Instead of video, here are some new screenshots.

Unfortunately, these screenshots can’t show the slick zooming in/out when the user taps on the battery pack or on the speedometer/ammeter/temp gauges.  The user can use finger swipes to scroll the individual battery cell displays to show all the cells. I still need to work on this code (it’s a bit jerky) but that’s not a big deal.

Note: all gauges are active at all times, so even though the speedometer gauge gets shrunk down when the user is viewing individual cell data, it still shows the current speed.

I had hoped to show the charge status indicator, but unfortunately, my charger (the Delta-Q) isn’t properly programmed yet, so it refused to charge the battery pack.  Still, it’s coming along nicely, and I think we’ll be starting in on Curtis support within the month.

That’s all for now.

Eric

The motor mount consists of two parts: a face plate and a belly support.  The face plate bolts to the motor face with 4 bolts and then to the frame with two bolts.   It fits perfectly:

AC-31 test mounted in frame - right side view

Ideally, we’d have a matching plate for the rear end of the motor to support the weight, but since the AC-31 is so long it’s not practical to do so.  Instead, Kale fabricated a cradle shaped belly support that takes the weight of the motor (~100 lbs!).  The belly support bolts to the frame and the motor rests on top of the U-shaped cradle.  It’s just meant to support the weight of the motor, not prevent the motor from twisting around it’s axis (that’s what the face plate is for) so it’s not bolted to the motor.

The AC-31 test mounted with the motor face plate - left side view

Currently, the belly mount cradle is about 1/4″ too large in radius compared to the radius of the motor, but that’s because it’s going to have a 1/4″ thick rubber mat between the motor and the cradle to provide vibration damping.  I still need to buy that material, but it’s not expensive (about $5 for a 1′ x 4′ strip from Coastal Farm & Supply).

If you look closely at the left side view, you’ll see a bit of coat hanger wire tying the face plate to the frame.  That’s just there to keep the mount from moving since it’s not bolted to the frame yet.  It doesn’t make any sense for me to hard mount to the frame right now because I need the 1/4″ rubber mat for a proper fit and I’m going to be bench testing the motor & drive system anyway (which means taking the motor out completely).

I was a little concerned about the main electrical power connections being so close to the frame (this isn’t very obvious from the pictures) but Travis pointed out that the cables can be disconnected from the mount points provided so it should be okay.

Eric

Since the SPARC XEV uses a Ninja 250 for various donor parts (rear shock, swing arm, wheels, tires, brakes, etc.) I decided to save some money for the initial version by using motorcycle style handlebars and motorcycle hand controls (specifically, hand brake levers, twist grip throttle, etc.) since I had those parts available and paid for (from the original electric motorcycle conversion project).

As you can see, the lines installed just fine with no problems.

The brake lines go from the brake lever main cylinder to a Y-adapter which splits the line into left and right (one line per wheel – one disc per wheel).  While there is a little awkwardness to fitting the Y-adapter (I should have gotten a few straight banjo fittings instead of all 35 degree angle fittings), it all went together decently without much hassle.

So there I was, thinking that it was smooth sailing from then on.  All I had to do was flush and fill the system with new brake fluid, bleed the system, and I’d be ready to do some brake testing.

Alas, all was not smooth sailing.   Along comes a little surprise – the bolt screws holding the brake reservoir cap on are stuck (rusted? gummed?) and trying to unscrew them with a Phillips screwdriver gets me nothing but stripped screw caps… argh.

Brake reservoir with stripped screws

So, for now, I’m at an impasse.  I’ll have to figure out how I can get those screws out without damaging the rest of the reservoir.  I’m not sure how I’ll do that just yet.   In fact, I’m wondering if I should just dump the hand brake lever and go with a foot pedal but we’ll see.

Eric

Just a quick note to folks who haven’t checked out our forums (where I post much more often).   We’re making steady progress with the SPARC XEV project.

Both seats are mounted, with the front seat mounted on a set of seat sliders to allow for forward/rearward adjustment.  The 4-point seat belt safety harness for the driver is also mounted.  I ordered and received new stainless steel brake lines for the front disc brakes and plan on installing those this weekend.  I also have the Magura twist grip throttle and right hand brake lever temporarily mounted to see how well they fit together (answer: pretty well).  I need to remove the other hand controls (lights, starter switch, turn signal switch, horn, etc.) from the donor bike (a 1990 Kawasaki ZX600D) so I can re-use them on the SPARC.

The Delta-Q Quiq charger has been programmed for the Headway cells (72V pack) and the Curtis controller is already programmed for the AC-31 running at 72V, so we should be good there.  Travis is in the process of getting the controller talking to his computer via serial so everything will be ready for me to put together in the SPARC when I’m ready.  The battery pack holder still needs to be fabricated though, so it will be awhile before any powered runs (although I might do some short downhill rolling tests once the brakes are done and tested).

Lee is working on a new body design for the SPARC but we’re not ready to show anything publicly yet.  It’s difficult to design a body that is both aesthetically pleasing, yet functional and aerodynamic.  Still, it’s a fun challenge and definitely one of the most appealing aspects of the design process.

Tomorrow Travis will be coming by to work on things with me, and I’m hoping to make a lot of progress then.  I want to post some new pics and a video of the xenoDisplay showing data from the Lithiumate BMS.   So look for updates over the weekend!

Eric

The SPARC was designed with the idea of keeping the batteries in a central compartment in the belly of the vehicle.  This keeps the weight centralized and low which helps with the stability of the vehicle.  Furthermore, in order to keep aerodynamic ground effect drag to a minimum, the battery bay tapers inwards near the ground.  The resulting cross-section of the battery bay is trapezoidal in shape so the battery pack utilizes a “zig zag” pattern to best fit the cells within the bay.

The maximum pack size is a 96V 100AH pack (9.6KWH).  Since we use Headway 38120S cells (10AH, 3.2V nominal), this comes out to 320 cells.  However, for development purposes, we’re going with a 72V 100AH pack (7.2 KWH) for a total of 240 cells.  The challenge is to fit all these cells into the bay which is approximately 43″ long x 11.5″ high (maximum) while minimizing distance between banks (to minimize connection losses), weight, and material costs, yet maintaining sufficient airflow, rigidity, and ease of fabrication.  A pretty tall order it turns out.

The design we’ve come up with seems to meet these requirements… But in some cases (dimensions) just barely.  The pack is made up of  “modules” that are 40 cells (arranged in 10P4S configuration) supported on each end by aluminum (maybe plastic) plates that have been machined (CNC/Laser/Waterjet/etc.) to hold the cells.  The number of modules determines the overall pack voltage.  6 modules = 72V, 7 modules = 84V, and 8 modules = 96V.  The modules are connected to each other by threaded rod (M10) with bus plates paralleling each 10P subpack.  The entire pack is then supported by aluminum side plates that hold everything together and keep things rigid by use of a “slotted tab” type of interface with the module end plates.  By assembling with slots & tabs, we’re able to build the pack holder out of nothing but flat plates while maintaining rigidity, protection, lightness, air circulation, and minimizing the amount of wasted material.

72V 100AH battery pack design - length is approximate

This pack is very compact and makes very efficient use of the space.  However, it will be difficult to assemble, and will require that the BMS cell boards be connected via wires instead of direct connections (as they are on our test pack).  The question right now is overall length of the pack.   A 96V pack will be very tight lengthwise.  However, if we can make the pack less than 43″ in length, we should be golden.  I hope.  Right now, it’s not a worry with the 72V pack, but the goal is to allow a 96V 100AH pack for the most range & highest performance.

Battery Pack High Level Data from the Lithiumate BMS

It’s still pretty rough around the edges, and you can expect to see a lot of rearranging, tweaking, and overall optimizing, but right now, it’s very functional and works pretty well if I do say so myself.

Currently, the xenoDisplay shows the following information supplied by the Lithiumate BMS:

Total Pack State of Charge (0-100%)

Total Pack Voltage (0-6.55kV)

Average Cell Board Temperature of the Pack (-127 to +127 deg. Celsius)

Individual Cell Voltage (2.0V – 4.55V)

Individual Cell (board) Temperature (-127 to +127 deg. Celsius)

Individual Cell Resistance (micro-Ohms)

Since the Lithiumate continually spits this data out as a raw byte stream, the xenoDisplay continually monitors the status of each cell in the pack.  The update rate is once per second.

Individual Cell Data Display Screen

In the battery pack detail screenshot, you can see that there are several cells that are not reporting.  This is because I accidentally broke one of the chintzy, home-made, thin gauge connecting wires that goes from the cell boards to the BMS.  Travis is coming by on Thursday with a replacement set and also a new cell board to replace one that was found to be defective when we hooked up the battery pack.

There is a lot of data that is flowing out of the Lithiumate, and this is only some of it.   Later on, I’ll probably add more gauges/info displays for the Lithiumate, but right now, I just wanted to focus on getting the most important data displaying and establishing communication functionality.

I have to admit, it’s pretty fun (and VERY convenient!) to monitor the battery pack from anywhere in the house.  I have the pack and bms set up in a basement office right now, and I can easily check the status from a room in the 3rd floor (two floors up).   Can you do that with your display? =)

Eric

In keeping with the over-arching goal of keeping the cost of the SPARC down to minimal levels whenever possible without compromising efficiency, performance, or safety, I decided to go with seats that are typically used for Dune Buggies.  Yes, that’s right, the SPARC has dune buggy seats.

High Back Polypropylene Dune Buggy Seat

Why Dune Buggy seats?

Well, first off, they are made of polypropylene and are tough.  They are built to be abused not only by the extreme forces and movements encountered when careening over sand dunes, but with extreme environments (direct exposure to desert sand, full sun, extreme temperatures, and water).  These seats will take a beating and then some.

Second, they are extremely light.  In order to maximize efficiency, we need to minimize weight (without compromising strength).  Each seat weighs approximately 13 lbs according to my bathroom scale.  That’s incredibly light for a high back bucket seat.   For comparison, most cheap “racing” (I use the term loosely) seats weigh about 3x as much.

Third, they are inexpensive.  I bought a pair for $70 total from a guy who had abandoned a home made Dune Buggy project.  (note to self: let’s hope I don’t follow down the same path).  You can buy them brand new online for about $60-70 each if you shop around.   That’s pretty hard to beat for something this light and durable.

But they’re hard plastic – isn’t that uncomfortable? Surprisingly, no.  They’re actually pretty darn comfortable.  The seat back is at a pretty comfortable angle, and the contours seem to fit most people pretty well.  If you like some padding anyway, I know they have padded covers that fit this seat as well.

So that’s today’s design discussion.  Like I said, a pretty mundane topic, but even the mundane is important when you’re trying to build a new vehicle from scratch.

Now back to build progress.  Today I mounted the front (driver’s) seat. That doesn’t seem like a lot, and it’s not, but it did entail finding and procuring seat sliders/brackets (~$17 + shipping from speedway motors)  and the proper bolts to go with the sliders. Because my seats are slightly different in dimensions than Kale’s seat, I had to re-drill the mounting holes in both the frame tabs and the brackets.

SPARC XEV Front View with both seats in position

There were a couple minor annoyances to overcome besides the mis-matching mounting holes. The seat slider brackets had four 1/4″ bolts welded in to mount the sliders to the frame (or maybe the seat). My seat takes 3/8″ bolts, so I had to cut & knock the 1/4″ bolts out. Time consuming, but not that difficult with a hacksaw and hammer.

The other annoyance is with the link “wire” provided with the seat sliders. Because the seat sliders have locking mechanisms on each track, there is a cable/wire provided to connect the lever that is on one slider to the mechanism on the other slider. The problem is, the wire is hopelessly too weak and too short. It’s already bending out of shape, and I wouldn’t be surprised if it broke within a week or two. I’m going to take some sturdier coat hangar type metal and replace the flimsy wire.

Closeup of the Front Seat - see the slider lever?

The rear seat still hasn’t been mounted yet, but that shouldn’t be very difficult. It’s just a matter of drilling the correct mounting holes in the frame tabs, and then bolting the seat on.

That’s it for today.  Stay tuned for more updates to come!

Eric

p.s. sorry about the low quality pics.  I used my iPhone since it was handy.

SPARC-XEV Prototype Frame

The frame for the SPARC XEV has already been fabricated from Aluminum and some judicious amounts of steel in critical sections.  Kale Kotecki of K2Metals in Grand Rapids, Michigan did the fabrication.  As you can see, Kale did an incredible job.

Even though only one seat is shown, the frame is designed to hold two passengers in a tandem configuration.

Due to the extensive use of high strength aluminum, the frame is very light yet stiff.  Total weight is ~250 lbs as shown.  The final vehicle weight will be higher of course, but still projected to come in at 700 lbs or less.

xenoDisplay with a Black & White Daytime Theme

Xenopi Studios is proud to announce our first product for Electric Vehicles: xenoDisplay.

xenoDisplay is a combination of software for your Apple iPhone, iPod Touch, and iPad and hardware that allows you to monitor your Electric Vehicle’s onboard systems via a dedicated wireless connection.

xenoDisplay is currently in development.  For more information, please go to the xenoDisplay Product Page.

An early rendering of the SPARC eXperimental Electric Vehicle prototype

One of the projects we have at Xenopi Studios is a battery powered personal electric vehicle called the SPARC XEV.

This rendering shows an early design for the prototype frame, and it includes a body shell design rendered on top.  Since this rendering was made, the vehicle design has changed significantly, so this picture isn’t really representative of the final product, but it’s fun to look at nonetheless.

We’ll post more information about this vehicle in the near future.