Friday, August 1, 2008

Enough hype - how much money would I save?

There has been a lot of hype when it comes to how much an electric vehicle costs. Such false claims make it so people have much higher expectations of an EV than they should. Some cite figures as low as a penny a mile, which may be true if just counting JUST the electricity but that does not cover all the costs.

So, here are the true costs I anticipate having for my EV

The cost of electricity is really quite inexpensive. The often cited figures of $0.01 a mile that electric car owners often cite are probably not that far off. For a full charge, the BugE is rated for around 1.5KWH. My electric cost is around $0.08/KWH, so that's $0.12. To put things into layman's terms, to charge the BugE, the charging unit takes around the same energy it takes to leave a porch light on at night.

What some people forget when citing EV operationg costs is that lead acid batteries are "used up" with every discharge cycle.For example, for the BugE, a full set of Optima D34M-950 batteries should be around $760. They are rated for 300 full cycles (or more partial cycles if I don't discharge them as much). I'm expecting a full discharge could give as much as 20 miles at 30mph under ideal conditions. If I go half the distance before charging, I may not do as much damage, so I may be able to go more miles. If I go faster, wind resistance becomes significant so I can't go as far. So, analysis is rather difficult unless some standard of performance is assumed. So, let's assume a full cycle, 20mi at 30PH. So, assuming 300 cycles, that would be 6000 miles before I would replace my battery pack. If we assume a new battery pack (with shipping and/or taxes) costs $800 and divide that by 300 trips, we get$2.66 per trip. Adding in the cost of electricity for the trip, we get $2.78. So, it would be like I had a car that got 20mpg paying at least $2.78 for petrol. I qualify that figure since hills and irregular speeds would decrease the range per charge by quite a bit.

What this shows is that a BugE might save money if gasoline starts going above $3/gal but it's hardly a revolution in doing so. Plus, I'm giving up quite a bit of performance to get the cost savings. However, if I did a full size conversion, I get more performance but per-mile costs go up too since I'm hauling around more vehicle as I go each mile. So, if I was to do a full size ev-conversion using 4x the batteries, that would mean roughly 4x the cost to go the same number of miles. No wonder we don't see many EV's on the road!

Of course, different packs have different costs. Lithium is more expensive but also has a longer service life with better performance. My personal favorite is the Edison nickle-iron design. Those cells are pricey but they have better performance per lb than lead and boy are they are tough! Some nickle iron batteries used in the railroad industry have been in service for over 30 years! Using those batteries would make the BugE significantly more favorable as a transportation solution. Unfortunately, I am aware of no nickle-iron pack in a size suitable for the BugE.

So, if I'm not saving money by using lead acid batteries, why bother? The repair costs are where I anticipate big cost savings will be. This is because several systems such as exhaust, cooling, climate control, transmission, ignition, airbags and other expensive accessories do not exist (if they don't exist, they are totally reliable). I'm accepting that more little tune ups for the BugE may be needed, especially in the first few weeks of operation. However, the fixes will be rather simple and inexpensive compared to maintaining a petrol car. I am also expecting that the maintenance cycle will be different than on a regular car. For example, I would expect tire lifetime to be similar to motorcycle tires which tend to be replaced every season. Since the BugE extends the season, the tires may need to be replaced twice a year. Although this is more often than automotive tires, the BugE tires are only $20/ea. and of course, I only have three of them. I may also have more wear on the rear tire since that is what propels the vehicle. I'm assuming the wear on the brake pads would be similar to a motorbike, which should probably last around 10,000 miles.

I have been tracking my expenditures rather closely. So far, I've spend $8100 in materials and anticipate spending close to $9500 when I'm done. This includes all materials, batteries, & additional tools I had to purchase for the project (such as the tool chest). I am also including materials that I lost to mistakes (such as the expensive galvanizing paint, stripping & repaint materials). As for trips to the stores, I'm satisfied claiming $5/retail trip. So with 20 trips, that comes to $100. If an online purchase was done, the shipping cost was included. If purchased via retail, sales tax is included. I am NOT counting tools I already had such as screw drivers, pliers, socket set, a 4" grinder & small Dremel set. (I think all tools I've used so far would be safely less than $300 - especially if shopping at places such as Harbor Freight.) If building more than one BugE, I'm sure there are significant savings that could be had by buying materials in bulk and splitting the cost across many units.

There are lots of unknowns in this area. Hopefully, the BugE will be driven in the rain more than a regular motorbike. It also can be driven in the winter on days where there may be no snow, but where salt may be on the roads. So this may lead to more corrosion problems than I would see with a regular motorcycle. The canopy, could become scratched over time with multiple applications of RainX. The controller electronics, although simple, will be in a cold moist environment so they may not hold up too well. The motor in theory should last a long time.