Friday, December 18, 2009

Long Overdue Video

Here is the video of the first drive. Took way too long to get them off the camera and into the blog but here they are. In this first one, the squeal is the brakes (need adjustment)...

In this second video, you can hear how loud the drive is which is something I am working on. On the GPS (which you can't read) the car gets up to 62 MPH. Not too bad for two 10HP, 72 V motors direct driving the rear wheels in what amounts to 4th gear. Now if I can only get motors on the front wheels.....

Friday, November 6, 2009

October.... OOPS, November update...

Kind of missed the October update for a couple of reasons; a job change coupled with not a lot progress. Basically, I spent the month working on sourcing a hub motor for the front wheels and designing the interface for the cool little embedded computer I bought.

First the motors - I found a hub motor on (basically, a market place where Chinese businesses can connect with buyers) that might meet my requirements. I have ordered one that should be here early next week and I'll get a chance to see if it is going to work. It is a BLDC motor and controller rated for 6KW so it will be interesting to see how it works. The other interesting thing I found was a blog by Shane Colton. He built and mounted a couple of BLDC motors on a Razor scooter and designed the controller to power them; really cool stuff. But the main reason the oracle of the internet (otherwise known as google) directed me to his blog is that he has an idea for an axial flux BLDC motor that would be PERFECT for my hub motors. If I could get four of these motors plus the 10KW controllers......

As far as the little computer. One of my hobbies is programming little embedded computers so of course, the Electric '02 is going to have to have one (or two, or three...) And since a battery monitor is pretty much a requirement with the value of the batteries I'm carrying around, I thought it would be really interesting to combine it into a touch screen computer that could do some other things (mp3 player?, GPS?, etc). I bought a Technologic Systems TPC-TS7390 which is a Arm based computer with a mounted LCD touch screen running Debian Linux. I found the Qt Gui programming language and after a lot (too much in my mind) work setting up the development environment, I'm starting to work on the GUI. It isn't much to look at yet but it is fun. But this lead me to my other great google find: Automon. This is an application built by Donal O'Connor on the same TPC-TS7390 that interfaces with your car's on board diagnostic system (otherwise known as the thing that turns on the "Check Engine" light). Cool thing about Automon is that the OBD system is always collecting information about how your car is running and Automon is able to access that real time. Donal designed a cool interface that allows you to see engine rpm, speed, temps, etc. Really something worth while to check out.

Well I guess that is it for now. I'm hoping to have more to report next time.

Tuesday, September 15, 2009

September Update - ITS ALIVE!!!

The big news for this month is.... The car is on the road!!! Or rather I guess I should say that the car has been on the road. When I initially was planning for this conversion, I wanted a 4 wheel drive car so I sized the motors accordingly. Right now, I only have the rear motors installed (still haven't figured out how to get motors on the front wheels yet). This means that I only have half power and since I went with direct drive, I'm having some issues with hill climbing power. As for straight out flat speed, I've had the car up to 62 MPH (my goal was for 65) so I am right on track there. But when I try to drive the car back up our driveway, which is VERY steep, I can only make it up about 20% of the time. I'm guessing that if the battery is at anything less than full charge, I don't have the torque to get the last 10 feet. What is interesting is that acceleration seems fine. I can get to 60 in about 15 sec which isn't neck snapping but not horrible.

So, now it is time for a re-evaluation. My options are:

1. Figure out how to get motors on the front wheels (most desired)

2. Get bigger rear motors and figure out how to install them in the limited space (see photos)

3. Re-gear the drive to a higher ratio (difficult due to available components and loss of top speed)

4. Up the voltage from 72V to 96V or 120V (requiring new motors and controllers)

5. Rip it all out and re-install the transmission for a more standard conversion (least desirable)

Some other issues I still have to address. The chain noise is rather loud, figure out where to put the fourth battery, speed sensor, body work, battery management system, redo front battery mounts, etc..... I knew when I started this that it was a process that probably had no end. There is always something more to be done but that is what I like about it.

Anyway, here are some pictures of installing the rear drive. I also have some video of the first drives but I still need to cut it together into one video.

Monday, August 10, 2009

August Update

Time for an update: I've been working on lots of different things and making a little progress, the largest was the transmission. The guys at Commercial Machine Service finished up the transmission and I installed it where the rear differential used to be. Of course, I had to make the rear wheels go around using electricity so even though the batteries aren't fully mounted yet, the controller board isn't finalized and I don't have the pot box installed, I hooked everything and low and behold, I have electric motion!!! (I'll video if anyone is interested).

However, not everything worked like I hoped. I'm using a chain drive so the center distance between the input and output shaft must be such that the number of links in the chain is a multiple of two. In my case, the chain ended up needing a half link. Unfortunately, these aren't made for the motorcycle chain I'm using because the half-links are weaker. So, I had to add a full extra link to the chain, making it very loose. Since the center distance between the shafts is fixed, I'd always intended to put a tensioner in because the chain will stretch. Now, it is just going to have to take up more slack. So, I'm working on a design that will fit in the tight confines of the drive, be adjustable, and be able to reverse. More on this later.

Controllers - I laid out the controllers on a piece of Plexiglas and I've gone through a couple of iterations, but I'm still not satisfied. I figure that I will mount them above the motors but I don't want to take up too much room in the trunk, so I'm still adjusting. One thing that is coming together is the method to keep the controllers cool. Again, to keep the cable runs short, the controllers are going to be in the trunk and I was having a hard time coming up with a way of providing enough air flow. A couple of people have used water cooling but mine aren't designed for it. However, I found these: . Secure them to the bottom of the controller with some heat sink compound in between then route the antifreeze to a radiator in the slip stream and Voila, cool controllers.

Battery Mount - I finished up a battery mount for the front batteries but I'm not super happy with it. I've said before, metal fabrication is NOT my strong suit and the mount looks like it. However, it is functional and I figure that since this project probably will never be totally finished, I'll add a professionally fabricated mount to the list of things to be redone.

Batteries - I was part of the group buy from EV Components. I was heading over to Seattle towards the end of July and I thought I would save myself some shipping cost by picking them up myself. Unfortunately, a customs snafu delayed the batteries and they weren't available for my trip. So now I'm having them shipped but that means that I still don't have my full pack. Soon.... hopefully soon. When they get here, I'll have all the components and then it will be time to get this thing driving!

Guess that's all for now. When I get something finalized, I'll post some pictures.

Wednesday, July 1, 2009

Front Battery Mounts

Spent some time last night working on how I am going to mount the batteries in the car. Since I'm going to have the rear wheels driven by motors in the trunk, the logical place is up front where the ICE used to be. Since I'm planning on having four packs, I need to find a place to put the 96 batteries and no matter how I try, they aren't all going to go in the front. Still, I think I can get three up front which will nicely replace the weight (~360 pounds) and I won't have to monkey with the suspension. I'm thinking the fourth pack is going to go where the gas tank was but I haven't made up my mind about that yet.

Since I'm trying a bunch of different configurations, I came up with a different way to simulate the pack rather than the cardboard box method. I got some foam insulation from Lowes and cut it up into 96 LiFePO4 battery analogs. This made it very easy to pack (pun intended) the batteries into the front of the car to determine the best way to get most of them up there.

Now I just have the job of fabricating what I came up with. I tried a little gas welding and let me tell you, it is HARD!! Metal fabrication is definitely not my strong suit so I'm probably going to end up with something that will at least initially, be bolted in. Not my preferred solution, but you gotta work with what you have.

Monday, June 29, 2009

Back after hiatus....

I know... It has been too long since my last update. I've been working on several things but it seems that nothing is getting done. So, I haven't updated with any progress. Well, I just went to the machine shop doing my transmission and PROGRESS!! Back when I started this, I had the idea of doing a four wheel drive car using a motor for every wheel. The first step was to build a new gearbox for the rear wheels and here are the results. It is not 100 percent complete but you get the idea.....
The guys at Commercial Machine Services are doing a great job basically building a prototype using pictures I drew on a scrap of paper. Soon, I'll be installing this in the car and seeing the wheels spin using electricity.

Friday, April 24, 2009

First Battery Set Up

I finished putting together, at least in a temporary setup, last night. I plugged in the charger this morning to give the batteries their first charge and after about an hour, the Volt Blochers have started shunting, just like they are supposed to. Take a look:

Thursday, April 16, 2009

First Set of Batteries

I got the first set of batteries yesterday. I bought 24 Thundersky 60Ah LiFePO4 from Elitepower Solutions. They were shipped very quickly and it was exciting when the UPS guy showed up because the batteries are such a significant investment in this whole process. I also bought a cell balancing circuit board from Volt Blocher. I finished soldering those up last night so the next step will be to hook up the entire pack with the Volt Blochers and get the batteries their first charge.

Sunday, April 12, 2009

While waiting for my gearbox to be built, one of the things that I didn't like about the '02 was the dim headlights. Cars really have gotten much better since 1974; driving the Beemer at night was pretty scary with all the deer we have around here. So, I found a set of Xenon HID lamps on eBay that fit the '02 and boy what a difference. I'll get some before and after pictures and post them.

Out with the old....

As all conversions start, the first thing you have to do (besides decide, design, plan, order... you get the picture) is remove all the stuff associated with the gas engine. This is a grimy, greasy job but it really makes you feel like you've accomplished something. Above are some pictures of the process. At this point, I have removed the engine, transmission, drive shaft, muffler, radiator, and gas tank.

Friday, April 3, 2009

Design Considerations

Ok, an electic car but what do I want....
One thing to think about here in Montana is snow. And from this picture of our driveway (note, this is 3 April and we just got 2 inches of new snow), four wheel drive might be nice...

The Electric BMW 2002

Hello everyone... I have embarked on a project to convert our 1974 BMW 2002 to an electric car. I figured this blog would be an easy way for those who might be interested in the project to follow along and maybe encourage others to do something similar.

I've been interested in electric cars for a long time. With electricity being something that can be produced locally, it makes sense to me that something that is as important to our way of life (the car) be powered by something that I could theoretically produce, instead of gas, which I HAVE to buy from someone else. As we learned last summer, when oil raced to nearly $150/barrel, we still had to buy it, forcing us to cut back in other areas. I believe this was the final tipping point that pushed us into our current recession. But enough of politics... for now.

Why the BMW 2002. Quick answer: we already had it. Longer answer: the BMW 2002 is an enthusiasts car. There are clubs, races, web sites dedicated to the '02 but so far I have yet to find one that has been converted to electric. Obviously, it isn't the ideal car to convert because it is relatively heavy and not very aerodynamic, but hey, see the short answer.

So, without further ado, away we go.