Sorry for the lack of updates… once again. We’ve been really busy.
BUT! The end is in sight. We’ve buckled down and decided to spend the $1500 odd on a battery pack, so once we have batteries it’ll all come together!

Today we made the cars very own heavy duty extension cable (thanks to alot of scrap wire donated to us) and we have begun to mount our battery chargers, AC breakers, and main power bar in the trunk of the car. Also found an old dial voltage indicator perfect for the trunk next to the battery pack. It’s starting to look a bit more professional!
More updates soon, I promise!

First off, we’ve taken it for some more test drives and fixed some of the kinks, the major improvement we’ve added is an actual gas pedal. Ian got a bit fancy and created his own accelerator using a 1K potentiometer and some careful calculations. Using solidworks he designed gears to spin the potentiometer when the gas pedal is depressed. After the model was complete, it was printed using a rapid prototyper at the college – yes we -printed- this part. Check it out.

Freshly printed inside the rapid prototyper

Closeup

Kind of hard to see, but here it is mounted to the gas pedal shaft. When the pedal moves, the large partial gear goes up or down spinning the small full gear which the potentiometer is attached to.

Took it for a test drive, and the pedal worked great!

…For about the first 20 seconds. Then one of our used batteries died. HOORAY!

I managed to pull it into a nearby parking lot before we lost all momentum. We got out and looked around for the problem – at first we thought it was the accelerator, but after smelling the trunk it became apparent that it was the batteries. Since all the batteries are in series, if one fries, none of them work. Here are some pictures from the adventure.

Checking connections...

Nothing beats the smell of sulphuric acid in the evening!

Solution: Tow it home.

With…

Riding lawn mower!

We received some strange looks and vehicles slowed down to watch our slow tow operation

We were crusing back to the shop at a solid 5km/h!

Other updates include the addition of the automatic brake vacuum pump (turns on whenever the pressure is too low), and fixing the speedometer! It’s top speed tested was 80km/h on half a set of used dead batteries!

More updates coming soon! We may bite the bullet and purchase batteries this week from Interstate Batteries (they offered us a decent discount).

Anyways, pictures speak louder then words so here’s today’s collage!

Step 1 of any project. A to do list!

Cleaned out the trunk and mounted the batteries, chargers, and wired everything! We have a passenger seat again!

Look's pretty slick with the roof in the trunk mount!

Started salvaging parts from one of the broken forklift speed controllers. Our main targets: 2/0 wire and heavy duty contactors!

Making a new grill to accomodate an air cooling vent for the motor - Probably painting it yellow and then stenciling "DEL SOL" in the front so it looks like a european license plate!

We could leave it clear... but i suspect it will get dirty and scratched...

Who needs a machine shop when you have a drill press!? A nice little battery terminal I made... which then broke. But here it is anyways!

ALWAYS check your wires... I had some fun welding the battery terminal! SHORT! On the plus side, if, being MacGyver's as we are, we could easily weld something using our electirc car! ...life or death situation only though, don't want to wreck our batteries!

Kill switch contactors wired in parallel to handle the current

A conveniently placed firewall for all our wires!

Mounting the speed controller

Our Clark 36V/12V DC/DC converter - took ages to mount - multiple brackets and screws we couldn't see!

Turns out our speed controller can output info to a computer! So, we're going to find a small computer and a 9" monitor and bam we replace the need to buy expensive voltmeters, ammeters, temperature gauges, and other gauges! Plus we'll have a car computer, how cool is that?

A passenger seat!?

It looks like a car again!

Our current speed control method... Surprisingly it works quite well!

All hooked up to the speed controller!

All it needs is a new paint job...

And now for what you’ve really been waiting for…

TEST DRIVE #2!!!

Anyways here are some pictures to start you off!

Conestoga College donated 10 used batteries to us! 6 of them seem to be good while the other 4 are dead

Having the bumper off probably doesn't help it to look legal...

Everything crammed in the passenger seat

Charging her up!

Finally got a cord for the speed controller so we could program it on the computer. Hooked up everything and we were ready to take it for a spin! Here are the videos!

Here’s a picture of one of the battery chargers we bought off eBay. Hopefully good for our purposes! 36V at about 25amps (125/250ah). Their really small which is nice, hopefully they perform once we get batteries!

The super slim EZGO 36V Golf cart charger

First test:

First test run of the system - filling with water

Pump after clearing system of water (hence the water on Ian's shop coat)

Added foam to reduce shock and vibration from the car

System mounted

Filled with anti-freeze. If anyone asks, its our kool-aid boiler.

All mounted and ready to go!

So for a $20 pump, a $5 kettle, and about $25 worth of ABS pipe fittings… We have a fully functional car heater! Not too shabby if I do say so myself. Kits like these sell for $400 online from EV suppliers!

Making the screw on mount for the cylinder

Mounted to car

Spent a good hour in TSC looking at ABS pipe fittings trying to make a resovoir for our heater system… Gave up there and went to Home Depot and found what we needed right away!

Constructed our new ABS kettle

Just have to attach the pump to one side, and then route it through the cars heating system!

As soon as we see some free time we have lots of things we can do on the car:

• Vacuum pump ready to be installed
• Heating system ready to be implemented with pump
• Sanding bondo
• Painting bodywork
• Setting up the speed controller
• Finishing the sound system
• Cleaning out the car
• Finding the speedometer cable

We also have a large amount of welding cable coming, so really the only thing left is batteries. Thinking about getting a forklift battery pack cheap and taking it apart. Still need a charger though…

With any luck we’ll be done by summer… hopefully.

By: Ian Hillier

Lead acid

Pros:

• Cheap
• Readily available. Because lead acid batteries have been around for so long, they have become widely used, mass produced, and easy to use.
• Proven technology. Lead acid batteries have been around since the beginning… they work.
• Larger selection of chargers (inexpensive). There are chargers being mass produced for forklifts, boats, RVs, and many other applications which would work great for an electric car. Because there is such a selection, we could get closer to what we want for a relatively low cost.
• Lead acid batteries are recyclable and therefore are not as bad for the environment as most people believe.

Cons:

• Heavy – lead acid batteries are about 3 times the weight of lithium.
• Large and bulky. This causes mounting problems. If we were converting a pickup truck it would not matter but since we are using a small sports car we have limited space. We would like to mount as many batteries under the hood and in the place of the gas tank but this will be like playing tetras with batteries.
• Limited life. Depending on the amount of use and how you treat them, lead acid batteries will become useless in approximately 0-7 years. If we are going to be paying $1000+ on a battery pack then we would expect at least a life of a few years. An expensive charger along with regular full charge will significantly extend the life of the battery. However, an electric car is very hard on its batteries so we could only expect a life between six months to three years.
• The oxidation reduction reaction occurring within a lead acid battery is strongly dependent (just like all reactions) on temperature. At low temperatures, the reaction does not happen fast enough to produce the needed current. This means the car will not function as well in the winter as the summer.
• Charge time. A lead acid battery can be discharged approximately five times as fast as it can be charged. To properly maintain a lead acid battery, it should be charged using a staged intelligent charger and should be fully charged regularly. 70 percent of the charge occurs in the first half of the charge time. Because of this, it is easy to neglect them by not allowing a full charge which is essential to the life of the battery.

Nickel metal hydrate

Pros:

• Lighter then lead acid batteries.
• Much faster charge time but require intelligent chargers which would be expensive.
• Are made from environmentally friendly materials.
• Higher capacity.

Cons:

• High self discharge rate (over 30% per month).
• High internal resistance along with a large voltage drop when supplying high currents.
• Lower energy density then lithium ion batteries
• Expensive. For the price, lithium ion would be better.

Lithium ion

Pros:

• About a third of the weight of lead acid batteries.
• Offers high current output capabilities with a low voltage drop.
• Can be formed into a variety of shapes to fill the available space. This applies more to small electronic devices where only one cell is used. Since each cell is significantly smaller then a lead acid battery it would be easier to place effectively.
• Low self discharge rate (approximately 5% per month)
• Are low maintenance and do not suffer from any kind of memory effect.
• High energy density.
• Much faster charge times then lead acid batteries.
• Almost 100% charging efficiency because they do not heat up while charging.

Cons:

• Limited shelf life. A lithium ion battery will age by increased internal resistance and therefore lower current outputs and lower capacity. For our purposes we can expect a life of between 1-3 years.
• Require built-in safety devices which take up valuable space within the battery:
  • Shut-down separator (for over temperature),
  • Tear-away tab (for internal pressure),
  • Vent (pressure relief), and
  • Thermal interrupt (over current/overcharging).

• Require specific charging techniques. The manufacturer’s guidelines should be followed.
• Expensive to manufacture, expensive to buy.
• Fairly new technology still

Conclusion:

We have decided to use lead acid batteries. This is because they are inexpensive and the best choice for a first conversion. Lithium batteries would have significantly higher performance but as we are students we don’t have $10,000 to spend on batteries. Lead acid batteries will also give us the opportunity to upgrade in the future as they are a relatively low-cost investment (compared to lithium ion).

Anyways, got out at 1:30Am – get to my car and find a lovely surprise! Not too sure what hit it because its a very low dent… Possibly a trailer hitch? Anyways, this morning I took the bumper off and popped out the dent from the inside.

Click for a fullsize view

There’s still a bit of a shallow dent left but it won’t pop it out. Could use a bit of touch up paint, but other then that it looks normal again. Amazing what you can do if you just try (neither of us ever took auto in highschool, everything we’ve done has been new and a learning experience).