# How can I reduce 3A down to 1A?

I am finishing up my quadcopter build, but forgot to buy an UBEC. My ESCs are OPTO, a fact I unfortunately did not realize until I had bought them. So, I am attempting to design my own circuit to reduce the 11V 3A battery I have down to 5V 1A for my receiver and flight controller board. So my question is this: can I use a simple 5V regulator to reduce the voltage and amperage? Or will 3 amps going into the circuit fry the regulator? I read that putting 2 regulators in parallel will increase current; however, I believe that is only for the output of current from the regulator(s). Any and all help is appreciated!! Thanks in advance!

2 years ago

All you need is to regulate the 11V down to 5V, the current will take care of itself. If the 5V circuit is only going to draw 1A, then you will be OK. Using a linear regulator though, and it will get VERY hot. You will have to fit a heatsink to it.

thank you so much!

2 years ago

Yhea, No worries about the current; your device will draw only the current it needs. you definitely want a regulator like steve suggested. I believe he was talking about the LM-7805 ( 5v @ 1A ) In theory this works, but at 1A you are basically maxing out what it can do; hence the massive heat sink.

Try finding a LM-1084 (Adjustable V @5A) It is also available in fixed 3.3,5 and 12v. I always keep a few of these around. Anything that draws over 750 ma I will usually use these purely for heat management. If you buy the adjustable one, it give you some options for other projects. All you need is a few resistors to change the output voltage, Or make a constant current supply. you can search Google for "LM-317 calculator." The 317 uses the same calculations.

Even If you don't need the extra current, it will drastically reduce the heat coming off of it. and even though it is rated for 5A, and your batt is 3A (did you mean 3AH?), it will only take what you project needs. Check out the Diagram, let me know if you need anything :P