Thursday, December 30, 2010

Lipo and LIFEPO4

I'm doing a interesting mixed chemistry setup that uses the best of LIFEPO4 and Lipo in a diode summed system.
My motivation in doing this stems from the fact that the 40AH Thundersky cells just don't put out enough voltage under load (Sag). For EnerTrac this makes it difficult for my customers to get a true understanding of the power and speed of the 600 series motor, when test riding my bikes. So I need a way to boost voltage under load, without replacing the complete battery pack.
 In the above picture you'll see the CA meter (lower) and a second smaller meter up top. The top meter monitors the Lipo pack current while the CA meter monitors the total system. Up to 1.5C or 60 amps, the LIFEPO4 batteries run the bike, then as current exceeds 60 amps or beyond 2C the LIPO kick in. At 100 amps the LIFEPO4 pack maintain 1.5C and the Lipo pack does the remaining 40 amps. My 40AH LIFEPO4 cells now never see much over 60 amps while my 20C rated Lipo see as much as 200 amps peak.
The Lipo are bulk charged with a separate Meanwell type power supply. Separate balance units are used as needed, they are connected in parallel with the display units.

I accomplished this by exploiting the fact that Thundersky cell have much higher IR than the Lipo cells and setting the Thundersky pack to be at a higher no load voltage. The diodes are 150 volt schocky diodes.
Testing was done on my Dyno. The box under the bike is the Lipo pack 25S 2P

I have only done 4 miles of road testing before the snow hit. I had the Lipo up to 100 amps while the LIFEPO4 stayed under 80 amps during this on road test.
My Dyno Currently can only do 100 amps continuous, measured at controller input. My plan is to do a video record of the display system so I can record in real time the speed, current of both batteries and then put the data in a spreadsheet.
My data so far shows temperature not to be a big problem I've had the batteries on test from 45F to 70F
My big concern is
The 4 to 1 AH ratio - is it correct, only on road testing can determine that.
Battery pack
I think the battery box weights more than the batteries.
The big challenge was getting all the hardware into the bike and still be able to get the skins on.
The bike with the skins back on
I have under belly skins that will mostly hide the Lipo battery box

More data is needed but my testing to date, shows it's possible to mix two chemistry types and use the best characteristics of each respective battery type.


Saturday, December 25, 2010

Custom Wheels

We have been busy working on using our existing 602 and 603 motor and integrating them into aluminum rims. This is a customer job in progress. We machined all the parts in house. We started with a RC components rim and worked from there. One thing you'll notice is the dual rotors for dual disc brakes.
 This is a 16 inch X 3.5 inch rim.
 With the customers permission I'll show the wheel fitted to his fork.
EnerTrac can now offer rims from All American Wheel

2011 will be the start of custom wheels from EnerTrac.

Enertrac is also doing custom spoked wheel at different sizes and widths.
We just finished this wheel for a customer in CA.

3.5 X 17 inch
Warp 9 rim 602 motor

The next update we'll show is forced air cooling. We have been testing it on our dirt bike build. The blower motor is temperature and throttle position controlled. Our experiments are leading us to believe that twice the output power maybe possible with our forced air cooling method.

Tuesday, November 30, 2010

Chopper wheel

As powerful as the 602 motor from EnerTrac is it really wasn't powerful enough for the 600 to 800 pound 
chopper Hence the DU-602 product. Its two motors locked together using one controller.
Two stators one on common shaft

The axle is 250mm long. I can get cast aluminum rim 16 to 21 inches in size any width

Wednesday, October 27, 2010

If it needs an electric motor, EnerTrac will move it

One place a very efficient traction motor is needed is in Solar cars. The only motor to address this market at the 10KW power level is way expensive, like 6 times the cost of a EnerTrac product. EnerTrac is capable of doing the same job being a 10KW product.

EnerTrac is offering a two speed motor 602/604 that can vary the torque speed ratio depending on the winging chosen. For the solar car application we are hand fitting the bearings and doing other trick to squeeze as much efficiency as possible out of the motor.

Can EnerTrac claim to be as good a a NuGen motor, I'll let the teams decide. What I do know is at our price many more teams can enter the engineering challenge of solar car racing. I'm sure properly used the EnerTrac 602/604 will prove to be a strong contender in the solar drive system world.
Newburgh Free Academy Solar Racing Team
EnerTrac is proud to be supplying the motor for this team and bring a race ready car down in price so many more can experience the challenge. We are preparing the motors now, They are built, being tested and characterized, every motor for this application will be custom built and individually tested.

Saturday, September 11, 2010

E-transmission refinements

I now have over 100 miles on the 4 turn /2 turn system.
The most important operating parameter is not to switch when there is drive current in the phase wires. I designed a simple system to detect throttle position using a micro switch on the throttle body

When in the zero throttle position the switch is closed
 allowing winding switching

I also added momentary push button switching with the use of a latching control relay

Friday, September 3, 2010

GPR-S at EnerTrac

In the Northeast, this could be the most GPR-S motorcycles in one place (someone correct me if I'm wrong) Okay they are just rollers

GPR-S Rollers

Dyno in action

Tracking down a vibration

Thursday, September 2, 2010

EnerTrac and the future

Originally Posted by Richard230 on
I do like riding the GPR-S because of its small size, light weight and low seat. However, I don't think the small chassis has enough room to pack in enough batteries to keep up with the Empulse - but you never know. Maybe EMS knows something that I don't.

My Response:
I have three GPR-S rollers in my shop. and when set up with the MHM-602 In wheel motor with the new (not yet released) two speed winding, it will creat a very competitive bike that will hold as much or more battery than the Empluse. How that's going to play out in terms of manufacturing, I don't know yet, but I'll be showing technology that will give Bramo serious competition.

I also hope to be showing next year a chain drive BLDC outrunner motor capable of 20KW continuous and 60KW peak running in a GPR-S. This will be a monster of a motor will be mounted at the swingarm pivot. All this work is being funded by EnerTrac directly no venture capital no government hand outs just dam hard work. Currently none of this work is affiliated with any other company.

I must say Brammo has motivated EnerTrac (me) to bring technology to the forefront that I thought would take two years. My goal is show bikes that can take huge amounts of batteries and perform as well or better than anything out there.

With EnerTracs limited capital its hard to know how it will all play out. Next year will be interesting, I doubt Zero is sitting around doing nothing.

Sunday, August 29, 2010

E-transmission part 2 testing begins

We got the bike back on the road and i did the first test ride and the results are interesting.
The goals of this experiment were two fold
  1. The main goal was to better match the C rate of the batteries to the motor, reducing locked rotor amps. Essentially impedance matching the motor to the batteries, without question this goal was achieved. What this means is from a standstill to about 30 MPH half the current is needed when in 604 mode to achieve the same torque as a 602 two turn motor. Then at 30 MPH I drop the throttle flip a switch and continue in 602 mode. The controller has no problems with the switch from four turn to two turn and back again. 
  2. The second goal was more of a hopeful goal being even better performance, this  is yet to be obtained. Electric motors are interesting animals and very different than there ICE counterparts. While a ICE engine build power with RPM electric engines have most of their torque at the low end of the RPM range. I was Reving out the 604 mode before switching to the 602 mode and from 20 MPH to 30 the performance dropped as the motor became voltage starved. To really test performance I should have switch out of the 604 into the 602 much earlier. To do this fast enough to realize a performance benefit shifting really has to be fast and probably automatic. I believe there is performance to be had as long as no time is wasted shifting. With 100 volts of battery the max top speed in four turn mode is 35 MPH
Actively switching from a four turn motor to a two turn motor works and results in a reduced starting current off the line. An active impedance matched motor reduces the peak current demand on the batteries allowing a peak of 2.5C instead of 5C for the same performance one would get with the standard 602 two turn motor. Also there is less controller switching and less high order harmonics wasting heat in the motor. Performance gains have yet to be measured.

Friday, August 27, 2010

E-transmission part 2 work continues

Working on the relays to switch between two and four turn
Remember this is a test development mule so don't expect to see neat wiring, functional is the best you get here.

Monday, August 23, 2010

E-transmission part 2

Well I spent the weekend recofiguring the winding for a 602 motor and except for a few snags and false starts its finished. Not installed in a bike yet but running in the test stand and I can configure the winding now as a 2 turn or 4 turn winding, on to the electronic side of doing the switch on the fly. We also added more slots in the axle for the additional wires.

Saturday, August 21, 2010


I spent the day yesterday rewiring a 602 motor a two turn motor into a 4 turn motor. I pulled out enough of the winding so I can switch on the fly between a four turn and two turn winding. The thinking is, start off the line with the four turn winding then switch to a 2 turn winding for high speed. I expect the switch point to be around 30 MPH. This should increase the off the line torque and improve the low end efficiency of the motor. This is pure R&D, no product offering is being considered as this time.

On a second note we have three GPR-S EMS rollers in my shop. Are they Demo bikes for the 600 series hub motor, For sale as complete bikes, answer, both mostly I want to show the possibilities the 600 series motor offers. It will increase the battery capacity of the GRP-S by 30% without any performance hit matter of fact I expect a performance increase.

Thursday, August 19, 2010

Motorcycle Market

The full thread and feedback can be found at

By Makoto Fukumori on Aug 17, 2010
Published on Yomiuri

With the domestic motorcycle market languishing at about 10 percent of its peak, due mainly to declining interest among young people, the industry is betting that eco-friendly innovations will rejuvenate sales.

The so-called Big Four domestic motorbike manufacturers--Honda, Yamaha, Suzuki and Kawasaki--are introducing electric motorcycles in an effort to reinvigorate the market.

Motorcycle sales overseas have been increasing due to growing demand in Asian and other emerging economies.

Read more HERE

 My response to the article

I want to say I love E-Motorcycles Love that there is no engine heat up my ass love the quite and love the low end torque, it's just a amazing new lsenseof riding. But it is still riding a motorcycle and fact means its still a recreational product in the USA.

The motorcycle market is failing just like the boat market, Problem is people see motorcycles as a recreational item and not transportation in the USA. Electric motorcycle aren't going to change that thinking.
A good economy will help but only as far as people are buying recreational items. Changing the mindset of people to think of motorcycles as transportation, with the way people drive cars around here, well good luck. Plus motorcycles really aren't for most, I ride one 20 to 40 miles every day and I'll be the first to say it's not for most people, at least not riding the bike as everyday transportation. The focus and skills needed to stay alive on a bike on a every day basis just is not part of the skill set of most people no matter how much training you give them. A Sunday joy ride a few times a year, which is what most people use there bikes for, sure. Anyway that's my rant on selling E-Motorcycle in the USA. In Europe the picture is better maybe much better.

I want to add the big four may be getting into electric scooters for a reason us motorcyclist don't see. The growth may be in bikes that keep it slow and safe to get a new market segment riding, the scared and frightened.

Those who follow electric motorcycle at one time or another have found the forum The other day it crashed and had no useful backup. So if I write something I think is important there, I repeat it here on the blog, So much got lost its beyond sad, its not just the information, its the history of how thing evolved its the flow of information and exchange of ideas that was lost, that forum had character and that is something that happens over time. Now time is starting anew. 

Monday, August 16, 2010

Why Raw feed

This is where those who want to know about EnerTrac, and what the company is thinking can come. Also you can read some unpolished from the hip talk about the EV world.

It's the place to learn what we are working without the marketing fanfare, just plain talk
Who are we anyway start at

I'll start with what we are working on
here is the scoop A motorcycle hub motor with the RPM/volt of a 602 (10 Rpm/Volt) with the torque of the 603. All this is meaningless if you never rode the EnerTrac Motors but for those who have this is number one on the wish list and early next year the wish will come true.