So this is pretty basic, I took pics so I could show my buddy, not intending to do a diy thread. But it came out pretty good so here goes... feel free to ask questions if I missed anything.
This is a DIY 100 watt HPS light with remote ballast and hood.
This can be scaled up for any size HPS, but you will need to scavenge a different box if the transformer doesnt fit.
Materials
Power supply from old computer
Hps outdoor/security light
hps bulb
Computer power cord
Lamp cord
Shop light hood
12 inches of #8 threaded bolt stock (or 4, 4 inch #8 bolts)
Washers, lock washers and nuts
Couple of chains to hang the light
Metal coat hanger
Drill, hack saw, adjustable wrench and a few screwdrivers
First gather the parts
for the HPS stuff you have a few options:
EBay
Craigslist
Electrical supply warehouses
Home depot/lowes or other hardware store
eBay always has a ton of hps stuff for sale cheap. But you have to keep looking to find good deals. If you can get the wattage you want for sale as an outdoor light or security light, just make sure its a ballasted hps light. Youre basically looking for an hps security light that you can gut and reconfigure to a remote ballast.
Sometimes I will search hps 100watt instead of hps 100 watt. The auction with no space between 100 and watt is a typo and doesnt come up in many searches so it gets less bids and will sell for less, also I always wait to the last hour to bid.
Craigslist can be hit or miss, but there are hps lights or "security lights" on craigslist fairly often, as many people are "going green" and converting there HID outdoor lights to more economical fluorescents. I recently saw a posting on CL where a local contractor was selling about 50 hps lights at 30.00 a piece. They had just removed them from a commercial building due retrofitting with more efficient lights. They are out there, you just have to look. Gymnasium lights often are HPS lights as well.
Electrical supply warehouses, check the phone book or yahoo yellow pages. Most small to mid sized cities have a few. If youre in a remote town in the middle of nowhere this may not be an option. If you can find one, just tell them you need a transformer, igniter, capacitor and mogul socket for whatever watt size light you want to build. They may or may not have a wiring diagram but they are easy to find on here or on the net. Sometimes there is a decal on the component itself with a wiring diagram. There are also "pulse start" in which there is no capacitor, just an igniter.
Home depot/lowes or other hardware store: I would use this option as a last resort, but I have seen them on sale for $40 or $50 bucks, sometimes less. Just check out the outdoor lighting isle and look for a deal.
Most of these come with the bulb, but I have seen them on
amazon.com for as low as $7 (I know, there are those of you that will swear up and down that the hps bulbs off the shelf at home depot or lowes arent the same or as good as the $50- $120 grow bulbs, they may not be but they work just fine for me, nice thick dense budz)
Once you have the hps components you are ready to go
I used a 100 watt hps security light components that I got on eBay for $25 delivered. I mounted the transformer and pulse start igniter in an old pc power supply box. (Please note that I used an empty box, I didnt just plug the hps light into it). Gutting the pc power supply was easy; just leave the terminal in there so you can still use it to attach the power cord. I used this box because it has plenty of vents and holes to let the heat out. I then used the existing pc power cord to power it.
The transformer has 4 holes going through it, I cut the bolt stock into 4, 4 inch sections and mounted the transformer an inch of the bottom of the pc power supply box, this way its not touching any walls of the box and disperses the most heat. Use the washers, nuts and lock washers to secure it in there.
I used a 14 gauge lamp cord to make the mogul socket remote. You could just use a ballasted security light right out of the box by just adding a power cord. But the ballast gives off a lot of heat and its not as mobile for adjusting height as just a bulb with a light weight hood is.
If your relatively handy and know the basics about electricity this is pretty straight forward. This 100 watt light would be perfect for a 1 plant or a micro or lst grow. I added a hood that I made for free out an old shop light hood. Just trim the hood to the desired length and drill a few holes at either end. I bent a metal coat hanger to make hood hangers at either end.
I use this light as an extra light with my 400 HPS. I ended up with more females than I had planned and needed more light!
If you have any doubts about your ability to wire this, dont do it or get help from a friend that knows (or ask for help on RUI) - faulty wiring can cause fires. The biggest thing is making sure its hooked up correct and there are no lose wires or bare/exposed wires. If its hooked up wrong it just wont work, if its hooked up correct with bad connections that is where bad things happen, check all connections twice and then check again! Get the screw on wire nuts and use electrical tape to make sure no wires (no bare copper) are exposed anywhere. Also, never place anything on, above or near your ballast. It needs air to vent its heat. I keep my ballasts out of the grow area to keep heat down, thats the whole point of making this a remote ballast.
Hope somebody can use this info, feel free to ask questions or post your own diy hps ideas or pics!