solar cell battery charger

We bought our '04 in Oct '03, and a couple of weeks later the lines were six months long. As a charmed engineer, I bought and did everything you can imagine, including building a solar charger as a backup for the 12V system - which is what the cigarette lighter socket would be connected to if it were ON when the car were OFF (it must be modified to achieve that).

Useless. Unnecessary. And for the high voltage system, the difference in vehicle performance would be unmeasurable unless you used the entire outer area of the car, and even then it would be tiny. The way to improve mileage is to

(1) accelerate smartly when nothing's in front of you (2) avoid using the brake

That's right, keep your foot off the brake... with that mindset, you drive properly and can get more than the average.

Great car, isn't it?

Bill wrote:

You don't say whether it is the sedan or the hatchback. I don't know about the hatchback (I think it's the same) but in the sedan the lighter socket is disconnected when the car is off. It can be modified to be live, and some people have used the solar charger you describe to keep the aux battery charged when they have to park (as in long term parking at an airport) for more than a week or two. Most modern cars have the same problem - the alarm system slowly drains the battery.

This affects only the aux battery so no change is seen in fuel economy.

Mike

Bill: Charging thru the cigarette lighter only charges the 12 volt battery, and this would have no effect whatsoever on the 273 volt main traction battery.

Dick

On the Prius (doesn't matter the model year), the 12v accessory outlet (aka cigarette lighter) is switched off when the car is off. So, if you want to use this battery charger, you'd have to either modify/ rewire the outlet to always be on/hot, or you'd have to wire a 12v cigarette outlet directly to the 12v accessory battery.

for the power outlet mod:

Such solar cell battery chargers as you describe are used by people who do not use their car very often, or are planning on leaving their car undriven for quite a while (such as at an airport parking lot). There are various parasitic loads on the 12v system, most notably the alarm or SKS system if installed, that will slowly drain the 12v battery during extended periods of non-use (besides the natural self- discharge). The solar charger would keep the 12v battery charged up, so that you wouldn't need a jumpstart when you return to your car.

When the car is off, the hybrid traction battery is electrically disconnected from the car. So no solar charger will directly affect the charge level of the hybrid battery.

Would there be a benefit to fuel economy by using a solar charger? Well, once the Prius is started the hybrid battery wouldn't have to recharge the 12v accessory battery as much if the 12v battery is already recharged by the solar charger (and therefore the gasoline engine wouldn't have to run so long to recharge the hybrid battery if needed). But I doubt that you'd see a measureable change in fuel economy. Mainly, you'd just be able to start your car because you didn't let the 12v battery get flat in the first place.

Congratulations on your purchase. 8)

But you had to remind me about how Toyota really screwed up the Pioneer orders...

Back in 2000 through early 2002, the Prius was only available in the US through an internet ordering system. You place your order, and about 4-5 months later your car would arrive at your specified dealer. Cars were delivered to dealers based on where there were orders, and by the time in the queue. (You could get one sooner than that, if someone else in line ahead of you declined their car.) Early

2002 the internet ordering system was retooled for the RAV4-EV, so the Prius became a regular off-the-lot purchase (with all the price negotiations and dealer hassle that involves).

Late spring 2003, Toyota sent letters to all those who had ordered Prius in the original internet ordering system (who Toyota termed Prius Pioneers), offering them first pick of the newly redesigned 2004 Prius. These were also ordered online, in what was called the Pioneer ordering system. Orders were placed June-July 2003.

Unfortunately, Toyota pretty much ignored the Pioneer orders, and just sent out cars willy-nilly to dealers, whether they had a waiting Pioneer order or not. A former co-worker of mine walked into a random dealer and got his 2004 Prius off-the-lot in one of the early deliveries of Sept. 2003, while I had to wait until mid-Oct. to get mine (ordered first week of July, 2003) off the list at my dealer. At some dealerships, the Pioneer order list didn't get fulfilled until Dec-Jan, while at other dealerships again people were just walking in and getting theirs (like the poster above).

What was the point of the Pioneer orders, if Toyota didn't bother to actually ship them their cars on a timely fashion? It got them some marketing/demographics info, but it also got them a lot of frustrated early adopters...