Do i lose or gain amps when converting 12v 10a to 5v

Using Arduino Motors, Mechanics, Power and CNC
1

Hello, I am trying to power some long 5v LED strips (https://www.amazon.com/gp/product/B01CDTEG1O/ref=ox_sc_act_title_1?smid=A35UAT07QG3EC6&th=1) and what to use a 12v 10a power supply. I want to convert the 12v 10 amps to 5v. Do I loss or gain amps when converting from a higher voltage to a lower one? Thanks.

2

You loose some energy because no converter is free from losses, but they are usually small.
When the converter runs from the input source and provides the output Amps, and voltage, required, You are safe.

3

12V * 10A = 120 Watts, 120W / 5V = 24A * efficiency. If efficiency = 95%, 24 * 95 / 100 = 22.8A.

4

Why not use a 5v power supply directly ?

5

@LarryD, I would, but I already have a small size 12v 10 amp power supply brick.

6

And how are you going to go from 12v to 5v ?

7

@LarryD, I will probably use something like this https://www.amazon.com/Converter-DROK-Adjustable-Regulator-Indicator/dp/B00HHQ0VP4/ref=sr_1_10?crid=2GTQLE1BTEWGO&keywords=12v+to+5v+converter+20a&qid=1638578288&sprefix=12v+to+5v+20a%2Caps%2C208&sr=8-10.

8

Suggest to go straight to 5v from mains..

9

It should be able to do what you want. But note you are right at the max for the 12/5 converter. Typically these cheap converters have two issues.

  1. They "stretch" the specifications. So its more like a "hopeful" 20A.
  2. They can be electrically noisy.

But as long as you don't expect to operate the LED's at their Max you should be OK.

However I would suggest an alternate for your consideration:

Meanwell 5V 26A

Its a higher cost but:

  1. Meanwell has a good reputation of delivering what their specifications are stated at.
  2. Its UL approved.
  3. It provides you with all the current you require.
  4. It leaves your 12V available for other projects.
  5. It is in one package.
10

In a ideal world, you’ll get just over double the amps.

It comes down to finding the most efficient way of making the conversation.

11

Hi,
How many strips and what length?

Tom... :smiley: :+1: :coffee: :australia:

12

@TomGeorge, I'm using these lights https://www.amazon.com/gp/product/B01CDTEG1O/ref=ox_sc_act_title_1?smid=A35UAT07QG3EC6&th=1, they are 16.4ft and are 5v.

13

Hi,
90W per strip
P = V * I

I = P / V = 90 / 5 = 18A per strip.

How many strips?

Also note this;

  • The LEDs at the far end of the strip might be dimmer because of the added resistance and voltage drop that occurs during the current flows to that end of the strip. The solution is adding DC5V voltage every 16.4ft or 32ft according to the actual situation .

Tom... :smiley: :+1: :coffee: :australia:

14

@LarryD,

What would be the problems when stepping it down with a buck converter?

15

No problems.

However, it’s one less component that is not needed if you use a 5v supply directly.

16

You get max 8A according to the product page you linked

17

when you reduce voltage the current increases as with increasing voltage the current reduces. Ohms Law (P=VxI) cannot be broken, there will be losses whenever converting but that is because we are introducing Resistance where Power is lost in the form of heat.

18

Please rephrase.

19

That isn't Ohm's law, Ohm's law is E=IR.

20

Yes it is...

V=IR is the same equation as P=VI. Someone isn't up to speed with how algebra works. :laughing:

(edit - Seems that was me. :crazy_face: The formula for power bounced into my head and I was too quick to reply.)