SOLAR TODAY Blog


>>Adventures in living renewably
November 24, 2008, 7:34 pm
Filed under: Electric fun, Transport

An update from the do-it-yourself scrounger:

Electric commuting: I now have a couple of months’ experience riding the Yamavolt electric motorcycle conversion to work and around town. The bike runs very nicely, thank you.

Real-world experience suggests that, in future, recharging infrastructure is going to be critical. I have no trouble riding to work and back because, thanks to our set-up at the office, I can recharge the bike in the warehouse. But running errands downtown is a problem, because I can’t recharge while shopping. When this set of batteries poops out I’ll invest in a NiMH pack to double the range.

Charging overnight

Charging overnight

If I worked in an office without a recharging outlet in the parking structure, or if I lived in an apartment building, electric commuting would be sketchy. I’d have to run a very long extension cord out some window and out to the parking lot.

Even with my own parking slot with a dedicated recharging outlet, I’d want the vehicle to have at least three times the necessary range — 30 miles for a 10-mile commute — to assure being able to get home if charging weren’t available at work. In future, every parking meter and garage space ought to be a charging station. In 20 years, parking vendors should be retailing kilowatt hours instead of renting tiny patches of real estate on an hourly basis.

If I were in the inverter/transformer business, I’d be gearing up now to serve the future auto-recharging market. If I were an architect, I’d be figuring out how to wire parking garages for overhead charging circuity.

Solar water heating: I made progress on my cobbled-up solar water-heating system over the weekend. The Butler Sun Systems heat exchanger wand was a ten-minute job to install in my water heater tank. Just open the 230-volt circuit breaker, shut the cold-water feed valve, drain a few gallons out the bottom of the tank through a garden hose, and disconnect the one-inch hot-water-out line. That revealed a collar inside the tank measuring 3/4″ across, too narrow to admit the heat exchanger wand, which has an outside diameter of 7/8″.  I broached the thin steel collar with a 7/8″ hole saw, in about 10 seconds flat.  Used the hole saw instead of a 7/8″ bit because its smooth sides wouldn’t damage the water-out threads. The wand then slipped straight in and snugged down quickly. I had hot water again in three minutes.

The next step was to pressure-test the 30-year-old collector boxes on the roof. I bought these at salvage a couple of years ago for $30 each, and they’re a standard 4’x8′ insulated-box design with copper fin tubing inside and tempered glass outside. I have two of them canted 40 degrees from vertical facing dead south, and soldered them together last week. I rigged plastic tubing to the four outlets with a pressure gauge, a ball valve and a fitting to take the garden hose. When I turned on the water, the system filled up quickly. I closed the valve and checked the gauge: it showed 130 lb, the city water pressure.

90px-old_faithful_geyser_calistoga_californiaBut the water heated up quickly and at 140 lb. one of the soldered joints between the two panels began to weep. Then it bubbled. Then one of the plastic tubes blew off at the top, with a sound like a very large champagne cork headed for orbit, and a geyser of steam shot out.

You should have been there.

I drained the system into a five-gallon bucket and found I’ll need about three gallons of propylene glycol.

Next step is to separate the panels and connect them again with solder-free unions. Soldering those joints is tough for two reasons: They butt right up against the aluminum frame, so it’s hard to get at them; and the internal fin-tubing functions as a fabulous heat sink. It takes a long time and a hot flame to make the solder flow evenly. The end of the copper pipe sags and doesn’t want to stay round.

Anyway, it’s nice to know that this system will boil water even on a late-November day in Colorado.

Onward!

Advertisements


>>Yamavolt cruises
September 19, 2008, 11:30 pm
Filed under: Electric fun

Took the electric road racer out for a spin Friday evening and did 4.5 miles around the neighborhood. That means half a mile uphill, half a mile down and repeat. Had a voltmeter on it to watch the state of the batteries.

Went out at 51.5 volts and finished at 48 volts — a 3.5 volt drop for 4.5 miles looks great, because that’s the distance to work. The regen works fine. On the first lap, voltage dropped to 48 at the top of the hill, then ran up to 52 on the way down and settled at 51 as I started lap 2. That was the pattern. On the final lap, voltage dropped to 42 at the top of the hill and came back to 48 at the finish. A minute after I dismounted, voltage recovered to just over 49.

I was easy on the throttle and stayed under 30 mph, but that’s just my estimate.

On Saturday morning I rode it up to Chautauqua — a mile, with an elevation gain of 430 feet. No problem going up, and the batteries regained most of their charge coming down. Regen isn’t really strong enough to provide effective braking — the machine easily coasted up to about 60 on the downhill bit with the throttle closed and would have kept accelerating without use of the drum brakes.

So later in the afternoon I did a full-throttle blast up the block. Hit 60 and had to drag it down on the brake to sweep the corner. Sweet! I’m going to have to ride in stealth mode.

Going for light weight was definitely the right choice. This machine will be killer efficient if I can find a good stack of NiMH batteries. If I can cut battery weight in half, the bike will be back down to race-rig empty weight of about 180 lb.

Meanwhile, the ancient tires must be replaced. The rubber has hardened and the powerful brakes lock the wheels far too easily.

Thanks to Sam Randall for today’s photos.



>>Yamavolt hits the road
September 18, 2008, 5:25 am
Filed under: Electric fun

Yamavolt ran its first mile this evening. I rolled it out into the street, turned the switches, and hummed around the corner. The motor is strong off the line. The bike accelerated very nicely to about 30mph, then pulled more moderately — I backed off the throttle at about 40mph.

After a half mile going up a modest hill I turned around and coasted back. Can’t tell if the regenerative braking works: I’ll have to rig up an onboard voltmeter to see if the voltage climbs with the throttle closed. The bike has no sidestand yet so I leaned it gently against the old Guzzi for the portrait here (the two bikes were manufactured no more than a year apart).

It’s not exactly silent. There’s a hum from the chain and the 35-year-old front drum brake makes a bit of a scrape on each revolution of the wheel — that, I trust, will disappear as the brake shoes shine the rust off the iron lining of the drum.

The bike is not comfortable. When I raced this thing I was about 20 lb. thinner and a lot more spry. It took a couple of tries to fold my legs more or less painlessly so that my feet rested on the rear-set pegs.

One mile produced about a 1.5 volt drop. At full charge, this bank of batteries should be good for 55 volts, and it’s theoretically safe to run them down to about 36 volts without damage. If 1.5 volts per mile is what I’m going to get on average, then range should be about 12.6 miles, at about 80 watt-hours per mile. I’ll take it: the target with this battery set was 10 miles.

The wiring is robust but it’s an aesthetic nightmare, and rain would short it out quickly. I’m afraid I’ll have to cut the bottom out of that beautiful aluminum fuel tank and hide all the circuitry in there.

The bike is on the Soneil 48-volt charger for the night. I’m hoping for the full 55 volts by morning, and will try a two-mile ride on Thursday evening. If the drop is still 1.5 volts per mile, I’ll ride it 5 miles to work on Friday.

Next step: Bolt on a kickstand, head and taillights.

Whee!



>>Yamavolt runs!
September 17, 2008, 5:05 pm
Filed under: Electric fun

I soldered the last circuit last night and plugged everything in. Turned on the switches. The LED on the controller blinked green and red. I twisted the throttle. Nothing happened. I recycled all the switches. Still nothing.

I turned everything off and went into the house to look at the wiring diagram again. When I came out, the controller light glowed steady green. I turned the switches back on and twisted the throttle. The chain whirred, the rear wheel rolled. Success!

So — I have to wait for the controller to boot.

Road test tonight.

No new photos because the bike is an ugly mess of cables and fuses and wires, all looping around the controller and motor. I need to get this snake nest cleaned up and properly insulated. Also need to bolt on a kick stand, headlamp and tail-light.



>>Yamavolt wiring
September 11, 2008, 12:37 am
Filed under: Electric fun

I’m about halfway into wiring it all up. I have wiring diagrams from D&D, the motor manufacturer, and Alltrax, the controller company. But the diagrams assume the system is going into a souped-up golf cart, and they don’t specify things like wire gauges. I’m trying to mate heavy cables with assorted connecting devices, and wondering why a heavy high-amperage bolt-on terminal at the motor end of a 6-gauge wire has to mate up with a wimpy little slip-on terminal at the controller end. I envision closing the power switch and watching the thing burn.

There’s also a handful of resistors and slow-blow fuses and switches, all from Radio Shack, all needing to be soldered in at appropriate places. Once it’s all wired up and running I’ll have to create a reasonably weather-proof housing for the nest of wires, and find a safe place to mount the switches.

Onward . . .



>>Yamavolt: Mechanicals complete
September 1, 2008, 12:26 am
Filed under: Electric fun

The Yamavolt electric motorcycle reached mechanical completion on Sunday. It now weighs 205 lb with batteries and motor installed.

The chain runs over a 13-tooth drive sprocket to a 72-tooth chainwheel. In theory this could give me 60 mph at 4800 rpm, but we’ll see what the four small lead-acid batteries will do. I’m going to program the controller for a maximum 35 mph, which will keep me more-or-less moped legal in Colorado. But I’ll have enough acceleration to move with traffic.

The motor sits on a thin rubber damper made from an old innertube, and it now has an anti-torque link to keep it from rotating in the motor mounts. It fits as if the 35-year-old chassis had been built for it. The original Dunlop tires still hold air. I’ll replace them after the machine is running.

The controller and charger will go in the empty triangle under the rear of the gorgeous (empty) aluminum tank, which I haven’t had the heart to remove. The whole rig should then weigh 212 lb. Still hoping for a ten-mile range.



>>Yamavolt progress
August 22, 2008, 6:16 pm
Filed under: Electric fun

The sprockets and batteries are in. I bolted up the big custom-made 72-tooth rear chainwheel and it’s a perfect fit. There’s barely enough clearance for the chain to pass the rear shock absorber spring, so I’m going to fiddle up a set of bushings for the shock mounting, to move the whole unit outboard about a quarter inch. The 13-tooth power sprocket is another matter. It’s a standard Yamaha part made to fit the output shaft of a Yamaha transmission. I dropped it off at a local machine shop to get it mated to the electric motor output shaft. The shaft needs to be turned down and the sprocket bored out to match. Then I need a collar with a set-screw to hold the sprocket in place. This is far more expensive than just boring out the sprocket and spot-welding it in place, but it will allow me to replace the sprocket to play with the gearing.

The four 12-volt 18-amp-hour batteries arrived in one 50 lb. box. Over the weekend I’ll start building the framework to hold them, and wire them up to the controller and throttle. In theory, late next week I’ll be able to slide the motor back in, hook up the drive chain and cables, and ride off into the future.