Battery and Vehicle Running Costs

This page is still under construction and the tutorial is a draft. All statistics with the # mark in front are not referenced. Those that are have a number in front and can be matched to their source. If you believe a statistic is wrong, or you believe you have a source, or a more reliable source, please let me know:

Part1: Justification. If your here reading this, chances are you already believe in the EV. So this may sound like I'm preaching to the choir, but this information can be useful in "converting" others, particularly if you have to do so to fund your conversion. So, here are the reasons you could use to justify an EV conversion:

• CO2 emissions, burning each litre of petrol releases between 2.3 and 2.7kg # of CO2, depending upon the blend and fuel quality, this does not include the emissions related to sourcing and refining the fuel. in contrast, 100% coal sourced electricity results in approx 0.96kg # CO2 per kwh of electricity delivered to your local power point.
• Particulates and smog - An EV does not directly contribute to particulate and smog emissions. Electricity sourced from a coal power station does of course result in particulate emissions, however these are approx % less than that from burning petrol # . Here in WA, the majority of our electricity (55%), (90% OFF PEAK AT NIGHT) is sourced from coal in collie. Thus, EVs charged in Perth , does not contribute to smog in Perth . The interesting thing regarding the off peak electricity, is that generation is largely independent of demand at night. A Coal power station is the third least "throttleable" power sources available today, (behind geothermal at 1, and nuclear at 2). It takes 10-12 # hours to cold start an coal fired power station. Indeed the night time generation is currently determined by what the daytime demand was the day before, and the projected daytime demand for the day after. Therefore, when an EV is charged at night, the increase in emissions is not proportional to the amount of energy drawn.
• Personal economic - depending on how much performance is required, the ongoing cost of running an EV is extremely low. (This is explained in more detail later). Indeed if only a moderately powered car is needed (0-100 in 10-12 seconds, 0-400M in 20-25seconds - similar to 90s barina), than the purchase cost can also be lower than a same powered, same chasis/body petrol car. As with most things, when it comes to performance, the sky is the limit.
• Country economic - in 2004, Australia produced 150% # more sweet light crude oil (the stuff lpg and petrol is made of) than that consumed by Australia . This includes the oil fields "borrowed" from Papua New Guinea . In contrast, Australia produced just 10% of the heavy crude oil used domestically (the stuff diesel is made of). As a result, Australia only broke even # by value on transport fuels imported and exported. Therefore, for every litre of petrol not used at the pump, Australia is able to export another $0.60 # worth of sweet light crude. For every litre of diesel not used at the pump, $0.80 # of crude is not imported.
• Maintenance - the required maintenance on a petrol car is almost astounding to the uninitiated. The following is the difference in maintenance between that of a petrol car and an EV, (doesn't include things common to both cars, eg tyres):

Part 2: Budget and expectations. So you've established that an electric car is a better way to commute everyday than a comparable petrol one. Now you need to establish just how much you are willing to spend. As with most things, you get what you pay for. On the other end of the spectrum, an electric Hummer will still be incredibly expensive and bad for the environment. Its important to keep in mind that EVs are bad for the environment, they just happen to be considerably "less bad" than a petrol vehicle. This is very much an excercise in working out how much you would be willing to pay for what degree of usefulness.

To calculate this i would suggest working out how much you spend per km on your current car on just fuel and servicing. Ignore common things like tyres, and if you are considering a DC conversion, brakes. The fuel side of things is easy, just measure the km you travel between fillups, and record how much you put in each time, making sure you fill all the way up each time. you might find it easier to make up a spread sheet such as this one: Prelude Milage (xls spreadsheet)

For the servicing side of things, just find out how much it costs to service your car and how many km between services. For the example car, the combination of fuel and servicing alone came up to $0.24 per km. so for 15'000km per year, its cost $3600 per year just to run.

The next step is to work out how many km per year the EV would be useful for each level of capability. Measure the distances between places you commonly visit, and take note of the minimum speeds to get there, and if at a particular level. For example, to and from work per day between thornlie and welshpool is approx 25km, needs a minimum speed of 50kmh (i wouldnt use anything less than 60 personally so that i can do the speed limit and not hold traffic up). The km per year therefore for a EV that could do 60kmh, and have minimum range of 30km, is 25*5*52=6500km=$1560. This assumes you need to retain a standard car and need to do a higher speed limit. If a capability level can replace your car, or one of your cars outright, then add to the $1560 number, the cost of insurance, licencing and registration. remember, the $1560 will have to cover these costs of the EV. To help with this step ive included a sample spreadsheet: Budget.xls

Next, work out how much of a premium you would be prepared to pay for things above your needs, for example greater acceleration, a better looking conversion. The above calculations is merely calculating what you would want to spend on an economy car, the electric equivalent of a barina. If your looking for something more like a Mustang, then expect to pay more. this is much harder to calculate, and really is different for everybody.

Part 3: Planning your conversion. Now that you know how much you are willing to spend, start researching possible donor cars. First check the car you already own, find out how much weight you can put in, and just as importantly, how much you can take out. For a cheap conversion, you are invariably looking for a car that can take alot of weight, as you need to use lead. For larger budgets, the options become increasingly complex. For the moment i will focus on the budget economy version. For a budget conversion, the qualities you are looking for are: able to arry lots of weight, has good fuel economy, can be bought at a reasonable price, is in otherwise good condition. Here is a spreadsheet that may save you some running about: conversion options.xls

Once you have chosen your donor vehicle, you need to decide upon possible battery and drivetrain combinations.

Coming soon - performance, batteries and drivetrain choice tutorial.

For an all round commuter, capable of 100km average distance driven between possible charges, work out y is to work out what you have paid to run your car in the past 5 years. If you keep your receipts, look through them, make a spreadsheet, or add them up the old fashioned way. For those of you who havent owned a car this long, use the RAC estimate for the price per km you do or would drive and multiply by your mileage per year. This of course assumes you want an electric car to do very much the same things.

Spreadsheet - Batteries

Spreadsheet - Batteries Ev's

the cell columns are more or less self explanatory the important cells are: F2: target pack voltage F4: wh/km of target vehicle F5: km intended to travel per year (for use in ROI and service life calculations) F6: ave discharge if known (otherwise leave it as is, and it assumes 60kmh ave speed times wh/km) - used for peurkert corrections where implemented X3: price of electricity X4: minimum range required from setup - needed for calculating service life X5: resale percentage - used for calculating residual value of batteries for other uses after life in car eg solar system. ill find the value for recycling and post it at some point if just junking X6: cost per km normal car - used for calculating pay back S1-3: used for calculating for standard 18650 cells

things need to consider: the max discharge rates on the AGMs are the listed CCA or CA ratings. the CCA rating is at -32c (i think), the CA rating is at 0c. at room temp, i know the optimas are capable of 2000A. might need to add this as a note or something as it skews the power/weight ratio of the agm batteries. kept the CCA ratings as n information resource.  km per replace is measured in thousandsd of km some of the packs are hybrids obscure columns: the useful Ah (I) is the peurkert corrected capacity. only done for some (L) cycle range thresh is the number of cycles before the pack no longer delivers sufficient range (Y) payback column is the number of years needed to pay off the pack based on fuel usage of a normal car (inputed by user) est years is the number of years the pack will actually last.

Performance (Spreadsheet)

the performance document: Intended to give an idea of power and torque curves of the selected setups. Input the values from your setup at the top and itll do the rest. you need: final drive ration (diff internal ratio), current limit of controller, system voltage, tyre size, vehicle weight. to select the motor, just copy and paste the information into the right place from the spreadsheet. (makes more sense when you have a look at it)

EV Energy Use (Spreadsheet)

the ev energy use document: intended to give an idea of the energy use of each vehicle listed. the energy use data is needed in the batteries document.

Moped Real World Examples (Spreadsheet)

The moped real world example is intended to qualify the indicated values of the ev energy document. A comparison with the fuel usage of a petrol model is in the works, i expect it to be up by the end of january.

Vehicle Running Costs - Large Vehicles (PDF)

Vehicle Running Costs - Small Vehicles (PDF)