# DIY AC Controller Build



## wilkes5 (Jun 1, 2012)

Looking to pay for someone to build a DIY AC controller for an industrial AC motor (around $1000). A guy from the forum suggested he would build one, but can't seem get a hold of him. Looking to save money from purchasing the AC-50 combo ($4300). 

Also, would want to pay someone to build or show me how to DIY battery charger (etc).

Always what is right.
Thanks


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## PStechPaul (May 1, 2012)

I'm planning to design and build a small AC controller for three phase ACIMs in the 2-5 HP range. For a standard 240 VAC motor the battery pack needs to be about 300V, but I have built a 24V-320V converter so I can run on just two 12V batteries. But it's possible to convert between any two DC voltages within reason for about $10-$20/kW (for 5kW or more). 

Please specify the motor you have, or plan to get. For the average small conversion, a 30-40 HP motor should be OK. And the rule of thumb is about 330 W-Hr per mile, so for 33 mile range you need 33kW-hr battery pack (maybe double that). So for 2.5V lithium you need 120 cells at 25-50 A-Hr capacity. 

I bought a nice Toshiba 15 HP VFD on eBay for about $80. A 40 HP drive might be obtained for $200-$300. I could not even begin to design and build a drive for even 10 times that price. If you want to build one yourself there are at least two extensive ongoing threads about that. Same thing for battery charger and DC-DC converter. Maybe you can find a bright teenager who could build something for you for cheap and/or as a learning experience. But expect to deal with some spectacular explosions!


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## bjfreeman (Dec 7, 2011)

need to specify the type of AC, like 3phase, BDLC or Squirrel cage.
50KW is tops?
have you looked at the current Build your own AC kits that are on the forums?
Good luck on getting one for under a $1,000. the IGBT alone could cost you $1,200.


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## PStechPaul (May 1, 2012)

wilkes5: You should reference your thread about a month ago. There was a lot of good advice, and pretty much enough to get started. But this is a DIY forum. If you want to pay someone else to do it, then it's not DIY anymore. 

http://www.diyelectriccar.com/forums/showthread.php?t=74840


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## wilkes5 (Jun 1, 2012)

A little late learing electronics, starting first "DC voltage" class voltage in fall. Thanks for pointing out the DIY AC kits on the forum, was unaware and will definity look into it. Seems to me, a good task for the beginner would be just to buy the equipment and hook everything up. From experience, DIY is subjective, from wanting everything MADE IN USA, have turned to DIY many times. However, how many of DIY's do everything DIY. Who makes capacitors, computer chips, ect. So maybe different levels. VERY VERY hard to do everything DIY. But if you can, and do it good (killing bad guys or without harming good life), cool. Just try an leave me alone and with no taxes please. 

Just like the other thread, looking to convert a 94-02 camaro/firebird (3500lbs) or a 94-99 toyota rav4(3000lbs) with as much performace as possible and range in the 50's. If it can be had with an used AC motor off ebay made USA with a DIY controller for less than the AC-50 combo or another DIY combo from the forum, so be it. Which ever way has the most MADE IN USA parts, wouldn't mind spending the extra tax doe to have it, as long as it saves my sould from 13 year olds working 12 hr shifts. Yea, i'm talking about the interals of a citrus controller (whatever it may be caps, inductors, MADE IN CHINA). Whatever option is most made in USA for the cheapest wins. If possesed the knowledge, would totally DIY with USA parts. 

But yea, as much performace as possible under 10,000. If can't go the back way, just going to buy the AC-50 and everything else from an EV supplier, even tho it might be more made in CHINA. Better than giving 40 dollars each week to DOHA or some other evil oil country in cahoots with the Dems. 

Will not have the funds to do anything til september.

Always what is right.
Austin


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## PStechPaul (May 1, 2012)

It will be nearly impossible to build everything from parts made in USA. But if you purchase things that are used or surplus, from US individuals and companies, the "damage" has already been done, and your purchases go into the local economy.

Something else to consider is that many countries do not have the safety nets that we do, for those who cannot (or even are unwilling to) work. It is rare for anyone in the US to starve or freeze to death unless they are mentally deranged or too stubborn to avail themselves of social services or charitable organizations.

When I was in Mexico about 15 years ago the people I was riding with stopped and gave something to someone begging on a street corner. Usually I would not do so here in the US, because many such people are running scams or use the money for drugs and booze. But they told me that Mexico does not have welfare, and such people are truly destitute and may very well starve if not helped. 

I think this also applies to countries like China, where it is better to work long hard hours for less than $1/hour if it allows you and your family to survive. And many people in the US are not even willing to work for minimum wage, because they can survive quite well on welfare or unemployment. And often their work ethics are not very good, and their education and skills are inferior to those of countries where such things are highly regarded.


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## Stiive (Nov 22, 2008)

So what happens here? Do I just give you my bank details or what?


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## PStechPaul (May 1, 2012)

I had to look up the AC-50 motor and controller:
http://www.electricmotorsport.com/store/ems_ev_parts_motors_ac50.php

So for $4300 you get a 96 volt AC motor rated 67 peak HP, 650A, 110 lb-ft torque, 6500 RPM, 89% efficiency, and 110 lb. Plus you get a Curtis controller, display, and wiring harness. Peaks at 3000 RPM and 550A on a 90V DC battery bus.

So that's 50 kW or 66 HP. But there's probably a lot of sag on a 90V battery pack. You will probably want about 200 amps maximum continuous or 18 kW or 24 HP. Probably about right for normal driving. I don't know anything about the controller but I assume it's pretty much like a standard VFD except made for lower voltage and higher current.

IIRC I found a suitable 30-40 HP motor for about $900, and it should be able to provide about 2.5 times that for short term use so it may outperform the AC-50. It's probably twice as heavy but still a small part of vehicle weight and battery pack. And a standard 240 VAC VFD rated 30 HP can be obtained for, say, $500. So there's $1400 vs $4300. 1/3 the cost, or, now you have almost $2000 for more batteries. Enough, probably, to go from 90 volts to 300 volts. And now your DC wiring for 40 HP will be just 100 amps, and the three phase motor wires will be about 50 amps, so something like #6 or #8 will be fine. 

But maybe the AC-50 is attractive because it is a "drop in" kit. However, it still leaves the battery pack, and a 90V pack at 350 amps for 40 HP will need a lot of really heavy connections. So I'm just trying to see how the cost analysis works out. And I guess I'm still thinking like a DIYer where part of the joy is the challenge of working things out and trying some alternatives.


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## bjfreeman (Dec 7, 2011)

I used this guys website. good Thread
http://www.diyelectriccar.com/forums/showthread.php?t=15363&highlight=2001+passat


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## Stiive (Nov 22, 2008)

PStechPaul said:


> I guess I'm still thinking like a DIYer where part of the joy is the challenge of working things out and trying some alternatives.


That's the spirit!


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## wilkes5 (Jun 1, 2012)

PStechPaul said:


> I had to look up the AC-50 motor and controller:
> http://www.electricmotorsport.com/store/ems_ev_parts_motors_ac50.php
> 
> So for $4300 you get a 96 volt AC motor rated 67 peak HP, 650A, 110 lb-ft torque, 6500 RPM, 89% efficiency, and 110 lb. Plus you get a Curtis controller, display, and wiring harness. Peaks at 3000 RPM and 550A on a 90V DC battery bus.
> ...


Thanks. Have no clue on the technical and how everything marries with eachother (volts/amps/sag/ect.). No need to try and explain. Had bought a book, it wasn't convert it, it was something else. However, was really disappointed because it didn't explain anything like marrying the different properties of the motor/controller/batteries. Had to send it back. It seems the industrial route would make more performace for less?


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## wilkes5 (Jun 1, 2012)

Stiive said:


> So what happens here? Do I just give you my bank details or what?


Do you build? Have always used paypal. Just send the money. But, don't know about getting scammed, it hasn't happened yet.


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## Stiive (Nov 22, 2008)

wilkes5 said:


> Do you build? Have always used paypal. Just send the money. But, don't know about getting scammed, it hasn't happened yet.


I build, I use paypal, you can send money. Perfect. 

Being scammed is subjective. What are the clauses?


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