# Converting 5V 2A to 20V 1.2A

Discussion in 'General Electronics Chat' started by LukeENG, Apr 30, 2018.

1. ### LukeENG Thread Starter New Member

Apr 30, 2018
2
0
Hi all,

I am planning on building a circuit that convert the output of my portable charger (5V 2A) to charge by portable speaker (20V 1.2A)

was hoping someone had done something similar or could help me

Thank you!

2. ### WBahn Moderator

Mar 31, 2012
23,396
7,101
So you want to take something that outputs at most 10 W of power and use it to charge something that requires 24 W of power?

3. ### LukeENG Thread Starter New Member

Apr 30, 2018
2
0

I believe so, yes

4. ### WBahn Moderator

Mar 31, 2012
23,396
7,101
If so, then what you are asking for can't be done. So don't waste your time trying. It's like saying that you have a water hose that outputs 10 gallons per minute and you want to know how to use it to fill your 50 gallon bathtub in 2 minutes.

5. ### Dodgydave AAC Fanatic!

Jun 22, 2012
7,655
1,272
You can get a DC to dc converter for 5 to 20V, but your current output will be less than 0.5A.

You won't get more out than you put in!!

6. ### ericgibbs Moderator

Jan 29, 2010
6,562
1,275
hi Luke,
As Dd says, 20V at ~0.5A, so to recharge a portable speaker 1.2Amp battery, approx (1.2A/0.5A) /0.7 ,would take 3.5Hrs.
E

Last edited: Apr 30, 2018
7. ### mcgyvr AAC Fanatic!

Oct 15, 2009
5,395
1,196
10 watts is all you have to work with..
Watts = Volts x Amps
So you can have 10V @1A or 1V @10A or 5V @2A but they all must equate to 10W and in the real life any conversion has some losses associated with it so you really have like 9.6W to work with or so..