[Driving] Homebuilt Locost 7 - from Motorcycle engine to Leaf power!

[johu]

Also verify that you get equal torque response in forward and reverse. That kind of indicates a correct syncofs

[Zieg]

Okay, I did not have the right syncofs. Everything is fine now, but I did have a rough few minutes getting it sorted out.

It was hard to tell with the car in the air but on the ground it was obvious, the torque response was very different in either direction. I tried a small change first and that felt normal, so I started driving but the first time I tried to accelerate slightly hard the car bucked and lost power. I had to cycle power to the inverter to get moving again. That was on a road with no place to pull over (stupid idea in hindsight) so I kept going, but the car tried to accelerate on its own again. This time I hit the brakes and it cut out again. I was not logging, but I wonder if it was tripping due to overcurrent? My one concern is that if it did trip and opened the contactors, could I have damaged the capacitor in the inverter? The car seems fine after adjusting the syncofs again, but I don't know how I would tell if the capacitor was blown.

Anyway, I finally pulled over to a safe place and started playing with the syncofs again, this time I tested by actually driving the car forward and backward until I found the sweet spot. Then I kept driving and it felt great. It pulled hard and there was no more uncommanded acceleration at higher speeds.

I even found a spot to try accelerating hard from a stop and discovered it's possible to spin the rear wheels. I can also tell from the video that the car is transferring a lot of weight to the back when accelerating this hard. I do think I am going to have to go with stiffer springs!

Lots of wind noise again, turn sound down. I think I was near 100% until the tires spun, then I was probably 75%...

[Zieg]

Wasn't able to go for another drive for a while because of work and weather, but I managed to sneak out for a bit today. I went to a nearby unmanned scale to check the car weight against the bathroom scales at home, and this scale said I was about 760kg with a 42%/58% front/rear balance. I'm hoping that's reading a bit high, because it would mean the car gained about 225 lbs of weight over when it was ICE, and I really can't see that. At home it was almost 700kg even with me inside. I did have some tools and such with me, but certainly not THAT much. The good news is, regardless of the absolute values, the weight distribution is better than it was with the ICE, so I'm happy. Going to try and get it weighed by a known calibrated scale when I have the chance.

Also, interesting anecdote, while coasting downhill at around 70 kph, I noticed that I was maintaining speed while completely off the accelerator. I still don't have any regen active, but it looks like on this particular hill, at that particular speed, wind resistance was enough to keep my speed constant. Google says it's about a 3.4% grade. Tough to tell the slope from this screenshot but here it is anyway:

This week I am planning to stiffen up my suspension a bit by changing the angle of the front shocks and new springs all around. I also need to replace some of my HV wire. I used 600v 2/0 welding wire in an orange mesh sleeve for my battery-inverter connection, but the SCCA rulebook says it has to be double insulated and shielded wire, so I had to spend almost $500 CAD on some 2/0 shielded wire from EV West. Ugh.

The other thing I need to do is replace the wiring to the charger and DC/DC converter. The rules state that 14awg and larger HV wire MUST be double insulated and shielded, regardless of how much current it carries. I used 12awg wire for the DCDC and charger, even though each set of wires sees 10 amps or less. So, I am just replacing it with regular 16awg wire. lol.

[jrbe]

I even found a spot to try accelerating hard from a stop and discovered it's possible to spin the rear wheels. I can also tell from the video that the car is transferring a lot of weight to the back when accelerating this hard. I do think I am going to have to go with stiffer springs!

If you're willing, do you have room to rework the rear suspension to add in some / more anti-squat?

[Zieg]

Hm, good point. It does have some antisquat built in, but I don't recall how much at the moment. If I wanted more I could just relocate the front brackets (or make them adjustable somehow), wouldn't be too hard. I'll see how it is with the new springs first though. What's on there now are just what I had laying around (275lb/in). I have a pair of 325# and a pair of 350# in the mail. Probably going to put the 350# on the rear first, then try moving the 275# to the front and see how that feels. Should put me in the range of 2.0-2.2 Hz depending on which scale is correct.

[EVSwap]

So cool, it definitely has way more torque than the motorcycle engine had off the line!