

Ask HN: How feasible is it to convert a petrol car to an electric car? - kagamine

EDIT: The link below from the BBC clearly posits the question of converting classic cars to electric drivetrains. If you are unhappy with that or found a link where 1 guy once made an electric Metro from a petrol Metro and you think no more can possibly be said on the subject, please move along.   
I can&#x27;t downvote yet, clearly many of you can, it&#x27;s like reddit rebooted in here.<p>still editing: for all the people focussed purely on &quot;now&quot;, think ahead 5-7 years. 2nd hand parts are common, development costs recovered, manufacturing costs in decline. Petrol harder to come by making a lot a of classic cars too expensive for the average car guy - now a conversion might be worth it in both time and bank.<p>Original post:   
From engineering and economic perspectives. Given that all existing cars have passed crash-tests etc and that the only real reason to go electric is environmental, does conversion make sense for many existing vehicles?<p>Inspiration for the question from here:<p>http:&#x2F;&#x2F;www.bbc.com&#x2F;autos&#x2F;story&#x2F;20150521-vintage-gas-guzzlers-ripe-for-a-battery-powered-reboot
======
dalke
Responding to the edited question, see this article from 1993 on converting a
car from gas to electric:
[https://news.google.com/newspapers?nid=2457&dat=19930921&id=...](https://news.google.com/newspapers?nid=2457&dat=19930921&id=hJ4zAAAAIBAJ&sjid=7TgHAAAAIBAJ&pg=1384,1657576&hl=en)
.

Every point you made about thinking ahead 5-7 years from now could have been
said in 1993. Second-hand electric parts became more common, petrol became
more expensive, etc.

Your edits come across as if you are chastising people for not thinking about
the future when, at least in my case, I'm pointing out that nothing about your
evaluation of the future has changed for decades.

Nothing really new can be said about your question because your question
itself is probably older than you are. It's certainly older than I am.

------
dalke
What does "feasible" mean to you, and how are sites like
[http://www.instructables.com/id/Build-your-own-Electric-
Car/](http://www.instructables.com/id/Build-your-own-Electric-Car/) and
[http://www.hybridcars.com/top-7-issues-electric-car-
conversi...](http://www.hybridcars.com/top-7-issues-electric-car-
conversion-25839/) insufficient for resolving your questions?

What does "make sense" mean to you? It does not make sense to convert a heavy
vehicle to electric because you won't get much range from the result.

In general though, no, it does not make sense. Otherwise more people would be
doing it. It's not like the idea is new either. I recall as a kid reading a
Donald Duck comic where Donald converts his car to electric then goes for a
ride with Daisy. Problems ensue, of course, as this is Donald we're talking
about.

~~~
kagamine
Given that there was a link in the question, what does "feasible" mean and
what does "make sense" mean? What does "pedantic" mean? What does anything
mean?

I am so sorry for having troubled you and for wanting to discuss something on
the Internet. To think that I made you type all of those words. I truly am a
monster.

~~~
je_bailey
The questions he posed are legitimate given his final statement. Converting
legacy cars to electric is a waste of time and money. Unless of course, your
definition of "feasible" and "make sense" is different than mine. Or maybe
there is a different question you're trying to get too. Like, is it feasible
to start a start up producing kits to convert cars, or a boutique conversion
company. Which in my opinion would be the best option.

~~~
kagamine
What, using Donald Duck cartoons as evidence?

~~~
dalke
The example is evidence that the idea of a gas-to-electric conversion is not
new, yes. Such evidence is trivial to find, so I didn't think it worth
pointing out a specific example.

If you want a concrete example, here's a newspaper article from 1993:
[https://news.google.com/newspapers?nid=2457&dat=19930921&id=...](https://news.google.com/newspapers?nid=2457&dat=19930921&id=hJ4zAAAAIBAJ&sjid=7TgHAAAAIBAJ&pg=1384,1657576&hl=en)
.

Looking over it now, very little has changed about the overall procedure.

------
seynb
Thinkin' the same thing. Actually, it is very feasible and affordable for a
low-range city car. The major factors are the cost of batteries, and range
anxiety. You can do conversions with in some cheap lead-acid batteries
generally for a total build cost <$3-4k. Cons: limited recharge cycle, weight,
not practical for >30km range (~18mi).

Lithium batteries are the best (either LiOn or LiFePo), super expensive
though. Tesla Model S 85kWh uses 7104 3.1mAh Panasonic 18650 cells. They
probably have a special purchase agreement ala Apple with Samsung NAND. If you
wanted to buy enough for 100mi range I crudely estimated the retail cost at
$15167.58 (vendor Orbtronic).

But there are people who spend $20k+ on conversions. Check out
[http://www.evalbum.com](http://www.evalbum.com)

Also at [http://www.forkenswift.com](http://www.forkenswift.com) they did a
conversion for $672CAD on a Geo Metro

------
valarauca1
Unless you have a lot of experience with power train engineering it will be
very difficult. The primary reason for this is that Electrical Motors have
different torque curves then Petrol. Petrol have their peak power/torque at a
non-zero RPM (dependent on fuel type, air temp, moving speed, etc.).
Electrical Motors have their max torque at stall, zero RPM, just starting.

Engineering an automotive transmission is normally a $1Bil+ over 10yr+
project. Normally automotive companies coolbrate on new transmission designs
(currently GM/Fiat are, and Ford/BMW kinda).

:.:.:

If you just want a hobbityst project not start a company, then its fairly
straight forward with basic Mech Eng/Mechanical experience.

~~~
kagamine
So it would be possible to produce a mass-produced replacement part targeted
at specific models, at least at first, using for example the Leaf drive train
and a conversion kit? I assume electric cars have standard axles++.

~~~
valarauca1
There is no standardization between manufacturers in the automotive industry.

When there is, its often because two models were developed as an collaboration
between companies, or a licensing deal between manufacturers.

Between model lines you'll see some part repeat, and some drive train
components repeated. But for cross manufacturers production it'd likely be
very impossible, this is done intentionally by manufacturers.

:.:.:

While some companies do manufacturer aftermarket drive train components. They
have licensing deals to get early dyes while production is under way. Often
partnering to lower the cost of the dye production ($10Mil +).

Often these specialize on high performance model lines, and the performance
company is very often a sub-division of the parent company. If you buy a high
performance transmission, drive shaft, etc. Your just buying an alternative
part designed by the same parent company, sold via a shell performance
company, which is part of the parent company, but exists largely as
advertisement for the high end market.

~~~
kagamine
By standard axles I meant that there are really only 2 types on production
cars in the last century, fully floating and not. Many of these parts may not
be "standardized" but they are interchangeable. Want Land Cruiser axles on a
Land Rover or Jeep? Not a problem.

Anyway, I wanted to discuss the feasibility of it now and in the future, not
explain-away any possibility of it because _it 's too hard to do_. The
automotive industry is full of small and large manufacturers willing to fill a
niche. I have a car with a replacement carb that requires conversion kit, and
a lead-free head on the engine. There are also disk-brake kits, engine &
gearbox conversions, suspension conversions... the list goes on.

~~~
nl
_Want Land Cruiser axles on a Land Rover or Jeep? Not a problem._

Err.

Well, it's _not a problem_ in the sense that yes, it is possible. But it take
choosing the exactly correct parts, custom machining and a fair bit of bodging
stuff together (eg[1]).

And that's just _axles_ , which aren't exactly the most difficult part of the
drive train.

Having said that.. yes, it's quite possible to convert conventional cars to
electric ones. See[2] for a place to start.

[1] [http://www.pirate4x4.com/forum/jeep-non-
hardcore/622698-toyo...](http://www.pirate4x4.com/forum/jeep-non-
hardcore/622698-toyota-axles-jeep-4.html)

[2]
[http://www.evmotors.com.au/services/quickguide.html](http://www.evmotors.com.au/services/quickguide.html)

~~~
kagamine
It's far more common among off-roaders than you know.

------
raihansaputra
Some conversion kits have been around for quite some time, but targeted
towards hobbyists. Some kits from EVWest [0] even retains the transmission and
the rest of the drivetrain, only replacing the internal combustion engine with
an electric motor and supporting devices (chargers and coolers), and a place
to put the battery in. They even have braking regeneration and replacement
heaters for the passenger compartment. Maybe the space to put the battery in
is the main hurdle in converting the car.

[0]:
[http://www.evwest.com/catalog/index.php?cPath=40](http://www.evwest.com/catalog/index.php?cPath=40)

------
JSeymourATL
Here's a cool 1972 Datsun conversion to model off-of>
[https://www.youtube.com/watch?v=apoeGMWF17c](https://www.youtube.com/watch?v=apoeGMWF17c)

------
louithethrid
Not interesting.. You could add a generator and electric motors, but then you
basically have a bad double conversion and extra weight.

You can strip out the motor, but then you basically are near building a new
car anyway.

Everything engineered is a series of well-weighted compromises towards a
optimum. Adding as a after thought a electric option to a gasoline car, is
going to be a bad compromise. Always. If you want a good compromise, build one
from scratch (just reusing chassis and gears) or buy one that is designed with
this in mind.

------
kozak
One of the main reasons why we consider electric vehicles to be so cool is
their low center of gravity, thanks to the batteries being located near the
very bottom (good to have them there, and also batteries are better not to be
damaged in a crash). Can we find such a place in existing cars? Maybe we can
use space under seats and in place of the fuel tank and the spare tire. But in
this case batteries need to come in small modules.

~~~
kagamine
You just described the location of most fuel tanks and exhaust/catalyst
systems. A conversion would not be a perfect fit, but an extension of the
vehicle's life, like the classics with replacement lead-free heads and an LPG
tank in the boot area.

------
johngalt
No from both perspectives. Engineering wise there isnt much cross over between
electric motors and ICEs. Think of all the systems that would need
replacement, removal or modifications. You would end up with an electric car
with exceptionally poor characteristics or an absurdly high cost to modify.
Crash test performance is also heavily dependent on overall design.

------
jodoherty
Wayne Bickley did a pretty cool electric conversion on his C4 Corvette:

[http://www.ndneyes.com/](http://www.ndneyes.com/)

I originally read about it on Corvette forum (I used to be a C4 vette owner
and was always looking for interesting tips or projects).

If you're mechanically and electrically inclined, it's more than feasible.

------
zurn
It would make more sense to convert existing cars to wood gas. Better carbon
footprint too - EVs are not great in that dept.

[http://www.lowtechmagazine.com/2010/01/wood-gas-
cars.html](http://www.lowtechmagazine.com/2010/01/wood-gas-cars.html)

