# Power supply for 16 Projectors 12V 2.0A

#### Forestmochi

Jun 5, 2023
1
Hi,

I’m looking for advice and recommendations for a power supply to simultaneously power 16 projectors that have 12V 2A DC input. The projectors also have internal rechargeable batteries with 10.8-12.6V 2600mAh/29.08Wh, however the projectors will always be connected to a power supply. I have included some pictures. The project will use mains AC power in Australia (240V 50Hz).

Can you recommend a power supply? Would it be best and safest to use a series or parallel circuit? Thanks

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#### Bluejets

Oct 5, 2014
7,144
So....use 16 2A plug in supplies.
Then if one goes down, no problem ...or/less of a problem.

#### Delta Prime

Jul 29, 2020
2,265
2 amps * 16=32 amps continuously. because all your projectors will be on simultaneously. switch mode power supplies 12 volts 32 amps are readily available I'll double that and put them in parallel fused 2 amps each one of your projectors but here's the kicker you're outlet 240 volt 50 Hz must be able to handle 32 amps and I would not run it at maximum being your circuit breaker must be more than 32 amps along with your conductors, the Gage of wires used in the circuit must be able to handle far more than 32 amps for safety. I say this with an over but it's of caution. Something to consider

#### Harald Kapp

##### Moderator
Moderator
Nov 17, 2011
13,834
here's the kicker you're outlet 240 volt 50 Hz must be able to handle 32 amps
Definitely not.
32 A × 12 V = 384 W.
384 W / 240 V = 1.6 A.

You could (ab)use e.g. a computer power supply, easily and cheaply available. Of course, @Bluejets' argument is worth some consideration: Using a single power supply will have al projectors off in case of a failure of the power supply. Using multiple power supplies, one for each projector, will have only the projetor dead whose power supply fails, the other projectors will contine to work.

#### Delta Prime

Jul 29, 2020
2,265
Definitely not.
32 A × 12 V = 384 W.
384 W / 240 V = 1.6 A
Each projector takes two amps to operate he has 16 of them he can live in never never Land and have a thousand volts service you still going to need two amps at 12 volts for 16 projectors

#### Harald Kapp

##### Moderator
Moderator
Nov 17, 2011
13,834
still going to need two amps at 12 volts for 16 projectors
I totally agree. 2 A per projector. That makes 32 A @ 12 V which computes to 384 W.
An ideal switch mode power supply will take 384 W from mains 240 V and step down to 12 V, preserving the power . Thus input power = output power = 384 W. To get 384 W from 240 W takes only 1.6 A.
Of course, no power supply is ideal. So one has to account for th eefficiency, let's assume 80 % (modern mains PSUs are much better than that). Then input power is higher than output power to account for efficiency whcih translates to Pin = 384 W / 0.8 = 480 W which is equivalent to 2 A input current.

The current from the mains outlet is therefore equal to or less than 2 A, By no means will it be near 32 A as you stated.

If one were to take your calculation, input power is Pin = 240 V × 32 A = 7.68 kW.
On the output side you have Pout = 12 V × 32 A = 384 W.
The difference between input power and output power would be Pdiff = Pin - Pout = 7.68 kW - 384 W = 7.296 kW. Where do you think this power difference will go?

By the way: the above calculation is valid not only for a switch mode power supply baut also for e.g. a linear power supply. Only the efficiency of a linear power supply is typically much less than 0.8.

#### Delta Prime

Jul 29, 2020
2,265
on paper yes in reality no for reliability even with forced air I would exceed the minimum requirements therefore this is a matter of opinion

#### Delta Prime

Jul 29, 2020
2,265
Wait a second are you a bot what's square root of 37

#### Harald Kapp

##### Moderator
Moderator
Nov 17, 2011
13,834
And the square root of 37 is somewhere near 6.08276...

Jul 29, 2020
2,265
Good night sir.

#### Harald Kapp

##### Moderator
Moderator
Nov 17, 2011
13,834
Just take a peek at the op's images. The first one shows the power supply for 1 projector stating 100 V - 240 V, 0.7 A max. Output being 12 V 2 A.
So definitely Iout > Iin

Moderator
Nov 17, 2011
13,834

#### Delta Prime

Jul 29, 2020
2,265
you're outlet 240 volt 50 Hz must be able to handle 32 amps and I would not run it at maximum being your circuit breaker must be more than 32 amps along with your conductors, the Gage of wires used in the circuit must be able to handle far more than 32 amps for safety. I
I see it now Oopsie Daisy
You're never in any harm forget about that part. You're okay. But for everything else I win. Nighty night

#### Delta Prime

Jul 29, 2020
2,265
So definitely Iout > Iin
All right I see where I went ( down under).
I suppose the next thing you're going to tell me is that when you flush your toilet in Australia the water rotates counterclockwise

#### Bluejets

Oct 5, 2014
7,144
All right I see where I went ( down under).
I suppose the next thing you're going to tell me is that when you flush your toilet in Australia the water rotates counterclockwise
Well, actually, if you use one of the units from Thailand, (commonly known as swirl-flush) ....then yes they do.

The coriolis effect on the other hand which is what you probably meant to refer to cannot influence the rotation either way as the orifice (amoungst other things) is simply not large enough and there is not enough wind or temperature influence no matter how much you can fart.

Best you get an education before you open your gob in future.
(commonly known as put the brain in gear before opening the gob)

Apologies for the off-topic Mr. Moderator, this just became too much................

#### Delta Prime

Jul 29, 2020
2,265
Apologies for the off-topic Mr. Moderator, this just became too much................
No apologies necessary that was a good one!
I like your style. No harm no foul.
Thank you for taking the time.
Time becomes more precious when there's less of it.

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