John Bonnett
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| posted on 19/11/11 at 04:19 PM |
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Anyone with experience in electric propulsion?
I'd be interested in talking to anyone who has experience in converting to electric power. In common with most people, I have had enough of ever
escalating petrol and diesel prices and I'd really like to become independent by going electric. Rather than build a car from scratch I'd
convert something like a Morris Minor. It would not be used for long trips and a 60 mile range would not be a problem. However, is it feasible to fit
an on board generator to recharge whilst on the move to enhance the range? A petrol motor driving an alternator perhaps?
I'd be very interested to speaking to anyone who has taken this route.
Thank you
John
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daniel mason
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| posted on 19/11/11 at 05:03 PM |
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What are you going to fuel your generator with?
I think the general consensus is you would need a huge amount of batteries,making it extremely heavy. And the constant electrical cost in re-charging
would be another large outlay. Although not as much as fuel.
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dinosaurjuice
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| posted on 19/11/11 at 05:10 PM |
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ive started buying parts for an electric motorbike project. only 10Kw motor, and enough battery capacity to do 30miles. I looked at trying to get more
range but the weight of batteries just uses more power, you cant win! even with the LiFePo4 batteries ive ordered there still heavy 
have a look at EV MX5 LINKY for some inspiration
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Benzine
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| posted on 19/11/11 at 05:14 PM |
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I looked into this recently but it's not quite there for me (as in it's a lot cheaper for me to do a diesel conversion/scratch build than
convert/scratch build an electric) A minor sounds good though, lithium batteries would keep the weight down nicely
http://www.diyelectriccar.com/forums/ is a good place for info
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Bare
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| posted on 19/11/11 at 05:14 PM |
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IMO the cost of the Electric bits alone will pay your existing fuel bills for several years.
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Neville Jones
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| posted on 19/11/11 at 06:06 PM |
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John,
I've helped in the development of a couple of electric car prototypes in last few years.
In the new year I'll be taking a set of moulds off a classic Mini, to do an electric version. (Only because I have a full set of the motors,
controllers, and running gear.) Everyone I've spoken to about it, wants to see the outcome with a view to possible(???) purchases. I'll
wait and see on that situation though.
Your biggest problem is weight. On the other hand, when the car is registered, the battery weight is excluded, for some vague reason, so what
I'm envisaging will come in well under 400kg's at rego, without batteries, so is a 'lightweight quadricycle'. Tax exempt, no
LEZ problems, no congestion charges, and all govt establishments have to supply a charging point foc, by legislation.
The only batteries worth looking at, at present, are lead acid deep cycle traction batteries, as in forklift or similar. They have the highest energy
density/cost at this stage. Other batteries are being developed, but costs are still stupidly high. The six batteries I look to use weigh 375lbs, and
after a few months use will drop down to about 100~120 miles range and give 50mph constant, which should hold up for about three years.
The cost of renewing bateries, new or old technology, is something no-one mentions, as well as the environmental recycling issues. The lead/acid come
out well on this point.
If you put in an engine and alternator, you end up with a petrol/diesel engine with an electric drive, just like the trains have been for many years.
Some manufacturers nowdays like to call it a 'hybrid', but it's just an ordinary petrol/diesel electric setup to an engineer.
Any more I can help with, over to u2u.
Cheers,
Nev.
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MikeRJ
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| posted on 19/11/11 at 06:14 PM |
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quote:
Originally posted by John Bonnett
I'd be interested in talking to anyone who has experience in converting to electric power. In common with most people, I have had enough of ever
escalating petrol and diesel prices and I'd really like to become independent by going electric. Rather than build a car from scratch I'd
convert something like a Morris Minor. It would not be used for long trips and a 60 mile range would not be a problem. However, is it feasible to fit
an on board generator to recharge whilst on the move to enhance the range? A petrol motor driving an alternator perhaps?
To start with you probably won't (or shouldn't) be using a 12v system. At this low voltage the currents required are huge and so are the
associated losses. Electric cars tend to use significantly higher voltages, maybe 100-200v.
0.25 kWh/mile seems to be a general rule of thumb for the energy needed in a gently driven electric car, meaning 15kWh for a 60 mile range. This
gives you an idea of the amount of batteries you will require e.g. a fairly large car battery of 100Ah capacity will deliver roughly 1.2kWh, so
you'd need maybe 12 or 13 of them to achieve your range.
To make any useful increase in the range the generator is going to have to provide a significant fraction of the power required to actually move the
car. Even a fairly large car alternator will be undersized (ignoring voltage issues), e.g. a 100Amp alternator provides a maximum output of about
1.4kW. so for each one miles worth of extra range you'd need it running flat out for about 10 minutes.
Lots of information available at http://www.diyelectriccar.com
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John Bonnett
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| posted on 19/11/11 at 06:24 PM |
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Thank you all for your replies with the links and the information. There's some interesting stuff there.
I appreciate that I'd probably never recover the cost of the conversion but I'd derive a lot of satisfaction and I admit not a little
smugness in being independent of petrol.
Neville thank you. PM sent.
regards
John
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JoelP
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| posted on 19/11/11 at 07:15 PM |
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more effective than a small engine to recharge the batteries via a genny, would possibly be a small engine to turn one wheel on any journey when you
know the batteries wont last. Ie if you know you are going 100 miles, have the little engine going constantly to assist the batteries. This should be
more efficient since you have removed a few stages of energy transfer.
Or, since a long journey is more likely to be at a steady speed, and at steady speed there is less penalty for weight, you could just add 200kgs of
batteries for a long trip, and only keep it light for short 'stop start' journeys.
How would you manage some regenerative braking? This is another key element.
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blue2cv
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| posted on 19/11/11 at 07:30 PM |
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Kits available less batteries circa £4k, same company converted a customers 2cv just under £16k for 50 mile range and 45 mph tops well worth it lol
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02GF74
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| posted on 19/11/11 at 08:32 PM |
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If it is about running costs, you'd be better off buying a small modern car with efficient diesel engine.
By all means give it a go but think about it, if the major motor manufacturer's are not able to come up with an electric car that ticks all the
boxes you mention, and they have tens of kazillions of pounds to spend on R&D, what make you think you can knock up one in the back shed?
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Dave Ashurst
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| posted on 19/11/11 at 08:44 PM |
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quote:
Originally posted by 02GF74
If it is about running costs, you'd be better off buying a small modern car with efficient diesel engine.
By all means give it a go but think about it, if the major motor manufacturer's are not able to come up with an electric car that ticks all the
boxes you mention, and they have tens of kazillions of pounds to spend on R&D, what make you think you can knock up one in the back shed?
The first version of Build Your Own
Electric Vehicle gave me confidence to think I could!
I haven't read this latest edition...
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paulf
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| posted on 19/11/11 at 09:25 PM |
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Strangely enough Ron Champion was once involved in an electric vehicle project, when he was an acquaintance of mine he was the manager of a youth
training workshop in the early 1980s and they were involved in a project to convert an MG midget to electric power.I think the car was fitted with a
milk float motor and battery's and was semi successful.
Paul
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inkafone
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| posted on 19/11/11 at 11:42 PM |
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http://www.batteryvehiclesociety.org.uk/bvsorguk/portal/
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Ninehigh
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| posted on 5/12/11 at 05:48 AM |
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Just as a thought, but maybe you could remove the petrol engine and whack the motors onto the existing gearbox. Given that there'll be a
stepdown (as the motor would be spinning about 10x (for example) of what the gearbox was expecting) would you be able to use less powerful motors.
I've just looked up that the Morris 1000's engine delivers 30-odd KW. Now could you use a 3KW motor geared down to 0.1 of the speed to
develop the same power at the gearbox? (The fraction might not be right but given rough numbers does my point stand?)
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BenB
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| posted on 5/12/11 at 08:32 AM |
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No amount of gearing will make a 3kw motor equivalent to a 30kw motor. If that was the case we'd just be driving cars powered by tiny 0.00001w
motors with big gearboxes
A standard milk-float has a 8kw motor IIRC. Why not just bung two of those in it. At least with 16kw you would get the performance of a Morris running
on two cylinders with a boot full of bricks (batteries).
I'm not saying it can't be done but it starts getting awfully tricky and expensive unless you're happy to have a milk-float (in
terms of performance). You have to balance endurance with performance with cost.
It really is amazing how many kW of energy IC engines give out. Even my old poxy tintop Micra with a whole 988cc of raw power had about 90kW.....
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John Bonnett
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| posted on 5/12/11 at 08:53 AM |
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Since I started this thread I've spoken to one or two knowledgeable people and they both say that gearboxes are a no no. They sap too much
power.
The lighter the vehicle the better will be the performance; common sense really but it does more or less rule out the Morris Minor which is quite
heavy to start with. So, a Reliant Kitten might be a better starting point. The price of motors is coming down and battery technology is improving all
the time so despite the misgivings of some of our Locost bretheren, I'm still hopeful that I can produce an electrically driven car for local
journeys at no more than the cost of a secondhand shopper.
Thank you for your input; it's good to hear what you all think.
regards
John
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hughpinder
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| posted on 5/12/11 at 09:45 AM |
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A 1.0 polo had a 40bhp = 25kw motor and would sit all day at 90 on the motorway. It was quite small, so had low frontal area.
So I'd say go for a small car, estate or hatchback to gibve space for a genny 25kw motor, batteries for 30 miles autonomy, register as fully
electric - free access to central london!
Then, after registration strap in (removable) a 8-10kw diesel generator. Since this is not the propulsion for the car, and is not permenantly fixed,
you can run it on red diesel/heating oil and 2 stroke (both about 65p/litre)/whatever you want, unless someone knows better. You may want to uprate
the rear springs a bit as a genny like that will come in about 200kg.
Regards
Hugh
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Ninehigh
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| posted on 5/12/11 at 06:22 PM |
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Motor off a Prius? I know the new one can do 30 for a couple of miles with the battery pack they carry
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russbost
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| posted on 5/12/11 at 07:40 PM |
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First I would have a look at the bvs that is linked to above - they've done it all b4 & have as much knowledge on this subject as we all do
on the general engineering side.
I would start with a cheap modern vehicle like a Matiz, Seicento etc, or perhaps something like a Capucino. Weight is absolutely critical as is
frontal area/drag & things like narrow tyres can make a significant contribution.
Can you do it when a major manufacturer can't? Well, yes & no, they produce a heavy, comfortable car with all the mod cons & it has to
drive like a modern city car does - think about it we make cars that do 0 - 60 in sub 5 secs, often much better, for less than £10k (easily!), a major
manufacturer wouldn't do it, because only a tiny % of people would buy it.
40Hp is actually 30kW not 25.
Batteries rated at, say, 100Ah will not produce 100Ah unless the power is drawn at relatively low current, even if you run at 72 or 96V (both fairly
common with EV's) you will be drawing fairly massive current, at least under acceleration, the higher current you draw, the lower the Ah rating
becomes & the more batteries you need.
If you use leisure batteries you have no warranty as unsuitable for purpose, you need traction batteries which are more expensive, & you
don't generally want to discharge them by more than around 50% as it significantly affects their life, you will need a lot more batteries than
is being suggested above unless the vehicle is very low powered or very very light/low drag.
I think the idea of a diesel generator could work (something I've been looking at for a while), if you had something making around 3 or 4kW at
the voltage you intend using - say 72 or 96V this could make a significant difference to your range rather than loading up more & more batteries,
you would want to be able to leave it running to recharge batteries anytime you were stopped & couldn't access 240V recharging power, not
sure about the safety & legality side of this issue, & TTBOMK this would be a specialist generator, I don't know of anything currently
made that would do the job. Because it can be run at a constant speed a generator could be vastly more efficient than simply running a normal diesel
engine is - you have to have an engine much bigger than you actually need for about 95% of the time the car is running.
This brings us to another issue, which is recharging your battery pack overnight or whatever, there are some mega chargers around that will charge
72/96V at a substantial amount of amps, but they are stupidly expensive (like several grand!!! )
I found this site very interesting & helpful
link
tho' unfortunately it's American & they have access to a massive range of batteries & motors that will cost you double to get over
here!
I find the whole subject fascinating & I feel that if you're prepared to sacrifice some creature comforts & possibly safety features
then it just might be do-able & without spending the megabucks that a lot pf people seem to throw at it. One of the main reasons I've not
done anything with the idea myself yet (besides a lack of time) is that I feel that really I would need the massive knowledge of an electrical guru
& I don't unfortunately know anyone who has the right knowledge/skillset - if anyone wants to volunteer their specialist electrical skills
please get in touch - perhaps we can both get rich!
I no longer run Furore Products or Furore Cars Ltd, but would still highly recommend them for Acewell dashes, projector headlights, dominator
headlights, indicators, mirrors etc, best prices in the UK! Take a look at http://www.furoreproducts.co.uk/ or find more parts on Ebay, user names
furoreltd & furoreproducts, discounts available for LCB users.
Don't forget Stainless Steel Braided brake hoses, made to your exact requirements in any of around 16 colours.
http://shop.ebay.co.uk/furoreproducts/m.html?_dmd=1&_ipg=50&_sop=12&_rdc=1
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NOTE:This user is registered as a LocostBuilders trader and may offer commercial services to other users
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Ninehigh
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| posted on 6/12/11 at 03:00 PM |
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quote:
Originally posted by russbost
I think the idea of a diesel generator could work (something I've been looking at for a while), if you had something making around 3 or 4kW at
the voltage you intend using - say 72 or 96V this could make a significant difference to your range rather than loading up more & more batteries,
you would want to be able to leave it running to recharge batteries anytime you were stopped & couldn't access 240V recharging power, not
sure about the safety & legality side of this issue, & TTBOMK this would be a specialist generator, I don't know of anything currently
made that would do the job. Because it can be run at a constant speed a generator could be vastly more efficient than simply running a normal diesel
engine is - you have to have an engine much bigger than you actually need for about 95% of the time the car is running.
I did think of using a 50 or 125cc engine (as in from a moped) that would purely run alternators (and maybe some heating via the water cooling)
I'm sure it would meet any emissions standards and you could use the original bits like wiring, ignition and fuel tank
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hughpinder
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| posted on 6/12/11 at 04:06 PM |
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Have a look for one of these:
http://www.cumminsonan.com/autostart/
They are used in coaches etc and automatically start/stop on battery condition to keep batteries charged for the aircon etc when the coach is parked
up
Regards
Hugh
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