Run 4 big 12V motors for water drone

General project help for Adafruit customers

Moderators: adafruit_support_bill, adafruit

Please be positive and constructive with your questions and comments.
Locked
User avatar
rokenbuzz
 
Posts: 26
Joined: Thu Jan 12, 2017 4:59 pm

Re: Run 4 big 12V motors for water drone

Post by rokenbuzz »

Technically it depends on the motor and maybe some other things I'm not really smart about. Like how quickly you can drain a battery without it overheating.
So are you back into the ROV project? What is your 12v motor for? What are the specs on it?

User avatar
rojithag
 
Posts: 86
Joined: Thu Aug 31, 2017 2:39 pm

Re: Run 4 big 12V motors for water drone

Post by rojithag »

Yeah so I'm asking because I wanted to order all my parts so that I could hook everything up. The motor is rated at 12v, 3.3A
The servo motors are 2.5v, 1.2A
The ultra sonic sensor is about 3.3v, 2A
All are estimates

User avatar
adafruit_support_bill
 
Posts: 88088
Joined: Sat Feb 07, 2009 10:11 am

Re: Run 4 big 12V motors for water drone

Post by adafruit_support_bill »

Lithium ion batteries are generally available in multiples of 3.7v. A single cell in series will put out between 3v and 4.2v depending on the charge level. But for most of the discharge period it will be pretty close to 3.7v. With 3 cells in series, the rated voltage will be 11.1v. That should be fine for your 12v motors.

To run the lower voltage sensors and servos, you will need to regulate the voltage to the appropriate level.
For your 3.3v sensor, you can use this: https://www.adafruit.com/product/1066
I'd double check your servo voltage requirements. I don't know of any rated for 2.5v. Most run on 4v-6v.

User avatar
rojithag
 
Posts: 86
Joined: Thu Aug 31, 2017 2:39 pm

Re: Run 4 big 12V motors for water drone

Post by rojithag »

You're right, So I have one 12V motor, the Pi, the Pi camera attached to the Pi, two servo motors both 5V, an ultra sonic sensor 5V, one pump at 5V and two other servo motors at 5V.

So is there any battery pack I can get to power all of this? How big should the battery be? (12V? 24V? or bigger)

I understand that I could use different chips available in adafruit to step down the power.
So i'm guessing if I go for like a 24V or greater voltage battery and step it down to smaller voltages using the chips everything might go well?

So my questions are basically
1) what single voltage battery could I buy for this?
2) what chips I need to buy to step the voltage/current down?
3) Could you link me to a battery I could buy please

Thanks

User avatar
adafruit_support_bill
 
Posts: 88088
Joined: Sat Feb 07, 2009 10:11 am

Re: Run 4 big 12V motors for water drone

Post by adafruit_support_bill »

Since your motors are your biggest load and are designed for 12v operation, I'd suggest either an 11.1v Lithium pack. or a 12v NiMH pack. Either one is rechargeable with the appropriate charger. We do not carry packs like these. But you can find them at Amazon, battery specialist sites, or sites that specialize in RC hobbies.

The 3.3v devices can run from the 3.3v buck converter linked above.
The 5v devices can run from a UBEC like this one: https://www.adafruit.com/product/1385

User avatar
rojithag
 
Posts: 86
Joined: Thu Aug 31, 2017 2:39 pm

Re: Run 4 big 12V motors for water drone

Post by rojithag »

Okay so my understanding now is that even though collectively all the voltages of the components added together is over 30+ volts I only need to consider what the biggest voltage drawing component is (which is the 12v motor) and get a single battery pack that can output 12V and then step down the voltage of this 12V battery pack to run the lower voltage components. Is that right?
Also why did you suggest a lower voltage than 12V? I would assume just get a battery pack that is directly 12V?

User avatar
adafruit_support_bill
 
Posts: 88088
Joined: Sat Feb 07, 2009 10:11 am

Re: Run 4 big 12V motors for water drone

Post by adafruit_support_bill »

get a single battery pack that can output 12V and then step down the voltage of this 12V battery pack to run the lower voltage components. Is that right?
Correct.

Code: Select all

Also why did you suggest a lower voltage than 12V? I would assume just get a battery pack that is directly 12V?
Lithium battery packs are always in multiples of 3.7v. So the closest to 12v would be 11.1v. At 11.1v, your motors will run about 8% slower than they will at 12v. But Lithium cells have a higher energy density so you will get a longer run-time from a smaller battery pack.

NiMH packs are always in multiples of 1.2v, so you can get a pack that is exactly 12v.

User avatar
rojithag
 
Posts: 86
Joined: Thu Aug 31, 2017 2:39 pm

Re: Run 4 big 12V motors for water drone

Post by rojithag »

Alright awesome. Which type of pack would you recommend for what I'm trying to do? The goal is to get a pack that will last long. So would Li-ion be the best? Thanks for all the help btw!

User avatar
rojithag
 
Posts: 86
Joined: Thu Aug 31, 2017 2:39 pm

Re: Run 4 big 12V motors for water drone

Post by rojithag »

Okay one more question, I want to buy a thing where I can put my three 3.7 V lithium ion batteries in.
Like a battery holder.
I want the holder to be able to charge the batteries inside it and also have an output for the batteries. I tried finding one but I couldn't.
Does anyone know anything that will do this?
I would really appreciate it.

User avatar
adafruit_support_bill
 
Posts: 88088
Joined: Sat Feb 07, 2009 10:11 am

Re: Run 4 big 12V motors for water drone

Post by adafruit_support_bill »

The goal is to get a pack that will last long. So would Li-ion be the best?
Lithium Ion would have the highest capacity per volume and per weight.
NiMH is a relatively close second. But it is less expensive and somewhat safer..
Okay one more question, I want to buy a thing where I can put my three 3.7 V lithium ion batteries in.
Do not attempt to make your own Lithium pack. It is not safe. Use a factory assembled 11.1v pack made from precision matched and balanced cells.

User avatar
rojithag
 
Posts: 86
Joined: Thu Aug 31, 2017 2:39 pm

Re: Run 4 big 12V motors for water drone

Post by rojithag »

Got it! Anyone product you would recommend?
Also do you have any knowledge on getting power from a USB port ?
If I tap into the red and black wires going into the USB port I should get my positive and negative terminals right?

User avatar
adafruit_support_bill
 
Posts: 88088
Joined: Sat Feb 07, 2009 10:11 am

Re: Run 4 big 12V motors for water drone

Post by adafruit_support_bill »

Got it! Anyone product you would recommend?
There are lots of good products out there. But you need to define your requirements:

* How much run-time per charge do you require?
* What is your estimated average current draw?
These two questions will help you determine the battery capacity you will require.

* What are the dimensions of the physical space available in the battery compartment?
* Are there any weight constraints on the battery payload?
Battery packs come in many form-factors. The answers to these questions will help you to select a pack that will fit into your drone.

Code: Select all

Also do you have any knowledge on getting power from a USB port ? 
If I tap into the red and black wires going into the USB port I should get my positive and negative terminals right?
that is correct. Most common USB ports are capable of supplying 500mA at 5v.

User avatar
rojithag
 
Posts: 86
Joined: Thu Aug 31, 2017 2:39 pm

Re: Run 4 big 12V motors for water drone

Post by rojithag »

I think I have the battery sorted out now.
The only thing I’m having problems with is the motor. I want to get a brushless motor as recommended in this thread, most brushless motors run at 18-24V and 30Amps his is a huge amp draw. I only have a 12V 9800mAh battery.
How would I step the current and volts up to run this motor?
Thanks!

User avatar
adafruit_support_bill
 
Posts: 88088
Joined: Sat Feb 07, 2009 10:11 am

Re: Run 4 big 12V motors for water drone

Post by adafruit_support_bill »

How would I step the current and volts up to run this motor?
By violating multiple laws of physics. Power is Volts times Amps. You cannot get more power out then what you put in. If you step up the Volts, you will get a proportional step-down in the Amps. That is the law.

Code: Select all

 most brushless motors run at 18-24V and 30Amps 
There are many smaller brushless motors available. For example, these are 12v @ 4-10A.
https://www.amazon.com/Hobbypower-1000k ... less+motor

User avatar
rojithag
 
Posts: 86
Joined: Thu Aug 31, 2017 2:39 pm

Re: Run 4 big 12V motors for water drone

Post by rojithag »

Damn I feel stupid haha. You’re right. So I’m going to go ahead and buy the one you suggested. Is my 3.6A motor driver enough to drive this?

Also is there any wiring diagram for that motor driver? I don’t know exactly where to connect the vcc and in0 and in1
I’m referring to the 3.6 motor driver that was recommended in this thread.

The wiring diagram is for an arduino, I can’t find the same pins on the PWM breakout version board.

Locked
Please be positive and constructive with your questions and comments.

Return to “General Project help”