[Tremelune]

The cooling system is flowin'! The Prius pump is strong, nearly silent, and only has one moving part. The system purged itself of air bubbles rather swiftly.

I ditched the 3/4" ID tubing, as it was kinking too much in front of the motor, and in the end was unecessarily large—I managed to get 5/8" ID tubing over the Leaf ports with a heat gun and some soapy water as lubricant.

I used PEX elbows to avoid any tight bends (3/4", but PEX uses a different sizing system), but they may not have been necessary after downsizing the tubes. They seem to be as good as steel and as cheap as plastic. The tubing might be too loose on them without clamps, but I'm gonna give it a whirl.

There was very little room on the left, so I wound up just stuffing the two tubes from the motor through an opening and wrapping them with more tubing as protection. My plan is to just keep an eye on things to see if the protection falls out, or gets damaged too quickly, or what. Getting tubes to the motor was very annoying, and it seemed like any useful cutting of the body would be visible.

I didn't have the Prius water pump connector, so I just filled the sucker with Fluid Film to prevent moisture from shorting anything out...I don't love it, but I'll wait and see before trying to find a connector.

At this point, I'm kinda just waiting on the axles before doing much more. Road tests will surely adjust my priorities and unearth some design failures.

 

[brian_]

I used PEX elbows to avoid any tight bends (3/4", but PEX uses a different sizing system), but they may not have been necessary after downsizing the tubes. They seem to be as good as steel and as cheap as plastic. The tubing might be too loose on them without clamps, but I'm gonna give it a whirl.

I definitely wouldn't trust PEX barbs with soft hose of any size without clamps. Even with PEX clamp rings are needed. With clamps, they should be fine, as long as the tubing inside diameter (before stretching) is smaller than the barb outer diameter.

 

[pickmeup]

Have you seen this?

 

[Tremelune]

"Costwise, it could be anything. Timewise, it could be anything."

 

[brian_]

Have you seen this?

No, but it's 26 minutes long and starts with a guy drinking coffee... so I'm going to take a wild guess that it's not worth watching. If there's something in it of value, why not tell us what that is?

 

[pickmeup]

No, but it's 26 minutes long and starts with a guy drinking coffee... so I'm going to take a wild guess that it's not worth watching. If there's something in it of value, why not tell us what that is?

hes using a leaf motor and batteries, its worth letting tremulene know as they are asking for feedback on the conversion, it seems strange he doenst seem to know of the great work that ESDI has done on already converting a mini with a leaf drivetrain.

 

[brian_]

hes using a leaf motor and batteries, its worth letting tremulene know as they are asking for feedback on the conversion, it seems strange he doenst seem to know of the great work that ESDI has done on already converting a mini with a leaf drivetrain.

Thanks.

If there is anything specific from this build which is interesting or useful, I assume that someone will add it to the discussion.

 

[Tremelune]

Axles, axles, axles!

It seems they were worth the wait (and $1400 price tag). These things are works of art, and fit perfectly with clearance everywhere. They machined the Nissan stubs to their own CVs and hub shafts. Beefy. Smooth rotation at all but full droop with the car in the air. With the car on the ground, they're pretty level, and the angle toward the rear is quite slight.

The shafts are equal lengths (though the boots make it look otherwise). It seems that the way I measured was optimal (or at least allowed the shafts to be equal in length within the in/out tolerance). Specifically, to position the motor in the subframe, I measured from the gearbox face on both sides (without the bracket that locks them in), which is distinct from how The Driveshaft Shop wanted me to measure for their purposes.

There is no torque-steer to speak of. I am pleased. My compliments to The Driveshaft Shop.

 

[Tremelune]

The Inaugural Flight

Brilliant. The car is brilliant. It's still a rat's nest of wiring, but it is a blast to drive. I currently have torque limited to 75%, and while it's not fast per se, it certainly isn't slow. I got to maybe 8,000rpm for a bit (just shy of 60mph), but not for long enough to get a real feel. Most of the driving was spent puttering around tight neighborhood streets at low speeds to see if any bugs came from all the shaking. There are some things I need to investigate, but overall it went smoothly!

I wound up installing Thunderstruck's CAN Translator, which basically sends Leaf VCU CAN messages off to the OBD-II port. This allows an app (such as OBD Fusion for the iPhone) to get information with regard to motor/inverter temp, RPM, current draw, etc. I haven't gotten things quite sorted yet, but for a rudimentary dashboard it is working well.

With ambient temperatures at 80°F and sunny, the inverter never went above 120°F. It spends most of its time around 95-100°F. At full throttle it spikes a bit, then settles back to 100°F almost immediately after power is reduced. The coolant tubes felt slightly warm to the touch after a drive. I couldn't get the motor temp 'cause something isn't right with my CAN Translator setup, but I'm workin' on it.

The batteries barely increased in temperature throughout the driving. They didn't even feel warm. I don't have a handy battery temp display, so I just reached back and put my hand on some module casings to check.

At 75% torque (~150ftlb), it'll spin the tires...The tires on there are old, hard, and cracked, though, so we'll see what happens with a fresh set. There's a strange phenomenon with regard to wheelspin...It seems like power is being intentionally limited until about 10mph, when the wheels start to spin. I'm not sure if it's Nissan or Thunderstruck, but it's curious. It feels like a "spare the drivetrain" measure, which I don't mind, but it'd be nice to have full torque at 0mph as long as nothing would snap!

Turning radius is unimpeded, and it still goes around corners like the legend it is. There is still a whole lot of work to do to make it reliable and nice, but boy...I'm happy with the way it drives just how it is. Well chuffed.

 

[pickmeup]

this is fantastic news! i cant wait to see some onbarod and drive by footage of it in action!

 

[skooler]

Awesome! well done

Sent from my SM-N976B using Tapatalk

 

[brian_]

The shafts are equal lengths (though the boots make it look otherwise).

So is the inboard boot on the left shaft (shown on top) compressed too much, or is the inboard boot on the right shaft (shown on the bottom) extended too much? Are the clamps on machined grooves in the shaft, or can you just release the clamps and correct the boots? It seems like a small detail, but the only thing that typically goes wrong with modern CV joints is that damaged boots allow dirt in which destroys the joints; protect them and they last forever... and a stretched or compressed boot is more likely to fail.

 

[brian_]

There is no torque-steer to speak of. I am pleased.

Way to bury the news of the first drive
Congratulations!

I got to maybe 8,000rpm for a bit (just shy of 60mph)...

So top speed is at least 79 mph (127 km/h) - lower than the Leaf due to the smaller tires, but would still be enough for me. Of course, lower top speed means more low-speed acceleration...

At 75% torque (~150ftlb), it'll spin the tires...The tires on there are old, hard, and cracked, though, so we'll see what happens with a fresh set. There's a strange phenomenon with regard to wheelspin...It seems like power is being intentionally limited until about 10mph, when the wheels start to spin. I'm not sure if it's Nissan or Thunderstruck, but it's curious. It feels like a "spare the drivetrain" measure, which I don't mind, but it'd be nice to have full torque at 0mph as long as nothing would snap!

To avoid shock, the system should limit the rate of increase of current (regardless of road speed), not limit the current to fixed ceiling only at low speed. I think this is about smoothing out jerky drivers rather than saving mechanical parts from shock. Many drivers would spin the tires on every start on a wet or icy road without this sort of tweak.

Whether the intent is to spare the mechanicals from shock, or the smooth the driving (and passenger) experience, I assume that this is deliberate, and in the Nissan code.

 

[Tremelune]

Thanks!

_brian, you are correct...about several things:

1) I'm leaking coolant from the PEX fittings. When the coolant goes over 100°F, the tubing starts to get soft and drip from where it exits the motor. I'm gonna clamp 'em. I'm running tap water at the moment, so no biggie. The motor has been staying around 110°F, and sometimes gets near 120°F under load. I'm not sure what to expect when the car is parked in the hot sun and then gets floored...Worst case, I'll ditch my fancy clear hoses, but I like them! My "overheat" temp is somewhat arbitrary, cobbled together from Internet research...I've seen 160°F and I've seen 200°F as inverter maximums, so I dunno. My hoses are specced to 150°F...

2) The CV boot appears to be stretched on the left inner joint. I got some good video of it in the link below. I think it's just a question of scootching the boot seal closer in, but if I have to get a new clamp (and tool) I will. I really don't want to have to replace CVs on a custom set of axles...As far as I can tell, the axles are working well. No noises even at full lock, and driving angles look mild.

3) I think 75-80mph will wind up being the top speed. Right now I'm using GPS for a speedometer and it's kinda flaky. As long as I can go on the highway safely, I'm happy. This is a city car for sure. 60mph was a guesstimate based off the calculated top speed and measured motor RPM. 😁

Other known issues:

- The rear motor mount plate makes contact with the body, and it's scraping paint a bit. When I pull the subframe, I'll have to grind a bunch off. No biggie (once it's out of course)!

- Something is popping or clicking when going from hard deceleration to hard acceleration and vice versa. I'm hoping it's the issue above, but I kinda doubt it. I'm gonna stick a camera down there and see if I can reproduce it consistently and see if there's anything visual that matches up with the sound.

- Range is limited by my 12v battery...I haven't driven far enough to understand the range yet, but without DC-DC, my driving time is however long it takes for the electronics and coolant pump to draw the battery below 12v...Luckily, this Mini came with a giant battery, so I'm just gonna use that until I know the weak link.

I don't have much for video at the moment, but there's this (oof, I don't like embedded links): http://instagr.am/p/CCfGiEoH2XV/

 

[schelle63]

You made it.
CONGRATULATIONS!

 

[Tremelune]

DC/DC is in the works. I bought a used Delphi 2.2kW liquid-cooled monster, in anticipation of very-heated seats, a rather silly stereo, and too much forward lighting...It's still comparable in price to other options, and it'll be easy to plumb coolant with where I'll mount it, so whatevs. It's CAN-powered, so I need some kind of 12v battery in the system...I opted for this little dude:

I had a thought, though. What if I turn the ignition on, and all the heated seats and stereo is on full, and I try and pull 60A from this little thing before the DC/DC converter is delivering power? Will it overheat and explode?

I'm trying to think of a way to wire it such that it'll power the actual ignition and DC/DC controller, but not the rest of the 12v system. The tricky bit is doing this while also allowing the DC/DC to always give it 13.8V when driving. I must mull.

 

[Tremelune]

Some niggles are cropping up after 50-100mi of driving:

- Front right motor mounts are contacting the subframe, so I'll have to notch that a bit.

- The gearbox scraped the ground at some point. Not much I can do until I install new springs/cones and adjust the ride height. The tie bar mounts are a bit lower than the gearbox, but out to the sides.

- Some relay sometimes squeaks or crackles when power is removed. No idea what that's about. (Edit: It's the special 5v relay, though I don't know why it squeaks.)

- The front tires will fowl on the body when turning (very) tight downhill...Another "until the springs" issue.

- Despite rotating smoothly from lock-to-lock, the axles were too short by like an inch. It's not clear if I mis-measured or was mis-informed, but new shafts are on their way. I started hearing some pops and squeaks when going from deceleration to acceleration, but it could still be the metal-to-metal contact where my motor mounts aren't clearanced right.

- Upping the power to 100% solved the weird throttle-delay-from-a-stop issue. Thunderstruck says setting maxtorque to 1300Nm gets the most out of the motor that they've seen, so I did that as well. I made sure my min and max throttle voltages were slightly inside the physical movement of the pedal (to ensure I was getting actual full and zero throttle).

- The tires spin readily from stop. These tires are old and cracked, so I reserve judgement for after there are fresh shoes...It seems like 55-60% weight up front would be better than 50-55%. Either way, this is a problem I'm happy to have. Torque steer exists, but remains negligible. We'll see what the new tires bring. When I get around to enclosing the batteries, they'll sit a foot further forward, which should help. If I add more batteries...maybe not.

The concept is proved, at least: It's easy to park and fun to drive. I still can't believe the thing more or less worked out of the box...I wonder what deeper issues lurk for the future...

 

[Tremelune]

You made it.
CONGRATULATIONS!

Thanks! The biggest phase is complete. There's still a lot to do, but I now have the confidence to make changes knowing that the end result is in line with what I was hoping for!

 

[brian_]

... I need some kind of 12v battery in the system...I opted for this little dude
...
I had a thought, though. What if I turn the ignition on, and all the heated seats and stereo is on full, and I try and pull 60A from this little thing before the DC/DC converter is delivering power? Will it overheat and explode?

I'm trying to think of a way to wire it such that it'll power the actual ignition and DC/DC controller, but not the rest of the 12v system. The tricky bit is doing this while also allowing the DC/DC to always give it 13.8V when driving. I must mull.

That's cute. Some cordless tools have bigger batteries.
AGM batteries are usually good for relatively high current, but 40 C might be a bit much.

The traditional ignition switch configuration has an "accessory" position before "ignition", and you're looking for essentially the reverse... which wouldn't work in a straightforward way because you don't want to be able drive (on the first position) without everything (especially lights, wipers, etc) functional if you forgot to turn the switch the rest of the way. How about a time-delayed relay for the accessories which comes on a few seconds (whatever the DC-DC needs to start up) after the "ignition" switch is turned on?

 

[Tremelune]

I like the timed relay idea...I started getting crazy with isolated circuits and realized I was being perhaps a bit over-protective...I think I found a reasonable solution by placing a relay between the aux components (dumb shit I'll add in the future), and the rest of the car. This way the unimportant heavy-hitters will never be able to draw from the battery directly, and will only power on with the DC/DC converter.

It still suffers from some factory heavy-hitters, such as turning off the car while my headlights and rear defrost are on, but...that just doesn't seem all that likely. I figure I'll put the 12V battery behind a 30A fuse, and worst case, it keeps blowing until I realize what's going on...I'm gonna wait for an actual problem before I start pulling apart the factory circuits.