AC or DC Electric Car?

My favourite EV conversion site is www.kiwiev.com. Gavin shows just how easy the conversion can be using off-the-shelf components.

I am planning to convert an Audi 80 that is currently taking up space in my backyard to electric, and I plan to follow much the same path, but I like the look of the Thundersky lithium cells : more capacity, less weight, longer life (and a whole lot more $) compared to lead-acid.

The Advanced DC motor/Curtis controller combination is quality kit at quite reasonable money.

Now, the solar cells. Your EV battery will be, say, 120V and 80Ah = 9.6KWh per charge. This equals 8 x ~120W solar panels operating for a long, sunny 10-hour day. (Yes, I know you said 180W, but that is their PEAK power, in practice they will average about 2/3 of this at best). Your round trip will use a goodly portion of your battery, so it would be best to design for a daily recharge. 8 Panels would be a bare minimum, and it would be a good idea to have more to cover days when the sun is not out all the time. If your charging system can also accept power from the AC mains, this would give you a plan B for when the battery is flat and the sun is absent.

If you decide to proceed with your project, I recommend that you scout around for a supplier of EV systems and components. There are quite a few to choose from these days, and they seem to be a very helpful bunch.

Best of luck.

you can drive 100,000 for the cost of the conversion and the electricity costs, so why do it?

being cool cost money. The electric car burns coal in the US, so it dirtier and the cycle from mine to wheel is lower efficiency than petro. You may laugh as you pass a filling station, but you'll cry when the electric bill comes in.

Hello Paul, I invite you to check my later posts, as I have devoted much time evaluating the issues vs the pros and cons of the public desire to convert to EV's for transportation. It is doable but with many restrictive problems to over come. Actually, I delight in finding new uses for "stuff" that has already been developed, that I found to be unique at one time or another, but is no longer at the fore front of modern development. WHY RE-INVENT THE WHEEL, WHEN WE CAN FIND NEW USES FOR IT? And; The parts needed for experimentation can often be found at discontinued parts prices or salvage companies.

TMF

Do you want a more efficient and cheaper alternative method of propulsion

Pedal Power

The only downside is that it will make you fit.

Have you considered using two DC motors, with time-duty ratings and alternating them so one of them is cooling off while the other is running? Just a thought... I always wondered if a jeep could be converted that way, with front and rear drives, and alternate them for cool-down on the highway and the street, but use both motors for 4wd requirements...

Check out UQM shaft-mounted motors, too, like the ones they use for diesel motor supplement, it may be an option...

That dual-DC motor post was mine, I forgot to log in...

Can't match that speed but using a rebuilt motor from a small shop electric vechile adapted to the transmission of a Chevy Chevette a 50 miles trip around town is easy. 130 amp Ford Alternator adapted to charge batteries on all downhill runs by riding directly on the rear tire.

The motor came off a Chusman Shop vechile.

Why riding directly on the rear tires?

This would have added to the "Unsprung mass", woulnd't it have been better taking it off the tail shaft, as mostly these run at a higher speed than the shafts after the diff?

No problem, shop around for a used 36 volt fork lift battery with about 75% duty cycle left in its performance capacity. This about when the renters of this kind of equipment demand a replacement as less than this cost too much lost performance for the laboring crew. Some of them come with an on board charging system as part of the set up. You will need to use several golf cart motors, 36 volt with a varied speed wiring system included. You will have to stack them to come on line as needed for the higher speeds that you desire, but you should be able to figure that part out, or you should continue to drive the vehicle as is.

TMF

Rudy,

It might not be advantageous to rewind the motor for lower voltage as it will require much more current from the frequency drive and the batteries. While it is safer to run a lower voltage, the system efficiency is better at higher voltage.

I agree that you are likely to get more power at high RPM and electric motors as opposed to IC engines do prefer the higher RPM. One should not hesitate to "rev them up" as they draw less current (because of the lower gearing) and have a better cooling from their internal fans. An electric motor transmission should be sized to operate at full RPM most of the time. This can be difficult on the transmission if it is not rated as such. That is why, a properly sized down converter should be used before a standard automotive transmission. A ratio of 0.75 to 0.5X could be used depending on the top speed expected.

A RPM gage and current/voltage gages are needed to operate properly. motor and batteries temperature monitoring is also useful for long life.

I find this to be an interesting answer, as it relates to a standard transmission. However Way back in the early 1960's I can remember driving a forklift manufactured in Germany, that utilized a VW motor as the power source, propane as the fuel source and had some type of hydrostatic/hydrolic transmission. It was capable of high power performance at slow speeds and high speed performance when the peddle was pressed to the floor. The engine speed was manually controlled by a leaver in the dash, much like a tractor or many forms of construction equipment. I see that there could be a possible connection for using this type of electric/hydrostatic combination to resolve the inefficiencies of powering electric motors a low speeds that are power draining with out a reasonable return for the energy input. AS a matter of fact even tho I accept that the motor cannot produce sufficient power run it self, it certainly can produce some power, that may be surplus beyond moving the vehicle at low speeds to at least help to restore some energy to the batteries, thus extending the the travel time for said vehicle.

By the way, this fork lift had only two peddles. As you pressed down on the right one the left one came up an equal amount, By pressing on the left peddle you could travel in reverse just as fast as you could go forward by pressing the right one. SO WHERE WERE THE BRAKES? You carefully returned the peddles to the equal position, as the transmission stopped the flow of fluid, so stopped the forklift.

As a previous poster stated that he could rewind a three phase motor to provide appropriate power for use with 36 volts of power source and forklift batteries are long lived, and deep cycled and many are rated at 36 volts, I see a possibility of combining an electric motor with hydrostatic transmission as a more reasonable solution.The higher speed of the motor when not being utilized to move said vehicle forward at high speeds could be re-energizing the battery pack to some extent.

Toomuchfun

Hello Rudy, I'm guessing that you are somewhere in Europe or have connections there. Maybe you might connect with someone at the ATLAS TOW MOTOR COMPANY, I think that they are based in either Germany or Austria. They are the Mfgs. of the forklift that I mentioned in another post. I have operated several brands of forklifts over a long career of asst. professions in my life. I have had a unique opportunity to evaluate many different forms of materials handling equipment. For the type of work it was designed to do, I have to say that the Atlas [VW] powered was dramatically superior to others, based both on the available power from the engine and the excellent hydrostatic propulsion system. I do believe that such a system could be modified for use in EV's for todays market, and while we search for better battery power sources, we have an adequate source with the industrial use batteries that can be placed in use today. Even if such combinations could only provide for commutes/trips of 150 miles or so, the use of these vehicles for daily short trips could ultimately pay huge benefits for society over all. AND AS THESE TYPES OF VEHICLES WOULD NOT BE DESIGNED NOR INTENDED FOR INTERSTATE TRANSPORTATION USES, MANY OF THE SAFETY FEATURES DESIGNED INTO TODAYS VEHICLES MIGHT BE RELAXED, RESULTING IN ADDITIONAL SAVINGS, MAYBE ENOUGH SO AS TO MAKE THESE COMMUTER VEHICLES AFFORDABLE TO THE MASSES.

TMF

I agree that the amount of information confuses a project like this. Being in the mechnical side of things I've found the same issue.

One thing I've considered as a small test project is converting a motorcycle or ATV to electric. Lower requirements, lower cost and a learn as you go project.