Motorbike Conversion - 1985 Nighthawk 750S - From Junk

[MattsAwesomeStuff]

Aha. It's actually an "EZ-Go" 25864G09 golf cart controller, which is a Curtis 1206-4301 (which is not written anywhere on it, you just have to know that).

And for future people who may come across this thread: http://products.jacobsen.com/img/manuals/28646.pdf <-- Manual for the golf cart, which has some controllery bits in it on page E-17, but not enough for me to figure the pinout.

...

Revisiting a couple rejected options I didn't discuss before...

I also have a controller from the forklift yard's junk bin that was marked: "Needs repair, low output". It's a Curtis PMC model: 1-187-067. 24-36v, 275 amps.

Again nothing comes up on google, and I couldn't get into it, it's potted shut. Drilling out the potting to find 6 screws underneath and some hammering later, it says on the board it's a "1204x-42". Hard finding that exact model, but at least it's a model that exists and I can find pinouts for.

So that's promising. You know, most of the time, in any place, when stuff is marked as damaged there's nothing wrong with anything but the technician, so, let me just see why the output might have been may be marked "low"...

Err... oh. Not the technician.

Looks like everything that's steel (mounting hardware) is rusted, everything lead (all the solder joints) are crumbly white powder.

I can't get inside the thing because the side boards are all soldered together. It's at least dozens of solder joints just to examine it further. FETS are I+R9207, (+- symbol?), can't find a datasheet on them.

I do like a challenge, and I do like repurposing junk, but:

1 - I don't know if it's in working condition.
2 - I have to make dozens of desoldering connections just to access the FETs and clean them.
3 - It's hundreds of soldering joints that are corroded, any one wrong and it probably won't work.
4 - Is the circuit board corroded internally?

Sounds to me like the 1204 is a shelf-it project, maybe turn it into a charger later.

I also pulled a GE Clark EV-T5 controller out of the junk bin last year which is 3x the size of the Curtis 1204 (as big as a double-slice toaster), but, it's only 24v and 75 amp (250amp at 50% duty cycle). The current is probably okay, but the 24v is just hot wet garbage (and I don't know if it's working).

So, I guess a bit more sleuthing on the 1206 as that's my best bet at something that might hit highway speed.

Normally I'd be happy with trial and error. Pain in the ass is, once I arrange the 18650s into their plastic holders, (head or tail in the correct directions)the entire pack has to be disassembled to get them apart again, let alone all the soldering. And soldering the batteries damages them a little bit each time I'm sure. A lot of my projects get abandoned when I hit a point where I have to backtrack because of how discouraging that is, so, trying to prevent that this time.

So, I'm kinda stalling out at this stage to see if I can get a higher voltage controller that I'm more sure will work before I double-down.

 

[amberwolf]

controllery bits in it on page E-17, but not enough for me to figure the pinout.

I might be able to help with that.

Since I dont know how much you know about them, Ive attached the cart schematic and notes on what I know or can surmise, wiht the controller itself inside the red box. Everyting outside that box is part of the cart, not the controller.

This is a controller for a sepex motor AFAICS, since it has a separate field coil connection from the brushes. I cant remember if sepex controllers can be used for series motors or not; its been too long since I read up on that. I think that you can simply leave teh F1/F2 busbars unconnected for series motors....

If you did have a sepex instead of a series motor, however, then one contact for brushes on the motor connect to the A1 busbar on the controller, and the other to the B+ busbar (which also connects to your battery positive. In the schematic they use a solenoid/contactor for precharging the caps in the controller and for a cutoff controlled by a keyswitch, between battery positive and B+).

If not using a precharge or contactor, leave J1 pins 6 and 7 unconnected, otherwise they drive the contactor coil.

The field coils go to F1 and F2.

B- goes to battery negative.

If youre using a keyswitch it connects to J1 from pins 8 to 9, otherwise you just jumper those together.

J1 pin 10 is unconnected since you dont use reverse.

J1 pin 1 gets jumpered to pin 3, and pin 2 is left unconnected, because you dont use reverse.

J1 pin 4 can be left tied to battery positive if you dont need to disable the controller during charging. Otherwise you can setup something at the charger port (like a magnet on the charger cord to open a reed switch) to disable the controller during charge so you cant ride off with it plugged in. (its possible that Im misreading the schematic and it actually needs pin 4 left unconnected to enable teh controller, but its easy to test).

J1 pin 5 connects to battery positive.

J4 is the throttle, and uses the switch between pins 1 and 2 to show whether throttle is engaged (so that any input on 3 and 4 are ignored if 1 and 2 arent shorted). Pins 3 and 4 probably go to a 5-10k potentiometer, between the wiper (center pin) and one of the sides. The other side of the pot would be left unconnected.

J3 appears to smply be another set of enable switches, jumpering from pin 1 to 2, and from 3 to 4.

J5 is probably a hall sensor used for speed monitoring; it will probably work without it but it may be usable to prevent an overspeed condition (I dont know what RPM it might be set ot limit at).

J2 looks basically like a jumper-programming block, though which pins enable or disable what options I dont know, so you might have to simply use it jumpered like it shows (or experiment). It might also be an option connector for another piece of electronics; I dont know (didnt read any of the service manual, just going by what I know of other curtis and similar brushed controllers).

 

[MattsAwesomeStuff]

This is a controller for a sepex motor AFAICS, since it has a separate field coil connection from the brushes. I cant remember if sepex controllers can be used for series motors or not; its been too long since I read up on that. I think that you can simply leave teh F1/F2 busbars unconnected for series motors....

I bet you have a 1206mx. X is for SepEx. It has a PDS ("Precision Drive System" aka "speed control and sensors"), mine doesn't. (Oh, duh, says there right on your diagram, "1206mx controller"). I linked the manual in my previous post, after it gives my diagram it gives the PDS diagram where your image came from.

Series motors technically have no speed control, only power control that might suggest what speed it might go which depends entirely on the load .

My Curtis 1206 only has 3 of the giant terminals, B+, B-, and M-. Then there's a row of 6 other numbered pins (Pin #5 is absent-at-factor, presumably for polarity idiotproofing).

I went through your pinouts and the diagram though, I agree with all of it.

I kept digging, found this: http://ev.evdl.narkive.com/0masMVv9/ezgo-controller-connection-diagram

"On the 5 pin style 1206 Curtis controller pin one and two are your 0 to 5 k/ohm throttle input. Pin three is half speed reverse and pin four is your key switch input to power the brains. The fifth pin is not used."

Sounds pretty straightforward. 1-2 pot. 3 ignore. 4 short to... positive when on (? that's where KSI goes on the 1204, which I do have a manual for). 5 ignore.

Well, after going through the much more complicated 1206mx... the 1206 dumbo system is easy, and I only just discovered the pins on the terminals are actually numbered.

Not sure why I was having trouble reading this before, pretty clear. Pin 3 had me confused but, just ignoring it I'm okay again.

So... I try hooking it up on a power supply...

Confusion.

1 - If the power supply is on B+ and B-, B+ and M- have the same voltage on my multimeter. Is that because there's no load, or, does that mean blown-short mosfets and back to square 1?

2 - I have 3 "E-bike throttles", of different styles. None of wires on them do what a potentiometer should do. Nothing changes when I twist, resistance doesn't is either infinite or isn't variable. I (foolishly?) presumed all throttles were just pots, is there something else going on in them?

 

[MattsAwesomeStuff]

Doing a little more research, I discover most e-bike throttles are not, in fact, potentiometers. They are instead, hall effect sensors based on a magnet, and some amplifier. So they output 0.8-3.8v or so.

I'm not sure if this is compatible with my controller.

The controller expects a 0-5,000 ohm potentiometer, but, it uses that to lower the voltage on some pin probably, so, by coincidence, 0.8v-3.8v might be what the controller ended up sensing and might be a plausible imitation, but, probably not.

So...

1 - By coincidence it will work anyway.
2 - I have to find some kind of pot that will work inside the mechanism.
3 - I have to order a different throttle entirely.
4 - I have to convert my signal to the right voltage using a microcontroller or something, which I've never used before.

This was the one part of the build where I was like "Well this is such an engineered solution, I'll just buy one, problem solved." Problem is not solved. Hrmph.

This is the first actual outright mistake I've made on the bike.

http://www.evwest.com/catalog/product_info.php?products_id=294 <-- I could spend $58 to remedy this. That's 3x what I paid for the bike, so, no.

I could half-ass a variety of solutions, epoxy a pot into the handlebar and have the end of the throttle twist it (presents a hazard if the bike falls over), etc. Don't really want to half ass it.

Not exactly sure what to do next. It's a minor problem, I currently have the original cable throttle hooked up to a pot box, but it's the size of baby's skull, cumbersome and annoying. It's solvable but not in an elegant and cheap way.

... More pressing is the fact that the controller itself appears blown.

 

[amberwolf]

I bet you have a 1206mx. X is for SepEx. It has a PDS ("Precision Drive System" aka "speed control and sensors"), mine doesn't. (Oh, duh, says there right on your diagram, "1206mx controller"). I linked the manual in my previous post, after it gives my diagram it gives the PDS diagram where your image came from.

I dont actually have one of these; I was just going by the diagram from your link--I didnt see a different one, only that one, but osme of the pages in the link come up completley or partially blank when I view the PDF. I guess the one with the correct controller diagram must be one of those blank pages. (its probably just my computer--wierd stuff happens sometimes).

I do have an old 1204, I think it is, that I used on CrazyBike2 with its powerchair motors; that was a long time ago.

"On the 5 pin style 1206 Curtis controller pin one and two are your 0 to 5 k/ohm throttle input. Pin three is half speed reverse and pin four is your key switch input to power the brains. The fifth pin is not used."

Sounds pretty straightforward. 1-2 pot. 3 ignore. 4 short to... positive when on (? that's where KSI goes on the 1204, which I do have a manual for). 5 ignore.

That sounds right, if its like the 1204.

I dont remember which + wire youd use for teh KSI, it might be the + out of the pot, or it might be B+. Its probably the same as the 1204.

1 - If the power supply is on B+ and B-, B+ and M- have the same voltage on my multimeter. Is that because there's no load, or, does that mean blown-short mosfets and back to square 1?

I dont know--it could be that its simply starting out with the bridge switched in a way that floats the voltages like that, until you apply trhottle and/or theres a motor on it.

You can use a multimeter on ohms or continuity to test for a short. Itll start out appearing shorted because of the caps, but as they cahrge up it should increase to tens of thousands of ohms and higher.

2 - I have 3 "E-bike throttles", of different styles. None of wires on them do what a potentiometer should do. Nothing changes when I twist, resistance doesn't is either infinite or isn't variable. I (foolishly?) presumed all throttles were just pots, is there something else going on in them?

Almost all ebike throttles use hall sensors, which do not start at zero volts, and dont go up to 5v. Typically their output range is around 1v to 4v, varying up to half a volt at either end. Because of that, they generally dont work with controllers like yours, even if that controller uses a voltage input rather than a resistive reader circuit (current).


A number of these brushed controllers like the curtis (and other non-ebike EV controllers) use safety systems on the throttle that require a pot because it uses the current flow thru the pot to determine if its connected or not, or if it has a problem, at power up / etc. If theres no current flow the controller may remain disabled until its power cycled wiht a pot of the correct resistance range connected and with the pot at its throttle-off position.

 

[MattsAwesomeStuff]

Controller Success!!

I basically sat with my thumb up my butt for 3 weeks, figuring the controller was broken because it showed full voltage on the motor output without the keyswitch or the throttle even connected, indicating blown mosfets. And then I was bummed about my throttles all being the wrong type and not being able to use them to test either.

So today I decided to actually just hook a motor up to it and a pot (had a 50,000 ohm rather than a 5,000 ohm, but, no matter).

Well lookie that that. As soon as there's really any load at all on the output, there's no voltage there, so, must have some high impedance path through the controller.

I used an 1800w treadmill motor (easier to carry onto my office desk), threw on the pot, shorted pin 4 to positive, and... nadda.

About to give up and then I tested the pot and even after checking it thrice, discovered I'd wired it backwards (so I was adjusting between 45k and 50k, rather than 0k-5k, and just never bothered to twist it all the way around to the far side).

And the damned thing spins. And it changes how fast it spins when I twist the pot.

A few interesting tidbits:

1 - The max supply voltage is 46.6v. Above that it shuts down. Since it was designed for a 36v kart, and 36v batteries are at absolute most 45v when boiling their electrodes, that's sensible. But it means if I want to use a higher voltage than that I'll have to reverse engineer it to find how it determines that.

2 - The min supply voltage is 28.4v. Below that it shuts down. Again since it was designed for a 36v kart, when your lead acids are less than 9.5 volts on a 12v battery they're plenty dead (heck they're dead by the time they actually get to 12v). Shouldn't be a problem for me, an 11series lithium pack is well dead below 33v (3v/cell) anyway. 28.4v is 2.58v per cell. That's already into damaging territory, but my low voltage cutoff is human-decision-based anyway, so I'm fine making the choice whether I want to stop or continue driving. I don't need it idiotproofed except perhaps to actual idiot level (I leave the lights on, ideally it won't murder my batteries).

3 - High resistance is low speed. The documentation didn't actually say which, controller might be built either way.

4 - Below some resistance, the motor cuts out. So it goes faster, faster, faster, dead, if you bring the resistance too low. I'll need to have my stop switch sometime before this, as, you'd come to a complete stop while at wide open throttle, ease off a bit and then backflip as it slams max power again.

....

Decision Time:

Do I design the pack for 46.2v and start soldering cells, or, wait for a better controller?

It will be a huge pain in the ass to change my mind later, it involves desoldering every single cell, and likely rebuilding the entire battery compartment since it has to be built around the frame.

On one hand, this isn't the voltage I want to run at. It might not even hit highway speeds and there's no way to find out until I try. That would be a huge disappointment.

On the other hand, I'm getting pretty tired of seeing other riders on the road enjoying their summer, while I have a pile of parts. And I don't have another controller to use anyway.

Maybe I'll split my battery pack into two full sets of 11series so I can rewire them for double-voltage later. If I upgrade the controller down the road, I can design it for whatever voltage and, 46x2=92v is an okay target.

Controller claims 275 amps, 46v = 12,650 watts = 17hp when completely topped up. Should be enough for highway speed if the motor will be spinning fast enough with that load. No way to tell. Not sure if the controller has overcurrent protection either, so maybe I can manually demand 500 amps and as long as it doesn't overheat it'll be fine.

Next up, start making cardboard battery boxes and seeing how/where I can stuff them into the bike.

 

[amberwolf]

mb u ing the controller was broken because it showed full voltage on the motor output without the keyswitch or the throttle even connected, indicating blown mosfets.

is normal; thes eground th eoutptu to spin motor otherwise open, cnt remember for sure.

1 - The max suppl

y voltage is 46.6v

. Above that it shuts down. Since it was designed for a 36v kart, and 36v batteries are at absolute most 45v when boiling their electrodes, that's sensible. But it means if I want to use a higher voltage than that I'll have to reverse engineer it to find how it determines that.

probly is board on side panel usin g cpmparator chip like 339 etc.



4 -

Below some resistance, the motor cuts out. So it goes faster, faster, faster, dead, if you bring the resistance too low. I'll need to have my stop switch sometime before this, as, you'd come to a complete stop while at wide open throttle, ease off a bit and then backflip as it slams max power ag

ain.

si protection agisnt shorted throttle wires.







Con

troller claims 275 amps, 46v = 12,650 watts = 17hp when completely topped up. Should be enough for highway speed if the motor will be spinning fast enough with that load. No way to tell. Not sure if the controller has overcurrent protection either, so maybe I can manually demand 500 amps and as long as it doesn't overheat it'll be fine

.

probly need big heatisnk adn maybe fasn to susiastn makx power. see diy elecrotric car forum for pics of peeoples curtis stuff fo rideas.

 

[MattsAwesomeStuff]

Dafuq happened to your reply? Looks like it went down the garbage disposal and then the software tried to reassemble it back into a ham.

 

[MattsAwesomeStuff]

Battery Bulk:

My big goal was to get 60 miles (100km) worth of range at highway speeds. I need ~140-200 watt-hours to travel a mile at those speeds.

I have these 4x5 battery holders, an 18650's average voltage through it's discharge curve is ~3.7, maybe 3.75v, cells are roughly 2000mah each (good ones are 2600, I'll stuff in as many of those as possible), so each 4x5 brick of 20 cells is roughly 150 watt-hours and weighs 2 lbs.


Battery Weight:

At a brick a mile, I need to find room to fit 60 of the bricks in the frame (9000 watt-hours). Since I'm doing strings of 11, might as well round it up or down to 55 or 66 bricks. It'll weigh about 120 lbs to do that.

Motor is 92lbs, so motor+battery is 212 lbs, plus the weight of wiring and the battery enclosure.

The original engine according to spec was 181 lbs dry. Plus fluids. Plus exhaust. Plus fuel.

I should weigh the bike now and compare it to the 467lbs it was originally.

In any case, I'm in the right ballpark I'd say.


Battery Sizing Layout:

My first big happy surprise. I had more room in the frame than I thought.

66 bricks is roughly 2 milk crates worth, bulk-wise.

Just looking at the bike, I figured there was no way I'd find room to fit them. I've been putting it off forever, but tonight I dummied up a bunch of empty battery trays and started seeing where they could go.

1 - Below radiator, in front of frame: 4x4 bricks, +4 if I remove radiator. 16-20 total.
2 - Below/between frame, below motor (as in pic): 3x4 bricks. If I double-stack (each stack is 2.5" tall), double that. Brake disc is 6" above ground, so I figure I'm okay with that clearance for city riding? 12 or 24 total.
3 - Beside motor: Sloppily, sticking out of frame, 5 first tier, 8 on second tier, 8 more on third tier. 21.
4 - Above Motor Right: 5x2 bricks. Three tiers. The mounting for the motor sticks out 2" so I have to separate right from left. 30 total.
5 - Above Motor Left: 4x2 bricks. Three tiers, but it's getting ugly to not narrow at the top of the frame. 24 total.
6 - Under Tank: 2x2. Not much space, hard to fit, but room for 4 total.
7 - Above Swingarm Triange: 3x2. 3 tiers. Nice and narrowly tucked, won't interfere with my thighs. 18 total.

Grand total: 125-141 bricks.

Jeez, I only needed room for 66.

Heck, I only have enough weight available for 66 (not 250-280 lbs).

I don't even have 141x20 = 2820 cells = 21kwh of cells. That's almost as much as a Nissan Leaf.


This isn't the layout I'll be using, or even the orientation, it was just the easiest way to slab up cell holders and ballpark the spacing available. If I'm over what I need by at least double... I can afford to make some choices based on cosmetics, not "What used to look like a motorbike now with a bunch of bricks".

I can skip the whole row in front of the frame. The 2nd tier below the frame. I can slim a whole row of bricks off of the left and right sides each. Still have room for 66. Easy.

Expecting my hubris to bite me later, but, for now I have some breathing room.

 

[parabellum]

It is better to use protected areas for the cells to have some margin of robustness for unforeseen events, like roll-over, slide, little crash or curb jump. So you can get the bike up and eventually drive home. You may also consider leaving front open, for direct airflow to the motor, for cooling.

 

[larsb]

Like it! Subd

 

[Voltron]

It's harder on the cells mounting them vertically... It makes the central mandrel inside the can bounce up and down, compared to having them mounted on their sides. Not sure how much real world difference it makes depending on how fast you cycle thru a pack...

 

[j bjork]

Interesting build
Any progress?

 

[MJSfoto1956]

Inspirational. I think I've read this thread three times now. Great work. Keep it up!

M

 

[CONSIDERABLE SHOUTING]

Not to resurrect a nearly year-old thread, but the content here is so fantastic I think it needs to be brought back up. I hope OP comes back.

 

[MattsAwesomeStuff]

Not to resurrect a nearly year-old thread, but the content here is so fantastic I think it needs to be brought back up. I hope OP comes back.

That's kind of you to say.

Umm, story.

TL;DR - It's been on a shelf for almost 2 years.

Last I was working on it, the driveshaft fell out and it took me a while to figure out how it might go back together (springs, circlips that don't act as circlips, etc). I was also skeptical about how well I lined up the motor to the driveshaft, there was a lot more vibration than there was when I first rigged it. Yeah the U-joint can handle it, but I didn't want it to have to.

And then my battery source dried up (place closed down/consolidated to another city).

I definitely have enough batteries to build the motorbike, that's not an issue.

But I definitely do not have enough batteries to build the motorbike and an electric car. I have barely enough to just build an electric car.

My planned progression was:
- E-Bike
- E-Moped
- E-Motorbike
- E-Car

I was also getting frustrated trying to plan out a battery box, and the space and weight and balance constraints of a motorbike are ugly. And I didn't have a place to properly weld (condo nazis), and later even a place to turn a wrench (condo nazis, can't even rotate your tires on common property, it's a "safety hazard", which is the catchall for "we don't like people like you, we'll call anything a safety hazard"). Narrowly, almost not allowed to even park the bike there at all (even though it fits in my stall sideways ahead of my car, it's "two vehicles" which is forbidden).

And, I run out of motivation to work on it in the winter.

So, if I only have enough batteries for a bike or a car, a car solves a lot of the frustrations I'm having with a bike.

... And...

Around 14 months ago, I was buying winter tires and saw an old car in their lot. It looked like a 2/3 scale, 1970s C3 Corvette. I was like "What is that? Is that a Corvette?" and they said "No, it's an old Opel GT, we sold it yesterday for $1500."

I'm not a car person, but the only car I've ever kind of wanted was a C3 Corvette, but they're far too expensive for a cheap hobby car, and a bit large and heavy for an efficient EV conversion. And there was never a year of Corvette that I liked perfectly. I liked the domed rear glass and the big curvy fenders up front. The C2s have the domed glass, and the C3s have the curvy fenders.

So here's this cute, 50 year old classic car, looks like a Corvette, happens to have the blend of features I like most about Corvettes that I can't even find on a Corvette, it's small 13.5' long, and light (2000 lbs), and for some reason super cheap because no one wants them.

Only, in Canada, they're almost all rusted or restored. That one I saw was the only affordable but not garbage one I could find in the Country, for months.

... but 4 months later someone found me one in Arizona. Actually 3, project cars, an estate sale of dead hoarder, and I had a week to pick them and everything else in the garage up or they were being hauled away for sheet metal so that the estate could use the garage to stage and sort the house.

Car #1 was going to be a V8 conversion, but it had no engine, and the transmission tunnel was cut away (to fit larger engine and transmission). But it was a dry desert car with hardly any rust, missing lots of the trim.

Car #2 was an unsaveable junker, but with an intact transmission tunnel, proper paperwork, and decent trim.

Car #3 was in best shape, primed, just needed some interior and a paintjob.

I have room for 1 car, not 3. Luckily another Arizona guy wanted the 3rd car. He and another guy in the Opel GT community helped haul the cars away, and moved 2 of them to the older guy's ranch and said I had about a month to pick them up.

I paid $200 for Car #1, $200 for Car #2, $200 for a pair of newly refinished seats, and $100 for the misc junk in the garage (which ended up including a brand new interior kit worth about $1,000). $700 total.

So I drove from Canada to Arizona with a Sawzall and 20 pack of cutoff wheels, and spend 4 days carefully chopping two cars into the pieces I'd need to make one, then mashing them together loosely enough to pass an ownership inspection. The guy was coincidentally selling his trailer so I didn't even rent a Uhaul, I bought his trailer and towed a car and half a car's spare parts back to Canada.

(the ugly one, obviously)

I planned on doing all the cutting and welding at night, in a "1 month free trial" storage unit, using spare car batteries and an inverter for power. Everything takes longer than I think it should. A widow work neighbor mentioned her garage door is broken and she never uses it, so if I mow the lawn once in a while, I'm welcome to use her garage for free.

It kind of sat there for the next 6 months while I helped other people with projects, but, the last 2 months especially I've been going at it steadily, almost every night. The two bodies are finally merged together and I'm starting the electrical portion of it now. (265 lb 3-phase forklift motor, Toyota Prius Gen 2 inverter repurposed, ~400 hp).

https://www.youtube.com/watch?v=3C7H-idrhwI

... so, EV news, but just not on the bike.

Back to the bike...

I am going to have a bunch of 21700 cells left over from these tool packs. I don't want them mixed in with the 18650s. They were supposed to be the battery pack for my electric Ruckus moped, (dead lead-acids for 3+ years), but, since this project started as a short-range motorbike, I wouldn't mind if it only had 10-15 mile range on it. So when the car is done, the bike will probably be revisited.

The bike really is just about ready to go and has been for 2 years.

It needs:
- Mirrors
- Horn mounted (Unless I already did?)
- Front signal arms repaired ($7 each apparently, will probably just buy them)
- Battery

I haven't forgotten about this thread, if there's updates I'll post them.

 

[CONSIDERABLE SHOUTING]

Holy shit! I think I was linked to that Opel thread through a different site; I never imagined it'd be you!

Yeah, the Opels are weird cars from a weird era- there's very few motors that can be swapped in because they had a european-only pushrod 4, and the 240Z appeared in 72' that was literally just a *better* car, from power to price to suspension. I think AteUpWithMotor's article said they intended it to be a "baby" C3 for people to "work" their way to.

C3s are cheap and easy to get a hold of and work on; the real problem is all their parts are good old' GM quality and randomly break, as my family found out when our's fuel pump blew a few weeks ago. You also have to know fiberglass, which SUCKS to work on- but otherwise, they're literally a car from 1955 mechanically.

 

[tylerwatts]

Matt I'd love to see your GT build, can you share a link please?
Also love your bike build and hope it lives soon.

Cheers
Tyler

 

[CONSIDERABLE SHOUTING]

Matt I'd love to see your GT build, can you share a link please?
Also love your bike build and hope it lives soon.

Cheers
Tyler

I *think* it's this one: https://www.diyelectriccar.com/forums/showthread.php/opel-gt-ev-restoration-and-conversion-200383.html

 

[tylerwatts]

Matt I'd love to see your GT build, can you share a link please?
Also love your bike build and hope it lives soon.

Cheers
Tyler

I *think* it's this one: https://www.diyelectriccar.com/forums/showthread.php/opel-gt-ev-restoration-and-conversion-200383.html

It's this one but found it from your link, thanks.

https://r.tapatalk.com/shareLink/topic?url=https%3A%2F%2Fwww%2Ediyelectriccar%2Ecom%2Fforums%2Fshowthread%2Ephp%3Ft%3D200587&share_tid=200587&share_fid=33831&share_type=t&link_source=app

Cheers
Tyler

 

[tylerwatts]

Matt what are the 21700 cells out of interest? Have you found a mounting system for them yet?

Cheers
Tyler

 

[MattsAwesomeStuff]

I *think* it's this one: https://www.diyelectriccar.com/forums/showthread.php/opel-gt-ev-restoration-and-conversion-200383.html

Nope, that's Flloyd's.

There were some actual electric Opel GTs, out of factory I think, back in the day. Hideous things with wheel covers, and lead acid batteries up to and including in the passenger seat.

One guy 10 years ago converted an Opel. It's the only one I've heard of.

And then I found the one while I was buying some winter tires. So then I went onto the Opel GT forums and said I was kind of looking at a GT as my EV project car. Which was somewhat embraced and somewhat shat on by the negative nancies, "Another one of our cars ("our", like the community asserts ownership over all that ever existed) is just going to end up in the scrapyard" and know-it-alls "You'll never fit enough lead-acids in there", and "Lithium isn't a proven technology, you must use lead acids" and other laughably out of touch old-man-set-in-his-ways opinions.

But most people were nice. Also, I can't do this without community help. I know nothing about cars, let alone quirky old cars that were only made for 4 years 50 years ago. So, a few months later one of the guys in the community finds 3 of them for sale near him. And would you believe it, none of the entitled "how dare you make it electric, another one of our cars is going off to the junkyard" losers was actually going to step up and rescue even one of "their" cars from the actual scrapyard. So I found a buyer for the good one, and I bought the other 2 and drove 3000 miles to get them. And, I haven't heard zip about how dare I do this to one of "their" cars since.

Anyway, by coincidence or perhaps word of mouth, after sharing what I'm buying on the DIY EV forums, while I'm gone to Phoenix to try to rip apart these cars and haul the shells home, I'm working dawn 'til dusk, not paying attention to forums. The guy who's place has the GT's tells me a few days in "So, since you announced doing this, 2 other guys have announced they're also building electric GTs"

Flloyd's one of those guys. For the first few months he was working on his, we motivated each other to keep working with our progress.

My build thread is scattered across 3 forums. A lot of the content is copy/pasted, but some differences.

The one Tyler found is on the DIY EV forum. That details most of the EV stuff.
The other one is on the Opel GT forums. That one's a bit hyper-specific to GT questions and car questions and restoration stuff, and answering some basic EV questions for the guys there. It's probably the most extensive: https://www.opelgt.com/threads/matts-electric-gt-projectlog.108355/
The third one is on the Open Inverter forums, and that's mostly to do with using their open-source hardware to hijack a Prius inverter as the speed controller.

Matt what are the 21700 cells out of interest? Have you found a mounting system for them yet?

Hmm, what do you mean by "what are they"?

21700s are a larger form factor than 18650. They're 21mm diameter x 70.0mm length, instead of 18mmx65.0mm.

18650s are what are in Tesla S and X models. 21700s are what are in Tesla 3 and Y models. You're starting to see more 21700s in tools because a single series string of 18650s is a touch too weak, but a double string is 2x the price. By bumping up the size just a bit, a single string is good enough for most tools.

I haven't figured out a mounting system for them yet. 18650 mounting grids are a few cents apiece. I haven't found (haven't looked really) any for 21700 form factor though.

Considering being lazy and just strapping them together in a box.

Considering using a 21mm forstener bit in a drillpress and either 1/4" ply or a pair of 1/8" PVC sheets and fabbing my own grid stabalizer.

I have 340 of them tested so far, and probably that many again still in packs to be tested. So, 700 perhaps total. Usually around 3300mAh. 8.5 kWh or so. Not great but enough to goof around on. 34 mile range at highway speed. It'll get me around town. If I'm going travelling, I'll tow a little trailer with my 4000w genny running (I'd need cargo room for whatever I'm roadtripping for anyway).

 

[tylerwatts]

Hi Matt

Sorry for my unspecific question, I meant what brand/model etc? I know the size designation. And thanks for sharing your logic for using them. Essentially I understand it is slightly better overall energy density in the finished package (rather than cell specifically). And you can recycle tool cells to build your pack.

I'd love to recycle but I haven't the skills or patience to recover the cells. I've found places selling tested cells which appeals to me. My worry was mounting/building the pack. I like the hex holders for 18650 cells but they don't seem available for larger 21700s. There are square grid holders, mostly from China, on Amazon, eBay and the Chinese sites. Not the best packaging but secure. I'm trying to cram max capacity into a small scooter hence wanting the hex format. Then there's the Vruzend kits and I was happy to compromise for their clever (simple for me to do safely) assembly but again only for 18650 cells. I might go this route anyway for packaging reasons but I'm following your battery build and love your car choice too.

PS, would you mind sharing a link to the Open Source forum you're building an inverter with etc please?

Cheers
Tyler

 

[MattsAwesomeStuff]

Sorry for my unspecific question, I meant what brand/model etc?

Hmm... Sanyo NCR20700A

That's not an endorsement of them, beggars and choosers and all that. But it's what Dewalt uses.

They're power-optimized cells, not energy-optimized.

I'd love to recycle but I haven't the skills or patience to recover the cells.

Skills are minimal. You tear apart cases, yank the cells into chains, peel off the positive side with pliers, cut off the negative side with a chisel. If you're using laptop cells then the nickle strips will be 1/2 as thick and you can peel the negative side too (on tool cells you'll rip the weld nuggets out of the cell casing, ruining the cell, so you chisel).

https://www.youtube.com/watch?v=seBJ5TUsTV8

I have a whole tutorial series on it filmed but not edited. Like all my projects for the last 10 years.

Patience... Yeah, I bought two 4-bank testers, so I can test 8 cells at a time. Cost about $100. I also built a pre-charge and post-charge rig, so the only thing I use the testers for is discharge testing. 4-6 hour discharge time. So even then, it was months.

I've found places selling tested cells which appeals to me. My worry was mounting/building the pack. I like the hex holders for 18650 cells but they don't seem available for larger 21700s.

https://secondlifestorage.com/ -- These guys might sell you tested cells cheap.

Also, on the top menu is the "repackr", you feed it an excel list of your tested capacities and how many cells in series, and it spits out which ones to use to make a balanced pack.

21700s aren't that much more efficient, density-wise. Packing-wise they're both cylinders, so you're wasting an identical amount.

If it's at all a concern to you, 18650s are probably more cost effective and easier to use. I would probably just go with that.

There are square grid holders, mostly from China, on Amazon, eBay and the Chinese sites. Not the best packaging but secure. I'm trying to cram max capacity into a small scooter hence wanting the hex format.

There are some hex grids available on eBay. I like square because it gives me air cooling around the cells.

You're looking at 79% efficiency for square tessellation, and 90% efficiency for hexagonal tessellation. So, only a 10% improvement.

PS, would you mind sharing a link to the Open Source forum you're building an inverter with etc please?

OpenInverter.org

My build thread is pretty sparse, and most of the content is scattered across other threads there.

https://openinverter.org/forum/viewtopic.php?f=11&t=383

The founder created an open source inverter.

One of the chief contributors, Damien Maguire, specializes in reverse-engineering Hybrid and EV inverters, then uses the software and brains of the Open Inverter to hijack the OEM EV inverters rather than creating the whole Open Inverter power stages himself. Old Hybrid inverters, especially Toyotas, are insanely bulletproof and idiotproof and can be safely overvolted and overcurrented to a huge degree. He's reverse engineered Teslas, Leafs, etc.

Like, my Gen2 Prius inverter can handle 480 horsepower and shuts down gracefully if you exceed its limits, and you can pick them up for $150 in a junkyard.

That's kind of the meta for DIY EVs right now, OEM inverters that are re-brained rather than building the Open Inverter hardware itself. Basically every commercial shop that does conversions uses knockoffs of the Open Inverter design.

Not really something you can take advantage of on a bike, maybe not even a motorbike, as EV inverters are between the size of a toaster and a microwave.

 

[amberwolf]

One guy 10 years ago converted an Opel. It's the only one I've heard of.

there are four over here (but i know nothing about them):
http://www.evalbum.com/type/OPEL

Considering being lazy and just strapping them together in a box.

if you do, without cell spacers/holders of some type, i highly recommend putting stiff insulation plates (fr-4, etc) between each set of parallel groups, so that no vibration (or anything else) that could possibly ever wear thru or damage the wrappers could cause a short between groups that are in different places in the series string.

cuz that's bad.