Raising the subject of range extending trailers

Post by **AMPrentice** » Mon, 14 Nov 2011, 03:15

the plastic trailers Ive been seen on the road with alloy frame/chassis
I dont know their name but also seen great looking motorbike aero trailers

The on from Glen George is not a good design with the friction surface
of industrial alloy plate finish.

Post by **Adverse Effects** » Mon, 14 Nov 2011, 04:25

Rattrap wrote:some sort of legal issue regarding having an engine running in a trailer while moving.

well there are fridge trailers that have there own ICE running all the time even when there being towed

Post by **glenn_aircooled** » Fri, 02 Dec 2011, 13:40

I just have this image of a strengthened rear bumper, some large pin conectors with retainers that the whole gen set just hooks into ....
number plate relocated. Come home , trolley the gen set to back of car , clip it in place, start the generator and off I go.
Thinks - 80 kg hanging on back of car might make the steering a tad light.

Its just that the extra drag of trailer and expense of trailer rego
does not appeal to me.

Post by **glenn_aircooled** » Fri, 02 Dec 2011, 13:42

I wonder what the maximum weight that can be carried above car roof is ?

Post by **Johny** » Fri, 02 Dec 2011, 15:16

glenn_aircooled wrote:number plate relocated. Come home , trolley the gen set to back of car , clip it in place, start the generator and off I go.
Thinks - 80 kg hanging on back of car might make the steering a tad light.

Its just that the extra drag of trailer and expense of trailer rego
does not appeal to me.

Wouldn't the drag be similar to adding that weight to the vehicle and thereby increasing its rolling resisance?
A single wheel trailer with dolly wheel, hard coupled to the vehicle, would not have to be registered (I think???).

Post by **Johny** » Fri, 02 Dec 2011, 15:24

glenn_aircooled wrote: I wonder what the maximum weight that can be carried above car roof is ?

According to the Subura Outback manual:
The load on the roof rack, including attachment devices (low-riders), bars, and cargo must not exceed 100 lbs. (45kg).
I think 45kg is pretty typical after a quick google.
Some of the Thule top-of-car devices say 100kg but they are for Tonka toys (4WD SUVs).
I can't imagine a generator drumming away above your head being too comfortable on a long trip...

Post by **woody** » Fri, 02 Dec 2011, 15:38

Is this this what you had in mind? (2nd photo).

Most tow bars are rated to 100kg downforce - you'd want something else to keep the balance and alignment I'd think. Trailer rego is pretty cheap though.

I also found some single wheel trailers too. Not sure on the legality in australia.

Post by **Richo** » Mon, 05 Dec 2011, 21:08

You defn won't be cliping a 20+kVA gen set anywhere

I can't really imagine lifting it to clip in on either...

Really is trailer drag that bad?

Has anyone done tests?

Website · Post by **Simon** » Mon, 05 Dec 2011, 23:17

Check out this post by Trev on The Back Shed forum.

He towed an 18kVA generator on a trailer 2000km to attend the AEVA conference.
Fuel consumption was 9.8Km/L.

Post by **Johny** » Tue, 06 Dec 2011, 14:23

Simon wrote: Check out this post by Trev on The Back Shed forum.

He towed an 18kVA generator on a trailer 2000km to attend the AEVA conference.
Fuel consumption was 9.8Km/L.

That trip had its concerns. I really don't understand why he had the problems with the cells getting so hot. Maybe running chargers continuously while driving isn't such a great idea. The software in the chargers could get quite "confused" about what was happening to the pack.

Post by **Richo** » Tue, 06 Dec 2011, 20:31

Yeah I'd like to see anyone clip that bad boy to thier car!
Or in the boot or stapped to the roof...

You go get the trolley and I'll watch you move it

Post by **Rattrap** » Wed, 07 Dec 2011, 00:56

Theres a vast difference between that 20kw trailer & the 1 i originally posted behind the Rav4EV. I wouldn't go near that Kabota monster but I'd happily tow the Long Ranger behind my imaginary Nissan Leaf

Post by **Rattrap** » Wed, 07 Dec 2011, 01:00

Also it weighs 350 pounds/ 158kg. Thats about the weight of 2 adults, the Leaf is a 4 seater so while the added weight would be felt for sure but it wouldn't be insurmountable.

Post by **Richo** » Wed, 07 Dec 2011, 20:43

Even a cut up motorbike plus charging bits really need to be in a trailer.
45kg on a car roof becomes a really nasty projectile in a crash.

I can imagine now a box full of motorbike bits clipped on to the back of an eV.
The eV is in a crash.
The box flys off and hits an on coming vehicle killing the people in the front.
The insurance company won't cover you for that.
I'm sure there is a classification for you inadvertantly killing someone that gets you in jail.

Even if you had it bolted to a structural part of the car and had an engineer sign off on it it would still be a fine line on the outcome of that crash.

In my opionion I don't see any other way other than a trailer for hauling a genset.

Post by **Rattrap** » Fri, 09 Dec 2011, 02:46

heres another concept;
http://www.gizmag.com/rinspeed-dockgo-concept/20773/

Post by **Richo** » Mon, 12 Dec 2011, 20:57

That's a good one!

Post by **Rattrap** » Mon, 12 Dec 2011, 21:51

I quite like that 1 myself. Quite nifty, easy to drive/tow/park. Allround winner in my eyes.

Post by **Johny** » Mon, 12 Dec 2011, 22:03

The extra set of rear wheels don't turn/track (I assume), so there is a tendency to rip the rear section off when the driver does a U-turn.

Post by **woody** » Thu, 05 Jul 2012, 17:48

Ecomodder Post by a NZer has a few ideas mixed together in a trailer:
1. Prius NHW10 ic motor and its electric motor
2. Wood Gasifier for fuel instead of petrol

Post by **coulomb** » Fri, 06 Jul 2012, 05:08

woody wrote:1. Prius NHW10 ic motor and its electric motor

Heh. That's one use for all those NHW10s that are going cheap because of their hybrid batteries wearing out.

Post by **unheardofinstruments** » Wed, 18 Jul 2012, 17:46

I just scored a permanent magnet generator from a wind turbine for my porsche 924 wreck range extending sleeper trailer project which is a lot lighter than a normal gen-set. It is 180V at 4000rpm. I think a small gas turbine aircraft alternator would be ideal or a fuel cell. ATM I go with what I can afford. I calculated 7.5kW for flat 110kmph travel for my EV so 10k would do for limitless range or even 5 would extend the range to double which is doable with a 50cc 2-stroke RC plane engine weighing 600g which is what I have and I plan to boost output by scavenging exhaust heat with solid state thermal generators (in your fridge butterbox) Ecomodder has a bunch of info on basic mods for economy which are mostly applicable to the EV. Bridgestone now make the Ecopia low rolling resistance tyres, aero mods such as a belly pan and the like make a huge difference, more than one way to can a skit. I plan to have solar cells and hydraulic regen on board my trailer. The pusher trailer is good for highway travel but I wouldn't use it in corners in the wet for example and it is heavy and I think it would help if it had a PMG or many alternators in it too. I have seen some great ones on EValbum.com. A generator would be better though as optimal rpm and lighter weight is possible. Gasification is a great idea and was proven in WW2 times and trans-Australian journeys have been done using one in a trailer. Hydrogen from electrolysis, water injection, acetone in the fuel, vaporizing carburetor, hyclone...no end of mods for better fuel efficiency are doable and easier for a generator running at one speed. A battery pack to DC dump charge the EV pack could be included in the trailer but with the right electronics in the gen set wouldn't be necessary. http://www.lightningcarcompany.co.uk/Li ... tning.html
use a new titinate battery pack with 10 000 discharge cycles to 80%DOD and it recharges happily in 20 minutes, not quite the 400Wh/kg Envia claim but that would be 20 years of driving for me and improvements are in the wings. No end of battery tech being developed and supercaps may win as well which are good for 1000000 cycles. Not for lack of solutions are we in this bind...

Post by **Johny** » Wed, 18 Jul 2012, 17:52

An interesting read but I am concerned over one of your comments.

unheardofinstruments wrote:....I calculated 7.5kW for flat 110kmph travel for my EV so 10k would do for limitless range.....

For anything other than custom build low-profile solar cars 16 to 18kW for 100km/h is expected.
How did you calculate the 7.5kW?

Post by **Rattrap** » Wed, 18 Jul 2012, 17:54

unheardofinstruments this sounds very interesting & something i would love to follow the progress of, please keep us all updated with your progress!

Post by **unheardofinstruments** » Sat, 22 Sep 2012, 08:42

The rear of the car makes up 33percent of the drag due to air. the wheel wells 21.4
under body 14.3
front 11.9
I will be doing wheel covers, closing the front and putting underbody panels in so I hope to get it substantially lower one day.
The drag co-efficient for the 924 is .31 and I estimated the frontal area as being around 20 feet square
coefficient of drag X frontal area X mph squared divided by 391 gives it in pounds so .25 X 20 X 4225 is 21125/391= 54 pounds of force

I think it was 808 revolutions per mile for 195/60/16's
I will try the latest low rolling resistance tyres next but I suspect the figure .0252 would be a ballpark rolling resistance factor on rough tarmac from .012X(1 + 110mph/100) which multiplied by the weight in pounds which is about 3250 multiplied by cos of the slope which flat is 1 so around 82lbs
so the force to overcome is about 136 pounds plus around 5% maybe for mechanical losses in the drivetrain which is intended to be relatively simple compared to most conversions where a gearbox driveshaft and diff are added to the CV's wheras I have a single pulley reduction drive planned with a toothed belt.
143 lbs
one horsepower is 550ft-lbs/sec so horsepower required being
force needed in lbs (143) X speed in mph (65)/ 375
so nearly 25 horsepower so the continuous output of the FB4001 at
30Hp covers that easy with 5 plus peak rating of 48Hp for 5 minutes (at 144V) available for hillclimbs and headwinds
which is also (torqueXrpm)/5252
or
2 X Pi/60 X (force x velocity)/550
wheel rpm = mph x revolutions per mile)/60
65 x 808/60 = 875rpm
so substituting terms Hp = (torque x mph X rev/mile)/5252 x 60
so torque required is 25 x 5252 x 60/808 X 65 = 150 foot pounds
the power at 60 should be about a quarter of that
.735 kW per Hp gives over 18kW so yes I was wrong, I had used metres instead of feet for the frontal area I think. So running the generator all the time will increase my range by a third only, regen could extend it maybe 20% in stop start traffic but for the highway I will need more power for sure. The added rolling resistance of the trailer could get rid of the difference or more, a 25kVA generator is more like it. Back to the aircraft alternator? 350cc two stroke motorcycle engine maybe, I have my old Yamaha RZ under the house which has a broken gearbox and I think 44Hp peak...
hmmmm...
without the gearbox it would be pretty light and in a cruisy rev range for the generator driving it directly from the crank at 4000 rpm...
The Volt has 55kW from 1400cc and a lot more weight

Post by **unheardofinstruments** » Tue, 04 Dec 2012, 06:52

Here is one of those little lightweight trailers in fiberglass mentioned at a $600 asking price it seems great. I wanted to be able to sleep in mine but this looks ideal for a range extender, it is even streamlined ok.

http://www.ebay.com.au/itm/221152532597 ... _cvip=true