Author: trorer@yahoo.com

It’s the last day of August – nearly a month since the last update! I’d like to say things have been moving at a furious pace but that’d be a lie. It’s been a busy month with travel, the Monterey car week (I met Cristian von Koenigsegg!), along with improved work on PassionList. I have a build date from Caterham for the chassis – early December. In the next few days I’m going to sign on a shop in Belmont – finding appropriate space was more difficult and time consuming than I had anticipated.

I’ve also been doing quite a bit of research on batteries and motors and decided that I’ll be going with Li-ion battery packs and an AC motor. My reasoning follows…

Batteries

In looking at EV applications, we’re basically dealing with three different battery types – lead acid, Nickel-based, and Lithium-based.

Lead acid

Lead acid batteries are familiar to us all – they’re in our cars as starter batteries and in electric wheelchairs, golf cars, forklifts, and many other applications. They’ve been around for a while and a known quantity. Many of the first EVs ran off lead acid batteries, including the EV1 .

When looking at an EV application, here are the pros and cons:

Pros

– inexpensive – low cost per watt-hour

– low self discharge

– capable of high discharge

– performances well across a broad range of temperatures

Cons

– low specific energy (low watt-hours per kilogram)

– slow to charge

– limited number of full cycles

Lead acid were a good choice for a long time, however battery tech has improved and given us better options.

Nickel-based

Nickel-based batteries have been a popular choice for portable devices and are at least a look. Mostly we’re dealing with Nickel-cadmium (NiCd) and Nickel-metal-hydride (NiMH).

Pros

– rugged, high cycle count

– takes well to ultra-fast charging

– long shelf life

– low cost per cycle

Cons

– low specific energy

– needs periodic full discharges

– high self discharge

– low cell voltage (1.20V)

Lithium-based

Finally we get to Lithium- based batteries – in the EV space these are the ones of choice these days (at least at the OEM level)

Pros

– high specific energy and load capacity

– long cycle life

– short charge times

– low self discharge

Cons

– requires protection circuit to prevent thermal runaway (i.e. blowing up)

– transportation regulations

– relatively expensive

For my application, it basically boils down to the following – lead acid are too heavy, Nickel-based are heavy and require too many for my needs, which leaves Lithium-based – the next decision will be what specific chemistry. That will boil down to a few other factors, most of which will be constrained by whichever supplier I decide on. Before I embark on that path there’s plenty to decide however.

Motors

This is a slightly easier question – AC (alternating current) vs DC (direct current). Many DIY EVs out there went with DC motors for plenty of good reasons – they were easier to source, less expensive, simpler, and required less voltage. Times are a changing, and there are several good reasons to prefer an AC motor in a modern EV.

– Regenerative braking! DC setups require a specialized controller for this, whereas an AC system is symmetrical in this regard. This improves efficiency drastically.

– Better torque characteristics – AC motors have a wider torque band.

– No motor brushes – this improves reliability and decreases service needs

– safety – if a DC power stage fails, the entire pack voltage is applied to the motor. That’s not a good situation. If an AC inverter fails you simply go nowhere.

It’s no surprise that every OEM EV out there today runs an AC setup.

Much of this material is from Battery University and Metric Mind.

One of the fundamental tenets of decision analysis is that a decision hasn’t been made until resources have been committed. Outside of my time writing up this blog, brainstorming, chatting with people, and research, no resources had yet been committed – this project was effectively just an idea.

Well last Friday that all changed – I plunked down a deposit on a Caterham. I’m purchasing it through Kapeña Motors – Rich has been pretty helpful so far and I think he’ll be a great resource once I start building the car.

This isn’t a cheap project mind you. I’ve decided to purchase everything through Caterham, including an engine and transmission. I don’t plan on using them – I plan on selling them. When one buys them through Caterham along with the chassis you get a great deal – I should be able to nab a nice profit on them. Still though, this is a pretty significant outlay – nearly $47k.

It’s a completely reasonable criticism that this is a bit of a waste – I could easily buy a used car and do the swap. I’m choosing not to do this for the simple reason that I want to assemble the car from the ground up in order to learn more about the manufacturing and design of these cars. I suppose I could disassemble and reassemble a car though.

Most of the new cars sans engine/trans are even more than what I’m paying for the whole package – apparently Caterham’s US distribution channel has changed quite a bit, so now it’s much less expensive to get into a car.

Well, onto the specifics! It’s a Caterham 280 in red with the R-pack (Engine – 1.6 liter Ford, LSD, racing seats + belts, sport suspension, quick release steering wheel, carbon fiber dash, upgraded brake master, black pack – cosmetics, light weight flywheel, and some other bits and bobs), 6 speed gearbox, and 13″ racing wheels.

Currently I’m waiting to hear from Caterham if I can get some CAD files of the chassis. I’m not overly optimistic – that seems like it would be quite generous, but the worst answer I’ll get is no. If I do get them I’ll be able to start the design much earlier which would help.

Next up – I need to figure out what exactly I want this car to do – this will help me pick out overall battery and motor specs.

 

Apologies for the stream of consciousness.

The goal of this first build is mostly to learn. I want to learn about the EV market through hands-on work, I want to learn about the engineering challenges an EV presents, and I’d like to improve my wrenching skills. Along the way I’ll get a bunch of new fun tools and at the end of the project I’ll have a cool car. So, why a Caterham? Why not convert an existing car? It’d probably be easier and cheaper.

My thinking is the following – at some point I’d really like to build and sell an entire car. What better way to learn about the design and manufacturing of the various subsystems than to build a car from scratch? From scratch would be a tough project though – I think it’s more reasonable to start with a kit. Plenty of kit car options out there – the biggest players (at least in the US) seem to be Superformance and Factory Five.

I’m not a huge fan of Cobra replicas. There are tons of them out there, and I dunno, they just don’t do it for me. Too fake. Same goes for the Cobra coupe and GT40. Hot rod? meh. It would be an interesting EV though – I bet it would rub some people the wrong way. The Factory Five GTM and 818 are pretty interesting and tempting. This guy built an electric 818 already. Here’s an interesting GTM hybrid.

I’m liking the Caterham out of all of these for two primary reasons – it’s light and I can find very few that have been converted to electric. Much like the Wrightspeed X1, I think an electric Caterham could drum up a lot of interest and publicity.

So perhaps building this car could serve another purpose – marketing. If that’s the case then I need to add an attribute – it’s got to be notable. In this case, that means making as fast as I can. I’ll probably have to get the higher-end model, I’ll have to get a more expensive powertrain setup, and at a minimum redo the suspension to handle the added weight. The project gets decently more complicated and substantially more expensive at this point.

I fully admit that this is all after-the-fact rationalization. I had the idea of electrifying a Caterham pop up in my head at the gym. I still like the idea and haven’t found good reasons not too. As for making it super fast? I’m still not quite convinced. Maybe that could be round 2. I don’t know quite yet.

 

Yesterday I wrote about chasing a crazy idea of mine. Gotta start somewhere though, and I have neither the money nor expertise to jump right into building cars for a living. Tackling building an entire car as a product is probably not a terribly good idea either – I may need to start with some type of component. I don’t know what that would be yet, but right now I think it’s more important that I start somewhere to get myself into the arena.

A few weeks ago I had the thought that building an electric Caterham could be an interesting project. It’d be a great way to learn the various subsystems, I’d have to do some proper engineering in order to do the conversion, and lastly I’d be getting my hands dirty and having fun. I fully admit that my wrenching capabilities leave quite a bit to be desired, so this’d be a good learning experience, no matter the outcome.

I’ll get to the car choice in a later blog post, but the decision I’m facing first is: Do I do this in my garage or rent a shop? Seems like a simple decision, right? Well I had enough conflicting thoughts running through my head that I figured I ought to suss it out properly. In order to make a good decision, I want to start with my goal. Ostensibly it’s to build an electric car, duh! There’s a bit more too it though – I want this to lead to something greater, hopefully clarity on the best path forward – I want this to be the beginning of something great, not just a dilettante wrenching in his spare time. Here are the notes from my notebook:

Pros for garage at home

• no commute!
• less expensive
• comfort and convenience
• easy for me to say I’m not that serious about this

Cons for garage at home

• Easily distracted
• Isolated
• might not take it seriously enough

Pros for renting a shop

• I basically have to take it seriously
• a place to go and focus – getting out of the house
• meet my neighbors and network
• benefit from neighbors’ expertise

Cons for renting shop

• lack of comfort and convenience
• more expensive
• I have to take it seriously
• fear that others will just say I’m delusional

The first items I can eliminate are those where I’m concerned about what I think other people are thinking (not necessarily what they’re actually thinking, just the fabrications in my mind) – these aren’t real and therefore useless in making the decision. Commute? Eh, not that important – it’ll be easy for me to avoid commuting hours and hopefully I’ll find a place within a reasonable distance. Comfort and convenience – things like A/C, available food, a place to take a break etc – I feel like these shouldn’t really matter right now. Cost difference – I’m estimating the delta between the options to be about $1300/month – not a huge number and not one that should dictate this decision – the car itself will be a large multiple of this!

When I look through what’s left and pick out what’s important, I’m mostly left with pros for renting a shop, especially when looked through the lens of what I want to achieve – namely I’ll take the project more seriously, it gives me a destination and place where I can focus, and I can meet people and gain from their expertise.

So there we have it – I’m going to rent a shop. I like this because it makes me a bit afraid and it’s more difficult. The decision hasn’t been made yet though – a decision hasn’t been made until resources have been allocated. Time to get working on that.

 

Ever get an idea simply stuck in your head? An idea that just won’t go away? Maybe you came up with it 6 years ago and dismissed it, however it keeps popping up. Maybe you pitched the idea to a few friends and they shot it down. And rightly so, I might add – the idea might be a bit too far out there.

I’ve attempted starting a few ventures in the past 6 years with limited (ok, no) success. Each time I face failure (internal or external) this idea keeps on coming back. Right now is another one of those cusp points. I’ve been working on PassionList.com for a while now (feel free to check out the prototype that’s up and running) but I can’t get around the fact that I….well, I just don’t have passion (pun slightly intended) for it. I think it’s a clever idea, and I’d visit and participate in the site myself. I don’t have a good business plan currently, and even though a new design is in process I just haven’t been putting in the time or effort necessary to make it a successful community.

I could work on it and launch it, or……I could dive into that pesky idea that won’t go away. It’s pretty simple – I want to start a boutique car company. I want to build a sports car that’s unique, a total blast to drive, and affordable.

The graveyard of defunct boutique car manufacturers (especially in the US) is a large one! My hypothesis is that most of these fail for the same reason – they’re usually the vision of a few folks with too much money – they spend a ton of that money building the next hypercar, then wonder why they can’t sell any of their $800k “Ferrari-beaters.” They sell a few at a loss and close shop.

What if a car was designed from the beginning to tackle this product/market fit? Using the tools of Value-based Engineering, customer needs and wants would be fully understood and would match the design from the beginning. I think it would be entirely possible to drastically reduce the cost of bringing a car to market essentially using agile hardware development – getting the customer in on the ground floor of the design process. Not too dissimilar to what Local Motors is doing, but this would involve a smaller team and (hopefully) dedicated customers.

Look, I don’t know if this would work. Development would still be expensive and the margins razor thin. It would still require outside investment and take quite a bit of time. I think there’s something to this idea however.

If we look at long term trends in the auto industry, there are 3 driving factors over the next, say, 20-30 years (in the developed world). Electrics will take over, autonomous vehicles will take over, and personal ownership is going to plummet. Those who will want to drive their own vehicle will certainly have a large enthusiast makeup. I’d like to build cars for those folks. A simple, bare-bones, fun to drive electric vehicle that looks great and unique – a fun weekend toy.

So, how to get started? That’s for tomorrow.

hi!