The size of the project can really vary, but it’s quite a small one, and I don’t need it to be very powerful, just something that can move.
I am choosing the right battery and supply for this. First of all the ChatGPT said that if I want safer battery option, I should consider using NiMH battery packs, as their chemistry is a way more stable/safe they almost never run out fire or explode. While they are less performant, but should be ok for my task, as soon as I pick the RC battery pack something like this:
First of all, I want to double check if it’s indeed the case, and these NiMH batteries are safer than 18650?
If it’s the case I want to use:
Buck convertor to do the 7.2V-3.3V conversion using this module from 1. amazon.se.
Put the power directly to the TB6612, as I understand it can take up to 10V
Questions:
I see that battery above has the white socket, as I understand this is called Tamaiya socket? I wonder how can I connect this to a buck converter? Can you advise which socket I can buy to adapt it to my buck?
I need to use same battery to power both HBridge and Buck, should I use some splitter, or how it can be done?
Which charger should I use for battery above?
Chat GPT suggests to add some fuse after the battery, to prevent problems, can you advise me on that?
Is NiMH indeed safer, but still usable option for simple car (and maybe in future drone project)?
I am choosing the right battery and supply for this.
Since you have 3V motors and the C3 can be powered by 5V, it would make more sense to use a 4.8V NiMH pack. No need for a buck. Connect the battery directly to the C3 5V input and to the motor driver.
Most of those hobby motors will work fine on 4.8V.
this is true - their chemistry is more tolerant to overcharge, short circuits, and mechanical abuse. 18650 cells have much higher energy density so the consequences of internal failure, overcharge, overheating are more important.
There are also lots of poor poor-quality 18650 cells out there...
That’s something I was trying to get better. As I understand the 5V input has the voltage regulator, that as chat gpt suggests acts like a variable resistor that puts the extra voltage to heat. So the bot said buck (that does pwm) is a way better for battery.
Up to you, a little heat vs a more complicated design.
A buck will also generate heat and are you sure that less heat will actually be generated by the buck?
Let’s see how much heat we are talking about.
The regulator will drop 4.8V-3.3V = 1.5V
The ESP32C3 uses a max 87mA while receiving.
1.5V x 87mA = 130mW, a minuscule amount
Your motors will be generating much much much more heat than that.
Ok, I agree with you. Probably there is no guarantee that buck will consume less then 130mW. Even it it’s the case probably the win will not be noticeable. Thanks for advise!
Not really but if you are concerned that something inside the car could maybe come loose and could short out the batteries, then it’s a good idea to have one. I have a little hexapod toy I made with two servos powered by 4 NiMH batteries without a fuse and never had a problem.
You can add your own connector in parallel to the one that is already connected. This way you can power the board or motors etc. and still be able to charge it.
I seem to have an issue with my project and the esp32c3 super mini I have. I want to ask if it’s expected that the board is super super hot. E.g. I can’t even touch it. And it even before I have connected the motors with HBridge. So now I try to use the built in diode on it, and that’s it. However it’s being hot. I don’t think it was like this before.
Maybe I have managed to damage it somehow, as I wired it to HBridge, and than plugged into computer to program it. However the HBridge started running motors (probably because legs had high level :(). I have seen it restarted couple of times.
Than I have moved it out of the board, and tried to program first. However now it’s hot all the time. Could you advise what is the reason, and what I should do.
No. "Warm/hot" yes. Untouchably hot means too much current is flowing throught something, and the resistance (electrical friction) in the board is making it hot at the speed of light... internally burning something that once opposed electric flow, now is a closed/shorted conductor.
Depending on the wiring and the H-bridge, this might be one cause... to high a power demand.
That means it caused a power interruption with your computer, causing a re-boot. The SUPER MINI is damaged and dangerous to use (could destroy your computer USB).
You also mentioned using a breadboard. Verify that it is not burned (shorted or opened) due to motor power going through its connections.
I wonder how to avoid cases like this in the future. E.g. it sounds like I should never wire the HBridge when controller is connected via usbc to computer, as it would require big current (I saw these motors, would consume up to 0.5A in the normal operation).
No. Do not connect a battery to the supermini at the same time it is connected via USB. You can only have one connected at the same time, never both at the same time.
