OFF/ON/OVERDRIVE photosensitive fluoro switch possible?

[Ken Seggerman]

Gretings:

I have recently learned how to make an overdriven fluorescent lamp
fixture out of two cheap 48" shoplights by rewiring a a pair of two-lamp
electronic balasts to drive one lamp apiece. I learned of this on an
indoor gardening forum. It apparently is an old trick used by tropical
fish fanciers.

The shoplights came with no switches, so I use a switched power strip,
and have the fixture controlled by a timer. I am about to replace the
outlet I use with a GFCI outlet.

I was wondering about the possibility adding switches to toggle between
regular and overdrive. Maybe this could be done only with swithces on
the input side of the balast, maybe not. If not, is it safe or even
possible to switch the high frequency, high voltage output of the
electronic balast?

If it is possible and feasable to safely swtich between regular and
overdrive, would it be possilbe to have a photosensitive device control
the fixture and switch between off, regular and overdrive depending on
the amount of available sunlight? I was quite pleased with my
inexpensive overdriven shoplight growing stand until I got the last
electric bill.

I have read that fluorescent fixtures are not compatible with ordinary
rheostat dimmers. I imagine that "dimmable" fluorescent fixtures use
specific pairs of balasts and controllers.

I have also read that ordinary photosensitive swiches are not compatible
with fluorescent fixtures. Are there photosensitive switches specific
for fluorescent fixtures?

Any suggestions or information would be appreciated.

thanks,
Ken Seggerman.

 

[Victor Roberts]

Gretings:

I have recently learned how to make an overdriven fluorescent lamp
fixture out of two cheap 48" shoplights by rewiring a a pair of two-lamp
electronic balasts to drive one lamp apiece. I learned of this on an
indoor gardening forum. It apparently is an old trick used by tropical
fish fanciers.

Not a "trick" at all, but it does beg the question of why you didn't
just purchase a lamp and ballast that gives you the light you want.
Overdriving a fluorescent lamp by a factor of two will greatly shorten
its life and decrease its performance.

The shoplights came with no switches, so I use a switched power strip,
and have the fixture controlled by a timer. I am about to replace the
outlet I use with a GFCI outlet.

I was wondering about the possibility adding switches to toggle between
regular and overdrive. Maybe this could be done only with swithces on
the input side of the balast, maybe not.
Not.

If not, is it safe or even
possible to switch the high frequency, high voltage output of the
electronic balast?

Not unless your switch is rated for the open circuit voltage of the
ballast. If this is an instant start ballast, the OCV is probably
about 1000 volts.

If it is possible and feasable to safely swtich between regular and
overdrive, would it be possilbe to have a photosensitive device control
the fixture and switch between off, regular and overdrive depending on
the amount of available sunlight? I was quite pleased with my
inexpensive overdriven shoplight growing stand until I got the last
electric bill.

Not until you find some means to switch the output leads.

I have read that fluorescent fixtures are not compatible with ordinary
rheostat dimmers. I imagine that "dimmable" fluorescent fixtures use
specific pairs of balasts and controllers.

Yes. Many fluorescent dimming ballasts dim to 1%. These are quire
expense and far beyond what you need. There are also less expensive
F-lamp ballasts that switch between two levels, and it seems these may
fit your application.

I have also read that ordinary photosensitive swiches are not compatible
with fluorescent fixtures. Are there photosensitive switches specific
for fluorescent fixtures?

Yes. See www.wattstopper.com for some examples. Many of these require
an interface between the photodetector and the ballast.

 

[Ken Seggerman]

Victor, thank you for the information and the link.

...but it does beg the question of why you didn't
just purchase a lamp and ballast that gives you the light you want.
Overdriving a fluorescent lamp by a factor of two will greatly shorten
its life and decrease its performance.

I just couldn't resist trying out such an inexpensive alternative to
commercially available plant growing fixtures. I guess I have stretched
the $8 shoplight as far is it will go.

best wishes,

Ken Seggerman

 

[AC/DCdude17]

X-No-Archive: Yes

You're stressing components far beyond their design specifications. Not
only will you experience a very early failure of ballast/lamps, it's a fire
hazard. Oh and home owners' insurance doesn't have to cover fires as a
result of a hack job like this.

 

[JM]

quoting:

Victor, thank you for the information and the link.


I just couldn't resist trying out such an inexpensive alternative to
commercially available plant growing fixtures. I guess I have stretched
the $8 shoplight as far is it will go.

Sylvania has ballasts that will drive T8 lamps up to 1.50 ballast factor.
Lamp life not guaranteed however.