# [Wet Thumb Forum]-ballast to drive 4 18" or 15" T8s



## imported_baj (Aug 5, 2004)

Hi,
I was looking for some ideas and pointers to a ballast I can use that can drive 4 18" or 15" fluorescent tubes, I am aware of the coralife ballast/endcap kits sold by bigalsonline. Are there any others? Also, Can i use a ballast that drives 4 bulbs of higher wattage to overdrive the 15W bulbs or is that a bad idea? 
Also, I have an old fluorescent fixture that cannot be hooked to a timer since its a preheat kind of fixture where you have to depress the "on" switch momentarily to get it going, can this ckt be changed such that it can be hooked to a timer? I couldnt follow the procedure given on the krib.
Thanks!


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## imported_baj (Aug 5, 2004)

Hi,
I was looking for some ideas and pointers to a ballast I can use that can drive 4 18" or 15" fluorescent tubes, I am aware of the coralife ballast/endcap kits sold by bigalsonline. Are there any others? Also, Can i use a ballast that drives 4 bulbs of higher wattage to overdrive the 15W bulbs or is that a bad idea? 
Also, I have an old fluorescent fixture that cannot be hooked to a timer since its a preheat kind of fixture where you have to depress the "on" switch momentarily to get it going, can this ckt be changed such that it can be hooked to a timer? I couldnt follow the procedure given on the krib.
Thanks!


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## dennis (Mar 1, 2004)

Baj,

Lets tackle the old florescent fixture first. Your best,cheapest bet is to go the the hardware store and buy a "starter" and a socket to hold it, The starter looks like a litte round can, about 5/8"across and 1.5" long with t terminals coming out of it. The socket for it will have 2 slots that the terminals twist into. Sinply get the appropriate sized starter for your bulb type and install the socket inline with one of the wires going to one of the endcaps. INstallation is easy, generaly the sockets(and florescent endcaps for that matter) require you to strip about 1/4" if insulation from the wire and insert it into one of the holes near the bottom of the socket. Inside the hole is a little brass spring that holds the wire in place and makes the connection. Should cost about $2dollars US









As for the ballast, while youare at hte hardware store, Lowe's, Home Depot, etc, bick up a ballast for running 4- t8 bulbs of the wattage youneed. All of the ballasts I have bought have been able to run from 3x15watts to 4x36watt t8 tubes. These kind can olny be over driven by hooking up a bulb twice, using 2 leades. So if you want to 2x overdrive 4 bulbs you would need 2 ballasts. The reason is that electronic ballasts tend to load sense the bulb abd therefore will only overdrive if you use 2 power leades. Personall I have found it better to use 3 tubes rather than to try and overdrive 2, but sometimes overdriving is the way to go. Check out this link to see some photos of a hood I made. In the pics the back bulb(with red wires) will be overdrive 2x and the other 2 bulbs regular drive. Overdriving 2x does not actually double your output, maybe 50% more at best.


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## imported_baj (Aug 5, 2004)

Dennis thanks. So I will need a starter for each bulb. I think I'll just go with NO and not overdrive them. I have 4 tubes lying around and wanted to rig up my own light fixture for a 10g tank, the link you gave me was very helpful. From that, I think you said the ballast can drive 4 bulbs, so you hooked up one bulb twice to the ballast to overdrive it? If you have it handy, could you please point me to the wiring driagram?
Thanks!


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## dennis (Mar 1, 2004)

Baj, you wont ned a starter for each bulb. The starter was only to make thae old hood you have work with a timer. That old hood has a ballast that needs a little "jump start" to work thats why you have to hold in the switch. Adding the starter to it will give it that jump









If its a 10 gallon, trust me you only need 3 tubes and they don't have to be overdriven. I can grow anything in that 10 gallona nd sometimes there is to much light. My rotala indica is problemattic due to its never growing vertically. Glosso never grows vertically either though so its worth it for that. It just creeps along the substrate







I would just use a ballast similar to mine and wire it for 3 bulbs. The wireing diagram is printed on the ballast and its pretty easy to understand. Basically you will have 2red, 2blue, 2 yellow adn a black and white. Black and white get attached to you power cord. Yellows are ground. They get attached to one end of the tubes. You split off from the bulb sockets so one yellow does 2 tubes. You attach one red or blue the the other end of each tube. Attaching more than one of hte red/blue wires will overdrive it. You can see that wiring in my photos. Good luck


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## imported_baj (Aug 5, 2004)

Thanks again dennis, I understand how this works. I guess I will chuck away that old ballast, looks like it is a prototype handmade by Edison himself. Anyone interested in an antique ballast?


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