LED strip light load on 5amp circuit

[Stu-Gibbo]

Hello,

Newbie here. Tried to find the answer through searching, apologies if I've missed it.

We are refurbing our house. I want to install RGBW LED lightning.

• 3 zones: A) Round the lantern roof light, B) Kitchen cabinets and Island C), Snug room (TV and cabinets)
• I would like them switched from the wall and App controlled.
• I asked the electrician to leave 5amp connection points in each zone so we can wire onto the lighting circuit.
• I estimate between 15-20M total strip length.

When I do the calculations (for a 24v 21W/m COB strip) I get:
20m x 21 = 420 watts total
420watts / 24v = 17.5amps max current drawn.

Am I right that this is far over the 5amp max load on the lighting circuit?
I've played with other numbers. To give a 3 amp max draw ( To allow for other lights on the circuit) would be:
3amps x 24V = 72watts.

Questions:
1. Have I got my sums right so far?
2. Is there a better way to do this?

Thank you,

Stu

 

[DPG]

That's the wattage at 24V. The mains supply voltage is higher, and so the current drawn from the mains will be lower.

Do the sums again but with the 240V mains voltage. There will be some power lost in the power supply unit, but fairly negligible.

 

[Avo Mk8]

Questions:
1. Have I got my sums right so far?

DPG just got there before me!
(It's about 1.75 amps. You'll be fine!)

2. Is there a better way to do this?

I would buy a driver for each location - don't know if that's what you are proposing.
So to specify a driver, just do your sum for the length of strip for that location.

 

[Stu-Gibbo]

That's the wattage at 24V. The mains supply voltage is higher, and so the current drawn from the mains will be lower.

Do the sums again but with the 240V mains voltage. There will be some power lost in the power supply unit, but fairly negligible.

Hi! Perfect. That makes much more sense... funny I asked the same question to 3 different LED suppliers and they all said the current would be taken at the 24V. Didn't make sense that I could have a max of about 5m!

Thanks again.

 

[Stu-Gibbo]

DPG just got there before me!
(It's about 1.75 amps. You'll be fine!)

I would buy a driver for each location - don't know if that's what you are proposing.
So to specify a driver, just do your sum for the length of strip for that location.

Thanks,

Yep, I'm going to put a separate driver t each location. Was just worried about overloading the entire 5amp circuit with the combined total.

 

[littlespark]

3 drivers at 3 locations will give different colours…

Ie, you can set them all the same colour, or purposefully different colours…


But if you use one of the slow fade from one colour to next type controls, they won’t all change at exactly the same speed….
Over even just a few minutes, they will be out of sync.

 

[Stu-Gibbo]

3 drivers at 3 locations will give different colours…

Ie, you can set them all the same colour, or purposefully different colours…


But if you use one of the slow fade from one colour to next type controls, they won’t all change at exactly the same speed….
Over even just a few minutes, they will be out of sync.

Thanks little spark. Good point but the drivers I'm considering have a sync and communication between driver function. So (as long as it works) they will be in sync and can all be controlled from a single RF remote / app change.

I'm looking an MiBoxer kit BTW. Though still very much open to suggestions if people have experience with specific products or companies. Bit of a mine field when it comes to checkin out the TrustPilot reviews on suppliers.