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Need help getting started....

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So I now enough about electronics to know I dont know much. I've taken classes in hs and college a few years back, and I've played around to a very limited extent with the arduino and some simpler adafruit projects, just to get my solder skills honed.

Now, I want to dive in! I want to start my own project, and dot know where to begin! So this is where I wanna start. I want to take a 18v dewalt battery and hook a 120 cord to it, so I'd need to transform 120ac to 18vdc. Now how do I figure out what components I need, and is there any software out there to help me draw a schematic?

Thanks for reading

EvanTheElectrician
 
You will need an 18V DC power supply that puts out several amps. A 120V to 18V 8A transformer will not likely fit inside the battery pack. A line-powered switch mode power supply is probably beyond your experience. See if you can find a 15 to 18V switching power supply commonly used with a laptop computer. They are usually small enough...
 
Couldn't I salvage parts off of an extra battery charger?

No, because the current supplied by the charger is about 1/3 to 1/10 of what it takes to run the motor. The battery is what normally supplies the large peak current required to run the motor when it is heavily loaded (or stalled). The charger circuit is too whimpy for that.
 
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So would I be confused in thinking that the charger trickles power in to the battery. And the motor draws more than a trickle of power???

That'd explain why my grinder can kill a battery in 5 min, when it takes 60 to charge!


Ok, lets say I wanted to hook up a usb port to one of my batteries... I would need more than a resistor of the appropriate value to get the 18vdc down to 3.2vdc correct? Then amperage would be to high and fry my phone, or whatever I tried to charge of my bat?


Thanks again!
 
So would I be confused in thinking that the charger trickles power in to the battery. And the motor draws more than a trickle of power???

That'd explain why my grinder can kill a battery in 5 min, when it takes 60 to charge!

A "fast charger" puts out more than a "trickle", but still less than about 1/3 of what it takes to run the motor. A "trickle" is defined as about 1/20.... :)
Ok, lets say I wanted to hook up a usb port to one of my batteries... I would need more than a resistor of the appropriate value to get the 18vdc down to 3.2vdc correct? Then amperage would be to high and fry my phone, or whatever I tried to charge of my bat?

A USB port delivers 5.0V, not 3.2V. Yes, it would take a "regulator" to convert 18V to 5V, either a switch-mode buck converter or a linear regulator.
 
You're awesome. Im gonna start looking for parts.

I know about places like mouser digikey and sparkfun... But if theres anything else I should know!



Also, how did you first start to learn? Should I just take some classes at my local community college?
 
There's also Farnell and Digi-key for parts.

Classes? I'm having lectures on EE, last semester being my last and the lecturers don't mention practical projects thrice. The 'net provides better references, it's how I completed my full-fledged solid-state weather transmitter hardware thesis project.... through this forum. :)

This is just my opinion, but anyone starting out on electronics should start with PICs since they cover a lot of topics on electronics. Again, just my take.
 
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