1989 Kawasaki EX500 (Ninja) - EV conversion, finished but still refining

Nice look, are you going for street legal?
Short answer is no.

Long answer is that it is properly titled and insured in my name as a standard motorcycle from 1989. Insurance on motorcycles older than a certain year, which mine is, cover liability only, not repair or anything like that. I live in Michigan, US, and the process of legally registering a custom-built or -modified vehicle is much simpler than what I've seen from Europe and Australia. It changes from district to district, but ultimately the process boils down to getting a police officer and a rep from the DMV to give it the once over and give it a new VIN. So I can do that, sure, but if I do that, I would need to declare all expenses, get taxed on this "new" motorcycle accordingly, and my insurance would double for this now-new motorcycle.

In any case, I pass by cops regularly, have done so for the past 2 years, and they love it. In my area, motorcyclists get pulled over for speeding, for riding without a helmet, or for modifying their exhaust to be excessively loud. A silent, cool-looking motorcycle, riding safely, is not going to be a problem for most police officers. And as far as I can tell, the worst that would happen to me is that I would get a ticket for illegally modifying a vehicle. The cost of the ticket would be less than the cost of the above-stated increases in insurance and taxes.

I think the situation would be different if I had done an EV conversion on a full-size car, driving at highway speeds, carrying my whole family. As it is, the law in my area simply doesn't care about motorcycles. And it's very well possible that I could get pulled over by a cop who decides to focus on the "fact" that EV's are dangerous and will explode at any moment. Nothing I can do about that type of situation, even if I did do the whole inspection process, so I just don't worry about it.

I actually went to a motorcycle skills course last year with my previous ride. The instructor, while he didn't single me out or act in any way unprofessional or unhelpful, made some comment about how my motorcycle looked fine, he was just worried about the batteries catching fire. I asked him if he worried about that with his tank filled with flammable liquid.

I'm not recommending anybody else do what I do in this regard. If anything, the completely lack of enforcement regarding motorcycles in general in my area is such a hilarious and disappointing juxtaposition against the (what I consider) overly exuberant restrictions we've read about on the forum regarding ebikes.
 
To your credit, you've designed everything to a high standard, I'd say it would meet the requirements in Australia. The only exception might be the battery enclosure but if I could make my battery lids from plexiglass/polycarbonate that would be awesome, especially for members of the public to see the inner workings.
 
To your credit, you've designed everything to a high standard, I'd say it would meet the requirements in Australia. The only exception might be the battery enclosure but if I could make my battery lids from plexiglass/polycarbonate that would be awesome, especially for members of the public to see the inner workings.
Thank you, I appreciate it. Regarding the choice of polycarbonate, it was inspired by @jonescg who also uses it for his battery cases, and I believe he's in Australia.

At one point I was second-guessing my choice of using polycarbonate. Then I saw this clip:
 
Slight improvement in my charging setup. I still have 4 of these modules on order, but I ordered them almost 1.5 months ago, still not arrived. So the past few weeks, I've had to use a single DROK boost module to charge the motorcycle off my 14s home system. Problem was that the 900w rated module, which I only realistically expected to perform at about 500-600w, was actually only outputting 130w max. Dumb. I've basically been charging my new motorcycle constantly, because at only 1.2 amps, it takes forever. Really cramping my style.

Luckily my #3 option finally did arrive after a month. I say #3, because in order to use this with my solar power, I have to plug it into my inverter. Therefore, I'm taking 48v nominal DC, inverting to 120VAC, then further converting it to 116.8VDC. I don't like that inefficiency at all. On the plus side, the charger is 98% efficient on its own, measuring AC in versus DC out, so that's good. My inverter (which I already had for my house, wasn't something I purchased specifically for this project) is 89% efficient, which is okay, but I'd still prefer DC-DC. Looking forward to those modules arriving...

IMG_20240628_145722.jpgIMG_20240628_153043.jpg

Nobody pay attention to my untidy solar wiring, please!
 
Nobody pay attention to my untidy solar wiring, please!
That isn't my focus, as much as an appreciation of the repurposed pallet boards!

Are you building a home quick-charger with those 4 (pending) modules in parallel? Hope they arrive soon.
 
That isn't my focus, as much as an appreciation of the repurposed pallet boards!
I build everything out of pallet boards. Everything.
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Are you building a home quick-charger with those 4 (pending) modules in parallel? Hope they arrive soon.
Indeed, that's the plan.
 
My modules finally arrived, so I was finally able to build a parallel boost converter charger. The results were...meh.

IMG_20240702_092023.jpg

It does work, but just like my first test module, these 4 all put out a max of 2 amps each at 116.8v. Making total charge power at about 850w. The total efficiency is about 85%, measured from watts leaving my 48v home system against watts entering the motorcycle battery. It's ok, not great. Now, my other charger that plugs into AC has a total system efficiency of about 85% as well. And this one puts out 1200w. But it does also require the use of my 1600w inverter, which I use for several house appliances. So I can charge the motorcycle, or make coffee and run the fridge, but I can't do both at the same time (unless I purchase a more powerful inverter, which I won't be doing at this point). Therefore, I have two substandard methods of charging now, and I could use either, but neither is really that great.

So I'll ask the forum once again. Does anybody know of a better way to charge my 116.8v motorcycle from my 48v nominal house battery, in the range of 1000-2000w?
 
Could several of these be put in parallel?


I'll take a look at this model and other similar, hadn't seen this one yet. Thanks!
 
Month later, I've been riding 25-75km every day that it's not pouring rain. All I can say is:

1_24Yrvoye3Aq5ktsRRpA0OA.jpg

An incredibly smooth ride, no more range anxiety, no stress on the build, the battery, or motor. Easy acceleration, great torque, good brakes... I could go on, but sufficient to say, this is a great ride.

Which isn't to say that I haven't run across issues. Some things I missed during the restoration and cleaning of the parts:

-Rear suspension was more worn than I thought. Replaced it with an upgraded shock from a ZR750 per the advice of the EX500 forum, and that was a tremendous improvement
-One of my front fork seals was shot, so I went ahead and serviced both forks, and that was great for all the bumps as well.
-Steering stem bearing races were worn. I didn't know to check them more closely when I originally cleaned them and replaced the ball bearings. But after 1000km, I started to feel stiffness in turns, and my local motorcycle mechanics suggested I remove the races entirely and replace with tapered bearings. What a difference that made!
-Charging is still slower than I'd like, at 1000w off my solar. Still looking for a solution to that.

It's been very educational and fun coming at this build (and the previous) with the experience I do have regarding electric motors and batteries, but little-to-no experience in motorcycles. Because I do it wrong, and in my opinion that's the best way to learn.

When I first got it running, I was blown away by how smooth the ride was. Then I upgraded the rear suspension: so much better. Then someone pointed out that my fork seals were shot, so I replaced those: so much better. Now I've fixed the front bearing: so much better. I had no idea the steering could be so smooth and easy! These are all things that experienced motorcyclists probably know to look for in the first place, but not me, and in a way it's been pretty cool to experience firsthand all the improvements the upgrades have made, one at a time.
 
Are there two disk rotors on the rear right side? I don't see the caliper on the large drilled disk, just the mount for it. Or actually what looks like a radial caliper mount might be a caliper for a smaller disk in front? It's hard to tell.
 
Are there two disk rotors on the rear right side? I don't see the caliper on the large drilled disk, just the mount for it. Or actually what looks like a radial caliper mount might be a caliper for a smaller disk in front? It's hard to tell.
Rear wheel has one disk and a radial caliper mount. This was added on. Front wheel has a single large rotor, which is stock for this model of bike.
 
The risks associated with using secondhand cells:

Screenshot_20240717-122447.jpgScreenshot_20240717-122500.jpg

This is not a drastic risk, or even a particularly significant downside. Still easily usable. But I do want to start with hyperbole, because people reading this thread need to know the difficulties attempting a battery build using secondhand cells. I know I've said it multiple times in the thread and I'll say it again: I do not actually recommend building a battery this way.

You can see that while all the cells are rather well balanced against each other, group 11 is a little bit low, and group 15 is a little bit high. Not by a lot, total deviation is less than 0.03v. And this only occurs at the fully charged end of the battery. We know that Li-ion has that steep curve at either end, and I know that when the cells get under 4.1v, the total deviation goes back down to less than 0.09v.

I don't keep balance function on all the time, but I am trying to get the deviation a little bit closer. Problem is that since I'm using contactor-controlled BMS, I didn't get a super-high-current rated BMS, which comes with a balance function that I believe is only 200ma. Against a battery of 90 Ah, this would take a rather long time to balance.

Why this is happening, could be a number of reasons. Mostly likely, I have a single "weak" cell in groups 11 and 15, and/or cells that didn't get perfectly balanced during my testing procedure. Not terribly surprising, when processing 1000 cells. And it's not a huge deal, I don't actually want to charge past 4.15v per cell anyway. Just want to keep others informed of what goes into builds like this and what could happen.
 
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You can see that while all the cells are rather well balanced against each other, group 11 is a little bit low, and group 15 is a little bit high. Not by a lot, total deviation is less than 0.3v. And this only occurs at the fully charged end of the battery. We know that Li-ion has that steep curve at either end, and I know that when the cells get under 4.1v, the total deviation goes back down to less than 0.09v.

I agree with your point about the used cells and not knowing the life they had before you, so there could be ones with more abuse than can be verified, but,

Isn't your biggest deviation < 0.03V ? Which I would think is pretty well balanced over 28 groups and 90 Ah of energy. Maybe brand new cells wouldn't show even that level of deviation over the ride time you have put in so far but you can find examples on here of people that got brand new cells and matched them properly and still got a few weaker ones in the bunch.
Maybe I'm too lax in accepting the difference on my aging cells? lol
 
I agree with your point about the used cells and not knowing the life they had before you, so there could be ones with more abuse than can be verified, but,

Isn't your biggest deviation < 0.03V ? Which I would think is pretty well balanced over 28 groups and 90 Ah of energy. Maybe brand new cells wouldn't show even that level of deviation over the ride time you have put in so far but you can find examples on here of people that got brand new cells and matched them properly and still got a few weaker ones in the bunch.
Maybe I'm too lax in accepting the difference on my aging cells? lol
So far I've never seen a larger deviation than 0.03. Yes, you corrected my typo, I'll fix it. And I agree with you, for me this is an acceptable deviation. Especially since as described, it only occurs at the top end of the discharge curve (perhaps it occurs at the bottom end as well, but I won't be letting it get that low to find out, if I can help it). Deviation depends on so many factors, like age, number of cells, discharge rate, but as you point out, it depends on what you're willing to accept.

For reference, I was impressed a few weeks ago with @j bjork and his post regarding a full charge of his pack to get ready for a long race. He was able to get his pack all the way up to 4.19v, resting, 0.001v deviation. That's impressive.
 
Anybody more familiar with ANT BMS than me, looking for clarification on a shutoff event I had this morning.

I was going for a short morning cruise, speed approx 100km/hr. Battery was relatively fresh off a full charge, resting voltage about 114v, probably sagging to around 112v at that speed. I had an open stretch in front of me, so I thought I'd try a higher speed. Increased to 120km/hr. I twisted the throttle a bit more, and that's when the BMS shutoff.

I am not discharging through the BMS; the BMS outputs to the DC converter, which controls the main contactor between the battery and controller.

Here's what the BMS log says about that time:
Screenshot_20240723-084445.jpg

Total over voltage warning? That doesn't make sense. I have my overvoltage protection set to 118v, which would be 4.21v/cell. Wasn't even close to that. Also, how could it have gotten that high? I was at 112v. I could imagine a scenario where I had activated intense regen braking, causing an inrush current spike and subsequent voltage rise. Except I wasn't braking at the time, I was accelerating/discharging, and anyway I have regen set rather soft, specifically to avoid high current charging.

Also, why did the BMS restart with individual cell voltages of 3.58/cell? They weren't that low at all. I went back in the logs, at those same exact cell values show up every time I restart the BMS.

In any case, I coasted to a stop, turned off the contactor, turned it back on, and everything worked as normal, no issues. Any ideas on what happened?
 
Update: went out again in an attempt to recreate the conditions. No dice. Still don't know why the BMS cutoff, the data it's giving me doesn't match with what was actually happening. Seems like just a bug/glitch, which is irritation. I'd rather it be something i can fix.

I was also thinking about:
why did the BMS restart with individual cell voltages of 3.58/cell

That would add up to a total voltage of 100v, and i've never gotten the pack that low yet, even during discharge/sag. Lot's of things not adding up...
 
Is the ~100v estimate for resting at restart after the anomaly, or under max load during the anomaly?
 
Is the ~100v estimate for resting at restart after the anomaly, or under max load during the anomaly?
The 100v resting estimate is what the BMS is telling me is happening, not what actually ever happens, during loads or at rest. I have a voltmeter on my dash, and the lowest I've ever brought it down is somewhere in the range of 105v.

Here, I went back in the log and found two separate occasions in the past, days apart, where the BMS registered a "power off" event. On those occasions, it registered min cell volt of 3.57-3.58, and max cell volt 3.59. I can assure you, the cells have never gotten that low before.
Screenshot_20240723-130434.jpg

On these occasions, no anomalies have happened. There's more further back, randomly, I just screenshot one of them as an example; they all register cell voltages of 3.5, voltages that the cells have never actually reached. Live voltage readings on the main screen register accurately, double checked with a multimeter.

One thing I'm going to try; I set the automatic sleep function to something like 2 days. Now I'm going to set it for more like a month. I wonder if turning on/turning off, or going in and out of sleep, has something to do with misreading voltages.
 
I haven't had that error happen again, my best guess is simply bad luck and coincidence: I think the BMS must have simply gone into its auto sleep mode, right as I was riding it, causing it to briefly interrupt power. Oh well, that's what you get when you use BMS-controlled contactor.

In other news, it was bothering me that I the cells weren't as balanced as they could be. I am planning a longer trip that might use my entire estimated range, and I would like to be able to charge the whole pack up to 4.19v per cell, instead of the 4.15v per cell that is my normal full voltage charge. From my previous post on the subject, the imbalance was really just the fault of 1-3 cell groups that were 0.015v higher than the rest of the pack, which was almost perfectly balanced. So rather than wait for the BMS to balance it with its auto balance function, at only about 100ma, I turned off the BMS, disconnected the balance leads, and directly connected a 2 ohm resistor to the problem cell group, for roughly 2 amps of drain.
Screenshot_20240726-130533-3.jpg

Don't try this at home, kids! But it worked rather well. I left it in for 5-10 minute increments, reconnected everything, and voila: 0.008v deviation, at the top end of the charge curve as well. Plenty for the rare occasions when I might need to completely top off my cells for a longer trip.
Screenshot_20240726-130533.jpg

On a related note. I kinda don't like ANT BMS. I guess it works and does the things I need it to do, but the interface and adjusting parameters is rather non-intuitive. And why the heck does it need to continuously
flash an LED on every series group while it's balancing?
Screenshot_20240726-130533-2.jpg

I know LEDs don't take that much energy, but 28 of them flashing continuously adds up to an unnecessary waste of energy, and noticeable heat added.
 
Ha! Someone saw my bike while I had it parked grocery shopping.
That's awesome, question is, how did you find the video? were you browsing along and saw it, and then had the lightning strike thought "hey, that's MY bike!":cool:

PS it IS a really sweet bike!
 
That's awesome, question is, how did you find the video? were you browsing along and saw it, and then had the lightning strike thought "hey, that's MY bike!":cool:
Nope. I was at a red light, and a guy on Honda CBR zoomed right up next to me to tell me that he's been seeing my bike around. He gave me his YouTube handle and told me he took a video of it a few weeks ago. Then he shot off when the light turned green at about 60mph in a residential!
PS it IS a really sweet bike!
Thanks!
 
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