I’ve come to a bunch of conclusions lately… and thought it may be helpful if I shared. This blog was started fairly recently as a way to organize my resources and links, and chronicle my efforts, but the research I’ve been doing has been over the last 5 years or so. Here goes.
First, I’m back to where I started for motor choices. Originally I picked the Agni, as a permanent magnet DC motor, and because it was fairly impossible to get information from Agni, and then getting some information from one of their resellers that said there were no controllers for PM motors that could do regen, I started looking at the separately excited DC motors, and then AC induction, based on the same resellers suggestion. As a result of contacting Sevcon directly (a controller manufacturer) and then Mars Electric, I got some considered advice and detailed answers. I’m back to the PM/regen controller configuration thanks to that. Thanks, John and Steve!
My observations about the process itself are this. I suspect these guys get a lot of crazy questions from people like me who sound like they are looking for easy answers without doing their homework. Having worked trying to support digital photographers for over a decade, I understand, but haven’t much patience for people who are in this position and don’t handle it well… sorry, but one very early exchange I had years ago was with a guy who basically, after a few questions, blew me off and said I was a dreamer who had no clue what I was doing, and I was wasting his time. The dialogs I had with other resellers were very similar in tone- not answering the questions, and curt, rude responses.
This is why I appreciated the help from Mars and Sevcon so much.
So, even now, I’d suggest doing all the research you can, read the books, (VERY helpful) talk to friends (VERY very helpful) read the forums (not so helpful), but most important, and most helpful, is look at what’s out there and what they’re using, if you can. Then you start asking questions. The questions and concerns I had about the Mars motor, as well as my battery choices were answered immediately once I learned, through John at Mars, that it was used in more than a couple of bikes that did what I needed to do.
I’d say the best advice I could give you in designing the bike is to understand, clearly, what you need the thing to do and design it specifically for that, or, look at a bike that is doing what you want, and copy it. Unlike when I started this research, now there are several production machines out there to look at. This solves more than a few problems, most importantly, issues like motor size and type. For me, I want to get as much efficiency and reliability as I can. It looks like the Mars PMDC motor will give me that.
I think the thing you have to also keep in mind is that there are no hard and fast answers out there, in spite of the attitude that many of the engineers have when discussing this with you. This is a new field, there’s a lot that needs to be separated between theory and practice. Engineers, (and I’m descended from a long line of them…) don’t like uncertainty, and above all don’t like to sound uncertain. When you’re getting advice, it feels like everybody has an agenda. They do, with the exception of a few. Again, the solution is to look at what’s been done, and what works, and weigh that against the advice you’re getting.
This may sound like I’m frustrated… I’m not now, but I obviously have been. It’s basically that this industry, and the EV conversion piece of it, is fairly technical, and only recently open to consumer purchases. At least that’s my theory. It feels so much like the computer business in the early ’90s. Pretty technical, in a state of very rapid growth, and fast turning from serving technically savvy geeks to serving the general consumer. There are the Gatekeepers- the techs who seem to enjoy making themselves seem like the holders of the key, and keeping the unwashed out, and then there are the guys who actually want to help people out.
It will be interesting to see where this whole thing is in another 10 years… will the EV component resellers still be around, will people still be building their own? I’m thinking not so much, as off-the-shelf products become available. Even now, they’re selling complete conversion kits- a smart move, especially since reducing repetitive questions from wingnuts like me is a problem… but when you can get a good road bike for normal money without having to build your own? We’ll see.
Look at the beer industry. OK, yeah, everything comes back to beer for me. In the ’80s I brewed my own, because there was nothing out there that tasted like my own, good, beer. Then came the microbrews, and I lost interest in brewing my own… why should I when I can walk into a store and buy beer that is better than what I can make? The result of the microbrew shift, though? More and more people are now interested in home brewing. Go figure…
One more bit of advice I learned from building a boat. The sittin’ stool. According to the bible of boatbuilding, Chapelle, I think it was, you need to have a stool to sit, stare, and think, right next to the boat. There are many times you have to simply step back and try to distance yourself from the task at hand, to give yourself a little rest and a bit of perspective. Luckily, for example, I didn’t run out at any given moment and buy a motor and controller- I would have bought 4 by now. There have been more than a few things that I should have given a little more thought to before diving in. It’s a learning process, and sometimes having a little set-down within sight of the project makes a world of difference.
…oh, and a beer, too. A nice Harpoon IPA would be good.