My first conversion: Jamis X2

[ronnbot]

Hi, it's my first post (but been on these forum a lot) and I'm about to convert a cheap mtb to an ebike. Got pretty much all the major parts and would greatly appreciate some suggestions on how to mount all the electronics and even some critiques on my component choices.

The bike is a Jamis X2 2011. Switched to road tires and added stuff like a rack to make it better for commuting. I already have another Jamis, an XC comp 211, and love it so didn't mind getting another Jamis. Also, it was only $140.

It's a 9C 2806 rear hub motor from ebikes.ca. Great thing about ebikes is that they're located in Vancouver, and minutes away from my home/office. Talked to the guys there a couple times and they know their stuff.

Got a Crystalyte Sensorless 25A and Cycle Analyst as the brains of this operation.

Bought 6 x 5000mah 4S 20C lipos from HK. I liked that they're in hard cases and the price was good at less that $25 a pop. I'll be wiring the packs to be 3s2p or 12s2p lipo cell configuration for 10Ah 44.4V. The 25A requirement should be easy for this packs. I think it's a good set for roughly $150. May decide to get 3 more to make it 15Ah, but I'll try 10Ah for now.

Didn't get a charger specifically for this setup, so I'm just using one that I currently have for my RC stuff. I'll be balance charging all 6 packs in parallel via the board to the right. Later, I might have to get a dedicated charger with a higher V so wouldn't need to remove the battery packs from the bike.

Just for fun, my 1/8 truggy with 2400W+ system and goes almost 90km/h and can pop a wheelie at 50. Initially converted from nitro to brushless more than 4 years ago. I find it funny that the ebike would have less power.

So there's the list. Do I need a BMS? How to mount them? Putting all the stuff in panniers on the rear rack would be the easiest option but the balance would be quite off. Suggestions?

 

[ronnbot]

Based on ebikes.ca's simulator, it should hit 30km/h at around 57% throttle and reach 46km/h @ WOT. Anyone used their simulator and find it accurate?

 

[dogman dan]

The sim is as close to dead on perfect as you will ever see.

Looks like you have a lot of stuff pretty well figured out. Not a noob to lipo is good. Hardcases is good, I do a lot of carping when I see naked lipos taped to a bike frame, but you really can just about do it that easy with the hard packs. Just drop em in a triangle bag would work fine on that bike.

Nice bike for $140. I assume that's not MSRP new. Perfect example of the kind of rear dropouts that make mounting a motor easy as pie. VERY GOOD.

The only nitpick I have is the choice of the faster winding. I'm the slow motor winding kook here, I just love the really slow windings, but tend to run them at 72v. A 2806 will lose efficiency on every stop sign compared to slower windings. A 2808 might have been a better choice if your route is going to have lots of stops. It just depends on how urban your route will be, and how long the ride. If it's more of a short sweet ride, then you'll never care, except for the bike taking off sluggish from each stop.

If it's possible for you to easily still return the unused motor, go trade it for a 2807. Still plenty fast at 48v, but just a tad nicer off the line. Or trade the controller, and just go straight to 72v. At 72v it might still be less efficient, but it won't poke off the line anymore.

 

[ronnbot]

Thanks dogman for the reply. The bike was from craiglist but I saw the 2013 at a local store for $499 and 350 for the 2012.

I was able to inspect the rear dropouts of the bike by looking at the newer version at the store. I agree with you that mounting the motor would be easy as pie. Actually, after picking up the motor, I mounted it and it was all good. Here's the drop out:

I was uncertain which motor wind of the 9C to choose. When I went to ebikes.ca, the guy said there's not much difference in practice between 2806 and 2807, and the 2808 would be slow on 44-48V. I'll think about it again and the motor isn't used yet so I should be able to exchange it if need be.

 

[dogman dan]

All of those windings work fine, but you got the fast one, which can be quite fun on 48v. You should see 30 mph.

It's just when you compare wh/mi on a route with too many stop signs that you wish for a 2808, and screw the top speed.

Fun is good, nothing wrong with that. I just need efficiency more on most of my bikes. My favorite bike is a winding that hits 33 mph on 48v. But often I ride it in a speed limited mode that gives me just 17 mph max. I get great efficiency in that mode, but the take off from a stop sign is like a snail.

The way to get your cake and eat it too, is to use slower windings, for bikes that run on 2000w or less. Then use a higher voltage, 48-72v to get the top speed back up to 25 mph or more. Once running a certain speed, all are equally efficient at say 25 mph. It's getting from 0-25 mph where you lose power into heat with the faster motors. All this applies only to big wheel bikes, in 20" rims, the lower gear makes the fast winding efficient.

It works, and the few that have listened really seem to like it. But the downside is all the wires on your bike having higher voltage, and often needing to use a battery with a very high c rate to keep it from being a huge boat anchor.

Bla bla bla. In short, you'll be fine with that fast motor, unless you have to come to a full stop every block.

 

[ronnbot]

Finally got around to making most of the soldering job done.

I made the harness to be able to series 4 packs. Then got 4 parallel adapters. I made a shorting plug since I'll be only using 3 of the 4 slots of the harness. Will get 2 more packs later to add the 6.

The harness with the plug and 3 parallel adapters. Since I can store the batteries in one place, there was no need to make the harness long.

I tried to make the harness compact so it doesn't look like a jungle with the 6 packs plugged in. It'll only get worse with 2 additional ones in the future.

Since I'm planning to add an additional 4s2p of batteries, I first need to do an exchange. I'm hope to return the Crystalyte 25A sensorless controller for the Infineon 25A and the 2806 for the 2808. The problem is that the Infineon 36-72V is not available till the end of the May, which is 30 days pass the purchase date. We'll see what happens. I want to be able to go higher voltage as my commute will involve some inclines. The move to higher voltage is key since the motor is practically limited to 25A.

Anyway, I tested the setup by temporarily mounting the wheel to my bike (should've done this sooner) and found some weird things:

Firstly, the wheel spins the wrong direction, which I found interesting as the wheel technically can be installed on a bike only in one way.

Secondly, the motor spin slowly with 44-48V even at WOT. Didn't measure it precisely but doesn't look anywhere near 46.1kph the simulator calculated.

Thirdly, I was told that the throttle can be plugged in to the CA instead of the controller. When plugged in to the CA, I see a bar on the display of the CA move as I play with the throttle, but the wheel doesn't spin. When the throttle is plugged in to the controller, the wheel spins, albeit slowly.

What could be wrong?

 

[sabongi]

Since you´re probably using the CAv3, it limits your throttle for default.
Go to CAv3 throttle setting and set it to pass trough!

And since you´re using a sensorless controller, just switch two of the phase wires of the motor, just like you do on rc cars. This will change wheel direction.

 

[ronnbot]

Finished the bike last week. It would've been done sooner if the batteries didn't take too long. Also, business trips, moving and 1 month long vacation hindered it a bit. Anyway, here it is...

Didn't initially plan on putting the battery and ESC in the pannier but couldn't find a triangle bag for the battery that I liked. Besides, I wanted to continue using these panniers, which can carry a lot of stuff.

Wires routed to the panniers.

I did manage to exchange the motor and ESC to a 9C 2808 and Infineon 72V 25A. The Infineon is smaller, cheaper, has higher voltage, better sealed and can also operate in sensorless; much better than the Crystalyte it replaced.

I started out with 12S2P 10Ah LiPos but added 2S - 3S (also 10Ah) LiPo packs from my RC for more power. The speed is good and acceleration is snappy. If I hadn't exchanged the motor/ESC, I wouldn't be able to do this.

One thing that makes me kind of scratch my head is that when I accelerate hard from almost a dead stop, the CA shows 4000W+. I didn't think the system would spike that high. I'm sure the LiPos are fine as they're rated at 20C continuous but not sure about the ESC/motor as they're supposed to be only be 25A. Or is the CA off? Hadn't spend much time configuring it. Also, the Infenion I got is some kind of demo with weaker regen. At least when I use it, it doesn't slow me down too much.

Here's the break down of parts and costs (not including taxes/shipping):
Bike - Jamis X2 2011 - $140
Conversion kit from ebikes.ca - 9C + Infenion + CAv3 + half grip w/ regen button + disc brake shim - $465
Battery - 6x 4S 5000mAh - $140
Misc - road tires + pannier + rack + better rotors + etc. - <$200
Total = <$1000

Note that cost of chargers, PSU and other material aren't included since I already have these things as part of my RC stuff.

Anything else I should do to the bike (besides remove the useless kickstand)?

Almost forgot to mention: ebikes.ca is awesome!

 

[ronnbot]

ESC and LiPos in pannier

Moved ESC under the rack for better air cooling.

Busy handle bar

Result of my ride home today. For comparison, it takes me about 40-45 mins by car with typical rush hour traffic. The bus/train would take longer.

The other side of the pannier stores the charger and PSU; as well as my work stuff (15" MacBook, clothes, etc.). Also added a top tube bag for my phone, wallet, etc.

Initially thought that having all that weight back there would ruin the balance/handling of the bike, but not really. Actually, the back feels more planted especially when breaking hard.

 

[ronnbot]

Last week, took the bike to work after being in storage since Oct. The motor wasn't as smooth as before so cracked it open:

Living in the Northwest, should've expected this. So I cleaned it up:

Also sprayed this after. Maybe it'll help?

 

[ronnbot]

The bike is reaching 3000km and it's been mostly problem free. I've done some work on the bike and here's how it looks now:


Basically, I moved the CA, re-routed wires, installed a suspension seat post, added a better stand and light, and replaced the tires/fenders. Also, I'm currently running 16s (around 66V). They are in my panniers (4x 4s packs on each side) with the charger and power supply:


The light is supposed to be 1800lm or 600lm x 3. Regardless of the actual rating, it is a vast improvement to what I was using before. It has 3 bright LEDs:


For one month in the fall, I kept getting flats; basically once a week. So, I remounted the original knobbies and added some Mr. Tuffy Tire Liners. No more flats but the tires were heavy and slow. There was a very noticeable drop in performance not just in handling - lower top speed, slower acceleration and faster draining batteries. So, I replaced the knobbies with some semi-slicks; they are Bontrager H2. Here it is with the new fender that has a mud flap:


I wish to drive it more, but I've only ridden a few times since I took the bike out of storage. It's still cold with patches of black ice all over the place.