converting a fluorescent strip light from 20W to 18W?

[hbeth82]

This is actually a question regarding my turtle tank but because you guys are all awesome, I hope you'll forgive me

The fixture I have for my turtle's UVB light is designed for 24", 20W bulbs. Unfortunately, the company that makes the bulbs has switched to making their 24" bulbs with 18W rating. I'm hoping that there's some way to alter the fixture (change plugs, starter, ?) so that I can use the 18W bulbs, rather than having to buy a new fixture.

So, any ideas? Will confess now that despite my years studying psychology, I know next to nothing about electricity and wiring, so please use small words.

Thanks!!!

 

[reflex1]

As long as the ends are still the same you should have no problem - just a little dimmer light is all - no harm - no foul!

 

[hbeth82]

As long as the ends are still the same you should have no problem

Unfortunately, for whatever reason, the 18W bulb doesn't work in my 20W fixture - it flickers intermitantly but never stays on. I never would have thought about it making a difference but for whatever reason, it does. The previous bulbs were all T12 whereas the new ones are T8 but according to the specs, the T8's should still work.

Is it even possible to change the fixture so that it would work with a 18W bulb? If it helps, here's the fixture I have, the Perfecto 30".

 

[reflex1]

Perhaps changing the "starter" would make a difference - gonna have to check with a qualified electrician I reckon.

 

[jimmiebsr]

You will have to change the ballast out to match the 18 watt T8 lamps. The output voltage and current is different on a T8 from a T12. By the wat the T meeans tubular and the numeral is the sive in tenths of an inch, hence T8= tubular, 8/10". I would try to get a rapid start ballast so no more starter needed.

 

[hbeth82]

You will have to change the ballast out to match the 18 watt T8 lamps. The output voltage and current is different on a T8 from a T12. I would try to get a rapid start ballast so no more starter needed.

Cool, a new project (and excuse to visit Home Depot), thanks! Physically, a T8 fits in the light okay, so you don't think I'd need to change the ends? If I am able to find a rapid-start ballast, would it be better to remove the starter or would it make any difference? Also, is this WikiHow an adequate explanation of how to replace the ballast?

Again, thanks!!!

 

[jimmiebsr]

Nope, the ends and length are the same. If you find a rapid start ballast ( should be all you can find ) take the starter out completely. It's not needed. The ballast should have a diagram on it for the wiring. The link is pretty much good. The wire colors to the lampholders may be different, just follow the diagram. Be careful with the output wires, will be around 500 volts there when lit. Won't kill you but will give you a bad attitude. Make sure to insulate the connections well ( no exposed wire).

 

[mfdrookie516]

Won't kill you but will give you a bad attitude.

and a bad hair day

 

[BillD]

You will have to change the ballast out to match the 18 watt T8 lamps. The output voltage and current is different on a T8 from a T12. By the wat the T meeans tubular and the numeral is the sive in tenths of an inch, hence T8= tubular, 8/10". I would try to get a rapid start ballast so no more starter needed.

Actually, the number is in 1/8s, hence, a T8 is 1 inch and a T12 is 1 1/2".

 

[thincat]

+1 Bill

 

[jimmiebsr]

I stand corrected! Hey, not my fault, had a tooth cut out and Vicodin seems to affect thinking? Imagine that!

 

[jsoong]

I would suggest an electronic load sensing ballast.

Your old ballast/starter doesn't work because it is fixed at 20W. An electronic ballast will sense the load & adjust accordingly, so you are not tied to the 18W in future. Plus the electronic ballast is smaller, lighter, and is quiet - no fluorescent hum, and possibly more energy efficient.

I have not seen electronic ballasts at HD (here, all they have are the heavy electro-magnetic ballasts - rapid start, but non-electronic.) You are better off going to a lighting parts store, they will be able to tell you what is needed. <Plus, electronic ballasts at my parts store is cheaper than HD .... at least in Edmonton.>

 

[hbeth82]

Awesome, thanks everybody. The last T12 20W bulb I have should be good for another 6-8 months so you may see this again come October or November.

Did go to HomeDepot to check out the ballasts and didn't notice any saying 'rapid start' and only a few indicated the recommended wattage. Most just gave the number of bulbs, length, and voltage. Thankfully I have plenty of time to figure this out!

 

[thincat]

I stand corrected! Hey, not my fault, had a tooth cut out and Vicodin seems to affect thinking? Imagine that!

Not to worry. No one blames anyone on this site. It was just a small adjustment. lol