This was the first version of the iQuad. The original concept was for an electric scooter with two wheels but somewhere along the way I switched to a four wheels plan. I really like the look of this one, the low front looks purposeful and the fat tyres are cool. The frame is welded 6061 aluminium, the first motor was 600 watts with a 100 amp, 24 volt controller. The rear axle was solid, which meant it didn't turn very well, with most of the weight of the rider on the back wheels it tended to want to just go straight ahead, predicably enough. I thought it would do that, but didn't expect it to be as pronounced as it was. The batteries were Panasonic 12v, 21 amp hour sealed lead acid ones. They were pretty heavy, and didn't seem able to deliver much current. The front suspension geometry allowed plenty of travel, but set up as it was the springs were too soft.
Time for an upgrade, I thought...
I changed to twin motors with way more power, Ampflow A28-400's. Rated at 4.5 Hp each, they were a big improvement. The controller was switched to a Robotec dual channel, 160 amp per channel model. We had a machinist make up some belt drive pulleys, and mounted them on race kart sprocket carriers. I split the rear axle so that each rear wheel could rotate independantly, with one motor driving each wheel. New front shocks with much stiffer spring sorted out the soft front suspension, though it's now probably gone too much the other way - the extra height puts more weight on the back, and the springs are now too stiff.
The old Panasonic SLA batteries were ditched and three 24v packs of good quality Sub-C cells went in instead. These still weren't up to the job, and several cells quickly overheated and died. That was an expensive lesson, and they were replaced with much lighter LiPo cells, 3 packs @ 22.2 volts and 10 amp hours. These barely get warm. The range with the LiPo's is 14-15 km over fairly hilly, rough ground, and top speed is 35 - 40 Kmph.
With the new motors the tendency to tip over backwards became much more apparent. The ergonomics are a bit suspect, footrests need an overhaul and some kind of protection from tipping over backwards would be good. I rebuilt the seat several times before giving in and bolting on a much comfier one made for a mini chopper.
The plan now is to start over from scratch, and use the lessons learned to make a new iQuad 2.0. The design objectives this time:
Lighter Weight. The current version weights about 45 Kg - not terribly heavy, but enough to be awkward lifting it into or out of a vehicle.
More Compact. Preferably able to fold up. As it is, once it's in the boot, it takes up most of the space, we can't fit the kids bikes in as well, or any luggage if we're going away.
Quieter. It's not noisy by any standards now - it surprises a lot of people who don't hear you coming. But the belt drives do whine a bit at speed, and there's the odd rattle here and there.
More Efficient. I want to use a smaller battery pack and get the same or better range. Batteries are expensive and have a limited life, so I'll be focusing quite intently on this. I don't need a longer range, but if it ever fell into the hands of someone who did, extra battery packs need be easy to add.
Convenient. Having had a Segway for a couple of years, I've become very used to the convenience of basically zero maintenance and easy charging.
Look Great. For my own satisfaction I want it to look really good. I'm aiming for a minimalist aesthetic, a bike with four wheels if you will. The simpler and cleaner the better.