Constant current driver replacement

Hey folks, i work for a relatively small company, but we are doing some big jobs. And right our headache is taking over outdoor lighting maintenance from other guys (you know that situation where the only way to know anything about light is to get up there on the pole and open it to read that sticker?) Even bigger headache are the drivers that are failing like crazy right now and we really need something universal.
My problem is that i dont know much about constant current drivers or LED's (except for those 12/24v systems), hell i was lost when i saw different max output voltages not to mention that programming driver output is like rocket sync for me right now (give me dip switches and im good )
Anyway, as far as im aware right now, all lights are from 20 to 40-50w, and up to 1050mA. Now, my boss does not mind paying extra for overkill driver, as long as it can be used on any of the outdoor led lights (it sounds stupid but in our situation speed is money).
Would it be a problem if we put 1050mA driver on a 450mA led lamp post?

BitFrosty said:

Would it be a problem if we put 1050mA driver on a 450mA led lamp post?

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Yes, that would have the same effect as connecting a 240V lamp to a 415V supply.

In simple terms the normal supplies we are used to working with are constant voltage, the voltage stays at a constant 240V and the current varies according to the connected load.
Constant current supllies however maintain a constant current by varying the voltage according to the load.


If you are replacing a 450mA driver then you need to replace it with a 450mA driver. The voltage range of the new driver doesn't need to match exactly however as long as it covers the same range as the old one, so if the old driver has a range of 10V to 30V and the new one is 10V to 50V it will be fine.

You can get constant current drivers with a selectable current output set by either dip switches or a setting resistor

Thx, for clearing that out, it actually makes sense (im just stupid).
Another question, is it possible to calculate voltage from designed current and led's resistance? I mean is V = I * R valid here?
I measured 144omh on one of the lamps, and designed current is 470mA on the label. By my calculation thats 67.68v (is it valid?)

BitFrosty said:

Another question, is it possible to calculate voltage from designed current and led's resistance?

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No, LEDs are a non-ohmic load and so do not have resistance, this is why they require a constant current supply and not a constant voltage supply.

Any LED lamp which is suitable for a constant voltage supply, such as a lamp for a standard light fitting, will have an internal current limiting circuit to give the actual LED chip(s) a constant current.

BitFrosty said:

(give me dip switches and im good )
Anyway, as far as im aware right now, all lights are from 20 to 40-50w, and up to 1050mA. Now, my boss does not mind paying extra for overkill driver, as long as it can be used on any of the outdoor led lights

Click to expand...

As per post #2, you and your boss may be aware there are programmable constant current led drivers, where you can set the drive current over quite a range (example below - though this one doesn't cover the range you need), in this case with the dip switches you love!
They are more expensive, but in your situation probably worth it. But seem to come with features you don't need, like dimming, so don't know if that will render them impracticable.

I'm no expert on this, but I imagine with a bit of research you may find something on the market that covers the range of voltage and current you need, and with the appropriate IP rating.
There are other slick methods of programming now, using Near Field Communication, so with the appropriate tool to match the whizzy programmable driver, you set it up from a handheld device (supplied by the driver people).
So your ideal scenario: climb the ladder with the programmer and new driver, read the label of the old one, program the new driver to the same parameter(s), swap them over, down the ladder - job done!
That is of course if you can find a programmable driver on the market that covers the range of pre-set currents over the voltage range that you need!