High efficiency 12V 40W flurescent lamp driver

[chingyg]

Hi guys, I'm making this solar powered project for my company. We need to be able to run those 40W fluorescent tubes on battery power. So i'm thinking of a direct driver to drive those tubes.

I looked all over the net for designs and basically there are the very simple one floating around on the 555 timer driving a transistor and transformer and the transistor driving a transformer with feedback coils. there is also circuits that incorporate filament heater and others

The main goal of the project is high efficiency and get the most out of the battery life, what design should I follow in order to achieve them?

 

[Ubergeek63]

you don't. a standard car battery is about 40AHrs. 12V@40W@80%=4A since that is about double the drain of the 20AHr rating you will be lucky to get 8 hours for 200 cycles on a deep cycle type never mind a car battery.

If you want life in the situation you want power LEDs focusing the light EXACTLY where you need it. i would suggest track lighting powered by the battery and hacking together the following:

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these lamps will put a LOT light at your workstations instead of all over the room and run fine at 12V.

BEWARE CREE LEDs!!! CREE specs junction temperature while Luxeon specs solder pad temperature. the end result is that while CREE specs are great, the Luxeons perform better!

 

[chingyg]

The lightning is for school's classrooms, here in Africa, some of the school don't have mains electricity and only solar, so LED wont work because of the cost involved in replacing all of them ...

 

[BrownOut]

A 555 circuit would be good for experimentation, but it's generally not the best to use for production circuits. A circuit that use a transformer with a saturable core and feedback is a good choice, but the characteristics of the transformer core is crucial to the efficiency. Most circuits on the web don't care and use poor choices for the core. Again, they are experimental. You should choose a core with a so-called "square" saturation characteristic.

 

[shortbus=]

Chingyg -Going here may give more in site to your problem International Rectifier - Lighting Products

 

[Ubergeek63]

The lightning is for school's classrooms, here in Africa, some of the school don't have mains electricity and only solar, so LED wont work because of the cost involved in replacing all of them ...

well you should have said so in the first place... how many 40W tubes and how much solar capacity do you have? Remember you can only rely on 25-50% of rated solar capacity and you need around 70W per tube if you have decent ballasts since you are trying to do multiple power conversions and you will need around 300W or more of solar capacity per tube.

the fact of the matter is that you would be better off hanging 1W LEDs on chains from the ceiling over each desk from the efficiency standpoint. a room with 25 desks would take 25W plus a couple aimed at the board instead of at least 6 40W tubes the throw light everywhere.

next time consider bringing up the target app from the start... i still think you do not have the capacity to run that much lighting... focused LED spots maybe but not enough to flood the rooms.

 

[BrownOut]

There is no need for multiple power conversions. You can use the inverter directly. Throw the old ballasts away, or sell them on e-bay.

BTW, there are premade solutions available to save you some design effort like this.

 

[CRISespecialist]

hi chingyg,,,i may suggest that you use inverter that has high power wattage with a 12volts car battery as a power source,sence dont have a car battery charger to charge again the battery if drained,due to no electric in that place,you can add solar as a charger for the battery,cris...

 

[colin55]

You can try this type of circuit:
It uses 24watts to drive 2 x 20watt tubes. The high frequency of operation seems to make the tubes quite bright:
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