Robot power question

Hello everyone!
I have a question about a robot I am currently in the design stage on. I have been monitoring the voltage requirements of the components I will be using and the amperes of each item. Currently, the project is going to require 3 seperate batteries, 6v, 9v, and 12v. The highest amperes needed are from the Sabertooth motor driver, 2x5 RC, requiring 5A continuous per channel, 10A peak. I was wondering if anyone has a suggestion, or schematic from a previous build, to create a board to supply each of the voltages from a single battery? I need to run a single 24v battery because of weight and space requirements.

My idea is to have either a 14.8, 18, or 24 volt battery which will then run through this board and supply 12v 10A (for the Sabertooth), 9v for both Lynxmotion’s Botboarduino and the SSC-32 (Both would need 35-50mA each), and 6v to run all the servos (Hitec servos - 3x HS-422, 3x HS-485HB, & 8x HS-645MG). I figured I would be safe with 12v 10A, 9v 1A, and 6v 5A.

So far, I have this in mind for the curcuit:
LM7809 for 9v (Mouser # 512-LM7809CT)
LM338T for 6v (Mouser # 926-LM338T/NOPB)
LM3150 for 12v 10A (Mouser # 926-LM338T/NOPB)

My only unknown is the LM3150. I personally have never used this chip. Is there another chip anyone would recommend to step-down the 24v to 12v 10A? Better yet, is there a different circuit anyone would recommend over this entirely? Any help, suggestions, tips would be greatly appreciated! If anyone needs any other information or has questions about my circuit I’ll be more than happy to answer. I’m really trying to get this circuit built fairly quickly to have it tested prior to installation.

Thank you! :smiley:

If you are going to do your own regulation and want to save power and run your circuitry in an optimal way, we recommend bypassing the on-board regulators for your microcontroller and other logical devices. Simply create a 5V signal using a 5V regulator and feed their logic supply directly.

It is easy to use a small switching regulator to generate 5V signals for logic supply, but it will be trickier if you want to regulate signals for motors. You will need much more current and thus your signal will generate lots of heat in your regulator. Please make sure the regulators are appropriately sized and that they use a heat-sink.

Also, it might be a good idea (and more efficient) to use motors that run at the nominal voltage of your battery instead of having to step down their voltage. Although we understand that hobby servos all run at around 6V.

Finally, for your choice of regulator, please make sure they can provide the desired output current at your desired voltage. Very often they rate the maximum current at the minimum voltage, which determines how much power (Watts) they can dissipate.