So I bought an 04 Prius this week. I got a pretty good deal and it seems to be a good shape.
I removed the rear seats and some of the metal brackets/seat belts, as well as the silly cargo cover and heavy trunk mat. That was 65lbs, or 2% reduction.
I ordered a hitch on Amazon, will be installing it as soon as it arrives so I can start using it for work, carrying my lawn mower.
My question now is, what's the best method to apply a few hundred watt hours of battery storage to the car? I have some old, nearly useless lithium ebike batteries (24-48v range). If I'm doing 20 miles a day, I can effectively improve mpg by 5% with a 250wh battery supply. I may eventually use my large 3.5kwh Leaf battery, but want to start small.
Do I find a dc-dc convertor that will change 26v to 200v? I don't think there is anything readily available like that. What about suppling the 12v system? There must be a step down dc converter in the car that takes the 200v down to 12v for all the little electronics, and headlights, etc? Does it use the 12v battery as a buffer? I could easily send my power to that then.
Overall it may not sound worth it to many people. At 50mpg and $2 gas, it's only 4 cents a mile. And 10cents/kwh and 250wh/mile, that's 2.5 cents a mile for a savings of 1.5 cents a mile. For my average of 20 miles a day. I would be doing it more for the satisfaction of achieving a higher mpg. And making some use out of my 'useless' batteries sitting at home.
I also wouldn't mind adding a small solar PV panel, but weight and aero may make it prohibitive. I have two 120watt panels, but I think they are 40lbs each
My parking spot at home gets a LOT of sun (I will want to shade it soon, to protect from heat). I am happy that the car already has fairly dark tints which is something I really wanted with all the hot sun we get in Austin. Also why I was set on the silver color.
As for other mods, I'll probably do aero hub caps, rear wheel skirts, some underbody smoothing with choroplast, windshield wiper blade shield, and maybe partially enclose my rear cargo rack with clear plexiglass for a partial boat tail. That aero work is obviously with more of an eye towards my highway driving and road trips. The intent is to make improvements with little or zero cost other than my time.
Another idea I have is a mechanical lever (bicycle shifter/cable) set to depress the accelerator at exactly the correct amount for "glide" mode (no transmission of power either direction). One nice thing about my driving is that I'm already doing a lot of 25-40mph around town due to traffic. Great opportunity to hypermile a bit and take advantage of the hybrid system. (lots of sitting stopped too).
I'm really excited that I finally have an efficient hybrid. It is very satisfying to have regen and not be idling needlessly.