Solar Segway!!

[GlennO]

But wait - if you get enough panels hooked up together you could just use them as wings and fly - no?

Or even flap those panels like a bird does.

Glenn

[quade]

Originally Posted by KSagal

The 20 watts that were mentioned were at a far lower voltage than is usable... Would that not require even more panels to be put in series just to get the 20 watts at a usable voltage?

Ok, we're going to have to go back to some rudimentary electrical 101 here so forgive me if you folks have heard this before, but it's a fairly simple way of explaining it.

Volts times Amps equals Watts.

A Volt is the amount of electrical pressure. You can think of it like water under pressure; psi.

Following this "water model" for electricity, then an Amp can be thought of as the width of a piece of hose and a Watt can be thought of as how much water in total flows through the hose at a given pressure.

(Obviously the following numbers do NOT reflect real world values but are being used for the purposes of illustration).

If I have a 1/2 inch garden hose at 20 psi, a certain amount of water will flow out of it every minute. Let's call that (simply for the sake of the model) 10 gallons or "water watts".

If I have a 3 inch fire hose at 20 psi, I will get 60 gallons.

Likewise, if I have a pump (the solar panel) that can supply 30 gallons per minute I can feed that out a big hose or a little hose, the pressure will vary depending on the size of the hose, but it will still be 30 gallons per minute.

Ok, now lets step back into the real world . . .

The total of 40 watts at 12 volts coming from each panel goes into a power inverter and gets bumped up to 110 volts. We end up with about 0.36 amps, but it's still (assuming no losses for our inverter) 40 watts of power.

Karl, you're right, we aren't going to be quick charging anything with this, but that wasn't the design goal. The design goal was to just tack on an additional 3 miles to the range.

[agrimensa]

glad to see someone thinking of this. I would be happy to ride under a cover of solar cells in the shade.

Anyway - the seg is probably running on 12v not 110.. this makes this a little better.

V.

[KSagal]

And here is the rub...

There are losses in the power inverter. They would be significant, given the low power levels to begin with...

The Seg operates at 72 volts (DC), I believe, but the 110 comes from the 110 VAC input requirement of Segway's charging system.

Going from 12 vdc to 110 vac will loose some power.

Assuming that the seg while in charge mode uses about 100 watts (110 vac) give or take after the initial phase, and that the panels produce 40 watts (12 vdc) and that is about 40% before that power is made usable... I do not think you will wind up with 40% available in usable power, regardless of the water pressure...

Now, since the system will not work at that level anyway, as an inverter would fail if asked for wattage it cannot produce, I feel this system is doomed as it is...

Further, I would say that any system as described, would produce so little usable power, and weigh and have enough wind drag, that the end result would be less range, not more.

As advances continue, as they do moment to moment, a solar booster may soon become a reality. It just will not work with the items previously mentioned...

Thanks for the lesson. This conversation has occurred many times, and there is always something to learn from it...

[MTOBATTERY]

Anyone know if you can run six solar panels in series to get the inverter out of the equation? I bet it's possible but I'd check with the panel manufacturer first.

[KSagal]

I believe that the segway takes in 120vac (in the US, 240vac elsewhere) and puts out a specific DC voltage to the batteries for charging...

I agree, if that DC voltage were to be recognized, and supplied directly, there would be a lot less power conversions, and therefore less power lost...

The guys with the fuel cell segway in Florida at fest did just that. They tapped into the batteries at the point where the battery leads connected to the boards, and did not supply power thru the transformer on the segway.

[MTOBATTERY]

You could tap directly into the harness and feed directly into the batteries just like they did. I would definitely recommend a voltage regulator to limit the output voltage so the batteries do not have the ability to reach overvoltage condition.