A 9v battery to power the Arduino and the 3 sensors
Four AA 1.2v rechargeable batteries to power the 4 motors
The problem is that the car runs very slow and weak.
My first thought is that the 4.8V I am supplying to the 4 motors means that each motor gets 1.2V, which is well below the minimum 3V they require. However I get confused when I see tutorials like this one (How To Make A Simple DIY Arduino Bluetooth Controlled Car At Home - YouTube) where they power 4 motors with two 3.7V Li-ion batteries, which means that each motor gets about 1.85V, which is still below the 3V minimum.
Am I understanding this right? If so, could I use two or four 18650 Li-ion Rechargeable Battery 3.7V 5000mAh (like this one Amazon.ca)? Are there better options?
I'm happy to post a diagram, the code or a video showing how the car runs.
To get any help at all, you must show a wiring diagram showing how you have the car wired and include the batteries. A block diagram would be fine to begin with.
What happens when you use more powerful batteries?
The OSEPP motor shield uses the ancient, inefficient and very weak L293D motor drivers, which waste most of the battery power. You will need at least 8xAA batteries to get useful power to the motors, and then, the driver might overheat and shut down.
Pololu has a good selection of modern motor drivers. This one works well for small motors.
Post a circuit diagram showing how you intend to wire the motors. This implies you are wiring them in series, which will not work well, and is not correct in any case with the motor driver you have.
the 4.8V I am supplying to the 4 motors means that each motor gets 1.2V
mbursztein:
My first thought is that the 4.8V I am supplying to the 4 motors means that each motor gets 1.2V, which is well below the minimum 3V they require. However I get confused when I see tutorials like this one (https://www.youtube.com/watch?v=Q36NbjPMV5k) where they power 4 motors with two 3.7V Li-ion batteries, which means that each motor gets about 1.85V, which is still below the 3V minimum.
Unless you are running your motors in series, another terrible idea at this point, your understanding is incorrect.
If you have a + terminal of a battery and each motor is supplied from the + terminal and each motor is connected to ground and the battery is 3.7V then each motor will be provided with 3.7V.
5000mAh Li batters at 4 for 25 CDN is a lie. Those batteries will not do the thing. Right now reliable Li sizes on Amazon are 3400mAh.
I'm was not confused when I made the post about running the Arduino and sensors on a 9V battery. It's a terrible idea, that you'll eventually figure out through experience.
Seems like NiMH sold as Li-ion, with Wh to confuse even more.
Definitely avoid that EBL brand.
Leo..
I don't know about that specific brand but there are now many commercially available 1.5V Li-ion batteries in AA and even AAA sizes. These contain standard voltage Li-ion cells plus a buck converter to get them down to 1.5V and apparently work well. I've not tried any yet at least partly because they're still expensive but I'd also expect that their current delivery capacity would depend on how efficient the converter was. But an interesting use of technology.
A neat idea, except that you will get no warning of it running low I suspect - they will suddenly turn off
without warning. That alone may be a deal breaker for many uses.
