Battery Power

[kevinisnekkid]

I know the common recommendations about batteries. "Keep motors & chips seperate"... The project I'm working on needs reliable power on both, and I would prefer if I can use a single battery (bank possibly). I'm looking into giving microcontroller brains to my full sized boat. The engine has a battery charging circuit for a 12v battery. Since I have a nice source of charging power, I would like to use that for the microcontroller circuits.

I will be using a SLA battery for main power to start the engine, and steer the boat. Should I use a seperate small battery for the microcontroller, and have the main battery keep it charged? Or can I just use a voltage regulator for the small electronics?

-Kevin

[Rebelgium]

Do you know how a car shuts off a your radio and other electric appliances when you start the car? That's because the startermotor draws so much current that the voltage of the SLA battery drops...
So I recommend a separate little battery for you MCU and other electronics.

[ArcMan]

I also prefer a single power source for my bots.  The key is to elimate as much noise as possible to the electronics.  I do that by passing through a diode, adding 1000 uF per amp of caps, and using the VR's recommended caps on the input and output.

[Admin]

How about this:
Connect your 12V battery to a separate smaller battery with a diode (forcing current only one way, and dropping the voltage a few volts). That way the smaller battery always gets charged, but doesn't drain when you use your boat.

[kevinisnekkid]

Admin,
  That's perfect! Why didn't I think of that? Thanks!

-Kevin