Newbie... Need help with wiring kids car

[Thunderface]

I have a Kids Battery Powered vehicle I want to upgrade.

It is 12V & I want to convert it to run faster & for longer. I will use a Dewalt 20V battery to power it. I have purchased an adaptor with an inline 30a amp fuse for the battery. I also purchased a voltage controller to dial the speed of the motors as desired.

https://www.amazon.ca/gp/aw/d/B0995KCNB4/ref=ya_aw_od_pi?ie=UTF8&psc=1

https://www.amazon.ca/gp/aw/d/B08R7H4D3K/ref=ya_aw_od_pi?ie=UTF8&psc=1

As far I know this will work to speed up the motors. My concern is the electronics in the car. The lights & stereo. I would like them to continue to run on 12V. I've read that a buck converter could be used to drop down the voltage before it gets to the electronics. Something like this:

https://www.amazon.ca/gp/aw/d/B078Q1624B/ref=ox_sc_act_image_1?smid=AFHAE9RJVUMB&psc=1

or this

https://www.amazon.ca/gp/aw/d/B076H3XHXP/ref=ox_sc_saved_image_2?smid=A3JJM7S8SDXVXM&psc=1

But I don't know where to add this in the circuit.

From what I can see, the best place to put it is somewhere after this 7 pin connector coming from the main circuit board. Its where all electronics get powered from. Any thoughts how I can do this?

 

[barry]

First of all, running a 12V motor at nearly twice its rated voltage may make it run faster, but not for long.
And depending on the current draw,it might be easier to use a linear regulator to drop your 20V to 12V.

 

[Thunderface]

First of all, running a 12V motor at nearly twice its rated voltage may make it run faster, but not for long.
And depending on the current draw,it might be easier to use a linear regulator to drop your 20V to 12V.

Thanks for the quick reply Barry
I can get direct replacement motors that are rated for 24 volts instead of 12v. Would that solve that issue? Any thoughts about how to send extra voltage to the motors only & not the lights & radio?

 

[barry]

You can get a 12V motor that runs at 600 RPM or a 12V motor that runs at 2400 RPM. There is more to consider than voltage. I can give you a 12V motor that will run at 2400 RPM, but I guarantee it wont move your kid's car an inch.

 

[Thunderface]

You can get a 12V motor that runs at 600 RPM or a 12V motor that runs at 2400 RPM. There is more to consider than voltage. I can give you a 12V motor that will run at 2400 RPM, but I guarantee it wont move your kid's car an inch.

can we put aside the motor variables? haha do you know of a way to keep the electronics running at ~12v except the motors?

 

[KlausST]

Hi,

To step down from 20V to 12V:

There are ready to buy DCDC converters. In your case they are called "buck converter", or "step down converters".
Input: 20V battery. Mind the voltage may vary a lot: maybe 15V ... 22V. It depends on the battery type.
Output: 12V. To drive everything but the motor. You need to determine how much current these devices need maximum. Add some margin.
No need to be isolated.

Often made mistakes:
* mind to integrate "under discharge protection". Else leaving the car ON over night may kill your battery.
* wrong wiring of high currents and switched (motor) currents may cause a lot of trouble. From malfunction to EMI problems (in worst case it jamms emergency radio. Not very likely, though.)
* also be sure to use correct wire gauge, you don't want to be your child to be involved in a plastics car fire.

Klaus

 

[Thunderface]

Hi,

To step down from 20V to 12V:

There are ready to buy DCDC converters. In your case they are called "buck converter", or "step down converters".
Input: 20V battery. Mind the voltage may vary a lot: maybe 15V ... 22V. It depends on the battery type.
Output: 12V. To drive everything but the motor. You need to determine how much current these devices need maximum. Add some margin.
No need to be isolated.

Often made mistakes:
* mind to integrate "under discharge protection". Else leaving the car ON over night may kill your battery.
* wrong wiring of high currents and switched (motor) currents may cause a lot of trouble. From malfunction to EMI problems (in worst case it jamms emergency radio. Not very likely, though.)
* also be sure to use correct wire gauge, you don't want to be your child to be involved in a plastics car fire.

Klaus

Thank you for the reply Klaus

Where do put the buck converter to keep electronics (lights/radio) and motor voltage separate? How do I determine where to put the converter?

 

[KlausST]

Hi.

Are there options? ;-)

* common GND
* In: 20V battery
* out: 12V (line to all the 12V supplied devices)
So the converter is between 20V and 12V.

You definitely need to draw a sketch of your ideas. We will correct it, if necessary.

Professionals draw schematics and sketches ... although they have a clear idea in mind of how it should work.
Often hobbyists try to avoid it (generally, not personally you), but in my eyes it's more important for hobbyists to write the ideas down before they start to work. It's good to avoid mistakes, to be able to review the work after months, to communicate in a forum.

Klaus

 

[betwixt]

100% behind Klaus on this, knowing the problem is 90% of the way to finding a solution.

Basically what you need to do is isolate all the wiring that must run on 12V from the rest of the wiring that might have a higher voltage. Fit a 12V regulator between the higher voltage side and the 12V so the 12V remains constant as the other side might vary.

Brian.

 

[barry]

You need to know how much current the 12V circuitry draws in order to select the proper regulator.