Harpkatt Introduction Possible 32 Roadster Conversion

It'll make an awesome EV! It's just like the old jalopy days. Take a car, make it cooler, faster, more bitchin' than before. Use new parts, salvage parts, stuff that wasn't made for cars and make the car go...then go faster...then go father...then make it look cool.

Back in the mid-90's, I got interested in EVs. A cat named Roderick Wilde did up a '29 Ford Roadster as an EV. Looked like a regular StreetRod, but it was electric! It was so unlike the glorified golf carts most of the converters were building out of econo-boxes.

Back in those days, it was all lead-acid batteries...now, there are some prime lithium batteries available from salvage, or even new. Some brave guys are even using hobby lipos which have a high power:weight ratio, but a high danger factor as well. Apply the same hotrod philosophies (lighter/stronger/better efficiencies) to your Roadster as an EV that you did as a dino-burner, and you'll do well.


I'm doing a '53 Hudson Hornet at the moment, dual AC-50s and about 44kWh of Tesla batteries. Not the lightest EV ever, but not nearly the heaviest, either! It should scoot.

The toughest thing about any build is coming up with a car you'll love enough to go all the way with. I did a couple of VW Rabbits, back in the day, and I tired of them before I was done, and I hated them when they were done. You must love your StreetRod already...and you'll love it even more as an EV!

Communicating with an EVSE is easy- there's this sweet little box to do the job for you:

http://modularevpower.com/

The charger is a device you have to buy and build into your vehicle. Which charger you buy depends on the voltage of pack you choose. The EVSE is just a somewhat smart electrical socket- it checks for ground faults and makes sure there's a vehicle present before the power is turned on. It doesn't do much for what they cost, but if you're going to use public chargers it's nice to have a J1772 port and an AVC2 to connect that system to your charger. That said, I charge mine nearly 100% of the time from 120VAC with a regular extension cord via a GFCI outlet.

If you're going with an AC50/51, you have two choices: 96V nominal 650A or 144 V nominal 500A. The lower voltage one gives you more torque. But don't be confused by the "nominal"- the maximum voltage of the 96V controller is well over 96V- something near 130 IIRC- take a look at HPEVS's website for more details. Your range demand will determine how many Ah you need. Take your expected vehicle weight, including batteries, divide by 10 and that's how many Wh per mile you'll need, round numbers. Divide the result by about 0.7 because you don't want your battery to be flat at the end of your range if you want it to last, and you will expect to lose some capacity as the cells age. If you know your voltage (how many cells in series you'll have) and you know how many Wh you need for your range, you can calculate how many Ah each cell must be.

Your options for batteries are Volt, Leaf or Tesla, pretty much. The prismatic LiFePO4 cells most of us used in our builds are a previous generation of technology- reasonably reliable, and a nice chemistry for DIYers because it's tolerant of mistakes, but the batteries are expensive and have about half the energy density per unit weight and volume than the OEM vehicle batteries.

Cells then need to be paralleled at the cell level. If you're using Volt cells, which are probably the cheapest, your choices are limited as the pack breaks down only into discrete chunks of a certain size. There are lots of threads here, especially Yabert's Smart ForTwo high power version, and Duncan's Dubious Device, which give you more info on how others have used Volt packs.

You'll need to either buy a battery management system, or you'll be the battery management system. Those systems are cheaper the lower the voltage you use, because you need one input channel or celltop board per "cell", which means per group of cells in parallel. Some here get away with being the BMS themselves, but none of the OEMs do that, nor in my opinion should you. A BMS is minimally necessary safety equipment when working with Li-ion batteries.

Unless you're putting in a mega stereo, don't bother with a DC/DC converter. Instead, put in a 12V battery sized for your needs and just parallel its charger's AC input with that of the main pack charger. That will give you perfect isolation between your 12V and high voltage systems (which you NEED), at a lower price than if you bought a DC/DC. You need the 12V battery either way. Some like the convenience of the DC/DC instead- it's a matter of budget. I bought a DC/DC and would personally have saved the money if I had to do it over again.

^^^^
Great info above by MM! As for the mechanicals, it's a bit like a jigsaw puzzle if it's something strange (like a Borg-Warner T-85 with OD), but there are many off-the-shelf adapters for some common trannys, like a Tremec 5-speed, which will also give you an overdrive.

You'll probably only use a few gears...start out in 2nd or 3rd, then maybe shift higher for highway speeds. The thing is, you won't need to slip the clutch because electric motors don't need to idle like a gas engine. Some guys don't even put a clutch between the motor and tranny, just a straight coupler. Having a clutch is slightly safer because there's another way to disconnect power to the wheels, it makes the car seem more conventional to drive, and gear changes can be smoother if you're not a wizard with the stickshift. Clutch vs. no clutch is one of the big debates in the world of EVs, lol, and some cats get very passionate about their choice, hehe.

In many ways, a motor swap to make a car into an EV is very much like an engine swap in a gas-burning hot rod (an electric motor is a "motor", and an internal combustion engine, or ICE, is an "engine", in more technical terms).
You remove the parts related to the old unit, and fab/build/adapt some parts to make the new unit fit, and give it everything it needs to work. If you understand how a cordless drill works, an EV is very similar, but more powerful. The higher power needed to move a car needs respect because just like gas cars, there are forces that can burn/injure/maim/kill/etc. Just be as careful and respectful with an EV as your 700hp dino-burner, and you'll be fine, lol!

The AC-50/51, or whatever else you choose, is simpler to mount than any V8. You connect up the motor to your choice of trans with an adapter plate...Check with CanadianEV for off-the-shelf adapters, EVWest.com, EVTV.com, (or many others), then fab up some mounts from the motor to your frame. It's surprising how conventional it will seem to someone who builds hotrods.

Batteries and battery boxes are like the fuel tank(s). The motor will be a lot lighter than the engine, but the batteries will be heavier than a fuel tank. With current technology...you may come out even on weight from the old ICE, especially if comparing to a monster engine. Depending on what batteries you use, and how many of them, you'll come up with places to put them that are safe and secure. It's super cool that you have some flexibility with EV components...you can make a car handle much better because you can put batteries low, and in different spots to balance the car.

I've included some photos of my T-85/R11 tranny, ready for its adapter plate. I did use the clutch, FWIW. I know a guy who didn't in a 60s Falcon van and he's happy too. We'll see how it goes, lol...Good luck!!

Performance isn't really a concern. Range is more my concern. Not that I'll be driving 100 miles everyday. But I do worry about range anxiety. My understanding is AC will give you better range and reliability. I'm exact sure whats unreliable about a DC motor though. The close I can get it to and OEM drive train I think the happier I will be. Also theres a leaf motor on ebay right not for about 500$ Not that I'm gunna jump the gun and buy it. I'd like to have all my eggs in a row before I start doing anything. In my head it should be fairly easy to put the drive train together once I have all the parts. Since I already have a frame and front/rear suspension I can build it and place the body on it. Makes mounting batteries, motors and wiring very simple.


I should also mention I am friends with someone who owns a pretty successful Junkyard, I'm hoping I can get a motor fairly cheap through him. There's also a 2013 Leaf for sale that I stumbled on that has a ton of body damage but is supposed to still run and drive. 23k miles 3000$ This is what kinda got my gears wound up to maybe finally pull the trigger. But I'm afraid of all of the Leaf software security stuff since A) never worked on one B) I'm awful at programming coding and basically any computer after windows XP. which is terrible since I'm only 27. But I do things a little different. No Phone, No TV etc. I'd just rather spend the money/time building Everything.

I wish I knew somebody local To Long Island that could use a hand doing a conversion,or new about this stuff. I;ve heard theres a guy in Bayshore Long Island that does conversions,but according to his website seems like he doesn't have a physical location.

Hi Chris
The next conversion I do is going to be a Leaf - treat the whole car as a sort of EV kit!

There appears to be three ways to do this
(1) bugger about with CANBUS and programming
(2) Use all of the Leaf - bits and leave them connected so that they "think" they are still in the Leaf
(3) Use the expensive mechanical and power electrical bits and substitute a different "Brain"

No (1) sounds HARD
(2) sounds difficult but doable - if you have the whole Leaf
(3) is probably harder

If you want simple + power then go DC

Re-using the whole Leaf is very tempting. But going that route, i.e. fooling the vehicle control system into thinking it's still in a Leaf, doesn't give you the option of increasing the battery capacity I don't think, at least not easily. And one Leaf's worth of battery won't meet your range needs/wants.

DC isn't unreliable, it just needs maintenance of the brushes and cleaning to remove brush dust. It doesn't give you regenerative braking though. That's a 10-15% range penalty, so not much- but it also acts like "power brakes" and makes driving a lot more comfortable and fun, reducing wear on your ordinary friction brakes to basically zero.

If performance isn't your primary worry, go AC. If you want simple and can afford it, the AC50 and Curtis controller are EASY- no programming or screwing around. If you're not going to salvage a forklift motor and build your own controller, the AC50/Curtis package are about the same price as a bought controller and a new DC motor. But they do cost some money.

If you don't salvage the whole Leaf, you'll also need a good amp-hour gauge, which takes care of current flows into and out of the battery and acts as your fuel gauge. A lot of people here have used the JLD404. I have an E Expert Pro- it was very expensive (about 3x what a JLD404 would have cost) but is a very easy to use and reliable gauge.

The Curtis controller comes with a Spyglass display which will give you a rolling display of RPM, current, voltage, motor temperature, controller temperature etc. Using the display and a Menu pushbutton, you can monitor and adjust all the parameters needed for a normal car conversion project.

As far as simplicity Goes I have been considering the Curtis/AC50/51. How much exactly will performance suffer vs a DC? I'm not looking to build a race car. I do want regen braking though.

I've spent hours researching in the past few weeks and repeatedly, I see high cost of conversion. Tons of people estimate15k-20k. considering the usage I expect that seems high. Where is the hidden cost here?

AC51 and Curtis kit are about 5k. Which Is what I'd spend on an ICE all said and done. So that's fine.

Then batteries. I get that cost varies here. if I expect to spend6k$(or less if My junkyard buddy pulls through(he always does)).

Fabrication cost are all on me,,I can source material/scraps for free usually. I already have the car(most of it). I'd just need an Adapter to the Trans.

What else am I missing here? Wiring adds cost that I know. I'll be able to get my hands on a 277 VAC Charger no problem. So what now?

What kind of rear gear ratios do you guys run btw? What works best with an EV Torquey gears or highway gears?

Your range comes from your capacity minus your consumption. The light that burns twice as bright, burns half as long. If you want to be able to go far, you'll need to find the balance between the power you can store onboard, and the power you need to use to move yourself, the car, and whatever else you carry.

My very first plan for an EV was for an early Lakes' style racer. Early (28-34) coupe or roadster, skinny tires, the kind of streamlining tricks guys did back in the 30s and 40s to go fast on the dry lakebeds, but with lights and license plates.

With modern battery tech, and what you're working with, it oughta be doable. The Leaf pack is great for the weight, and so is a Volt pack, but you might need to double up whichever you use to get to your desired range.

If you keep it a highboy, you might be able to arrange Leaf battery modules between the frame rails, under the floor...good for CG and uses otherwise wasted space...
Take care! Brian