1971 Corvette EV Conversion
 

OK, We have finally started this project. We have been planing on doing this for months, but haven't had time to start. On Saturday we use the truck to pull the car from down back where it was parked. We pulled it up near the garage where we spent almost an hour cleaning off all the mold and sap from the car. We removed some of the carpeting that was moldy. We had to use the pressure washer to remove all the junk. With the car clean and free from all critter nests, we proceeded to push it into the garage. we had to turn it 90 degrees CCW to be able to back it into the garage. It took out about 10 minutes to the the car in the garage as it was very hard to push because the brakes were dragging a bit. Once it was in the garage, We began the deconstruction process. We started with the simple stuff under the hood. We removed what was left of the AC dryer and its connecting hose's, then we removed the extra vacuum lines that went to the headlights, those will not be lifted with the vacuum like they use to be, so that stuff went into the box too. Next we started draining the antifreeze. Most seemed to have leaked out from sitting for so long, Only got about 1.75 gallons out. Thats all we got done on saturday.

On sunday we had a little more time to work on the car. We wanted to try and start the engine and get a little video of it so that we could sell it. We put a fresh battery in the car and about a gallon of gas in the tank. We ended up needing to add a new wire to the + side of the coil because there was something wrong with the built in one. Once we added the wire, it started right up.

After that, We finished removing the Fan and shroud as well as the radiator, alternator, belts and some other small things.

Video #1: http://www.youtube.com/watch?v=rH1yQpbYHhM
Video #2: http://www.youtube.com/watch?v=i-tsHDy89lw
Video #3: http://www.youtube.com/watch?v=yB2V5py_rIs
Video #4: http://www.youtube.com/watch?v=rsU2yw-mnFs

I also had some more time last night to get some more work done. I was able to remove both the seats, and the A/C controls in the cab. I finished removing the remnant carpet pieces that somebody used for the floor carpets. All the extra parts are cleaned out of the cargo area as well.

For the car our goals are to be able to bake the tires, as well as be able to drive it further then across town. We are aiming for around 60-80 miles per charge, but will be sacrificing range for performance. Since its a Vette, it has to be fast.

So far we have been thinking of going with 22-26 optima yellow top batteries, the D31T ones. These will be wired in series and parallel to give 150A/H and 144V. We have also been looking at lithium batteries, but we need to find them at the right price.

For a controller, I plan on building a modified version of P&S 144V open source controller. I almost have all the details worked out about it so it will be up to see soon.

For a motor we are stuck between 2 different options. Our first choice is a Warp11 motor. This will be mounted in the traditional way, with the clutch still in tact. Our second choice is 2 Warp9 motors stacked vertically, mounted into a custom made housing, coupled by 3 inch supercharger pulleys and belt. on the lower motor would be a special adaptor for mounting the pulley as well a bearing mount to support the torque of the top motor. On the other side of the bearing would be the clutch mount, and you know the rest. The 2 motors would look very nice and still leave alot of room in front of them for batteries. If we do 2 motors we could put them inline instead. As I said, were not sure what were going to do.

I believe the 2 motor setup would be a better choice, producing above 60 HP between the 2 motors. This, I believe, Would increase the top speed of the car greatly, While providing incredible amounts of torque in the low end. But, I do realize that it would have poor effects on the range of the car.

I also plan on building a BMS system from scratch. This will include modules for each batteries, as well as a central computer to monitor the packs and alert if there are problems.

Well I think thats it for now. I would love to hear your comments.

-Adam

Picture #1: Rick washing car
Picture #2: Engine bay
Picture #3: Interior before being stripped
Picture #4: Engine bay after Radiator, Fan, Shroud and Alternator removed
Picture #5: Interior stripped

P.S. I promise that following posts wont be this long. :D

I was thinking about a project like this the other day!

Very interested to see it evolve. I agree as a 'vette it HAS to be fast.

Subscribed!

Great looking project I can't wait for more pics!

From a purely performance standpoint 2 motors would definitely be superior, but only if you are already exceeding the power handling of a single motor. Its more about "motivation" than how much motor you have. Twin motors won't perform any better than 1 if you're driving it all with a 500a Curtis. With the added weight probably even worse. Even a single 9" would likely handle all the peak power you're going to be able to push into it unless you're going >1000a or >200v

2 does increases your sustained output by a factor of 2, but only as long as the batteries can keep up, which isn't long enough generally to warrant it.

In terms of range I don't think 2 would effect things as much as you suspect. Most people think this way because we are so used to dealing with engines.....big V8s get worse mileage than 4 cylinders even driven at the same speed. But in EVs its all about wh/mile and 2 motors operating at 90% efficiency doesn't use any more power than 1 motor operating at 90% efficiency, unless you're pushing things so hard that the 1 motor is overheating.... The added weight is more of a concern.

If this is your first conversion I would recommend a single motor from a headache / simplicity standpoint. I really, really wanted twin motors but in the end I was glad I went with just 1, there was plenty of other stuff to keep me busy instead.

Looks like an awesome project.....keep that momentum going!

Nice Vette!

I liked the videos fast pace and also seeing the sun go done.

I think a single Warp11 is just fine. Gobs of torque and with the transmission you should have no problem showing off.

Though, you will be hard pressed to get 60-80 with Lead Acid batteries. 60 miles of range is usually the limit and that usually needs 144 volts and 240 Ah golf cart batteries, about 1500 lbs of lead.

With 144 volt 150 Ah your range will be closer to 32 miles. A Honda Civic driving Econo style will get 40 miles using 144 volts and 170 ah of batteries, so 60-80 miles using lead acid in a Vette will be hard pressed, if not impossible.

And yes, jack rabbit acceleration has HUGE effect on range, and so do these stupid MA hills!

Make sure that you controller can produce 250 AMPs continuously too. I just spent the past few days figuring out the power required for a lot of these hills, and my Kelly doesn't hold up at all, and a Curtis probably wouldn't either because of the rather high Current needed for climbing at anything above 5 MPH, (Been there, and doing that....putt putt putt up those hills...)

Three words: lithium, lithium, lithium.

I have 1320# of PbA in my pickup ('94 Toyota i.e. it's small) and it's a pig going up hills. I figure I could get better performance with about 400# of Thunderskys. Lead's gone up in price and lithium has come down. $1.10/AH is the best price I know of now (http://www.evcomponents.com/SearchResults.asp?Cat=28).

Imagine taking 900# out of any vehicle...

Great project BTW. Here's a couple of links that may be helpful.

Russ Reiss' 1974 Chevrolet Corvete
Michael Shoop's 1987 Chevrolet Corvette

Thanks guys for all the kind comments and advice! Its people loving my projects that gives me motivation to work hard on something to show off.

@ AmpEater: Dont worry about the controller. While Im not ready to let the details out yet, I will say its Very Capable. About the motors, Im not worried about the difficulty with mounting or wiring 2. We both are electricians as well and I have a deep background in electronics engineering. For the actual mounting part...Well I have 2 CNC milling machines and a manual lathe, as well as tig, mig, and oxy/actl welding outfits. I plan on manufacturing everything myself, From the adaptor plate and coupler down to the new digital instrument cluster.

@ TheSGC and Frank: Im hoping to use lithium even if it is a small pack, I can fit 1 string of 45 LFP160 TS's weighing in at 555lbs. Thats 3 times less then 24 optimas...and a bit more capacity. Its just shy of 8k bucks though. So I dont know yet.

@ Frank: I have seen the Volt Vette before, but did not know about the other one. Im going to be emailing him as he only lives about 1 hour away from me!! The 74 vette is also a C3 so the 2 cars are alot alike. I will see if he has ran into anything I should know about.

@ stevey_frac and robchalmers: You can check out the website @ Welcome to EVVette.com for more pictures.

-Adam

I just realized that your Engine compartment is HUGE! That will be great for adding all those parts and having room to work in.

Having you own CNC machines and milling tools will help A LOT, and same with the welding. I had to buy a new drill press for my latest adapter plate design and use a 4" hole saw to cut 3/4" and 1/2" aluminum and it was scary.

I found in my conversion, that the adapter plates and the coupling was the easiest, only second to removing the engine. The hardest part was waiting for the parts and wiring up all the little electronics, finding out that you need a few trips to Radio Shack for relays and connectors, then wiring up more.

About battery prices, 24 Optima's is about $5.1K and the same amount of lithium to get the same power as those Optima's is about$ 5.9K, so why even go with lead? You get about Half the useful power from lead acid batteries, and with lithium you get most of the power. So, in theory, 144v 120 Ah LiFePO4 is better than 144v 200 ah lead sled, due to the difference in Puekert's Effect and the difference in weight.

What are you looking at for 120Ah LiFePO4 batteries? Thinder sky's go 40, 60, 90, 100, 150, 160...

I would probably use the 160's. In the spec sheet there rated to 3C so thats 480A continuous, and 1600A peak. I dont think the high current pulls in the 1000A range would cause much damage to them.

-Adam

Sky Energy (EV Components have them) and they are supposedly better than TS and somewhat cheaper, with a 4C continuous rate.

First of all, weird. I'll bet your background is more in machining and/or auto work, whereas mine is electronics. Guess its all relative.

And excellent point about the cost of lead....gone are the days of "cheap lead now, lithiums later"....if you're dropping 5-6k on batteries anyway......

AmpEater, my background is Electronics! Machining was quite simple enough, using AutoCAD to design up everything took a bit of time, but not much.

What killed me about the electronics was that most of the connections were not compatible with each other, and having rewire chunks of the cars electrical because they were old and would quit out on me.

Wet lead acid batteries are still cheap, but AGM and sealed cost nearly as much as lithium. My next pack might be 8 volt floddies, then Lithiums, unless lithium prices drop like a stone next year, which is possible.

If you go with 2 motors, I like the inline mounting idea better. A belt system is going to be fragile (think 500+ lb/ft of torque) and inefficient, and, unless you build a bearing carrier, will wear out the bearings on both motors. If you got two 9" motors, one double-shafted, you could mount them inline and really take advantage of that long engine bay.

I'd have to second the lithiums (if you're looking at two motors, monster controller, custom digital dash, etc., what's an extra $1-2k to save 900 pounds?) If you absolutely must go with AGMs, look at the Exide Orbitals. They can dish out more current than the Optimas for a similar price, and there have been quality control concerns on the EVDL about recent Optimas.

Good luck, and keep us posted!

nice project.

If you mount 2 motors inline, make sure one can freewheel while the other is turning.

Basically, put a sprag (high torque, obviously) between the first and second motors, so your constant drive motor is the one closest the transmission, and the motor further from the tranny (the "1st" motor), is used for extra torque when necessary, but won't drag down the first motor (it's not much drag, but it's drag).

You'll want to regear to take advantage of the excess torque that these motors produce, and the relatively low RPM's that they can work in. Probably better to keep the same transmission ratios, and re-gear the rear-end, to lengthen the final drive ratio.

Lighten up anything you can afford to. If you can afford a 1 piece fiberglass front end, go for it. Anything to save weight, or offset the weight of the new components.

BTW - Regarding the Ford Truck... That cap is definitely not helping it's range... LOL.

With most of the inline motor setups I've seen, both motors share the load full-time. You could disable one motor to up the efficiency slightly, but I imagine you'd have to do some fancy contactor work to switch the controller from a two-motor setup to a single motor setup.

I would put 2 motors in-line; this seems to be the most popular setup. You can change gearing and run w/o a transmission (assuming you will use a powerful controller.)

Typical issues with 3rd gen vettes is rust in the trailing arm area and windshield pillars. They're interesting to work on and great looking!

Jim Husted actually sells a Dual motor setup, the Jimpulse 9. It has a single armature so there is no need to couple the motors together and even looks insanely sturdy.

http://www.evcomponents.com/ProductD...ode=Jimpulse+9

Through one of these in your Vette and you will be worrying about killing your transmission instead of not having enough show off power.

High Guys,

To answer a few things, The trailing arm area of the car is in very good condition, as well as the windshield pillars.

It is not likely that the funds will be available for a 2 motor setup. But if we were going to be putting in 2 motors, We would probably couple 1 warp 11's instead of buying a dual prebuilt 9" for 5,750.

I haven't had much time to work on the car this week. Were hoping to get it up on jack stands and some more stuff removed from the underside this weekend. Maybe get the engine out if we can find a place to store it while were waiting for it to sell.

The transmission that is going in the car I believe is rated to 500Hp so I dont think it will be destroyed too easily.

-Adam

.

Hi Guys, (I typed the right thing this time :D)

So the car got put on jack stands last night and we set into the underside. We unbolted the exhaust from the engine. We started taking apart the existing power steering box, and got the transmission lines disconnected. We also got all the engine mount bolts out and all the wires and hoses disconnected. All we need to do now is lift the engine out!

Tonight, I was able to finish removing the exhaust system. I had to cut the exhaust in the center where it goes through the frame. Then it came out in 2 pieces. Not too bad for 15 Mins of work.

Tomorrow we hope to make room out in the little garage so we have a place to put the motor and transmission when we pull it out. If we can make some room, We will be pulling that out tomorrow. I think if we can get that pulled we will be making real good time on the removal of all the ICE components. 2 weekends.

I will upload the 2 time-lapse videos and all the pics from this weekends work, either tomorrow or monday.

I also hope to bring home a shipping scale on monday and weigh all the components except for the engine to get an idea of how much it weighs.

-Adam

A sweet project. I can't wait to see it finished! :)

Nikki.

Alright, another weekend past, and alot more work to show. The Engine Is Out! it was a large feat of Sunday due to the fact that the engine hoist was bent due to a mishap with moving a 2200lb machine. But we took a big hammer and beat it back into shape for the lift. It took us about 2 hours to remove the engine with the transmission attached. We had forgotten to undo 2 small power steering lines and some weird cable that connects the transmission to the steering column!? We still dont know what it was for. The engine and transmission we guess weigh about 800 lbs. It was very heavy. All cast iron 327 block and heads.

I have been looking into batteries over the past week and a half and we are almost certain that we will be using some form of lithium! Not sure which yet, but it will most likely be 45 of the Sky Energy 120Ah cells at the minimum. Maybe 180 or 200 Ah cells depending on how much else goes into the car.


So here are the few time lapse videos of the deconstruction nights. I was able to get 2 angles for the pulling of the engine.

Putting the car on jack stands and removing exhaust:
http://www.youtube.com/watch?v=0zRgw_1i0CI

Removing the engine:
http://www.youtube.com/watch?v=bvxi4-KQaw8

And:
http://www.youtube.com/watch?v=mMIHwSs04r8

So hopefully over the next week or so I can finish removing the AC components and the rest of little unnecessary thing along with the rest of the steering linkage to prepare for the Rack and Pinion conversion.


Pictures:
http://farm4.static.flickr.com/3475/...004eda4a_o.jpg
http://farm3.static.flickr.com/2459/...cccc9f04_o.jpg
http://farm3.static.flickr.com/2618/...63f2c35c_o.jpg
http://farm3.static.flickr.com/2650/...a2f652a8_o.jpg
http://farm4.static.flickr.com/3437/...dcd21d6a_o.jpg
http://farm3.static.flickr.com/2520/...daf1662c_o.jpg
http://farm4.static.flickr.com/3438/...93563f01_o.jpg
http://farm3.static.flickr.com/2525/...ccb48405_o.jpg

Well Enjoy.

-Adam

P.S. I got a few surprises for later on in the week.:D

Excellent. Love the time-lapse video.

From this site: http://www.35pickup.com/mulligan/weight.txt

It appears that the small block Chevy from the 60's and 70's weighs around 575 pounds, and your battery pack would only be about 445 pounds. So add in the motor, controller and racks, subtract the exhaust, gas tank (18 gallons of gas weigh about 110 pounds!), accessories and other ICE components, and you're probably talking only a couple hundred pounds over stock. That's going to be a killer car.

Clev,

Dot forget I am removing the THM-400 automatic transmission that weighs 134 lbs without torque converter and fluid.

This will be replaced with a T10 transmission. I actually have 2 T10's, 1-3 speed and 1-4 speed. The 3 speed is almost brand new with only a few thousand miles on it. The 4 speed is unknown condition and will be gone through and parts replaced if needed. What do you guys think we should use? 3 Speed or 4 Speed? We also have 2 sets of rear end gears for the car, We believe 4.11's and 3.36's. The 4 speed weighs about 70lbs dry. Thats about half the weight of the THM400.

Were very happy that we will be less then the weight of the car with all the electronic components. We hope to balance the car for optimal weight distribution.

-Adam

Cool, even better. :thumbup:

Most EV's use just a couple of gears, so if you can get a good combo of ratios in a 3-speed, I'd use it and save having that fourth unused gear spinning around. Plus, a newer unit will probably have better bearings that will waste less electricity.

More Good News!

I finally figured out what the transmission is that we have. I went out to the garage last night and got the numbers off of the castings and started searching the internet. This morning I had some replays on some forums and some links to identification sites. Basically what it comes down to is we have a Muncie M20! Basically for you who done know what this is, It is a very rugged transmission.

-Adam

Ok, A few questions and some updates. We have decided that we will be using the Sky Energy cells. Not sure the size yet, they will be the 120's at the least.

My question is, Will the Warp 11 be enough motor to make the corvette go at least 100 Mph?? Its not something that will happen too often, but its a requirement of the project.

What I could figure, And please correct me if I'm wrong, is the spec sheet says the motor produces 43HP at 72V and 453A. So that would be 32,616 W. The battery pack we are using will be 162V charged so figuring with no sag at the same amperage, ( 162V x 453A ) the motor should be outputting 73,386 W. Thats 2.25 times the output power or 96.75 HP. Is this correct? That should be continuous output power correct? Do you think this is enough power to make the car do what we want?


So we were able to get some more little work done this week. We removed the gas tank and the rest of the AC system. Last night we took out the whole dash to be able to work on the wiring and heating system. The car is looking really EMPTY!

I have also been working on a program that will run on a 7.1" touchscreen monitor in the center dash. This program will control and monitor the entire car(Gauges, BMS, Motor Controller, Charger, and System Settings). There will be no physical gauges in the car, only virtual ones. The program will interface with the BMS system that I am working on, to display all charge and discharge information, as well as individual cells to find weak ones before they become problems. The controller section will be displaying all controller information such as temps and currents and voltages. The charger section will display charger information suck as charge times and estimated charge time left and things like charge cost. Lastly on the list is the settings page. This will hold all the system settings as well as settings for the charger, controller and BMS. It will be able to export a backup of settings incase something happens as well.

All the graphics have been designed from scratch by my friend Kyle. It is a very sharp looking system.

Here are 2 pictures, 1 of the Home Screen and 1 of the Overview Screen.

-Adam

http://farm4.static.flickr.com/3435/...887bfddd_o.jpg
http://farm3.static.flickr.com/2588/...3a9c8258_o.jpg
http://farm3.static.flickr.com/2602/...9ef2b72f_o.jpg

So here is the other thing I have been working on. I have been working on a version of Paul & Sabrina's Open Source Motor Controller capable of very high power output. I started with a the heat sink from a car stereo amplifier. I then designed a power board that fit in the heat-sink. The power stage board holds 21 Mosfet/Diode pairs. I have upgraded the diodes from the 60A STTH6002CW 's to 90A APT30S20BCTG 's. The capicators have been upgraded to 820uF from the 470's. There is 42 capacitors. Totaling 34,440uF. The controller should be capable of about 1680A continuously, With the pairs capable of 6720A for 8.3ms. At 165V that is 1.108 Mega watts of power. The continuous power is about 303kW of power. The controller will have the option of being water cooled if I need it. If it can stay cool by just the air moving over it, I will not using the water cooling, Saving weight.

I plan on using this controller at 162V, driving a Warp 11.

I have not tested the mosfet/diode pairs yet at 162V to see if they will hole up, but I have some parts on the way so testing can begin.

So here are some pics of the heat-sink and some renderings of the completed controller.


Heat Sink:
http://farm4.static.flickr.com/3441/...4f277a83_o.jpg
http://farm3.static.flickr.com/2666/...e20590c8_o.jpg
http://farm4.static.flickr.com/3439/...534c64d0_o.jpg

Renderings:
http://farm3.static.flickr.com/2450/...543f2401_o.jpg
http://farm3.static.flickr.com/2448/...753b34d3_o.jpg
http://farm4.static.flickr.com/3458/...8eac3761_o.jpg
http://farm3.static.flickr.com/2651/...c866da6a_o.jpg

No Water Blocks:
http://farm4.static.flickr.com/3511/...223a4e77_o.jpg

With Water Blocks:
http://farm4.static.flickr.com/3472/...0cb719cc_o.jpg


-Adam

this looks like a verry interesting project the corvette should be a good car for the conversion its sleek low resistance and kindah light im keeping my eye on this one .
i was wondering about those controllers and how they work is it a solid state version of a row of relays raising the power in stages ?
trying to see how its build i seen some drawings that look loke its the same scematic multiplied a couple of times

Wow, that is a heck of a lot of power!

Hello whatahyaknow,

The controller uses 21 mosfet/diode pairs. A mosfet is basicially an digital on/off switch. These mosfets are rated to 130 Amps, and the diodes are rates to 90 Amps. I have derated to 80 Amps maximum continous current to keep them from being destroyed. The diodes are really the limiting factor.

There is a microcontroller that creats a frequency called PWM (Pulse Width Modulation). This is a high frequency square wave that tells the mosfets to turn on and off. With the PWM you can control the output voltage and current of the controller, Thus controlling the speed.

Here is the latest schematic of pauls controller. My controller uses this schematic as a base. I upgraded the diodes to the higher rated 90 amp ones, but these are twice as expensive Paul calls for 10 mosfet/diode pairs, All I did was increase this to 21 to increase the power of the controller.

Here is the schematic for refference.

-Adam

so if i understand correctly its not like you turn on 1 2 3 4 5 etc banks in line to turn on the power but just divide the switching across more banks/switches(diodes) when youre running a bigger set of batteries (more volts) making the power that one bank gets to deal with lower or the same as whith the lower voltage .
its now starting to dawn on me you can basicly add swiches and banks upto infinity to get the amount of power you want to put intoo it switched , allthough it must be harder to dose the amount of power comming out
the power steps up twice as fast when you double the switches and open the trottle
so finetuning becomes sumting like writing the bible on a grain of rice
it will take some time i bet to make it work in my mind so i can see whats happening with the programming when a switch(diode) stays in the open poition and all that

amplification in this case basicly means being able to switch a bigger current with a small signal

Adam,

Did you also add more mosfet drivers to the control section to handle the increase number of mosfets? Seems like there was a timing issue when a single driver interfaced to that many mosfets due to wire length differences.

Eric

Hi Eric,

Simply, Yes.

I have 3 driver boards that each drive 7 mosfets. These 3 driver boards will be connected by 3 pieces of cable all the same length. All the traces on the 3 driver boards are exactly the same length as well. Thus, allowing the pulses to reach each mosfet in almost unity.

-Adam

A picture of the layout of the driver boards.
http://farm4.static.flickr.com/3480/...ff80b0a6_o.jpg

This is looking real pretty Adam. I like this a lot better than incorporating the driver on the controller board. It gives the builder a lot of options for meeting their (amp)power requirements. :thumbup:

Eric

If you liked that you might like this as well. Here is a picture of the controller board layout. the board in this layout is 2.0 x 2.6 inchs.

It is almost all surface mount also.

-Adam

http://farm4.static.flickr.com/3521/...fa753dd5_o.jpg

I almost forgot. Here is the picture of the layout of the power board. The big square in the middle is where the control section goes. It use to be smaller, then I expanded it to fit the current sensor section.

http://farm4.static.flickr.com/3461/...b30885ba_o.jpg


-Adam

Adam,

You already had my attention, now I am drooling. Gotta clean up my keyboard.:eek:

This is fabulous work. I take it you do this for a living when you aren't up to your elbows in grease.:confused:

The limitations that I saw in Paul's basic kit seem to be totally solved with your design/implementation. I was worried that I would need more amps with my application and it seems you have solved that in spades. Paul has been saying that his will support 500 amps with no problem and that is with 11 mosfets sharing the load. Can I safely assume that your design will handle more than 1000 amps? I know that the mosfets are designed with a limit of 200 volts and Paul mentioned that he thought that 144 volts was the max safe limit that should be followed. But then again you are looking at 161(?) volts. Is your confidence in that limit based on any other changes that you have made?

I am still in the design stage of what I want to do. And what you have here seems to fit quite nicely for me. Any chance that you are going to offer a kit or at least pcb's and bom to aid the ambitious folks lacking in EE skills like myself? I'm sure that I am not the only one thinking along these lines.

Nice work and I appreciate you sharing those purdy images.:D

Thanks again.

Eric

HA, I wish this was my job. I am a shipping and inventory manager for an energy management company thats part my father-in-laws. I just do this stuff as a hobby. I do a small amount of electronics stuff for work, Like right now im working on a custom wireless monitoring system to get some signals across a very large mall. Its very interesting.


Well, First off I would have not come this far with the controller if it wasn't for Paul, he has come up with a terrific design. My budget was just above what he had planed for. Thats how this became. Paul says 50A per mosfet/diode pair. That is with the regular diodes that hold the controller back. The ones I am using are good for 90A each up from 60A. So even at the low end of 50A per pair, that 1050A total for the controller. If you bump it up to 80A for my upgraded parts, thats 1680A total.

As for the voltage, Right now, I'm setting the limit at 144V like Paul's controller. We are working together to raise the voltage hopefully above the 162V goal of mine. I have drawn up a simple test circuit board with 2 mosfet/diode pairs and 4 capacitors. I will be using this with a 14.4khz PWM generator circuit. I have up to 20 SLA batteries I will be hooking up to the small power circuit to measure the voltage spikes. I have a 2HP treadmill motor on the way for a load as well. I will start with 11 batteries fully charged at 12.74V each, yielding 140.14V. I will take a measurement on the O-Scope, then add a battery and repeat. I will be charting open voltage, load voltage, current, and temperature in an excel table. Depending on how bat the voltage spikes are at the certain measurements, I will keep adding batteries. 16 Batteries fully charged will be 199.04V, So I dont think I will be going that high. I do hope to be able to make it to 14 batteries for an open circuit voltage of 178.36V.



I can say I will offer at the least the BOM, but there is almost nothing different from Paul's, just a few components. I would like to offer a kit, but i don't know if that will happen. If I can find a supplier in the states for some form of heat sinked case, I will purchase one and modify the design to fit it.

-Adam

Eric, you are right that there should be a separate driver board. I want to make that change too. As adam has demonstrated, there is basically no limit to the power when you have the flexibility of changing the driver board. It really doesn't belong on the control section.

It will also make assembly and disassembly much much much easier too (if you ever wanted to do that). I can't wait for Adam's controller. He thinks big!

Also, those surface mount control boards are tiny! I bet that would be way cheaper in bulk.