Wrapping It Up

The end of the school year always seems to bring with it an urgency to finish a project or two. This year is no different. We were fortunate enough to be selected to diagnose and repair a 2006 Toyota Prius with a sick battery. Some day we will have our own battery reconditioning equipment; in this case we installed an aftermarket reconditioned battery. The unit came from a very reputable company and carries a three year warranty. Our students did an outstanding job of interpreting the data that they gathered and had the battery out of the car in a time frame that would rival that of much more experienced technicians. They then removed the battery cover and pinpointed the failing battery module. If only one module were bad, we could replace it with another one with a capacity similar to the others. In this case there were multiple modules that, while not as bad as the failed one, were also on their way out. When the replacement battery arrived, it was quickly installed and road tested. I cannot overstate the educational value of this "real world" training experience!

In other news, the electric conversion of our off road go kart has gone quite well. Next year's class will take up where we leave off and perform whatever final modifications they deem necessary. They will then disassemble it and send the frame out for powder coat. While we wait for the frame to return, most of the other parts will be cleaned and painted. We still haven't decided on a name for this project; the name "Assault & Batteries" has been tossed around. If you have an idea, let us know. A few facts about the cart: it is QUICK. The top speed isn't great, but the torque is impressive. We are running 80 volts through a 36 volt motor, so the armature speed is very high. The only problem is that we are using the old mechanical speed control from the donor golf cart. The series of resistance coils reaches temperatures near 700 degrees. It's just a matter of time before it melts, so next year's class will replace it with a solid state pulse width modified type unit. The steering system is rather crude, so a rack and pinion unit will be installed. The fact that there is still work to be done does not reflect a lack of effort on our students part. There was a lot of modifications to be done and I am proud of how far this group has brought this project forward. 

The end of this semester doesn't mean that this blog won't see any activity over the summer. The NMC Barbeque, the National Cherry Festival Cherry Royal Parade and other interactions with the public will keep us busy until August. Stay tuned. Until then, enjoy these pictures of our latest project as it looks today.

 

A Busy Semester

A lot has happened since the first day of class. But.... let's start with some business from last semester. We have acquired the software to "tune" the Small Shock mini bike. It turns out that one of our students has quite a knack for programming! Eric has managed to reprogram the bike's controller to provide a big increase in performance. However, the cold weather and snow depth here in Michigan prevents us from driving the bike far enough to gather the data needed to calculate how much range was lost with the new profile. That didn't stop Eric from taking a short (and very cold) test ride. Now, on to current news: we have a new project. A Manco Scorpion off road go kart was acquired and immediately lost it's gasoline engine. The new power source will be the electric motor and axle from an old golf cart. Our plan calls for upping the power from 36 volts to 80 volts. The golf cart's flooded lead acid batteries will be replaced by the lithium iron phosphate cells mentioned in the previous post. The class has been learning to manually charge these batteries with the constant current/constant voltage method. In the build process, some of the students will be learning to use the MIG welder, plasma cutter and other equipment needed to perform the modifications to our kart.

Eric works the software.

A screen grab of the software.

A frozen Eric checks the data logger.

Pete and Nick separate cells from battery packs.

Charging the LiFePo4 batteries.

Our new project. Seats two for twice the fun!

Removing the gasoline engine.

Mock up of the new power source.

Bring On The Next Semester!

It's the middle of December and the semester is winding down. Next week, final exams will be over and the shop will be more or less quiet for a few weeks. That's when preparation begins for the spring semester. Our Hybrid Electric Vehicle class is held then, so now is the time for reviewing last year's curriculum and looking for ways to improve on last year's lessons. One addition for the next crew of recruits will be the "hands on" experience of re-purposing lithium ion batteries that were used in diesel hybrid buses. We will be working with Grand Valley State University in the development of curriculum as it pertains to reconditioning and reusing these batteries. The class will disassemble the battery packs and, after the fore mentioned testing and reconditioning, reassemble the cells into battery packs that will be mounted in our Small Shock mini bike project (and possibly the AntiPrius project, too!). Another activity that I would like to include would be the construction of permanent magnet electric motors. There are a few science kits out there that include all of the needed parts for this endeavor. This would deepen the students' understanding of both motors and generators. Class starts on January 13. Stay tuned!

 

Almost Finished

Small Shock has been through the shake down phase, disassembled, sent out for powder coating and reassembled. The remaining work involves finishing details of the wiring and some more minor tweaks. The regenerative braking system is now controlled via a thumb switch on the handlebars; this week we will integrate it into the regular drum brake which is activated by a hand lever. The semester is over and classes have ended, but our students are eager to return and finish the project. The next post will include much more detailed information concerning our project. Stay tuned!

Haedlight has been converted to LED

LED rear tail/brake light

With big brother AntiPrius

 

"Small Shock" Electric Mini Bike Project Update

"Current" news: it's alive! Our HEV class project "Small Shock" is up and running. Let's start with some information concerning what makes it go: five Werker 12 volt, 44ah batteries wired in series provide the 60 volts for power. Turn the key and listen for the contactor to close; now the current is flowing to the Sevcon Gen4 inverter/controller unit. Twist the throttle and this unit inverts the direct current of the batteries to alternating current and sends it to the 3 phase AC motor. This brushless permanent magnet motor is capable of putting out up to 19 horsepower. Clean, quiet horsepower. The sensation of driving the bike is quite different then a conventional mini bike; totally smooth and almost silent. The only noticeable noise is from the chain - and an almost imperceptible low whirring sound from the tires as they roll over the pavement. A Cycle Analyst digital dash provides data concerning battery voltage, energy usage, speed, distance and regenerated energy that has been directed back into the batteries.

A few notes about the work that remains to be finished before the end of the semester: final tweaks to the wiring - it is important to us that the wiring harness look as professional as possible. This should be finished soon. The DC to DC converter must be installed. That will convert the 60 volts from the battery pack to 12 volts. This will be needed to run the headlight, taillight and brake light. We may also need to add cooling fans to the heatsink for the inverter. Once these tasks have been finished, the students will disassemble everything and the frame will be shipped out to a local company for powder coating. The same bright green that adorns the AntiPrius project will be applied. The wheels and some of the accessories will be painted silver. We have only three weeks to finish and it will be close. If you are in the Northern Michigan area on May 19th, Small Shock may be seen at the NMC Barbeque, along with the AntiPrius and our hot rodded GEM electric car. More info about the Barbeque here. 

Failure Analysis

The above image shows a failure of the highest degree when it comes to Hybrid Electric Vehicles. The dreaded P3009 (High Voltage Leak Detected) trouble code could be attributed to several problems. Battery modules leaking small amounts of electrolyte, problems within the air conditioning compressor and a few others come to mind. Burned out stator windings in a 2001-2003 Toyota Prius drive unit are a distinct possibility as the miles roll up. A Prius model year 2004 or newer uses a boost converter to increase voltage to MG2, which is the main drive motor within the transaxle. Higher voltage means that less amperage is needed to drive the wheels. Less amperage means less heat is generated within the motor, leading to longer life. Click on the picture for a closer view; you will see that the windings were hot enough to burn off the insulating coating that prevents the individual wires from conducting current amongst each other. This condition seems to be less common to Prius owners who have regular maintenance performed at the recommended intervals. The transmission fluid that Toyota recommends has been improved since the original Gen 1 Prius was released. The newer fluid is better at providing some insulating qualities that the earlier fluid lacked. Repairs for this condition involve either new stator assembly from Toyota (figure on spending around $2500.00 parts & labor) or replacing the entire transaxle with a used unit ($1500.00 parts and labor). There is no way to predict whether a used unit is "near failure" without partial disassembly, and warranties on used parts are often very short and may not include labor.

Let's Get Rolling!

The Small Shock project is underway with help in the form of a grant from the NMC Foundation. Actually, I should state that it has been underway for a number of weeks! The Spring 2013 Hybrid Electric vehicle class has been in session since January and we are well into our studies. An update to our project is long overdue. Our plans to re-purpose the Heathkit mini bike frame were dashed when it was obvious that the poor condition of the frame (rust from the inside and a major crack at an important structural point) would not provide the necessary strength needed to support the batteries. A trip to Actron Steel yielded a bundle of 1" X .095 wall tubing and the game was on. We are fabricating a new frame from the ground up. It is our good fortune to have a few experienced fabricators in our class! The main structure has been bent up and welded together. This paves the way for some improvements on our original design. The engineers at ElectricMotorsport.com provided awesome support when it came to recommendations for our drive system. The new plan calls for 5 AGM style batteries. Our lab is now blessed with a Sevcon Gen 4 controller/inverter and Mars 19 horse power, 3 phase AC permanent magnet motor. 

Also in the mix is a DC-DC converter to drop the 60 volts down to 12 volts for the few accessories that are in the plans. Another feature will be the Cycle Analyst digital dashboard and battery monitor. This unit will calculate watts, amps and volts instantaneously as they are drawn from the battery. It will also allow us to check net values since the batteries were last charged as a sort of fuel gauge to determine remaining battery pack energy. Speed, distance and regenerative values will also be logged.

This first week of March should see our frame nearly complete with the motor brackets fabricated and installed. Once we have procured our batteries we can begin work on the framing in which the batteries will reside. Small Shock has generated a lot of interest in what goes on in the HEV lab here at NMC and has hopefully inspired some of our students to think about getting involved in the next generation of electric transportation.

Possible Configuration?

Diving into a 3D modeling program with no prior experience was no fun. After struggling with Sketchup 8 for a couple of weeks, here is what I think is a pretty good idea of what our "Small Shock" project should look like. The batteries are not quite to scale, but the image will serve it's purpose for now. Credit for the Doodlebug mini bike model that I started with goes to JDL3.

"Mini" Project

A former student generously donated a 1960's Heathkit mini bike to the HEV program today. Adam Parzych asked only that we return the gasoline engine to him - no problem, as this project will not involve gasoline, oil or any fluids at all! Our next class will be converting it to electric power. Normally, a project like this would be involve a few flooded lead acid batteries, a simple speed controller and a DC motor. It would no doubt scoot around and be a blast to drive, but have limited range and a low WOW factor. Our plan is much more ambitious. Roll this around in your head for a minute: let's power this way cool classic with nickle metal hydride battery modules scavenged from a Honda Civic Hybrid battery package. Instead of a direct current motor and simple control unit, let's install a three phase AC induction motor. A special control unit / power inverter will convert the DC power to AC and handle the speed control duties. The process will include hours of fabrication - not only the electrical system but metal work for brackets to mount the batteries, motor, controls, etc. As with the AntiPrius project, we will get this one running, then disassemble everything for paint and powder coat. I'm thinking that the same wild green color that graces the AntiPrius would look great right here. But we have plenty of time to change our minds. In our  lab, all input from students and faculty are considered and I can't wait to start hearing everyone's ideas for bringing this former 60's throwback into the modern world.

Almost Finished

Our class has been hard at work with the final assembly of the AntiPrius project. Just a few more details to finish up and we will be ready to head down to Michigan International Speedway for the Square One Education Network Innovative Vehicle Design event on May 5th.

 

 

 

Now That's Green!

  Our AntiPrius project is in the home stretch. Some background for those of you who just got here: The first NMC Hybrid Electric Vehicle class transplanted the components from a wrecked 2004 Toyota Prius into a tube frame dune buggy (aka sand rail) in an effort to build a vehicle suited for training purposes. Visible and physical access to all of the hybrid components is a key factor of the design. We have been tweaking the design of the vehicle for over a year, so it was finally time to disassemble it and send out the frame and some of the pieces for powder coating. Our current HEV class had the car down too the bare frame in less that 3 hours. I was quite impressed not only with their organizational skills but also with the way that they worked together as a group. Until today, our "trainer vehicle" has been in raw metal form. Constant wiping with light oil has held back the rust so far, but we needed a permanent solution. The powder coat provides a rock hard, easy to clean finish. And it doesn't look too bad, either! The original plan was to use a powder coat that mimics chrome plating (at least that was the claim). After seeing samples of the finish in person, it was obvious that nothing looks like real chrome unless it really is chrome! So the choice was made to go with a green finish. Not only is green part of the NMC logo, it represents the green thinking that embodies what the hybrid electric vehicle movement is all about - fewer emissions and using less fuel. 

Batteries

  This week our class began the portion of the course that focuses on battery technology. The students have removed the batteries from our Ford Escape, Honda Civic and Mercury Milan hybrid electric vehicles. They also removed the battery package from our AntiPrius trainer vehicle, which is the same as any 2004 to 2009 Toyota Prius. The AntiPrius battery package has  been disassembled right down to the individual battery modules. A total of 28 modules make up the package. At 7.2 volts each, that adds up to just over 200 volts. The modules are connected to each other in series by bus bars (flat strips of metal with holes in them). We were not surprised to see corrosion on the bus bars, as our studies have found that this problem is not uncommon after 100,000 miles. The point of this exercise is to train our students in the art of rebuilding hybrid electric vehicle batteries. I am often asked the question of what happens to all of the large hybrid and electric vehicle batteries when they have reached the end of there service life. Do they end up in the landfill? Can they be recycled? Will they bring about the end of our planet? Rest easy. There is now an entirely new industry springing up around the millions of HEV and EV vehicles on the road. HEV battery failures rarely render the entire battery useless. The usual scenario is that one or two of the many individual modules that make up the battery can no longer retain and give up energy at the same rate as the rest, resulting in loss of power, a drop in fuel economy, warning lights, and other problems. Businesses such as Re-InVolt will test all of the modules in a battery by running the modules through multiple discharge/recharge cycles to determine their health and capacity. Poor performing modules are recycled and the battery package is reassembled with only the properly performing modules. The finished product is available for a fraction of the cost of a new battery and come with a warranty. The result is that used batteries from crashed hybrid vehicles are in high demand. It would be foolish to dispose of even the worst hybrid battery; there are simply too many valuable parts inside of them! To add to the demand, many ecologically minded persons have found that they can use the individual battery modules in small groups to power electric bicycles and scooters. Others have figured out that with a small package of these modules they can power their campsite all weekend. And some folks have built portable 110 volt A/C emergency power supplies with them. 
   I feel extremely fortunate to have the support of the forward minded department heads at Northwestern Michigan College who saw the demand for training in this new technology. Thanks to them, the students who finish our class will have a valuable skill set to offer their future employers. Over the next few weeks, students will test and treat the batteries from our small fleet of HEV's. There are over 2.5 million Toyota Prius HEV's on the road today. Add to that the rest of the automaker's offerings and it's obvious that the demand for qualified technicians with the skills to maintain and repair these vehicles will surpass the available workforce. 

Bus bars connecting the modules

Corroded bus bars

Battery bottom showing temperature sensors

Individual battery modules

Ford escape battery

Charging an individual Prius battery module

Toyota Hybrid Synergy Drive

Our Hybrid Electric Vehicle class is undertaking a new project, thanks to the generous support of Gene's Auto Parts here in Northern Michigan. A Prius transmission arrived at our doorstep this week, along with inverters from Toyota and Honda vehicles. The transmission is equipped with Toyota's Hybrid Synergy Drive unit, which blends the power from two electric motor/generators with the power from the internal combustion (gasoline) engine. It allows strong hybrids such as the Prius to operate on electric power alone. I cannot overstate the value of having our students dive into this unit. Textbooks and lecture can provide an understanding of the systems that are used in HEV' but "hands on" training has no substitute. After disassembling the unit, the class cleaned up all of the components. Next week, we will cut away the cases and assemble the unit to provide a cutaway view for use in display and for future training. 

Big Display

Teaching automotive technologies today involves a good deal time spent demonstrating how to use a scan tool or oscilloscope to view and gather data and/or electrical waveforms. Those demonstrations become difficult when trying to present the data on a laptop computer screen to a group of students (yes, most of the programs that we use today are computer based). Eighteen students divided by one 15" display equals the possibility that someone gets left behind. We are resolving that problem with a large screen TV and a rolling cabinet in which we can store all of our test equipment including test leads, laptop computers, scan tools and various other pieces of testing equipment. We're tackling this project "in house" with the help of NMC tech staff. We started with a rolling cabinet and built a raised counter top. Under the counter will reside a PC, keyboard and mouse. A switch will allow us to swap the display from the PC to another input (scan tool, laptop, etc.). A webcam on an articulated arm will act as a document camera to magnify and display parts and documents. The camera will have a clip which will allow us to remove it from the arm and place it under the hood (or anywhere else on the vehicle) and allow all to view the subject matter at a very high resolution. We are about halfway through the project and should have it finished in a week or two.

Enlightening

We are in the process of installing all of the bits and pieces needed to make the Hybrid Trainer Vehicle legal for use on the street. After studying the Michigan Vehicle Code, I found that we would need mirrors, lights, a windshield and a few other items to make it come together. The mirrors are installed, as are the headlights, taillights, brake lights and turn signals. The taillights, brake lights and turn signals are high efficiency LED units. The cool thing about that is they appear to be clear, but light up red or amber when energized. Actually, the lights are merely mounted. Our next class starts next week, and they will design and implement the lighting controls and wiring to get everything on line and working. I can't wait to get them started!

The turn signals are below the headlights, to the outside.

Turn signal on the left, taillight/brake light on the right.