What battery should use for 4wd robot

Other Hardware Motors, Mechanics, Power and CNC
1

Hey guys,

I try to create my first robot its a 4wd robot and I'm using a l298 dual drive for controlling motors.

For now my code work well on have robot on my hand the left and right motors are working as I expected, but on floors my wheel dont turn as expected now i'm using a pack of 8 AA alkaline batteries.

When I connect this to laptop recharger with output of 15v everything work well and fast :slight_smile: So I think maybe 8x1,5v are not enough to run robot as I want even with a output of 12v (8x1,5) I think i dont have enough amps?I'm think well?

Wich type and capacity I need in order to run this project?

Thanks for help

2

Looks like a good start!

Get out your trusty DMM and measure the average running current for the robot.

Multiply the average current in mA by the number of hours you want the robot to run to get the absolute minimum battery capacity in mAh (milliampere hours).

To be safe, use batteries with twice the calculated mAh capacity.

3

jremington:
Looks like a good start!

Get out your trusty DMM and measure the average running current for the robot.

Multiply the average current in mA by the number of hours you want the robot to run to get the absolute minimum battery capacity in mAh (milliampere hours).

To be safe, use batteries with twice the calculated mAh capacity.

Thanks for your quick answer.
I'm not a guy with much experience with this, how I can measure average running current?

My goal it's running this robot for a small amount of time let's say 15 minutes maximum however in the future I'll try mapping the environment and sent him back to the recharge when battery are low. I hope this is not too ambitious :slight_smile:

4

how I can measure average running current

If you don't have a DMM, now is the time to get one.

Use the current measuring function, starting with the 10 or 20 ampere range, and measure the battery current while the robot is moving normally.

5

jremington:
If you don't have a DMM, now is the time to get one.

Use the current measuring function, starting with the 10 or 20 ampere range, and measure the battery current while the robot is moving normally.

I've one, but don't have sure how measure the current?

I use DCV sector to measure the voltage I dont know where i can measuring the current? It's on DCA section?

https://scontent.flis2-1.fna.fbcdn.net/hphotos-xpl1/v/t34.0-12/12939100_1161667023851536_2390927_n.jpg?oh=93964f12f0906228566946cd414c6ffe&oe=56FED67A

So I need to connect DMM in series with battery circuit? Let's assume I'm using my laptop charger with 15v its useful for measure amps?

Thanks I really appreciate or help

6

jremington:
If you don't have a DMM, now is the time to get one.

Use the current measuring function, starting with the 10 or 20 ampere range, and measure the battery current while the robot is moving normally.

Hey I've create a sample about what you request me

That are correct? Is how i measure the current? So question is that is depending from batteries? Or depending what current dc motors are consuming? So this motor are cosuming about 0.85 amps? Is that rigth?

Thanks again

7

One of many, many tutorials: How to Use a Multimeter - SparkFun Learn

8

jremington:
One of many, many tutorials: How to Use a Multimeter - SparkFun Learn

Hey thanks for our help,

I've also follow this tutorial https://learn.sparkfun.com/tutorials/how-to-power-a-project

So in theory, I have this components :

Dc motors : 190mA no loaded and 250mA loaded lets say average 220ma
arduino : 20ma

total for my circuit is (220 * 4) + 20 = 900mA

I've read with DMM and average on my circuit is about 960mA proximally what I've calculated. That is correct?

9

Looks good!