----- Original Message ----- From: "Lee Hart" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Thursday, October 10, 2002 8:53 AM Subject: Re: Cross country charging challenge.
> Christopher Meier wrote: > > ... Support vehicle carries the packs on a trailer, along with the > > pack-changing equipment (if necessary). Solar panels on the trailer > > keeps the next pack to be used topped off :-) > > Aha... now here's a fun idea. A normal-sized car can't carry enough > solar panels to power it. But how big a trailer can a normal-sized car > handle? Could it tow a semi-sized but very light flatbed trailer covered > with solar cells -- enough to power the car? This is a fun thought exercise. Let's take QM. At 35 mph, she draws about 4kW. But the trailer's going to add some drag, so let's make that 5kW. On second thought, after my Woodburn experience, let's make it 6. You can get [being optimistic here] 50W per sq foot of panel. So 6kw / 50 = 120 sq ft. Well, that doesn't sound so bad. That's only 10' * 12'! How much would said panel cost? Well, it says here that I can buy these lovely BP panels for $3.75 a watt. Um...$22,500. Anyone want to donate $22,500 for a experiment? Of course, the othe rproblem is that 50W/sq foot is only when A: the panels are cold (they lose efficiency as they heat up) and B: they've got full sun In reality, after a few hours of cruising the desert, they're going to be putting out more like 35W/sq foot. So, 6kw/35 = 170 sq foot (I rounded) Or 17' * 12'. Unfortunately, we just pushed the price tag up a bit too. Now we're looking at a cool $30 grand.. Then there's the question of what you do when things get cloudy.. S.
