Open Source Electric Supercharger

[neutron256]

Originally Posted by Wild Weasel

This is true... but I think it's exciting to see this sort of thing going on. For my part, I'll be very curious as to how this progresses.

Rob has put a lot of effort into the development, so I don't imagine he'd be terribly thrilled to see this DIY thing become a roaring success... but that's the nature of pretty much everything, isn't it? I actually think it's somewhat likely that the guys here start running into a number of pitfalls along the way that end up demonstrating what a good deal Rob's kit really is and showing that there's a bit more to this than slapping a few bits and pieces together and calling it a day.

I know I'm over-simplifying what you guys are up to, but you get the idea.

For what it's worth, I know there's instructions out there describing how to build your own somewhat basic but probably functional system, though without the advanced motor control that Rob has. I know this because I was asked to review them, probably with the end goal of an endorsement. In the end, I just kept quiet about the whole thing because, while it wasn't necessarily bad, I thought the actual work involved was well beyond the capabilities of pretty much any average DIY enthusiast.

The guys here will start discovering that as they go. I'm reasonably sure though that whether they end up with something that works well or not, a lot of people are going to have a lot of fun working on this.

Thanks for the words of support.

I agree and don't expect to have instant success building this. I'll be lucky if my first prototype has much effect at all and imagine I'll go through several versions assuming I can get it to work at all. As for Rob I think he's pretty safe. Even though a lot of the parts are off the shelf the few custom parts that are required are just not within most DIY'ers ability to fabricate.

I truly would love to see Phantom turnout an affordable kit and hopefully this thread will raise interest for it once it is available, and maybe even generate some good ideas that Rob can incorporate.

[neutron256]

Well after talking to some experts I'm less inclined to try and make my ultracapictor idea work. Not that it's not possible, just more complicated and bulkier then I originally thought. Plus I'm sure I can find something fun/useful to do with some huge ultra capacitors.

I'm not completely giving up on it but I'm going to put that on the back burner for now. So time to start looking at other battery options.

[Wild Weasel]

Originally Posted by neutron256

I'm not completely giving up on it but I'm going to put that on the back burner for now. So time to start looking at other battery options.

Have you considered using a couple of motorcycle batteries? Sometimes the simplest ideas are best...

[unijabnx2000]

or lawn mower batteries, they are like $20.

[neutron256]

Originally Posted by Wild Weasel

Have you considered using a couple of motorcycle batteries? Sometimes the simplest ideas are best...

Agreed, and for now I'll probably end up going with three 12V SLAs. The question now is what is the optimum size.

[neutron256]

So I've been thinking a lot this weekend about how to best setup the charging system. Last night it occurred to me that I'm really putting the cart before the horse by trying to design the whole system at once.

So for my first prototype I've decided to go with a hefty LiPo pack that I'll charge outside of the car and just hookup for testing/experimenting. This will also give me a good power source for design/testing off the car.

For testing I'll just locate the battery/controller setup in the passenger's footwell and run the connections to the motor/throttle sensor through the firewall. This will let me keep the battery from being exposed to the heat of the engine and allow me to keep an eye on it. Just to be on the safe side I think maybe I'll fabricated a battery box, and keep a fire extinguisher handy.

[jamesm]

Originally Posted by neutron256

So I've been thinking a lot this weekend about how to best setup the charging system. Last night it occurred to me that I'm really putting the cart before the horse by trying to design the whole system at once.

So for my first prototype I've decided to go with a hefty LiPo pack that I'll charge outside of the car and just hookup for testing/experimenting. This will also give me a good power source for design/testing off the car.

For testing I'll just locate the battery/controller setup in the passenger's footwell and run the connections to the motor/throttle sensor through the firewall. This will let me keep the battery from being exposed to the heat of the engine and allow me to keep an eye on it. Just to be on the safe side I think maybe I'll fabricated a battery box, and keep a fire extinguisher handy.

a fire extinguisher won't help. keep the batteries i a lipo sack.

[neutron256]

Originally Posted by jamesm

a fire extinguisher won't help. keep the batteries i a lipo sack.

The battery box would be the same idea to contain the battery if it goes into thermal runaway. The extinguisher would not be to put the battery out, but rather to put out anything else that might decide to light on fire.

I'm not that worried about thermal runaway since I'll be keeping well within the specs for the battery pack, but better safe then sorry.

Edit: But thanks for the suggestion. Good input.

[BRS]

Electrician reporting in.

I have been reading up since the a123 cell fad started.
All the information we need is provided by the RC hobbyists and electric motorcycle crowd in the last five years.

On the hobby side.
The larger RC planes have very high current, light weight AC motors. Seems to be perfect solution given we all want to shave pounds of our BRZ's
I have taken these motor apart and inside you find aluminium Neodymium and tolerances beyond belief. This is why you see big brush-less power in tiny motor packages.
Of course we are driving a greater load here, but we are still moving air.
The greatest part with these is the Controllers aspect. On the market today, for example, helicopters controllers. They have governor programming via USB. All plug and play. NAME your flavour.

Drawback of course is the massive heat produced from the controller and debris getting into unsealed ventilated motors. Remember, these are used to flying through the air where neither of which is a problem.

[neutron256]

Originally Posted by BRS

Electrician reporting in.

I have been reading up since the a123 cell fad started.
All the information we need is provided by the RC hobbyists and electric motorcycle crowd in the last five years.

On the hobby side.
The larger RC planes have very high current, light weight AC motors. Seems to be perfect solution given we all want to shave pounds of our BRZ's
I have taken these motor apart and inside you find aluminium Neodymium and tolerances beyond belief. This is why you see big brush-less power in tiny motor packages.
Of course we are driving a greater load here, but we are still moving air.
The greatest part with these is the Controllers aspect. On the market today, for example, helicopters controllers. They have governor programming via USB. All plug and play. NAME your flavour.

Drawback of course is the massive heat produced from the controller and debris getting into unsealed ventilated motors. Remember, these are used to flying through the air where neither of which is a problem.

Heat is my biggest conceren right now. Heat on the motor, speed controller, and batteries all of which don't react we'll when they get too hot.

The more I think about it the better sealed, water cooled RC boat motors sound.

[BRS]

An ideal motor would be one with a water jacket. Controller just needs a cute box/heat sinks properly sized and not too far from the motor. Motor leads must be as short as possible with PWM controllers. Lithium Phosphate do produce heat but they also lack performance at cold temperatures. Temperatures is the name of the game for reliability sake also for charge/discharge rates. You must also consider BMS, Low volt protection and cell balancing.

All in all, we need to mount low and where air can cool everything.


In this article are power requirements for a given CFM
http://www.turbomagazine.com/tech/04..._supercharger/

[neutron256]

More parts arrived!

-Compressor Housing & Wheel
-Motor
-Speed Controller
-Misc. Wires and Connectors.

I've already taken measurements for the compressor back plate, and 3D printed a test piece for fit testing. The fit is great, I'm going to tweak the size a little to see if I can get it closer, but it may be as good as its going to get.




Next step will be fitting the wheel to the motor shaft. This will be tricky, and where having a custom built motor would be really nice. It's an 8mm shaft and the wheel has a 6.5mm hole. It's critical to preserve the wheel balance so great care will need to be taken with any machining.

[Bigmaxy]

Bearing quality of the motor you choose should be a factor that you consider also. I have used Turnigy motors and Neu motors and the Neu are definitely a quality unit that are efficient and can spin happily at very high revs.
I've not used or researched the water cooled unit you have chosen though and Turnigy are getting better and better all the time so I'm definitely not saying anything bad about them. It could be an awesome choice.
As you know magnets don't like excessive heat either so a motor that is working in it's comfort zone will obviously prolong life. That water cooled jacket could be a good thing even though it adds a bit of complexity.
Good idea to give the charging system a miss for now also IMHO.
Great work!!

[FT_Monk]

How about using two big motors and gear it up to get the desired RPM. Big motor with lower speed has the torque to spin gears and draw less current.