# Why controllers are high price.



## TelnetManta (Jun 5, 2008)

Tommy,

I've watched your youtube videos and have to ask why you removed some of the controller build series? Did you change your mind about showing the controller build start to finish so that you could sell them yourself?

I think that the DIY EV market needs a controller "kit" so that those of us with the ability or lack of funds can build our own controllers while having the ability to tailor the voltage to our specific needs.

Ben


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## BridelessRacing (Aug 28, 2008)

I need a controller to handle between 96 and 120 volt. When can I have it and how much with and without the radiator kit?


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## Tommey Lee Reed (Sep 2, 2008)

TelnetManta said:


> Tommy,
> 
> I've watched your youtube videos and have to ask why you removed some of the controller build series? Did you change your mind about showing the controller build start to finish so that you could sell them yourself?
> 
> ...


Hi Ben,

I did show how to build a speed controller, and was willing to sell a kit.
I do think its best just to sell the complete controller with all the heat sink and water cool system, everyone kept asking about the heat sink and how to get them.

The first unit will be 120v 500amps with water cooled for about $800.00 on the market, but I have to first get backers to help in a company to sell on the market.
$800.00 is a lot for any controller, but is the cheaper then any other on the market to day.
The Gator water cooled will perfrom better then most controllers under high loads.

With less dollars and more sence, I do believe it will be a big name soon.
Gator Controller!!!!!!


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## TelnetManta (Jun 5, 2008)

I would imagine that you'll need to build a few and get them out in the "field" to prove your design before you'll get any bites on your investor search. If you need someone to road test one let me know 

Ben


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## judebert (Apr 16, 2008)

Otmar is far from greedy. His Zilla controllers are extremely good quality, and he provides outstanding customer service. He incorporated feedback from his community very quickly. His contributions have probably done more for EV awareness than any other person or product in history. 

He has posted multiple times on the EVDL on why the Zilla is priced as it is. I recommend that anyone interested in buying or building a high-quality controller should searching the archives for his posts. Some of his posts are quite relevant to anyone trying to start a business.

I look forward to your contributions, and buying your inexpensive 2000+A, 72V-156V controller. Until you have a going concern, I would recommend against making blanket statements that disrespect established members of the community.


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## TX_Dj (Jul 25, 2008)

Tommey,

If you need help proving the design in the "real world" to get investment backing, I'm sure there are some out there who would be willing to provide their vehicles as test beds for just that.

I'd have to imagine though, that they'd expect you to provide demo units as a "freebie with postage paid return" with "no obligation to buy" and "no liability for cost in the event of damage caused from operating within the design specification"... I.E. you providing units for free to those who are reputable and responsible...

IIRC, this is how Ot got started proving the Zilla controllers, by loaning design prototypes to people like John Wayland and letting "Plasma Boy" try to destroy them and/or refine them.

Like Jude pointed out, Ot has been very forthcoming as to why Zilla controllers are so expensive... and IMHO worth every penny, even if they're outside the scope of my budget.


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## frodus (Apr 12, 2008)

Tommy Reed returns! (this ought to be great ..... he'll just slam all the controller manufacturers to make his product sound great).

So far the spec of 120V and 500A for $800 seems pretty doable..... but is that 500A max? how long in minutes will it run at 500A? is there a programmable setpoint for current limit? How much amps can it run continuous? Is the water cooling isolated? 

From the video I saw, it looked like you took a Curtis controller and put your own stuff inside it... doesn't sound like you built much....


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## Tommey Lee Reed (Sep 2, 2008)

TX_Dj said:


> Tommey,
> 
> If you need help proving the design in the "real world" to get investment backing, I'm sure there are some out there who would be willing to provide their vehicles as test beds for just that.
> 
> ...


I have all the tester needed to put on you tube, as for Zilla's over price controller make no sence to me, people just want a controller that works for them. 
Anyone that thinks they need 2000 amps to dive on the road needs to rethink their EV, most EV will not need 1000 amps.
2000 amps is a waste of energy and just to show what not to buy, this is why most people won't buy a Zilla.
One more thing they burn up too! They have some problem with the hair ball, so really $4500.00 for a zilla does not mean its problem free.
I want the price to come down for speed controllers, the price have went sky high for one reason, and that is greed!


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## Tommey Lee Reed (Sep 2, 2008)

frodus said:


> Tommy Reed returns! (this ought to be great ..... he'll just slam all the controller manufacturers to make his product sound great).
> 
> So far the spec of 120V and 500A for $800 seems pretty doable..... but is that 500A max? how long in minutes will it run at 500A? is there a programmable setpoint for current limit? How much amps can it run continuous? Is the water cooling isolated?
> 
> From the video I saw, it looked like you took a Curtis controller and put your own stuff inside it... doesn't sound like you built much....


You have seen some of the curtis controller I rebuild for scooter and more.
But if you seen my other videos on the Gator controller that is built from the ground up then your will see how well its is.
I offer the only controller that will have a continuous load at 500 amps with water cooling, no other will offer that for the price.
Curtis 1231 will have 2 minute load for 500 amps, and othe much less like the kelly will not even get that high of output.
Kelly 144v 500amps will not allow you to go 450 amps, it will shut down or burn up what ever take place.
logisystem have made their controller like the Curtis system, that's a fact!


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## mark1030 (Jul 28, 2008)

Tommey Lee Reed said:


> I want the price to come down for speed controllers,


Why would you want that if you're selling a competing product?


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## Tommey Lee Reed (Sep 2, 2008)

mark1030 said:


> Why would you want that if you're selling a competing product?


Why not bring down the price?

This would allow more people to convert to ev, the US government you hate this to happen.
Companies charge this price to keep anyone to convert with a low income.

$800.00 is too much but will bring down the price on over price speed controllers, even Curtis 1231 is up to $1,700.00 because of Zilla not producing any more controller right now.

Those who like the price are those that sell them!


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## TX_Dj (Jul 25, 2008)

Tommey Lee Reed said:


> Anyone that thinks they need 2000 amps to dive on the road needs to rethink their EV, most EV will not need 1000 amps.
> 2000 amps is a waste of energy and just to show what not to buy, this is why most people won't buy a Zilla.


Right, most people won't buy a zilla, either due to price or no need for that much power output... however, the people who NEED a zilla will still buy one... those people being the majority of the serious contenders in NEDRA. Now, you may come back and say that NEDRA is a waste of resources- but they have undoubtedly provided more to squash the "slow golf cart" myth than any other entity in our hobby. Electric is the wave of the future in drag racing, and Zilla makes that possible.

No, I probably don't need 2000 Amps in my commuter vehicle- that's why I'll go with a 500 Amp controller. I can't even afford batteries that will supply the latter, let a lone the former... but if I could, I might just go with a Z1K for the same reason that someone might put a 500 horsepower engine in their car. Sometimes it's fun to "jump the gun" or make a little smoke, or squeeze your brain to the back of the brainpan.



> One more thing they burn up too! They have some problem with the hair ball, so really $4500.00 for a zilla does not mean its problem free.
> I want the price to come down for speed controllers, the price have went sky high for one reason, and that is greed!


If you're not breaking things, you're not racing. Slam away, Otmar has a fair price for what he produces, considering his ability to supply and the demand for the product. Basic economics.

If you can make a product that can compete with a Curtis 1231C for half the price with a proven track record that looks like it will remain a viable product line for half as long as Curtis has been around, then by all means, I might buy one...

Otherwise- bashing the so-called "competition" for your vaporware is unprofessional and I dare say unwelcome... Bring a tangible product to market. Let the consumer draw their own comparison and either bash your equipment or your competitors... But all I see is a "promise" and negative comments about the people who actually have a product on market today...


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## frodus (Apr 12, 2008)

500A continuous.... Do you have proof of that? or are you just talking up your controller like you did 6 months ago on EVDL?

What about scope screenshots/pictures... What Temp are the parts rated for? What are you using for a load?

Or how about you post a 10-15 min video on youtube of your controller running 500A continuous.


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## mark1030 (Jul 28, 2008)

Tommey Lee Reed said:


> Why not bring down the price?
> 
> This would allow more people to convert to ev, the US government you hate this to happen.
> Companies charge this price to keep anyone to convert with a low income.
> ...


You're still not making sense to me. Why would you care what everybody else charges for their controllers? If you can sell a better controller for less than anybody else, why would anybody buy one from the other guys? And if everybody chooses to buy your controller, what difference does it make what the other guys charge?


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## frodus (Apr 12, 2008)

Just do a search on www.evdl.org for "tommey reed" and read a little bit....

thats all he does is slam people and quote some high current numbers and still doesn't have a viable product NOR a cutsheet with current/time and temp rise/time.


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## Bowser330 (Jun 15, 2008)

Lets not get all judgemental on how tommy has been and thus fall into doing the same ourselves....

Tommy, Please make some prototypes and get them running. You might even want to sponsor someone on the boards who has a build and supply them the controller...The testimonials from these members will get other people interested in your product. Like others have said it will be tough to get funding upfront...

I applaud you for creating a controller for a lower price. You really are doing a service to the industry/cause. Just try to concentrate on your product more than other products...so we can see what you can do...


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## Guest (Sep 29, 2008)

Don't be so quick there my friend. We know Tommey and what he has done. Check youtube for all his stuff. You will then change your mind. I will let his stuff change your mind. : )

You will see! 




Bowser330 said:


> Lets not get all judgemental on how tommy has been and thus fall into doing the same ourselves....
> 
> Tommy, Please make some prototypes and get them running. You might even want to sponsor someone on the boards who has a build and supply them the controller...The testimonials from these members will get other people interested in your product. Like others have said it will be tough to get funding upfront...
> 
> I applaud you for creating a controller for a lower price. You really are doing a service to the industry/cause. Just try to concentrate on your product more than other products...so we can see what you can do...


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## Madmac (Mar 14, 2008)

At $800 you will make the same amount of profit as any of the well known names. The difference is you do not supply any of the hidden advantages.

You will not be insured, as the designer you could be sued if the motor control fails and results in death, the customer will end up having no support from the product insurance company. You will almost certainly vanish if legal action threatened to bankrupt you.

You will not put the unit though EMC emission and sensitivity testing. You will not be able to legally sell into Europe, if you do the product can be impounded and the customer looses out. Not sure of legal requirements to sell into the US market for a product like this.

You will not have the resources to make sure that any design error does not cause long term failure. Many products get placed on the market only to fail 9 months to a year down the road as one or more components is being stressed for a very short period of time.

Lastly as noticed in another thread on this forum you would expect the designer to choose parts suitable to do the job not something that is very cheap and will work but with a wide range, your 500 Amp current limit is likely to be anywhere between 300 and 700 amps. The devil is in the detail on designs like these.


You could of course sell as a kit and then the legal responsibility rests with the kit builder.

Madmac


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## jamesweirick5 (Jul 26, 2007)

Tommey Lee Reed said:


> You have seen some of the curtis controller I rebuild for scooter and more.
> But if you seen my other videos on the Gator controller that is built from the ground up then your will see how well its is.
> I offer the only controller that will have a continuous load at 500 amps with water cooling, no other will offer that for the price.
> Curtis 1231 will have 2 minute load for 500 amps, and othe much less like the kelly will not even get that high of output.
> ...


Where are your videos posted?


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## PStechPaul (May 1, 2012)

This is a very old thread. I think this product has fizzled. His website has been suspended:
www.rotarypistonengine.com 

Here are some links:
http://peswiki.com/index.php/Directory:Tommey_Reed_External_Combustion_Engine
http://dreamer3000.wordpress.com/tommy-lee-reed-circual-vaned-engine/

I didn't like his attitude, and his language skills were sorely lacking. I think he was blowing smoke. You can build a motor controller for cheap. But to build a good one, that you can support, takes a lot of good design work, testing, and infrastructure. I manufacture a product that I can build for about $500, and I sell the package for $3995 list. But it was several years of engineering and it fills a need for which my customers are willing to pay. And I offer many discounts, and quick effective support, which my customers appreciate. Many of them have been using my previous product for 10 years or more, and I support them as well. The website for my product is:
www.ortmaster.com


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## MPaulHolmes (Feb 23, 2008)

I do a $600 motor controller kit for the last few years, and I'm making a killing! Anywhere from $100-$300 take home per month! LOL. I really understand why companies charge what they charge. If I had an employee, I'd be making like negative $3000 per month. The only way I can keep doing it is to have a separate job that pays all the bills. If I raised the price, no one would get it. If I lowered the price, I would officially be working for free.


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## jamesweirick5 (Jul 26, 2007)

MPaulHolmes said:


> I do a $600 motor controller kit for the last few years, and I'm making a killing! Anywhere from $100-$300 take home per month! LOL. I really understand why companies charge what they charge. If I had an employee, I'd be making like negative $3000 per month. The only way I can keep doing it is to have a separate job that pays all the bills. If I raised the price, no one would get it. If I lowered the price, I would officially be working for free.


Does anyone have any simple pwm controller designs to copy. I need current limit and maybe ramp up speed. The 555 timers start at 10% and go to 90%. I think I need 0% - 100%. I want to start with a basic solid simple tested design.


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## PStechPaul (May 1, 2012)

jamesweirick5 said:


> Does anyone have any simple pwm controller designs to copy. I need current limit and maybe ramp up speed. The 555 timers start at 10% and go to 90%. I think I need 0% - 100%. I want to start with a basic solid simple tested design.


Actually, if you need a design to copy, you should not be attempting a DIY project at this level. There are many good controllers available at fairly reasonable cost, and any money over what a full DIY design is well spent for the engineering, safety, and reliability of the design. 

For what you want, a PIC or Arduino or other microcomputer is ideal. The design is very simple, in theory, and parts are inexpensive, but "the devil is in the details". You may want to search this forum for others who have built home-made controllers and have had all kinds of failures. You will probably need to spend $5000 or more just for batteries, so another one or two thousand for the motor and controller is a small part of the equation.


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## Arlo (Dec 27, 2009)

MPaulHolmes said:


> I do a $600 motor controller kit for the last few years, and I'm making a killing! Anywhere from $100-$300 take home per month! LOL. I really understand why companies charge what they charge. If I had an employee, I'd be making like negative $3000 per month. The only way I can keep doing it is to have a separate job that pays all the bills. If I raised the price, no one would get it. If I lowered the price, I would officially be working for free.


 Paul you know what its like lol. 

I'm in the middle of my 100kw bldc controller build and my cost on the parts is 600-800$ plus the 60-80 hours to build it. 

Now that can be reduced if you order more parts at once to get the cost per item down and design it so some china company can assemble it or part of it but you still have to remember you need to pay your self back for r&d and you need to cover incidentals like if "Johny lets get my car done fast" buys one from you and hooks it up wrong and pops it but lies to you about what happened and you warranty it... and other possible warranty possible law suits etc. You cant do this to cheep or its just not worth it.

The good news is as more people build them the price will come down! 
And companys like IXYS or IR are working to make better/cheeper componets all the time!


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## Sunking (Aug 10, 2009)

Tommey Lee Reed said:


> Speed controllr have been high in price for one reason, greed!


I know this is an old thread but that is just a silly statement. It is about supply and demand. Speed controllers are a niche market with almost no demand, so they are still considered a Custom Product. It cost a lot to build 100 units if even that many per year. Build 1,000,000/year and the price drops 75%.


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## Tesseract (Sep 27, 2008)

jamesweirick5 said:


> Does anyone have any simple pwm controller designs to copy...


Just get yourself a UC3842 current-mode control IC and have it control output current via feedback from a Hall effect transducer. Add a suitable MOSFET gate driver IC and off you go.

Just don't forget that Natural Selection is always working for the good of the species...




Sunking said:


> I know this is an old thread but that is just a silly statement. It is about supply and demand. Speed controllers are a niche market with almost no demand, so they are still considered a Custom Product. It cost a lot to build 100 units if even that many per year. Build 1,000,000/year and the price drops 75%.


Yep, though I hasten to add that the prices for some of the products aimed at the DIY EV market are often barely higher than the parts cost despite the very low sales volumes. The combination of low pricing and low volume definitely has a chilling effect on innovation...


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## jamesweirick5 (Jul 26, 2007)

Tesseract said:


> Just get yourself a UC3842 current-mode control IC and have it control output current via feedback from a Hall effect transducer. Add a suitable MOSFET gate driver IC and off you go.
> 
> Just don't forget that Natural Selection is always working for the good of the species...
> 
> ...


Sounds good. The UC3842 has 100% duty cycle (I think it needs it). Do you know of any circuit diagrams or controllers using it that I can copy?


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## Tesseract (Sep 27, 2008)

jamesweirick5 said:


> Sounds good. The UC3842 has 100% duty cycle (I think it needs it). Do you know of any circuit diagrams or controllers using it that I can copy?


You could try reading the datasheet... If you want me to design something for you my rate for such engineering services is a very reasonable $80/hr + materials and expenses.


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## TheSGC (Nov 15, 2007)

Tesseract said:


> You could try reading the datasheet... If you want me to design something for you my rate for such engineering services is a very reasonable $80/hr + materials and expenses.


You should charge more, I'm $125/hr + materials up here in New England.

As an engineer I expect a controller or other devices to cost 3-5x the cost of materials or more in mass production. I run a prototyping business where the development of say a DC controller would be close to $20k in my books, AC controller closer to $35k most likely. I primarily design medical devices but and AC inverter is on the menu when I get free time.


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## mizlplix (May 1, 2011)

I don't really know this Tommy fellow, but his inability to express himself in any literate fashion has me doubting his engineering skills also.

Internet boasting and dissing has become a good way to lose any credibility you may have had also.(for anyone)

Miz


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## Tesseract (Sep 27, 2008)

TheSGC said:


> You should charge more, I'm $125/hr + materials up here in New England.


Oh, yeah, I know my hourly rate is low, hence why I described it as "very reasonable"... 

Now if you want to hire "Evnetics" to design something, rather than just me, then the rate is $150/hr + materials. But now you've got an embedded systems programmer and 3D mechanical cad/fabrication services at your disposal. And this is not a pie-in-the-sky number: we've actually done some contract design work.



TheSGC said:


> As an engineer I expect a controller or other devices to cost 3-5x the cost of materials or more in mass production....


Yep, pricing an electronic product at a minimum of 3-5x parts cost is the same rule of thumb I've tried to follow in the past. You may infer something about the pricing of our controllers from that last qualifying clause...


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## Stiive (Nov 22, 2008)

TheSGC said:


> As an engineer I expect a controller or other devices to cost 3-5x the cost of materials or more in mass production. I run a prototyping business where the development of say a DC controller would be close to $20k in my books, AC controller closer to $35k most likely. I primarily design medical devices but and AC inverter is on the menu when I get free time.


What your describing is not really DIY anymore... You should be developing for the love of the game, not to make money. The DIY market is too small to make any serious coin.

FWIW the cost of components on my board is about $550 including a $100 touch screen (+ $100k worth of development time ). Granted that's only good for ~30kW using the onboard VSI, but i've got plenty of larger IGBTs lying around too. Therefore you could easily make a 150kW version for under a grand (considering ~$200 per dual IGBT).
I wouldn't bother trying to make a business out of selling these, id never get my time back in moneys worth, however I have organised to give a few away at cost - seems such a waste otherwise.


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## Qer (May 7, 2008)

Stiive said:


> What your describing is not really DIY anymore...


Oh please, that's a load of BS. So you've done your own controller? Good for you. Did you also build the charger yourself? The DC/DC? The batteries? The motor mounts? The motor itself? Wound your own cables? Mold your own transistors? ...no? Why not?

Then I guess that with your own reasoning, you're not really DIY anymore...



Stiive said:


> You should be developing for the love of the game, not to make money.


Yeeeeeah, that was fun the first few years but it gets old after a while. Especially when some (mostly "potential" though, with few exceptions those that pony up are genuine) customers expect premium service and support but only want to pay DIY prices.

We've both seen exactly how pissed off people are in this forum when their precious cheapass bargain controller, charger or whatever blows up. If you want nice things you'll have to pay for them because quality cost to construct and produce. If you're too cheap to pay for the good stuff, things blow up. If you don't want to pay in green ones you'll have to pay with your own time and efforts but then the risks are bigger too since even a minor mistake quickly can get costly when the magic smoke sneaks out.



Stiive said:


> The DIY market is too small to make any serious coin.


You got that right anyway. And to be honest, the prices I've seen from all serious manufacturers that sell towards DIYers is a "love price". The same kind of hardware aimed at, for example, the industry tends to cost a whole lot more. Unfortunately that stack of bills I get at the end of each month doesn't have a "DIY setting" that will make them pay themselves. When I at the same time hear this whining that everything's too expensive is when that "love" starts to fizzle a bit...

I can't force anyone to pony up, that's fine with me. You want to DIY your own controller, admirable. You actually manage to get it to run and work reliable? Impressive!

But whining? Not really impressive.


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## Stiive (Nov 22, 2008)

Qer said:


> Oh please, that's a load of BS. So you've done your own controller? Good for you. Did you also build the charger yourself? The DC/DC? The batteries? The motor mounts? The motor itself? Wound your own cables? Mold your own transistors? ...no? Why not?


Why not? Because I'm not building nor planning converting an electric car. But that's not what I was saying, its not DIY because he's not doing it himself - he is, its not DIY because he would be designing it with a business mentally with the intent to sell.



Qer said:


> Yeeeeeah, that was fun the first few years but it gets old after a while. Especially when some (mostly "potential" though, with few exceptions those that pony up are genuine) customers expect premium service and support but only want to pay DIY prices.


Again, this is only if he's designing it with the intent to sell it, ie not a DIY project. It seems you have had a bad experience trying to sell to DIY'ers, perhaps you should also be encouraging against this?



Qer said:


> We've both seen exactly how pissed off people are in this forum when their precious cheapass bargain controller, charger or whatever blows up. If you want nice things you'll have to pay for them because quality cost to construct and produce. If you're too cheap to pay for the good stuff, things blow up. If you don't want to pay in green ones you'll have to pay with your own time and efforts but then the risks are bigger too since even a minor mistake quickly can get costly when the magic smoke sneaks out.


Indeed I've got nothing against the DIY support market industry. They make some fine products. 
A DIY project will as you say have issues, but are you saying theSGC could not build a commercial product of any quality to sell if he chose to?




Qer said:


> You got that right anyway. And to be honest, the prices I've seen from all serious manufacturers that sell towards DIYers is a "love price". The same kind of hardware aimed at, for example, the industry tends to cost a whole lot more. Unfortunately that stack of bills I get at the end of each month doesn't have a "DIY setting" that will make them pay themselves. When I at the same time hear this whining that everything's too expensive is when that "love" starts to fizzle a bit...


Yup, exactly why if he does chose to make his own controller, he should do it for the love and experience, not as a business model in an already saturated market. At the end of the day its his choice though, not that he sounded too serious anyway, and your response has blown this way out of proportion.



Qer said:


> I can't force anyone to pony up, that's fine with me. You want to DIY your own controller, admirable. You actually manage to get it to run and work reliable? Impressive!


Cheers, thanks.




Qer said:


> But whining? Not really impressive.


I really dont know how you can refer to my post as 'whining'. If anything, your rant comes fairly close.

Now untie your panties and shake hands


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## PStechPaul (May 1, 2012)

Amen! That post came out of nowhere and surprised me! I get what he is saying, but he took it a bit too far, IMHO. The idea of DIY is the learning process and the thrill of being able to say, "I built that", but in reality all of us are standing on the shoulders of giants who paved the way to our success by their great accomplishments. I do find it odd when someone asks for a "by the numbers" schematic and plans "to copy", and fairly obviously not willing to invest the time and effort to read and understand the basics of a controller. 

It is really amazing that so many people here, and on other forums and newsgroups, freely give of their time and considerable experience to those who are just learning. But in some cases people just want the quickest, cheapest way to get something done, or even to profit from the efforts of others without giving them the proper attribution or reasonable financial remuneration.


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## Tesseract (Sep 27, 2008)

Stiive said:


> What your describing is not really DIY anymore... You should be developing for the love of the game, not to make money. The DIY market is too small to make any serious coin....





Qer said:


> Oh please, that's a load of BS. So you've done your own controller? Good for you. Did you also build the charger yourself? The DC/DC? The batteries? The motor mounts? The motor itself? Wound your own cables? Mold your own transistors? ...no? Why not?
> 
> Then I guess that with your own reasoning, you're not really DIY anymore...


I think there might be some misunderstanding here on Swedish Programmer Dude's part... I believe what Stiive was saying to theSGC in the former of the two quotes above is that he should make an inverter for himself because it will be a "fun" project (if you are the type that considers elective dentistry without anesthetic "relaxing" then I suppose developing an inverter on your own might could be considered "fun" ).

Stiive also pointed out that the DIY market is too small to justify the development of an inverter as a proper product, which is more or less what I say every time someone here asks when we (Evnetics) are going to develop one. Indeed, I suspect that if/when we develop an inverter it will be for some other application/market first, and only later be adapted to DIY EV use.

So, uh, Qer... I think you might have misread this one.


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## TheSGC (Nov 15, 2007)

Wow, let me clear some things up...

I gave quotes on if someone *asked* me to design and build such a controller as a business contract. People keep complaining that controllers are expensive and I was trying to backup the reasons for manufacturer's price...

In reality I'd just do it as a "fun" project, I have a Solectria ACgtx20 motor sitting in my basement that I'd like to use for something someday and it needs an inverter.


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## Arlo (Dec 27, 2009)

Tesseract said:


> Just get yourself a UC3842 current-mode control IC and have it control output current via feedback from a Hall effect transducer. Add a suitable MOSFET gate driver IC and off you go.
> 
> Just don't forget that Natural Selection is always working for the good of the species...
> 
> ...


 Tesseract. I do a drag race hi program and I would like to make a cheep crude brushed controller for a 24v bar-stool we have. I looked at the data sheet and cant see a Throttle or pot input for the UC3842 would you just tie that into the current output??


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## PStechPaul (May 1, 2012)

The UC3842 and UCC38C42 are designed for switchmode power supplies using PWM and current mode, which means cycle by cycle current sensing and limiting. But it might be adapted as a direct duty-cycle controller using a variable reference from a pot. Here are the data sheets and application notes:
http://www.ti.com/lit/ds/symlink/uc3842.pdf
http://www.ti.com/lit/an/slua257/slua257.pdf
http://www.ti.com/lit/an/slva059a/slva059a.pdf

Maybe someone can supply an exact schematic and design advice for using this IC, but I would urge you to use something designed for the purpose, such as this IC from TI:
http://www.ti.com/lit/ds/symlink/tpic2101.pdf
http://www.nxp.com/documents/application_note/AN10513.pdf

The last link from NXP shows schematics for full H-bridge as well as half-bridge for unidirectional control like most EV controllers.

But I would suggest using a PIC such as the PIC16F684:
http://www.microchip.com/stellent/idcplg?IdcService=SS_GET_PAGE&nodeId=1824&appnote=en012134

With a microcontroller, you can design the hardware just once, and then reprogram it to whatever specific function and performance you like.

Unless you really _really_ want to build this yourself, I would suggest a ready made PWM control which you can get from eBay for about $16 including shipping:
http://www.ebay.com/itm/5A-DC-Motor...ule-DIY-MCU-Robot-Regulator-NEW-/320909883443

or even $10 or less:
http://www.ebay.com/itm/New-12V-40V...M-DC-Motor-Speed-Control-Switch-/280944740936
http://www.ebay.com/itm/10A-DC-12V-...roller-DC-Motor-Driver-Adjuster-/200834489152

or a kit:
http://www.ebay.com/itm/NEW-12V-60-...OTOR-VARIABLE-SPEED-CONTROL-KIT-/360508613690

it uses an ATtiny13A microcontroller:
http://www.quickar.com/dpwm.pdf
http://www.atmel.com/Images/2535s.pdf


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## Arlo (Dec 27, 2009)

PStechPaul said:


> The UC3842 and UCC38C42 are designed for switchmode power supplies using PWM and current mode, which means cycle by cycle current sensing and limiting. But it might be adapted as a direct duty-cycle controller using a variable reference from a pot. Here are the data sheets and application notes:
> http://www.ti.com/lit/ds/symlink/uc3842.pdf
> http://www.ti.com/lit/an/slua257/slua257.pdf
> http://www.ti.com/lit/an/slva059a/slva059a.pdf
> ...


 Thanks Paul. I have a couple pic18 chips if I need but I like the kit on ebay then I can make my own powerstage I guess I will need to look at it becausre I will need to limit the PWM on time or the full throttle untill the amps are under a threshhold to protect the fets. I would say 20amps is ok 20-40amps will be enough at 24v. Thanks for putting that all together.


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## Salty9 (Jul 13, 2009)

Intersil has a 3 phase bridge $6.75 at DigiKey http://www.digikey.com/product-detail/en/HIP4086APZ/HIP4086APZ-ND/821449

I am planning on using it as it is through hole mount and my dexterity is not what it used to be.


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