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Old 05-14-2012, 04:06 AM
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Default Are EV conversions economically worthwhile?

Hi All

I've set up this separate thread on this question of whether EV conversions are economically worthwhile for city commuting in New Zealand as the question was popping up elsewhere. Let's for a moment assume the economics is all that matters (Yes, I know it isn't but this is an exercise!)

Let's say you do an EV conversion for $20,000 on your existing car and it lasts 10 years. Let's say your existing car would have also lasted 10 years as a petrol car - so we've cancelled out a lot of comparative costs. Let's put no value on your conversion time as this is a fun project.

Let's also assume an interest rate of between 6% and 14%. That would be loan repayments of $51 to $71 a week to finance depending on whether you have put it on a mortgage or a personal loan.

With a regular city commute plus weekend driving I would think that an equivalent saving of that sort of money is expected, so from those that claim it is uneconomic, what are the costs that blow out the figures? Am I overestimating savings? Will the battery need to be replaced at huge cost early?

On the plus side to this calcuation is lower mechnical maintenance costs - what do they amount to? Also there is an expected rising cost of petrol - what savings contribution is that likely to be. I am also imagining the future cost of electricity may be constrained by advances in home electricity generation - do you agree?

Richard
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Old 05-14-2012, 05:32 AM
Duncan Duncan is offline
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Default Re: Are EV conversions economically worthwhile?

Ok
starting with a 4L/100km car a 25Km commute will save $2,50/day - minus 50c for the electricity - $2 a day
$500 a year
$5,000 over 10 years - no that's no good

50Km commute - $10,000 over 10 years

100Km commute - $20,000 over 10 years - but I haven't taken interest into account

If you have a 100Km daily commute - a $20,000 conversion will be marginal

- MOVE CLOSER TO YOUR WORK!!! - or change jobs!

Looking to the future - petrol will be more expensive - how much more?

In real terms the most expensive petrol I used was in the 1980's - its cheaper now relative to wages

John Key AKA -the smiling assassin took road user charges off EVs - but he did say it was temporary and would go back on - when??

Now if you start with a more thirsty car (my Legacy) then its better
8L/100km car a 25Km commute will save $5/day - minus $1 for the electricity - $4 a day
$20 a week -

a 50Km commute is $2000 a year - that would repay the capital

5% on 20,000 is $1000 a year

So a 75Km commute would be on the cusp -

That's still a long way to commute
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Old 05-14-2012, 07:04 AM
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Default Re: Are EV conversions economically worthwhile?

Quote:
Originally Posted by Richard Wood View Post
so from those that claim it is uneconomic, what are the costs that blow out the figures? Am I overestimating savings? Will the battery need to be replaced at huge cost early?
What parts do you plan to put in?
For example, if you use Lead Acid batteries, they have a shorter life than Lithium Iron Phosphate batteries.
What range do you expect to get?

Quote:
Originally Posted by Richard Wood View Post
On the plus side to this calcuation is lower mechnical maintenance costs - what do they amount to?
If you use a brushed DC motor, brushes need to be replaced, but that is not really a big issue. If you use a pot box, they can wear out.
You may have to replace the bearing on the electric motor - no big deal.

However, compared to a gas car, you won't need to change or do:
  • oil filters;
  • oil;
  • fuel filters;
  • air filters;
  • spark plugs;
  • valve clearance adjustments (depends on motor);
  • exhaust systems;
  • catalytic converters;
  • oxygen sensors;
  • spark leads / coil packs;
  • seals like rear main seals etc;
  • head gaskets;
  • intake manifold gaskets (on some cars, you have to take the intake manifold off to get to the spark plugs);
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Old 05-14-2012, 03:48 PM
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Default Re: Are EV conversions economically worthwhile?

Hi Duncan

Those milage figures look a little light for the city commuting example we're talking about, perhaps based on modern cars in ideal conditions? New Zealand cars average 10l/100km and once we focus in on a more typical 10+ year old car in city commuting with hills and stop/start driving it can only get worse. For example in my Civic, I travel a 30km round trip to work, which is pretty low for Wellington commuting from north or east. Once we include evening trips and getting around in the weekend dropping and picking up kids, going to shops and markets etc, I'd fill the tank once a week at $50-$70 a pop. When I used to use a Subaru it was more like $80-$100. Happy to hear other real life examples but I expect that is normal for the bigger city dwellers outside of the inner suburbs (Inner suburbs tend to have good bus options anyway). I assume you're joking when you say move closer to work or change jobs, given the higher cost of housing and difficult job market in the cities .

Crazy Al
Great list of all the costs that can be avoided. It would be interesting if anyone has a guestimate of what that might amount to over 10 years for a typical 10+ year old car. As for the other question, this is an exercise for those interested in the maths, but it's on the basis of a $20,000 expenditure on a car that will do typical city commuting. Let's say it's Lithium batteries and the ability to do 50km a day.

Richard
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Old 05-14-2012, 04:55 PM
Duncan Duncan is offline
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Default Re: Are EV conversions economically worthwhile?

Hi Richard

You need to move to Southland - cheap houses and short commutes

I thought my Legacy would be about the worst - 9L/100 - I can pick up something small and cheap dead easy

As far as the maintenance costs - my 12 year old Legacy has cost a total of $250 over the last three years

My previous Legacy died at 350,000K and 16 years old - and I could have kept it going but I wanted the suspension for my project
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Old 05-15-2012, 11:16 PM
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Default Re: Are EV conversions economically worthwhile?

Hi Duncan

I'm sure Southland has a lot to offer (looking out at the Wellington weather).

You've got off lightly with your maintenance costs, but I guess that is because of the short commutes. My 12 year old Legacy has had a few thousand spent on it and I'm pretty much keeping it only for long trips these days.

Cheers
Richard
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Old 05-21-2012, 03:51 AM
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Default Re: Are EV conversions economically worthwhile?

Here is an interesting related thread on an Australian forum.
http://forums.aeva.asn.au/forum_post...&title=6000-ev

If a car can be converted at A$6000 (not sure if that includes the coupling) then that makes things interesting and I was surprised at the idea of sticking to AGM batteries to reduce the up front cost despite acknowledging lower long term costs for Lithium. I guess a point here is that reducing up front cost can reduce risk if it ensures earlier payback.

Thoughts on this?

Richard
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Old 06-26-2012, 03:18 AM
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Talking Re: Are EV conversions economically worthwhile?

Quote:
Originally Posted by Duncan View Post
Hi Richard

You need to move to Southland - cheap houses and short commutes

I thought my Legacy would be about the worst - 9L/100 - I can pick up something small and cheap dead easy

As far as the maintenance costs - my 12 year old Legacy has cost a total of $250 over the last three years

My previous Legacy died at 350,000K and 16 years old - and I could have kept it going but I wanted the suspension for my project

A work mate had one it spent 4 of the 6 months in the shop geting fixed and it was southland
As far as cost goes if the petrol motor dies you get a replacement motor or car with a ev you keep the motor etc and get a new body

Last edited by evnz; 06-26-2012 at 03:20 AM.
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Old 06-27-2012, 08:09 AM
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Default Re: Are EV conversions economically worthwhile?

Quote:
Originally Posted by evnz View Post
As far as cost goes if the petrol motor dies you get a replacement motor or car with a ev you keep the motor etc and get a new body
Well said. Also, an off the shelf Electric Motor is not specific to a body.
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Old 07-02-2012, 02:55 AM
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Default Re: Are EV conversions economically worthwhile?

Jeez, if I lived in Southland, the heating bills would preclude me from owning a car!
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