Society of Robots - Robot Forum

Electronics => Electronics => Topic started by: Builder1 on September 03, 2008, 09:00:31 PM

Title: Car battery for power
Post by: Builder1 on September 03, 2008, 09:00:31 PM
Hello All,
I have told you in one of my posts that I was building a robot to patrol my property and for that reason it had to be able to navigate most any terrain. I have decided that it needs to be robust so that means it will have larger electric motors than most robots out there. Also, it would need a pretty large amount of energy to be able to operate for long periods of time. That is why I have decided to use car batteries for power.  I am using two electric motors for this robot, one for moving the rack and pinion gears to steer the front wheels and the other for driving the rear wheels. If I were to use a single car battery, how could I safely draw power from the battery for powering the wheels, steering, and powering the microcontroller? What would I have to use to lower the voltage so that the microcontroller and other small electronic components do not get fried?  Any suggestions will be greatly appeciated, thank you for your time.
Title: Re: Car battery for power
Post by: ArcMan on September 04, 2008, 08:50:12 AM
Hello All,
I have told you in one of my posts that I was building a robot to patrol my property and for that reason it had to be able to navigate most any terrain. I have decided that it needs to be robust so that means it will have larger electric motors than most robots out there. Also, it would need a pretty large amount of energy to be able to operate for long periods of time. That is why I have decided to use car batteries for power.  I am using two electric motors for this robot, one for moving the rack and pinion gears to steer the front wheels and the other for driving the rear wheels. If I were to use a single car battery, how could I safely draw power from the battery for powering the wheels, steering, and powering the microcontroller? What would I have to use to lower the voltage so that the microcontroller and other small electronic components do not get fried?  Any suggestions will be greatly appeciated, thank you for your time.

This advice has been stated many times in this forum, but I'll state it again...  It is not wise to use a car battery.  They can leak acid if tipped over, and they are not designed to handle repeated deep discharges.  Use a Sealed Lead Acid (SLA) battery instead.  They will not leak and are designed for repeated deep discharges.  I just bought 2 of them yesterday for my yard robot.  (32AH SLA).  They were about $69 apiece.  The 32AH and 33AH are used in electric scooters, so they're reasonably priced.
Title: Re: Car battery for power
Post by: Admin on September 06, 2008, 09:29:35 PM
If this is the case, you should use a separate smaller battery with a different voltage for the microcontroller. Microcontrollers draw almost no power at all, so a small battery will last forever.

Also, to control the motors, search for motor drivers.