Ian Hooper's Honda NSR150 conversion

Post by **zeva** » Mon, 02 Dec 2013, 01:02

Time to introduce my new EV project, conversion of a 2001 Honda NSR150:

This bike has actually been sitting in pieces in my workshop for a couple of years now, after I partially disassembled it one day after getting sick of the unreliable old 2-stroke dinosaur burner. Here's a pic of where it's at now:

This will partly just be a toy, but also backup transport if I happen to be tinkering with the RX7 and need to get somewhere. I have fairly modest goals: Highway capable, 40km range (at 60km/h), and acceleration no worse than original - not hard as it was only a 150cc. Here's the plans so far:

Motor: Motenergy ME1003. 72V, 12kW continuous; a bit like an Etek only bigger. The no-load speed of these at 72V is 3700rpm, but I believe these motors are OK up to 5Krpm so I plan to run a higher voltage pack, and limit the motor voltage to about 100V.

Controller: One of my MC600SPs (150V 600A DC). The motor is rated to 200A continuous or 400A for 1 minute. So I expect it'll have no trouble with 600A for a few seconds.

Battery pack: 36S12P pack of K2 26650EV cells, for no better reason than I have a few boxes of them sitting in my workshop from way back in the days when I retailed them through ZEVA. So it'll be 432 cells, 115V 38Ah (4.4kWh), about 35kg, 20L volume.

In truth I would rather not build a pack from 432 little cells but they are basically free, and they do have relatively good energy density which is useful in motorbikes with limited space.

Performance estimates: At 100km/h the rear wheel (Ø62cm) would be doing 855rpm. A drive ratio (simple chain drive) of 4:1 would have the motor doing 3420rpm, seems about right. The datasheet indicates the Motenergy ME1003 has a KV of about 51rpm/V (this is linear with PM motors), which converts to a torque constant KT = 0.19 Nm/A. So at 600A, the motor should have 114Nm torque, making 456Nm at the rear wheel, or 1471Nm acceleration force. Assuming 200kg weight including rider, that's about 0.75G.. should be plenty!

As this will be my first bike conversion, I welcome technical suggestions from anyone who has experience converting bikes. Is 40km range from a 4.4kWh pack realistic?

Website · Post by **Simon** » Mon, 02 Dec 2013, 01:49

I remember you getting that bike ages ago!

I think 40km range is realistic. My Vectrix has 42 x 40AH CALB cells (around 5.3Kwh)and can do 85km riding gently at 50-60kph and it is hard get under 65km range riding harder and faster to 80%DOD. I haven't tried or needed to test the range at 100kph yet though.

Post by **jonescg** » Mon, 02 Dec 2013, 02:03

4.4 kWh should get you about 60 km or so under normal use. If you gear it on the tall side your battery won't be too stressed. There is very little room in that bike, so I think to fit 4.4 kWh is doing well

If I could give one sentence of advice for motorcycle projects, it would be to make each component self-contained and easy to disconnect.

If make it so that you only have to remove one part to get at another, or even better access it directly, you have a stress-reduced bike. Having to remove every bolt from the bike in order to change a sprocket or speedo sensor is not fun.

Looking forward to watching this one progress!

Post by **zeva** » Wed, 11 Jun 2014, 02:54

I thought it was about time I uploaded some pics of the NSR150 conversion. The project has been progressing well, hopefully it'll be rideable in the next couple of weeks.

The motor I'm using is a Motenergy ME1003, a pretty torquey little permanent magnet DC motor. At 600A max it should put out a bit over 100Nm, and spin up to about 5000rpm from 96V (or more). I built a cardboard mockup before buying the motor to verify fitting.

The motor gets mounted to a 3mm thick steel plate which is fastened to the chassis in three points (two of them being the sturdy mounts the engine was previously attached to).

Here's the motor sprocket, built from a 7/8" bore boss welded to a 12T sprocket. It gives a drive ratio of 3.5:1, which will mean 3000rpm for the motor at 100km/h.

After measuring up the (readily) available space for batteries, I had to scale down the pack quite a bit. In the end I settled for 44S6P (~2.7kWh). The voltage is higher than the motor needs but I can limit motor voltage in the controller. I checked the fit of the planned pack with a cardboard mockup.

Then the long boring job of spot welding 264 cells together.. This is one "sheet" of 11S6P, and there are four of these stacked together with polycarbonate insulating panels between.

Here's the completed pack (minus housing) including BMS being tested.

The battery pack is to be housed in a steel frame, lined with polycarbonate. Here's the frame being welded up.

It ended up being just a bit too tight, so I had to remove and re-route a small section of steel tubing. Bit of a pain but things don't always go to plan!

Here you can see the fit of the battery box above the motor area.

The motorbike will be getting a complete EVMS2 system, as a bit of a product demo. Here's the Core mounted up the front (with wiring in progress), tapping in to the existing 12V harness for power and key signal.

After painting the motor and battery frames, I installed them on the chassis, mounted the motor and installed the chain. It's a brand new chain (cut to length) since the old one was unfortunately a few links too short.

And finally here's a pic from the other side, showing the back of the motor and MC600C motor controller mounted next to it. The controller is a bit lower and more exposed than I would have liked, but if there's one thing I've learned from doing a motorbike conversion, it's the lack of space and location options for large components!

I picked up some of the final components from EV Works today (DC/DC, charger, potbox, etc) so will be working on the electrics over the next week or so. The 2kW Elcon charger is unfortunately too big to fit anywhere on the bike - I might have to carry it in a backpack if I need to charge on the go. On the bright side, charge time will be about 80 minutes!

Post by **PlanB** » Wed, 11 Jun 2014, 23:27

Nice work again Ian, what do you use to spot weld the cells with?

Post by **zeva** » Wed, 11 Jun 2014, 23:36

It's a home-made capacitive discharge spot welder:

http://zeva.com.au/Projects/SpotWelderV2/

I wouldn't recommend building big EV battery packs this way in general though. It's a heck of a lot of work. The only reason I went this route was because I had lots of these cells lying around from a cancelled project and don't like seeing them go to waste!

The 26650EV cells do have great energy density though. It's quite a lot smaller than a Winston/CALB/Headway pack of equivalent capacity, which is particularly valuable in a motorbike conversion.

Post by **Bluefang** » Thu, 12 Jun 2014, 04:31

Awesome bike Zeva

What weight are you aiming for?

Really wish i had started my bike off with a NSR150 Donor, would have been so much easier and more fun. Great job building up the battery pack, no really looking forward to building up packs from even smaller 18650 size cells but they cannot be beaten for power to weight/size(going to get the parallel groups welded up first tho). Hopefully yours packs enough punch for a great bike.

Is there any room under the seat/tail for the controller? Might be better protected up there.

Post by **PlanB** » Fri, 13 Jun 2014, 18:16

Really nice job on the spot welder Ian. How many wh/kg you getting from the 26650 cells. I'd love to upgrade a Leaf pack to cylindricals for twice the range but the cost is half the price of the car.

Post by **zeva** » Fri, 13 Jun 2014, 19:04

The 26650EV cells are 83g for a 3.2V 3.2Ah cell, which comes out at 123wh/kg. Pretty good for LiFePO4.

From memory the 20Ah A123 pouch cells were also about that energy density, but much higher power and better packing / volumetric density. They'd probably be my first choice for a motorbike pack (if I had a reliable supply and didn't already have the K2s!)

Post by **zeva** » Sun, 22 Jun 2014, 03:38

The NSR is complete! And I've done a write-up of the conversion including lots of photos here: http://zeva.com.au/Projects/NSR/

I haven't clocked up many K's on the bike yet and I'm not sure what its range is, but it is a lot of fun to ride. Here are a few recent pictures..

The battery module just before installation in the bike:

The motor and motor controller:

Contactor, fuse, potbox, current sensor:

Completed bike minus bodywork:

Completed bike with bodywork - which few people would notice is now electric!

I'll get some videos of it in the near future too.

Post by **jonescg** » Sun, 22 Jun 2014, 04:06

Very neat job Ian! I would enclose that pot box a bit more thoroughly though. Could get a bit dirty and unreliable down there. Great battery build too!

I have to say I am generally in favour of using the original throttle cables instead of a fly-by-wire. Something a bit more resilient about the way it feels. You should get about 35 km range on that pack.

Post by **Richo** » Mon, 23 Jun 2014, 20:30

Awesome sleeper!

As a matter of interest what do you think the total cost would be to others (ball park figure)?

Post by **zeva** » Mon, 23 Jun 2014, 21:33

Adding up all the main parts (motor, controller, batteries, BMS, EVMS, DC/DC, contactor, potbox, charger) gives a total figure of around $6K, so I guess it wouldn't be particularly cheap to replicate. Plus maybe 50 hours of labour of course! The NSR150s make a pretty economical donor though, $2K buys a decent example.

Many of my decisions were based on already having some parts on hand, or using my own designs. I think something similar could be done for a couple of grand less, albeit with a little less performance and functionality, by sticking with 72V (allowing for cheaper controller and charger), using a more basic BMS, maybe using Winston batteries instead of K2s, and less instrumentation.

Converting a motorbike is certainly a much cheaper and easier proposition than a car though!

Post by **Rusdy** » Tue, 24 Jun 2014, 19:37

Nicely done! Any trouble getting it registered on road?

Post by **Richo** » Tue, 24 Jun 2014, 20:47

I don't know if I'd go as far as using Prismatics on a motorbike.
I think I'd rather suffer the Wrath of Li-po's than use prismatics.
Headways would probably make a reasonable substitute for the K2's.

Looking at one of the photos it appears that the chain is really close to the swing arm.
Is this causing the noise?

Have you tried for a top speed yet?

Post by **zeva** » Tue, 24 Jun 2014, 23:04

Rusdy: It's still on its original (150cc petrol) license, I haven't got around to relicensing yet.

Richo: I was just thinking prismatics are the cheapest option for kWh per $. But they do also have the lowest energy density and may be difficult to fit into the funny shapes available for battery placement on a motorbike. Headways would probably be easier. (I think Catavolt were/are using Headways?)

The front sprocket is 20% smaller than original so the chain is closer to the plastic bash guards on the swing arm. It could certainly just be the chain slapping the guard on the swing arm that's making the noise. I might try tightening the chain a little more (and make sure there are no tight spots) and see if the chain rattle reduces.

No top speed test yet, I haven't even tried it on a highway. In theory the motor would rev out to 150km/h, but I have the controller set to pull no more than 15kW from the batteries, so it might top out around 120km/h (since motorbike aero is so poor).

Post by **Thalass** » Tue, 24 Jun 2014, 23:46

Wow that's a mighty fine bike, Ian.

Post by **GRMarks** » Wed, 25 Jun 2014, 00:31

Nice job Ian. At least yours is finished, mine just sits in the garage at 95% done waiting for me to finish it. I made the mistake of deciding to re-make my fairings and covers to fit over the pack size I wanted. But the bike only looks as good as the covers and fairings and that take an awful lot of work to achieve. Because of weight I had to change it to a single seat (to use the weight of the passenger for the battery pack) and that means making new covers from scratch. the bike is border line on weight so all covers need to be in carbon fibre.

Once it is finished it won't look as cool as yours though!

Glenn

Post by **zeva** » Thu, 26 Jun 2014, 18:50

After some test-riding around the suburbs today (all 50-60km/h speed limits), I calculated the efficiency of the bike at around 47wh/km. With a 2703Wh battery pack, this comes out at a 57km range. More than I expected!

If I were to carry the charger with me in a backpack, and had 90 minutes or more to recharge at the destination (2kW charger), that's a 114km round trip range - which pretty much covers the entire Perth metro area. I'm pretty happy with this.

That said I suspect the efficiency would be a lot less at highway speed. I'll have to test that in the near future.

Post by **EV2Go** » Fri, 27 Jun 2014, 00:22

Someone that underestimates the range... that has to be an EV first

Post by **Richo** » Fri, 27 Jun 2014, 20:42

zeva wrote: I calculated the efficiency of the bike at around 47wh/km. With a 2703Wh battery pack, this comes out at a 57km range.

To 100% DOD?!?

Post by **zeva** » Sat, 28 Jun 2014, 02:18

Yep, 57km would be 100% DoD - assuming the cells are still up to spec.

I didn't actually ride it until flat though, that figure is an extrapolation based on energy used over a 15km ride.

Post by **zeva** » Fri, 10 Jul 2015, 01:44

A question for others who've done motorbike conversions..

I've decided to use the bike as a testbed for AC motor controller development, so I've stripped out the DC gear and will be getting one of the Motenergy BLDCs to put in instead.

Their brushless motors aren't as torquey as the DC one I had in there, so I'm thinking I'll really need to change the drive ratio. At present it's 12T front, 40T rear. I probably can't go any smaller on the front, so need to procure a rather big rear sprocket - maybe 60-80T.

Does anyone have a good source for such things, preferably to suit 520H motorbike chain?

Post by **bladecar** » Fri, 10 Jul 2015, 04:11

Hi Ian,

From the photo showing your batteries, and as a Vectrix rider who loves the low-down weight (as you would), it looks like you might notice the high-up weight on the honda. I had a Matchless 650 years ago and it was like a big pendulum taking it from one lean to the other. Do you notice any of the high weight when riding the Honda? Just reminiscing

Edit: Added a bracket

Post by **jonescg** » Fri, 10 Jul 2015, 05:51

Looking forward to how your homebrew AC controller goes. Would you be looking at a stepped squarewave or a pure sinewave controller?

Bladecar - the centre of gravity on a motorcycle is a funny thing. I've been told by many racers and frame builders that a high CoG isn't such a bad thing on a motorbike, but their idea of high is probably a few cm higher than wherever 'normal' is.

Voltron definitely handled better when it's CoG was lowered, but it's still high in comparison to a YZF-R1. There are no hard and fast rules. It just needs to be in the right spot, and how it affects the handling of the bike really comes down to the rake angle and the wheel base.