay.co.uk/ulk/itm/131535356625

Sent from my comfy chair.
[emoji16][emoji41] [emoji43][emoji848]

Thanks for the tip. I just bought some circular heatsinks (ModuLED Mega 13450-B-HBG).

 

[orrganic]

This all sounds great Terra I'm relieved to know your making a whole new one and not leaving yourself lightless should anything go wrong... Like I did to myself..
Anyway
I've just had a realisation in regards to hacking this in future. You could link the drivers in series to combine their amperage and match to the best suited cob, for example a cob that performs efficiently at a much higher amperage like 1600-1800-2100ma and puts out up to 100+watts at 150 odd L/pw.. Resulting in a bad ass upgrade.

I've successfully linked two 1050ma drivers with a three port wago connector that doubled my cobs output. I lost L/PW efficacy but it was better than less lumens to begin with. @BigSm0 please pull me up on anything that may be not so good advice if you see it. @Terra Firma hope this helps