Raising the subject of range extending trailers

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Rattrap
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Raising the subject of range extending trailers

Post by Rattrap » Tue, 30 Aug 2011, 15:12

Hi all,
I'd like to once again raise the subject of range extending trailers. In particular i am talking about small efficient diesel gen sets mounted on very small trailers like this;
http://www.evnut.com/rav_longranger.htm
With all the EV motoring hype about these days, at least in Europe & the US etc, not Australia where we are sadly way behind the 8 ball on the subject - as per usual, i would have thought that there would be more talk, more action on the subject. Clearly to my mind this style of range extender would negate any EV range fears.
I am very keen on owning a Nissan Leaf when they finally arrive on Aussie shores tho going by the estimated price i'm looking at 2014 at the earliest. However because of my rural home a trailer of this sort is a key part of the EV motoring picture for me. With the nearest local town just 20mins away on country road motoring (80-100kph speeds) an EV is perfect however the nearest major city, Launceston or Devenport are 45 mins & 1hr (110kph speeds) away. While these distances are easily within range of the Leaf one way, it would require a fast charge in either town & Hobart is totally out of the question being over 3 hrs away. With a trailer of this sort there would be no destination out of my reach.
Is there a reason why trailers of this sort aren't being talked about/ produced by now?
If the Holden Volt & other similar SERIES hybrids (not talking about the Toyota style parallel hybrid) can do it why not a range extending trailer???
Am i missing something?
I would very much like to hear peoples opinions on this.

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Raising the subject of range extending trailers

Post by EClubman » Tue, 30 Aug 2011, 19:20

I'm not a big fan of range extending trailers.
I mean, if you are going to use a fuel powered generator on a regular basis, then why not just drive a fuel powered car?

Think about where you are travelling to.
Where are you going to park? (Other than a harware store - not too many places in the city that you can park with a trailer)

Think about the charging system.
Will the car run while you are charging it via the standard onboard charger? Can you trick it if it doesn't?
If you use an external charger built in to the trailer, is it going to play nice with the car's internal monitoring stuff (hmm, I've consumed 100 Ah of battery so I'll shut down now to prevent damage to the batteries despite their voltage looking like they are fully charged...)

Think about the pollution and emissions.
It's more efficient to drive the wheels of a car with the fuel you burn than it is to convert the rotational motion of the generator to electricity, feed that through a charging system, and then use that electricity to drive a motor to move the car.

Is the EV going to be your only means of transport?
Can you take a different car for the longer trips?

Stuff like that

Mark

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Raising the subject of range extending trailers

Post by woody » Tue, 30 Aug 2011, 20:26

I'm a fan of range extending trailers :-)

But the key question is how regularly will you use it?

All Mark's questions above are valid too.

Possibly the range extender at optimum RPM is more efficient than an ICE car for the same reason that highway mileage is better than city mileage even though much more energy is required to travel fast.

If the range extender is going to let you sell your last fossil-fuel car then I think go with it.

Maybe the market for range extenders will be rental, similar to other trailers - I'm going to the snow, I need a range extender, with ski racks.

For me I've spent $80 on a tiny trailer and am going to put the ICE from the cortina in it with an ACIM ($80) + ebay controller ($300).
Planned EV: '63 Cortina using AC and LiFePO4 Battery Pack

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Raising the subject of range extending trailers

Post by Richo » Tue, 30 Aug 2011, 20:50

Rattrap wrote: Is there a reason why trailers of this sort aren't being talked about/ produced by now?


Because there aren't enough people with eV's to have a range problem.
And the people who buy an off the shelf eV do so with the range in mind so don't need the extender.

ie people buying a volt knowing it has say 30miles range obviously buy it cos they drive less than the 30miles.
A person who drives 100mils wouldn't buy the volt in the first place if it didn't meet thier requirement.
Thus no-need for a trailer.

I personally like them.
And think they should be a "rent" option for people.
Or RAC(V) for brake down purposes.
So the short answer is NO but the long answer is YES.
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Raising the subject of range extending trailers

Post by Simon » Wed, 31 Aug 2011, 00:14

Rattrap wrote:
If the Holden Volt & other similar SERIES hybrids (not talking about the Toyota style parallel hybrid) can do it why not a range extending trailer???
Am i missing something?
I would very much like to hear peoples opinions on this.


Do not let the Volt fans hear you calling it a Series hybrid, it's a "Range Extended EV". Image Image

I think a pusher trailer would be better. It could be used on any EV or even a broken down ICE.
A pusher avoids any need to modify (apart from a towbar) the car & protects your warranty.
You can also use it to recharge the EV enroute.
Last edited by Simon on Wed, 31 Aug 2011, 09:18, edited 1 time in total.

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Raising the subject of range extending trailers

Post by Johnh » Wed, 31 Aug 2011, 06:22

Try this one
http://www.jstraubel.com/EVpusher/EVpusher2.htm
cant really imagine getting it through Australian rego
but for a regen setup it would be the go.
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Raising the subject of range extending trailers

Post by Rattrap » Wed, 31 Aug 2011, 16:19

Series hybrids = range extended EV, got it. lol. As to my driving needs, on an average fortnight we normally do 1 trip to Launceston or Devenport per fortnight & maybe 6 trips to Hobart a year. 90% of our driving is well within the range of Leaf which is why i was so interested in an EV. Add to that the fact that we now have 3kw of solar panels on the roof has made EV's very attractive to me. A trip to either of the major towns mentioned would probable see me needing either a 30min fast charge, which i don't see as a problem once a charging network is established or several hours regular charge. There is a Nissan outlet in both towns & i would imagine they would be the first places to install the fast chargers. The regular charge wouldn't really be suitable as we usually have a long list of things to do or places to visit saved up for each visit. Because of the small size of the towns this only means actually traveling maybe a further 10 - 20klms. I'm not real keen on the idea of regular fast charges due to the potential shortening of battery life that can occur.
Clearly a range extend trailer i am interested in would have to be intelligent enough to work with the cars charging system, just plugging a diesel powered generator straight into the battery pack could never work. But after reading a little bit about the Volt which does essentially exactly what i would expect the trailer to do only with the ICE onboard, i can't see it as being too much of a difficulty.
It is in fact the Volt that is pushing my interest in range extending trailers. I have considered the Volt as an option however the idea of hauling round an ICE when i will actually only ever need it on average once a fortnight irritates me. I would much rather have a trailer i can hook up for those fortnightly or random trips where a little extra range is needed.
I will also be needing a second car to haul our caravan so perhaps its not going to be a problem for me however it does put me in the position where i am spending a pretty large sum of money to effectively only ever drive my EV to my nearest local town & no further, not without further fast charges thru the day. That seams counterproductive to me. This is the problem of living in a country area, distance between destinations ramps up dramatically.    I would much rather have the option of hooking up my trailer & drive my lil EV wherever i need to & save the ICE for those few times a year when we take our caravan out on the road (i'm talking probably only a couple of weekends a year)
The rental option would be a very good option, especially for city dwellers who may rarely ever need the trailer. However to my mind its not like we are talking about a huge investment, we're really only talking about a diesel generator - cheap as these days, & an electronic charging management system. For that matter for a trailer that is compatible with a wide range of EV's could well see just the generator on the trailer with all the charging management systems installed into the EV.
I don't like the idea of a 'push' trailer at all myself, a car only needs 1 engine to be doing the driving, a generator supplying the extra power needed to extend the cars range would be far more efficient.

This is where the current generation of EV's are going to trip up IMO, especially in Australia, for people like myself where most of our driving needs can be done with an EV but the occasional extended distance drives that are either out of the range of the EV or where a recharge on route isn't practical. It really relegates the EV to the 'second' car for a lot of Australian drivers. This wouldn't be a problem if we were talking about a $15k car, not however a $40k+ car! Range extending trailers either for occasional hire or own outright if more frequent trips are needed would effectively negate this issue IMO.
As for the low number of EV sales, this isn't the case in Europe & England where EV's are being snapped up faster than they are being made.
The number 1 real or imagined problem in most drivers minds when it comes to EV's is range anxiety, every EV article i read these days has some mention of it. This is why i just don't understand why trailers aren't being developed, to my mind there's a huge potential here.

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Raising the subject of range extending trailers

Post by Richo » Wed, 31 Aug 2011, 21:08

Rattrap wrote: The rental option would be a very good option, especially for city dwellers who may rarely ever need the trailer. However to my mind its not like we are talking about a huge investment, we're really only talking about a diesel generator - cheap as these days, & an electronic charging management system.


How big a diesel generator?

In my opionion a cheap 2-3kVA genset is not particularly useful.
More like 20kVA would be the go.
And they are not particularly cheap.
Even at that size you would be limited to ~80kph (dependant on car) any faster and you'll start draining the cells.

A commerical system with 20kVA would sell for more than $10k I would expect.
Not something every eV commuter would invest in.

And at this stage I would say it would be too early to adopt a method of transferring the charge to the eV.
ie some cars 144V some 320V some higher.
Although technically only a rewind away ;)

So the short answer is NO but the long answer is YES.
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Raising the subject of range extending trailers

Post by Simon » Fri, 02 Sep 2011, 02:23

Rattrap wrote:
I don't like the idea of a 'push' trailer at all myself, a car only needs 1 engine to be doing the driving, a generator supplying the extra power needed to extend the cars range would be far more efficient.

It seems the Volt has not been able to acheive good fuel economy. It's only rated for 37mpg! http://www.fueleconomy.gov/feg/phevsbs.shtml
Honda Civic Hybrid is 44mpg and a 2011 Prius is 50mpg.

Volvos V60 plugin hybrid diesel is claiming to acheive 120mpg though it is probably depleting the battery as well to acheive this.
Last edited by Simon on Thu, 01 Sep 2011, 16:27, edited 1 time in total.

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Raising the subject of range extending trailers

Post by Rattrap » Sun, 04 Sep 2011, 15:18

I downloaded this report on range extender trailers a while back & only just found it again, its an interesting breakdown on the subject. Some of it is a little over my head but still an interesting read.

Low_Emiss_Range_Ext_149.pdf

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Raising the subject of range extending trailers

Post by Rattrap » Sun, 04 Sep 2011, 15:30

I wonder why the Volt rates so lowly on fuel consumption? As far as the EV portion of the car, from what i understand an electric motor has about a 85% plus energy to locomotion transfer. Is the generation of electrical energy via a generator so inefficient? I would have thought using an ICE to create electrical energy would have been by far more efficient than using an ICE directly for locomotion. Surely an ICE running a generator can be dialed in for peak performance at a specific rpm rather than an ICE that has to perform over a wide range of RPM & torque demands.
Or did Holden just do it really really badly???

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Raising the subject of range extending trailers

Post by antiscab » Wed, 07 Sep 2011, 03:46

Rattrap wrote:from what i understand an electric motor has about a 85% plus energy to locomotion transfer. Is the generation of electrical energy via a generator so inefficient?



Yes it can be,
for a generator which you or I could buy, it will be.
for instance, most inverter generators at full power in the 2kw size is 450g petrol/kwh
non inverter ones are around 400g petrol/kwh but only at full power

a 2L engine is around 275g/kwh at 90% max torque (peak efficiency), but thats like 70kw continuous (it get progressively worse when you lower output.

anyway, the fewer conversions the better.

Parrallel hybrid is most efficient, with fuel injection changes in rpm don't have quite the effect on efficiency as it once did (but it sure affects power output)

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Raising the subject of range extending trailers

Post by T1 Terry » Fri, 09 Sep 2011, 14:46

Rattrap wrote: I downloaded this report on range extender trailers a while back & only just found it again, its an interesting breakdown on the subject. Some of it is a little over my head but still an interesting read.

Low_Emiss_Range_Ext_149.pdf

Did this unit ever hit the market? A lot of development work went into it that's for sure.

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Raising the subject of range extending trailers

Post by Rattrap » Wed, 14 Sep 2011, 02:28

Not that i'm aware of Terry.

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Raising the subject of range extending trailers

Post by glenn_aircooled » Tue, 01 Nov 2011, 13:47

what do people think of range extending by carrying generator - suitably housed and exhausted, is this even viable ?
I see myself occasionally wanting to do an extra trip in the afternoon after getting home from work. Any thoughts...
Cheers , Glenn... I am working toward that happy " I never stop at Petrol Stations " feeling    :)

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Raising the subject of range extending trailers

Post by Rattrap » Tue, 01 Nov 2011, 14:26

That is exactly the type of range extender i have been talking about Glenn. Viable? i believe so, check out the links i posted earlier, its a detailed study of the concept.
uploads/220/Low_Emiss_Range_Ext_149.pdf
http://www.evnut.com/rav_longranger.htm
I have not been able to find a unit available tho which is a real pitty.   I'm surprised the EV market isn't crying out for just this sort of device.
Last edited by Rattrap on Tue, 01 Nov 2011, 03:28, edited 1 time in total.

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Raising the subject of range extending trailers

Post by Richo » Tue, 01 Nov 2011, 20:35

How could you find one?
Production eV's are barely even released on the market.
And it would be a custom build for one-off home conversions.
Not very profitable/viable at this early stage.

It would basically be up to a home converter to build one for their eV and then hope that they will build you one assuming your eV has the same DC charging setup as you.

So the short answer is NO but the long answer is YES.
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Raising the subject of range extending trailers

Post by AMPrentice » Thu, 03 Nov 2011, 01:36

Would it be difficult to just spend the money on the new recycled
plastic tubbed trailers that have alloy frames then just fork
out extra for a whole new pack of batteries. You would need good
security eg. mobile phone tracking device and good alarm but it
could double as a solar storage pack for the house.

Another idea for other cars is to make an aero roof rack unit or carrier that can hold the extra batteries on the roof and solar
panel covered. The pack whatever you choose would last longer
than your main pack I suppose over time as it wont be used as much.

I have a feeling by 2014 the Nissan Leaf should have good range.
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Raising the subject of range extending trailers

Post by jag1475 » Thu, 03 Nov 2011, 02:32

Hi All
Rattrap, I agree with you regarding the Range extender. we know it can be done. AC Propulsion built on for the first gen RAV4 EV. thanks to Wikipedia we also know the the rav 4 had a 95 amp-hour NiMH battery pack has a capacity of 27 kWh,and from the stats i can find on line the output for the range extender was 20kW DC. I just think it will take time before someone does it we have enough smart people in OZ to make on its just going to be about the money and time :)

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Raising the subject of range extending trailers

Post by glenn_aircooled » Thu, 03 Nov 2011, 14:06

very nice info Rattrap. I like the research that went into that RXT.
I can see myself going through that process of design on a smaller set up & making a smaller prototype for myself. Great ideas in that research. Once I actually get my DC car going   :)
Cheers , Glenn... I am working toward that happy " I never stop at Petrol Stations " feeling    :)

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Raising the subject of range extending trailers

Post by Richo » Thu, 03 Nov 2011, 21:08

It would still have to be trailer.
I can't see a 500cc motorbike engine in a car.

A 2-3kW genset would only be for leaving the vehicle in one place for 6-8hrs to charge where there is no power.
So the short answer is NO but the long answer is YES.
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Raising the subject of range extending trailers

Post by Richo » Thu, 03 Nov 2011, 21:16

AMPrentice wrote: Would it be difficult to just spend the money on the new recycled plastic tubbed trailers that have alloy frames then just fork out extra for a whole new pack of batteries.


But $10k of batteries may double your range where as a $10k range extender gets you across Australia.
Having $10k of batteries laying around unused for 90% of the time isn't economical either.

Plastic trailers?!?
Sure that's not just a lining?

So the short answer is NO but the long answer is YES.
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Raising the subject of range extending trailers

Post by Rattrap » Fri, 04 Nov 2011, 00:31

I think your right, its a simple matter of market pressure either that or there's some sort of legal issue regarding having an engine running in a trailer while moving.
The trailer is the perfect place for it, why haul around all that extra weight when 90% of the time you won't need to. The RXT-G trailer is a really neat example of exactly whats needed.

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Raising the subject of range extending trailers

Post by Richo » Fri, 04 Nov 2011, 20:25

The NCOP14 does say that the engine must not be able to start/move while charging.
Luky it is just a guideline and not an absolute...

Given that in the future is will be a common item beuracratic red tape will be cut.
So the short answer is NO but the long answer is YES.
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Raising the subject of range extending trailers

Post by Rob M » Sat, 05 Nov 2011, 18:30

Some of you might not be aware of Glen George's trip around Australia towing a range extending pack of batteries in a small trailer. He was at Eucla yesterday so will be back in Perth this week some time. He was able to do almost 300k's on a charge. Most of the time he was happy to do around 200k's per day and have a look around as well.
Check out his website for details at http://www.co2race.net.au
There will be a welcome back reception next weekend so watch for details and bring your EV along.

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