Tostino's Ebike Rev-3 Recumbent

[tostino]

Well I completed building the 3rd revision of my bike a couple weeks ago, and i've just been tweaking it since.
The bike is a Sun EZ-1 Super Cruzer that I got for $150. It needed new tires, but that was all that was wrong with it. No rust or anything.
I got a 9c motor from Ebike-Kit laced into a 20" wheel. I had to dish it a little, and also bend my dropouts, and make a spacer that goes under the sprocket and contacts the frame.

After I got the motor fitted to the bike, and took it for a few test rides, it was time to rip the motor off the bike, and tear into it. It was time to mod it for delta/wye.
After opening the motor up, I noticed there was enough room inside to mount the relays, rather than bringing out 6 phase wires from that little shaft.


I modded the relays with solder wick to be able to handle more current without heating up.

View attachment 2

Detached the phase wire terminations.


I then got down to hooking it all together.


In the last photo, look closely at the hall ground wire, I cut it, and am using it as the ground for my relays. It then goes through a 200ohm resistor, and the three relays. On my handle bars, I have a switch that will energize my frame, and this engages the relays to switch to delta. With relays off the motor is in wye.

 

[tostino]

After a few test rides, there was something wrong in my motor, and I had a feeling it was because I used hot glue.

I had to pedal bike home, and open motor up, low and behold, the relays were not held in place and the phases shorted to stator. No damage done, so I start pealing hot glue off of everything, and I use some gorilla glue in place of it.


Another thing I noticed after a few more test rides, was that the phase wires were too hot to touch when accelerating, and running in delta. Motor comes off again, and I stuff some 12g wire down the shaft in place of the 16g. I also shortened it by about a foot. (sorry, don't have pictures of the process)
View attachment 2
Now they don't heat up at all.

My controller I got from Keywin is a 50a 12fet model that I modded for 65a. I beefed up all the traces on the back of the board, and soldered the shunt. I also enabled regen breaking.
Even when cruising at 40mph, or after accelerating hard, I do not feel it heat up. I also added 4 6800uf caps in between my battery pack and controller. I don't know if they are really useful, but they're there none the less .


My battery is in two parts. I have 6 milwaukee v28's in parallel hooked up together, and they give me about 15ah usable at 25.5v. My other battery I made out of Konions, and is 25.5v and 22ah (I have the cells to make a 2nd, and I am doing that now). I put the milwaukees and my battery in series, for 51v at the controller.
View attachment 1

 

[tostino]

So in Wye, top speed is 24-26 mph. In delta top speed is 39-41 mph.

Regen breaking is very useful from what I have seen. I average 5-7% regen, which extends my range by probably 1.5 miles or more pr charge, and it helps me stop quicker than manual breaks alone.

Here is a couple pictures and a video of a ride today. Sorry for poor quality.

http://jeeeep.com/ebike.avi

I really want to hear comments, or questions.
-Adam

 

[John in CR]

Great work Tostino and thanks for sharing? I take it that stock the motor was wound delta, so the WYE gives you an electrical "low gear". How much better does it accelerate and take on hills in WYE? How well does the controller handle "shifting"? I ask because the big hubbies I have are really fast, but I'd like more torque, and I'm already at a 20" wheel. I have even more space in the covers than on yours, so great potential to follow your lead.

John

 

[tostino]

The 9c is actually wye to start out with, and had a top speed of 25mph. After I added the delta to it the top speed is 40+ mph. So sadly, this won't give you more torque. I am in Florida though, so I have no hills what so ever.

The controller can perfectly handle the change, however, most of the time I let off the throttle when shifting. If you don't let off the throttle, one of the relays can switch before the others, causing a short with high current spikes in the controller, which may blow the fets.
However, I have switched without letting off the throttle before, and it didn't destroy anything, and just gave me a HUGE boost of acceleration as soon as the relays contacted.

FYI, most motors are wound in wye. I know the x5 can't even be switched to delta because of the stator setup. It is incompatible with delta.

So my advice is if you need torque, get the slowest motor you can for torque, and add delta/wye switching to get a better top speed.

Edit:
P.S. I have a total of 460 miles on the bike so far!

 

[tostino]

A little update on progress with my new battery. I ordered a bunch of cells from a forum member a couple months ago, and just got some free time recently. I got them all tested, and matched for resistance. This new pack is made out of recycled Konion "V" cells. I have them in 7s14p.

Presently on my bike, a 7s14p konion pack in series with a 7s6p E-Moli pack (which is smaller so I am limited in range).
My plan is to make another 7s14p konion pack, and put those in series. 14s14p should give me 18.9ah if I only discharge 1.35ah out of each 1.5ah rated cell, at 51v nominal.

I then am going to put my extra E-Moli to use by making a 14s3p pack to put in parallel with the konions. Doing so should boost me from 18.9ah to 26.7ah at 51v.

Here are some pictures of what i've done so far, and my attached excel spread sheet (if you're building a pack, I would at least take a look at it).

I'm getting ready to start soldering the wire to the cells. I'll be sure to get pics of that process too for anyone interested.

 

[tostino]

I have all my cells tinned now. Only about 3-4 hours of work till this pack is complete!

 

[dnmun]

you maybe should put diodes across the relay coil windings. if you can use a separate ground for the coils than the hall sensor ground you could reduce the chance of damaging the hall sensors. maybe you can tie the relays in place in some high temp silicone with zip ties across the body of the relay.

12G is impossible, almost, to get in there, but 14 g stranded would work up to 35-40A without getting hot, or too hot for this setup.

 

[tostino]

What are the diode's going to do by putting them across the relay coils? And if I could fit another ground wire down there for the relays, rather than using the hall ground I would. But I did manage to get 12g phase wires down the shaft, so that limits the space I have. How could the relays sharing a ground with halls damage the halls?

 

[tostino]

Done connecting the strings in series, and have the leads soldered on! Just cutting and gluing foam so I can tightly pack it into my box.

 

[amberwolf]

I really like the idea of putting the relays inside the motor. Keep us posted about how well that works long-term, as I will be doing a delta-wye on my motor after it's rewound, and that'd be a nicer way to switch than running the wires out of the motor first.

The diode across the relay coils is to short out the inductive kickback from the coil during turn off. You put the cathode on the positive end of the coil, and the anode on the negative end. One diode per relay.

 

[tostino]

Well i've got 606 miles on my motor so far (probably 590 since I had to re-glue the relays). With the gorilla glue, they are in place nicely, and I couldn't get them free by hand. I really think these relays will last for quite some time, because I don't shift while giving it throttle, which will cause arcs on the contacts and destroy them over time.

I'll get some pictures of the relays now with some use on them when I open my motor up to put the diodes on. What voltage would they have to be rated for with my 58v peaks?

And I just got back from a ride with my new packs, it worked flawlessly!
The voltage sag is less with the konion pack then with the milwaukees. It goes from 56v down to 53v when drawing 40a, rather than down to 51v with the milwaukees.

My Konions add up to 19ah at 51v (I don't count on them putting put 1.5ah/cell. more like 1.4ah).
I am now working on paralleling up my milwaukee batteries with my konions to build a 27ah 51v battery, that could put out 405a burst, and 270a continuous. Too bad my controller is only 65a

 

[amberwolf]

What voltage would they have to be rated for with my 58v peaks?

What voltage are you using on the coils to switch them on? That's the voltage to worry about. I presume that's not full pack voltage, but rather 12 or 24V at most?

If you've got any old power supplies laying around that have individual diodes for the input bridge rectifier, then those will probably work fine. (way overrated for voltage, and much more than sufficient for current).

If you don't have any diodes laying around, little 1N4001s should work fine.

 

[tostino]

I'm using full pack voltage. All the relays are in series, with a 10w 200ohm resistor inline. That keeps them within their rated amp limits.

 

[amberwolf]

Then divide the hot-off-the-charger pack voltage by three and that's the max rating they would generally have to deal with.

 

[tostino]

Then divide the hot-off-the-charger pack voltage by three and that's the max rating they would generally have to deal with.

Yup, they are rated for 14v in a car, so in series they'd be fine with a max of 42v (without a resistor), so a 36v pack. My pack hot off the charger s 58v, so I have an additional 16v I need to drop with the resistor.

I went through burning up a set of relays before I even thought about it on my old bike. Without the resistor, they got too hot to touch almost instantly. With the resistor, everything is cool as can be.

P.S. I just got all the batteries I have fitted on my bike. I think i'm going to go for a distance test ride later today. Lets see how long 1.4kwh lasts me .

 

[tostino]

I sadly haven't had time for a distance ride (though I did put 45 miles on the bike today).

However, today nearly ended in disaster. Let me explain.
I woke up today, and noticed my tire had heavy wear. The nylon was showing through in some spots. So I took a ride up to the bike shop to pick up a new tire. I didn't have enough time to change it before I had to go to class, so I just said to my self i'd do it when I got back.
So I make it to class, and almost all the way home, and I had to stop somewhere to do a little job for someone. I finish the job and start heading home again.
I am less than 2 miles away from home, going 40mph with cars behind, and in front of me when I hear a LOUD *BOOM* that sounded like a gunshot at first. My tire had blown out, and my back tire was tracking all over the place. I don't have all that much stopping power from 40mph with no back tire. Luckily, it is a 2 lane road with no curb, and grass to the side, so I get it off the road so I don't get splattered all over someones bumper. At this point i'm still going 35 off road, and trying not to lay it down and eat shit.

I finally manage to get it slowed down and safely stopped where I won't get killed, and see it wore through the tire and into the tube, which bursted open. At this point I call my girlfriend, who comes to pick me and the bike up in her truck .

That was a scare for the day. Don't need another one of those for a while.

Lesson learned, should have just taken the car...It's just not as fun (I guess neither is being dead though)

 

[amberwolf]

Wow...I have never seen a tire so badly worn, and I have a crapload of old tires from other people! I've got lots of them in really bad shape from age, cracking, sunrot, etc., but not worn like that one is.

I'm glad you made it safely to a stop; I've had not only blowouts but even a dropout failure while riding fairly fast, but I doubt I was even going 20MPH either time, and these were on regular upright bikes with no assist.

That's another reason I still want to make a dualie-wheel in back (where most of my weight is), so that when it does eventually blow, I still have a tire, traction, and handling capabilities for this 150-pound monstrosity I call a bike.

 

[tostino]

It was my fault completely. I was so excited I could do burnouts, and when I figured it out, I did a few. Those tires are SOFT and the rubber just fell off when I was doing it. Even with doing that, I still got 680 miles out of it lol. It was a brand new tire when I put the motor on.

 

[amberwolf]

Ooops. I guess that's good mileage for a tire with that kind of wear and usage! Most of the smoother bike tires I've had were pretty soft rubber; I guess it's partly to grip the pavement better, and partly just because they're all cheap.

 

[tostino]

Not a full range test, but I did go out yesterday, and had a 34.8 mile ride. It used 22.3ah. I averaged 31mph, and my top speed was 45.8mph (I don't know how accurate the averaging is, because I was going high 30s to mid 40's almost the entire time).

CA said I averaged about 33wh/mile. Doesn't sound too bad for the speeds i'm getting I don't think.

 

[dnmun]

not bad mileage at all considering how fast you are running, you really got 66A through the controller?

the diode is used to eliminate the inductive voltage spike on the relay switching wire. i worried that the spike could get into the hall sensors, but most probably not if it isn't a problem yet.

i know how hard it is to get the 12G inside there, i did one and it was a bitch, never again, 14G is gonna be my limit from now on. until i change my mind again. hehe.

 

[tostino]

I'll eventually open my motor up and stick some diodes across the relays. When ever I have to open it up again for another reason.

I actually just raised the amp limit from 66 to 85. I lowered my shunt resistance from 3.8mohms to 2.432mohms with a 7" 22g copper wire. Phase current is set to 135, battery current is set to 55. My controller doesn't get hot to the touch even after hard accelerations from 0 to 44 with WOT multiple times. Lets see how long it lasts . Worst comes to worst, i'll be ordering some better fets from Methods!

 

[dnmun]

don't worry about the diodes. there is nothing else on the high side except the battery. if it doesn't cause problems on your ground line, not worth the hassle. imo.

it is normal practice when there are other electronic parts on the same power line, but that is not the case here. plus it is an art to figure what diode actually would work best without creating other problems. maybe wikipedia talks about it in their electronics online textbook.

those FETs do seem to be quite capable, i have run them up to 90V myself and the 72V lifepo4 upgrade i did to the 9FET infineon controllers worked fine too. that is 88V hot.

 

[tostino]

I'm only running at a peak of 58v, and I don't know how that effects FET's, and their ability to handle current. I wonder if running a fet at 48v rather than 72v would allow it to carry more current before overheating?