How to get 1 amp from a 10 amp battery.

Thread Starter

idrbur

Joined Jan 11, 2018
70
Right you are. TS needs to buy a "powerbank".

I was trying to get TS to understand the typical newbie question = How can I get 1A from a 10A battery?

TS needs to understand Ohm's Law and power consumption.

10A @ 5V = 50W

If I only take 1A @ 5V = 5W, where do the other 45W go?
(Question is for only TS to answer.)
Again, no idea
I have never understood the consept of current properly
 

MrChips

Joined Oct 2, 2009
35,180
Again, no idea
I have never understood the consept of current properly
Ok.

Learn Electricity 101 - Ohm's Law

There are three values:

Voltage V
Current I
Resistance R

These three are related using any one of the following mathematical formulae:

I = V / R
R = V / I
V = I x R



Keep this triangle in your head as a reference.
If you know any two of the three values, the third is fixed.
In other words, when one value is fixed the other two are interrelated, you cannot manipulate the remaining two values independently.


Now we introduce power.

P = I x I x R
P = V x V / R
P = I x V

Notice that power is determined by two of the first three values. We do not need to know the third value because once we set two values the third value is also set.

power wheel.png


When a battery outputs 10A @ 5V, the load R must be equal to V / I = 5V / 10A = 0.5Ω

Does your mobile phone look like a 0.5Ω load. No.

If your mobile phone takes 1A @ 5V, then R = 5V / 1A = 5Ω

See the difference?
 

BobTPH

Joined Jun 5, 2013
11,651
Yet you probably plug a phone charger that takes 50 mA into a wall socket that can provide 15A. Why doesn’t the phone charger blow up?

Bob
 
Top