Hello, everyone!
Long time listener, first time caller. Ah, where to begin... First of all, I just want to thank all of you on E-S, and this forum in particular, for the interest, creativity, feedback and perseverance with this GNG kit and in the promotion of electric motor-ed things in general. It has tipped the scales in favor of me deciding to build my own electric bike. I have journeyed through all 123 (current) pages of this thread and it's been long but incredibly informative.
Some quick context: I live in Seattle. Everywhere you go there are hills. Many of the 10-20% grade variety. I got into biking for commuting back in April of 2012 and haven't taken the bus to work since. It's been a lot of fun, and a lot of work because I live near the top of one of those hills. Anyway, the bike that got me into it all is off to another happy owner. I am now on my sixth bike--all of which have been some version of restoring, restoring and upgrading, or building from the ground up. All this to say that I have enjoyed learning from 'zero' how to build and maintain my bikes. I like cars a lot and do DIY maintenance, but not at my place because I street park. But I can get my fix doing bike stuff!
So to the bike and its relevance to this GNG kit: Street only, 700C wheels (700x35 tires @ 704mm OD), mid-drive, and low to the ground. I want the top speed to be in city traffic range (25 mph, 30 mph max) and the range to be around or better than 10 miles. Ah spec'd at 10Ah just to start. The idea is a fun zip around the city/commute bike that delivers moped-legal levels of power and speed, but is bicycle-sized and can go up hills without burning up and then just rolled into one's apartment and turned off--no heat, no leaks, no burns, no oil, no mess. * Looks fun/cool, feels fun, goes quickly, isn't a hassle * Hub motors were on the consideration, but this city isn't friendly to them. I won't be pedaling because I don't plan on that being a part of the build--no BB stress, but will have to fully figure out the legal nature of this vehicle because of that. I have aesthetic/exterior design ideas along with this bike to complete this concept as well, but it first needs to exist.
Having arrived at this critical mass of information and CAD pre-development (Rhino), I humbly ask a few questions at this juncture:
1) The GNG is rated at 67kV at 48V unloaded. I believe I read the Volts-under-load amount many pages back, but can't find it. Bike+me=250-260 lb range. What have people seen at the 48V nominal/controller level when they've run it there? I suppose this is like crank hp and wheel hp in cars--what is the power loss? 44V effectively? 40V effectively? Do I make any sense? I ask in relation to top speed. I ran calculations based on the linked tables (page 1) and am a touch higher in MPH overall. I'm happy to gear down via front chainring sizes but want to "tune" it correctly or as close as possible the motor-output-under-load with my desired cruising/top speeds.
2) Do we have a power curve graph of the GNG? I've scoured and have come up empty...
3) I'm looking at different battery sources. Seems like the recently-mentioned conhismotor site has some decent prices on packs (among other sites). My bike frame design, which is completely custom (an "all new" design, what was I thinking??), allows for two NiMh D-cell packs as that was an early consideration. Who online has been a trustworthy source for you? [if the answer is to the effect of a friendly "go fish," I will go fish
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Thank you so much for your help! I hope to soon begin a build thread with pictures--all I have is two wheels, a fork, handlebars, and a headset. I am interested in your bracket kits, Mr. Lightning Rods; if not more on the chain/belt upgrade side of things (and hello from another Art Center College of Design alum!). Either way, I will be looking to buy this kit (or at least the motor) in some form. I know I've bitten off a very big chunk of steak with this idea in my head (and sketched on paper), but am chewing it slowly but diligently. Much I've learned already both here and my dad (a EE with an eye on electric motors and efficiency desire/interest for many things), and MUCH to learn still.
Cheers!
