Fluoros - power consumption

The low power T5's just trade off power consumption vs light output in my experience, mine didn't light as well as T8's so I wonder about the actual output vs official output.

From what I could research the T8's with a triphosphor and electronic ballast are about 100 lumens per watt vs 105 L/W for T5's. The basic T8 gains are 15% more light by getting a good triphos tube and 15% more on top of that for an electronic ballast to give 32% total light gain.

Right now I'm planning to light my new workshop with with single T8's fitted with reflectors.

"Trevor Wilson"

Sure, the ballast choke would then be more expensive - but would easily pay the increase back in reduced power bills and be FAR cheaper and FAR more reliable overall than an electronic ballast.

So called "low loss" iron ballasts are available but even better ones are perfectly possible to make. Seeing as the potential waste of even 0.5 watt in a iron transformer plug pak PSU is now ILLEGAL in Australia - I wonder why these are not being mandated too ??

.... Phil

So a quick test would be to wire four ballasts in series parallel and check the power consumption?. I remember an old ETI fluoro inverter project where they mentioned that the fluoros get brighter with drive frequency for a fixed power..... but forget to what extent.

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That makes more sense. Requiring more efficient ballasts (or at least pointing out the facts) would save a lot more energy as there must be tens of millions of them across the country. Many of them in workplaces and shops would be run all workday, and many at night also.

On the subject of ballasts: Replaced a faulty 18w batten (Associated Lighting "Cadet"). in the bathroom last week that would have been installed about 1976.

The Ballast was about 150% the size of a modern one and felt much heavier. (it wasn't one of the old Ferguson "flat" black ones).

Too late to give any more detail on it as it went in last weeks rubbish as fitting was rusted extensively.

Was replaced with a new 14w T5 batten that was on hand. (modern one with triphosphor tube and electronic ballast.)

Out of interest until it could be replaced we used a 11w Philips spiral CFL temporarily in there in a lamp socket on a flexible cord that was plugged into the power socket & noted that the new T5 fittings FAR exceeded the CFL in light output despite a 25% increase in wattage in the T5.

There was just no comparison in usable light output.

CFL's are less efficient compared to T5 and T8's, around 75% lumens per watt at best. Also new fluoro tubes are brighter than normal for a short period until the phosphors wear in a bit then gradually decline over time.