Third Conversion, ultra efficient (1993 Geo Metro EV)

[EVmetro]

Originally Posted by elhigh

Still grooving on the quality of your work.

I absolutely marvel at your all-up curb weight. 2026 lbs! WOW. There was a time when that was the kind of weight you might hope for in a glider, before you started screwing in the motor, tranny and batteries - never mind the interior.

With such a featherweight chassis to start from, I wonder what kind of steady-state range improvement you could achieve with a removable kammback, or other aero improvements. I saw you've done some with a grille block but don't know about any other mods you may have done. If anybody around here could put together a trick-looking kamm, you're the guy.

Looking forward to more.

I thought about doing a little more in the aero mod dept, but was after a build that was very drivable, lightweight, and appeared unmodified. I could still make some improvements on the underside of this one, and still may do that, but am still collecting data at this weight. From what I can tell so far, the biggest improvements are the weight, and the on demand regen system. Capturing ALL of the braking energy while having no off-throttle regen is proving to be remarkable compared to a typical manufactured EV or AC conversion running off-throttle regen. I suspect that having this thing freewheel instead of off-throttle regen gives a more pronounced effect on something of this weight, since it is easier to disturb the kinetic energy of a lighter vehicle than it is a heavier one.

[gasstingy]

I've been amazed at the entire build and kept my mouth shut while I watched, but I haven't seen any comments concerning the brake lights, so I'm too curious to not ask. As you have quite strong regen on your shift knob, I keep wondering if the regen button also activates the brake lights?

And, I agree that this looks far superior to a factory built anything. I am also jealous that I don't have similar ability to do such an outstanding conversion.

[skyking]

Good question. I have an exhaust brake on my truck and have to be mindful to flash the brake lights.
I just got here thanks to the newsletter, and all I can say is bravo! What a great build and I hope it steals some shows along the way.

[EVmetro]

Originally Posted by gasstingy

I've been amazed at the entire build and kept my mouth shut while I watched, but I haven't seen any comments concerning the brake lights, so I'm too curious to not ask. As you have quite strong regen on your shift knob, I keep wondering if the regen button also activates the brake lights?

And, I agree that this looks far superior to a factory built anything. I am also jealous that I don't have similar ability to do such an outstanding conversion.

Thanks. The controller has a brake light circuit in it that allows me to activate a relay for the brake light. In the controller settings, one can adjust how many amps of regen it takes to activate the relay. I think I set mine for 50 amps of regen before the controller sends a brake light signal to my brake light relay. So, there is no signal coming directly from the regen button, only from the controller after it senses a specified amount of regen current.

[EVmetro]

So I took her out for a range test yesterday, with two objectives in mind. The first was simply to explore the range capabilities, the second and most important was to ensure that it performed correctly as it ran out of energy. Normally, one does not run a lithium EV until it stalls, but since the canbus communication between the Orion and the Curtis is meant to protect the pack while underway, I wanted to verify my settings. Everything went smoothly for the first 100 miles, and this is when I finally got to watch the current get cutback. As the freeway would go up as an overpass, my lowest cell began to sag to 2.8 volts, which is where I have my controller programmed to begin cutting current. I could mash the pedal to the floor, but the lowest cell sag would not dip below 2.77. Once I would get over the overpass, I could pick up speed again, but it got tough to maintain 55mph eventually, so I finally pulled over and loaded it up on my follow vehicle and hauled it back to the shop. It was pretty cool watching the electronics step in and prevent the pack from intentionally being run into the ground. I ended up loading it up at 106 miles, two of the 36 batteries were resting at 2.95, and the other 34 were resting around 3.16. I will see if I can manually charge those two with my bench power supply after the pack is charged, hopefully they will have a little more room left at the top. The range is only as good as my weakest cell, since I can't use any of the remaining energy in the other cells after the lowest one hits the bottom limit.

[EVmetro]

Here it is out in the wild.



Here I am loading her up after a range test. I just pulled off onto the shoulder of the freeway when it was done, then loaded it up on my follow vehicle.

[elhigh]

That is a thing of beauty. Looking forward to hearing final numbers. Cracking past 100 miles range on a homebrew EV is the holy grail.

I wonder if you could set up some kind of a trickle charge solar panel on the roof? It wouldn't be much, but if you're like me oftentimes on the weekend the commuter sits for two days. It wouldn't pick up a lot of range but some is more than none - and a trick gas cars just can't do.

[foxgrockefeller]

I'm interested in turning one of my CRX into a similar machine. Where did you buy these batterys? May I asked what you likely spent on the build for controller, batteries, motor, single adaptor? I'm hoping I can do this for $3500

[EVmetro]

Originally Posted by foxgrockefeller

I'm interested in turning one of my CRX into a similar machine. Where did you buy these batterys? May I asked what you likely spent on the build for controller, batteries, motor, single adaptor? I'm hoping I can do this for $3500

The crx would make a fantastic conversion. As far as budget goes, you can convert a car for $3500, but you would have to make a lot of sacrafices. The forkenswift project on this forum is a really cool project the way it was built on such a small budget, and it was one of several budget conversions that inspired me as I was learning. I have done several conversions now, but they have been built to pretty high standards that required a bigger budget. The batteries were the biggest purchase on this rig, 36 batteries x $250, for $9k, followed by the motor and controller combo at $4k. The charger was another $2200, and the bms was around $1200. There were a lot of other items that probably added up to around $5k, and then there was a lot put into restoring the chassis, suspension, and interior. The restoration work was not really essential, but in my case it was important for the finished product that I was after.

This particular build certainly is above and beyond the $3500, but i would not get too discouraged about that. EV conversions are kinda like hot rods where you might be able to rattle one together for $1000, but it is easy to spend $100,000 or even more. I love beautiful cars, but deeply admire a build like the forkenswift as well. I saw somebody's build thread one time, and the subtitle read "built, not bought". That really struck home in my mind.

[phantom 309]

such an entertaining thread,.
kudo's for your craftsmanship.
$25,000 for an EV is a little out of reach for me.

A 5 yr cost comparison would be interesting, a gas powered used metro vs your ev metro.
Including original purchase prices etc. cost to operate etc.

cost to operate including electricity to recharge,.