Electric Kart Project

I’ve come to need a vehicle to test products I sell for my business. A motorcycle is too limiting for easy change of a motor, so I started looking at Karts. I wanted an offroad kart, but they take up a lot of room and I’d need a trailer. Then I found a nice Race Kart near me that was super cheap and didn’t have an engine…… and I bought it. It was in great shape and he threw in a Kart stand, Engine mount and a race computer. Plus, How cool is a Kart?

The Kart: Swiss Hutless Race Kart (Hydraulic disk brakes, adult size)

The drivetrain: I’m building so I can swap different motors into the chassis for test. I’ll start with the ME1507 and eventually test the ME1304


Battery: I found some Saft VL41M batteries for sale and I couldn’t turn it down. Working on getting these delivered now. I’m thinking I’ll try to pack as many as I can and do at least 2p. The cells have a 150A continuous and 300A for 30s rating, so that would be 300A continuous and 600A for 30s if I did 2p. I’d like to get as close to 72V as I can, but ultimately it depends on how many fit on the chassis. They’re large cylindrical, 41Ah LiIon batteries. About 8.75″ tall and 2.2″ in diameter with screw terminals for connection to buss bar. They weigh about 2.35lbs each.

BMS: Purchased a ZEVA V3 BMS, one BMS module for each side

Motor Mount: I’m getting 2 of them to test. The other will be used as a bench motor-mount.


Other items:

I’m trying to use as much of the items I currently offer at EMF-Power, so they get some extra testing, and people can see how reliable they are in practice. Plus, I can make tweaks and test for people much more easily.


Here’s a ME1507 and also an ME1304 setting on the frame for reference:


Pics of the batteries:

Out with the old and in with an Empulse R

So the time has come to say goodbye to my eVFR and to say hello to a 2013 Brammo Empulse R.


The eVFR started a few years ago and then an upgrade began to increase the performance and range. Between staying busy outside work and having a side business, I haven’t had the spare time required to finish. I’ve been dependent on EV buddies of mine for the fabrication/welding/3D CAD, so I have to work on their schedule. The electrical system has been together for some time now, but the mechanical side has all but stopped. So I started to look at my other options; buy versus build. After a lot of thought, I’ve decided to sell what I’ve got and purchase a production motorcycle.

So with that decision, I started selling everything. My eVFR chassis, my SV650, the electrical components (motor, controller, batteries, charger BMS) and my recently acquired battery testing equipment so that I could put it all towards the new bike. I figured the moving from DIY to Production I wouldn’t need any of my equipment. I’m still keeping Electro Motive Force, LLC. Open and have been still selling parts, but I don’t think I’ll be as heavily involved with battery testing from this point forward. I’ll still have access to my testing equipment if I need it, as it’s being sold to a friend of mine locally.

I then spent the last month or so researching everything I could on all of the bikes available. I’ve read the reviews, talked to people who own one, 3rd parties that have ridden one, watched videos, looked into the technology inside each one, look at what comes with each one. I talked to dealers like Harlan Flagg of Hollywood Electrics and directly to Brian at Brammo. After weighing all the pro’s and con’s of each, I feel that the Empulse has what I’m looking for in a bike.

I told Brian that I’d like to move forward, but there are no Oregon dealers yet, so we tried to figure out how to get my hands on one before the spring. Because of my proximity to Ashland, and flexibility on time, Brian said he’d let me know if there were any opportunities of purchasing a marketing/engineering bike if one came available. He told me the wait could be long or short, but I decided to be put on the waiting list to see what happens.

After about a month on the list, Brian let me know that there was an engineering bike available. It’s got 500 miles on it, but is otherwise a full production model. I requested their “White Noise” trim. They’re going to run it through their QC department to fully test the bike, and let me know when it’s available for Pickup or if they would be coming to Portland and could deliver.

I don’t have a solid idea of when I’ll have it, but I would guess early March, just in time for riding season to start. I’m excited to say the least.

P.S. I’ll keep this website up a while for posterity, but I likely won’t be posting any more eVFR related blog updates.

EVFR 2.0: Building the pack

It’s been a slow summer. I’ve been too busy this summer to get much done and David moved his shop. I haven’t posted lately, but I have been doing things on and off. I’ve also been riding my SV650 a bit. Really glad I got this to practice on while the bike is being finished. I’d rather learn on this than the eVFR. I wouldn’t want to drop either, but I’d rather drop the SV650 (Has frame sliders) than the eVFR with rare fiberglass fairings.

A few weeks ago I decided I wanted to bin my cells. I borrowed an IR meter from a friend. It’s an AC impedance meter and I realize it won’t accurately give me the DC impedance, but it will allow me to organize the cells into groups of similar IR values. I spent a few nights with my girlfriend testing the cells and writing their IR value on them (she’s awesome!). I got ~150 cells that measured between 5.0-5.9mOhm and like 30 between 6.0-6.9mOhm. One I thought was above 7, but was just the leads not attached correctly. I had some cells that were test-cells and some that were showing low voltage, so I set those aside for testing and further study/destruction.

Now that I had boxes of cells, I noticed some had a tiny number of rust specs on them. None of the rust was very bad, but I wanted to get a pack with as little or no rust on it as possible. Some of the ends where the epoxy is applied seems to have been contaminated, and in some cases appeared between the case and blue plastic covering. After organizing the cells, I have ~165 cells that are near 100% and are between 5.0 and 7.0mOhm. The rest are extras and will be used if I need to replace a cell. I plan on putting a small pack of 16 cells together in a 4s4p 1/2kwh arrangement as a test pack that I can also use with an inverter for portable power (could be used as a small emergency pack to charge the bike).

So after sorting the cells, I got the water-jet cut copper buss-bar de-burred and ready for assembly. I used groups of the same IR value to assembly each parallel group. This will ensure that all of the cells share the current as equally as possible. I think I need some longer Stainless Steel screws. The screws that came with the cells seem to be all over the place with regards to quality, and some of the threads were easily stripped. Despite 2 screw issues, the pack went together well and It measured 36.38V (~3.3V/cell). Here are some pictures of building the 11s5p smaller pack (located above the motor):

I’m going to David’s tomorrow and turning the pack over to him so we can start on the plastic holders/battery box.

I also re-started my Discharger project. I’ve gathered most of the pieces and put together a schematic. I’ve gotten help from a few friends Bob Simpson and John Muchow (designed the CC400 discharger I’ve got). I think we’ve addressed any issues that were lingering and figured an easier way to stop charging when an alarm is triggered. I’ve got a sort of Interlock right now. The Low-voltage alarm, Over-current alarm, Over-temperature alarm and Emergency Stop are all wired to a latching relay. If any of them trigger, the gate of the FET is pulled low, and the discharging stops. The contactors are only there to connect/disconnect the battery, and not to stop the test. Here’s a pic of the parts and of the schematic:

Anyway, that’s it for now. I’ve cut down on my social obligations and renewed my motivation for the discharger and eVFR. I’ll probably start building up the larger front pack this week if I’ve got time.

EVFR 2.0: Slow progress but new bike

I’m sorry it’s been a while since my last update. It’s been a very busy and unfortunate last couple of months. My Aunt passed away and then shortly after, my cousin got sick and succumbed. I went to My aunt’s funeral, and went to visit my cousin before he passed away. Mixed in with all of that, I had 2 family reunions to attend, one in Idaho and one in Montana, as well as a get-away mini vacation for my Girlfriend’s birthday. It hasn’t left me much time at all to work on the bike.

With respect to the battery pack, the plastic has not been milled due to my buddy moving his shop, so I need to shop around for a place that can do it for me. He did, fortunately, get the copper bussbars drawn, sent out and waterjet cut. They’re sitting in my garage right now and I can begin rough assembly of my pack. I want to match their IR in parallel groups as close as possible while I’m putting the pack together so the current is normalized between parallel cells. After that, I can do some bench testing of the entire electrical system while I work over the next couple months to get the plastic cut and a battery box fabricated. I’ll probably bring the bike back to my place.

Due to the unexpected family emergencies, summer vacations and relocation of my friend’s shop, I’ve had to put things off a little bit more. Oh well, my eye is still on the prize!

I’ve decided in the interim that it would be good to get some seat time, and I bought a 2000 Suzuki SV650. It’s sort of a street fighter with a nice tubular frame and naked look with circular headlight. I figure if I can go to/from work, I can at least get some practice in before my other bike is done. I’ve been itching to ride since I got my endorsement.

Anyway, that’s it for now. I expect I’ll be working on bussing the batteries for a couple weeks in between riding.


EVFR 2.0: Fiberglass fun!

Since Dave is working on the battery pack drawings, I figured I’d focus on other things like the fiberglass and headlights. When I first found the upper, it had no headlight holes in it. I decided to do a dual headlight conversion, but needed to fiberglass the lights into the fairing. I spent last night working a bit with Dave to cut out the headlight holes and make some tapered inserts to go around the headlights I’ve got. We also patched the gas tank filler hole. I’ll go back Friday to finish up the fiberglass and start sanding the fairings.

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I also got a race tail for the bike, but unfortunately it was damaged in shipment so it’s got to be repaired. I’m glad I’m still fiber-glassing stuff. Here’s a pic of it now, and what it should look like when its done (pic is from a gas bike of a guy I know).


So after all the fiberglass repair/filling/modification is done, I’ll get all the fairings mounted, drilled and sanded/bondo-ed so they’re ready for paint soon. It’s really starting to take shape.

I think I’ll keep it white, it’s a really clean look. I was thinking some Vinyl graphics, like a PCB design. I looked around one day and found the BMW Activee and it’s pretty much what I had in my mind. Simple silver shaded PCB traces on a white background. Nice and clean and unique. I’ll just have to get a hold of someone to do the vinyl. Here’s a pic of the Activee (courtesy of the e90post forum)