Raising the subject of range extending trailers

Open for any sort of non-technical discussion regarding EVs
Canberra32
Groupie
Posts: 238
Joined: Wed, 13 Jun 2012, 04:25
Real Name: Damian butcher
Location: Canberra

Raising the subject of range extending trailers

Post by Canberra32 » Tue, 22 Jan 2013, 01:26

Well as a tradie me and the boss have considered a range extending trailer.

But like the tool trailers with a big battery pack right at the bottom and solar on the top of the tool chest and on the big doors that open up.

Some merit there I think

unheardofinstruments
Groupie
Posts: 86
Joined: Tue, 26 Jun 2012, 15:08
Real Name: ron Berry
Location: Nimbin
Contact:

Raising the subject of range extending trailers

Post by unheardofinstruments » Tue, 22 Jan 2013, 05:37

I have been working on the hydraulic regeneration side of the range extending trailer idea today, sizing pulleys and magnetic clutches from AC units for the generator set too, I need two stages of reduction it seems but i haven't given up nutting it out further yet and found a very large pulley but i suspect to fit it in I would need a 90 degree drive too which is probably as much trouble as two stages.
It is 80% efficient doing hydraulic vs 40% for electric regeneration and would negate the extra weight of the thing a lot and possibly that of the car as well, you might not want to take it off if you do a lot of stop start high amps driving and it would prolong the battery life.
My gear motor/pump is only a few kilos and I suspect a reservoir and an accumulator plus fluid and hoses will add up but not too much and it is very simple, perhaps it would be worth doing a hydraulic electric drive in a car, it is not very smooth and the torque is brutal judging by my friends mad max hydraulic drive farm vehicle but having low rpm high torque is good and a much smaller motor could keep up. Heck it works for 20 ton excavators. I can use electric regen at the same time as well and I think it should be possible to run the generator set and use it to charge the hydraulic acumulator too (without driving the wheels with it) say while stopped at the lights to get ready for takeoff if it wasn't full. I am not quite sure how to regulate the generator for charging yet or how I could afford more batteries dollars or weight wise (I will have to calculate the torque the whole shabang would require next) but they would go in the tunnel nicely.
I wouldn't fancy attempting registering the trailer with it in either.
I like the fold up sides with solar cells idea, will do that one for sure I am working on the windows and getting the torque tube out atm. which might mean taking the whole rear assembly off, Image
Lucky I have no timeframe in mind.

User avatar
acmotor
Senior Member
Posts: 3595
Joined: Thu, 26 Apr 2007, 03:30
Real Name: Tuarn
Location: Perth,Australia

Raising the subject of range extending trailers

Post by acmotor » Tue, 22 Jan 2013, 07:12

The tradies solar trailer has merit, good for providing power on a building site too. Brilliant promo !

No offence to Glen George, or Louis Palmer for that matter, but the real travel record will belong to the first to drive around Australia... at the speed limit !

Just thinking out loud here, most of this trailer (or range extender) push thing has been done .....

I've seen these varieties...

ICE motored mechanical drive to trailer wheels.
kinda defeats the purpose of an EV ?

ICE motored gen set to charge EV batteries when stopped.
maybe better to find a power point ?

ICE motored gen set to charge EV batteries on the go.
series hybrid like. kW can be less than EV cruise kW or match it for
continuous range.

Chevy Volt address these first three without a trailer. Oz version has 'mountain mode' disabled so can't do the 2nd one. The third one only applies to part of the battery pack capacity. ICE always keeps battery from going below around 30% SOC so 110kW emotor has something to draw on. Overall, price and complexity are of concern. And you can't leave the ICE behind when you don't use it (90% of the time according to statistics).

Then there are the non ICE push (range extend) trailers...

Battery pack to suppliment EVs' battery pack.

PVs to charge EV when stopped.

PVs to charge EV on the go.

PVs + battery pack in trailer to suppliment EVs' battery pack.

.... and my fav. variety....

PVs + battery pack + emotor driving wheel(s) of trailer. 'Live trailer'

Self contained and needs nothing more than a tow ball and lights plug.
This can be used on EV or ICE. Yep 150MPG ICE possible !
The emotor need only be 10kW or so and only provide limited torque at low speeds. The 10kW would be set up for max efficiency at cruise of 60 to 100kmph. OK, more than 10kW if you want continuous range, but at 10kW it could take a 100km range vehicle 300km with maybe 20kWh of batteries.

The emotor push trailer would have a few possible control methods...

System would sense EV motor current with clamp meter and control pushing emotor to provide torque when EV emotor is asked to provide torque (eccelerator pressed).
If EV motor and trailer emotor are both AC then trailer could do regen braking when EV motor does regen etc. Just 60 to 80% of EV so system reamins stable and doesn't hunt. Push trailer is only intended to suppliment EV/ICE vehicle that vehicle thinks there is a tailwind and going downhill.

The second possibel control method ... a load cell in the tow hitch + wheel rotation speed + vehicle brake lights would allow push trailer to decide what to do for both ICE or EV.
If wheels are rotating > some minimum speed and brake lights are not on then ramp up the push. If tow hitch is pulling then ramp up push until trailer is pushing on vehicle.... and so on.

Now for those long trips (Australia crossings) just hire an 'epush trailer'. Pick up / drop off at service stations along the way. A bit like battery swapping (but then that was never going to take off).
Trailers can even sit in the open for a few days to charge from PVs.

Push trailer could also do 'push charging' for EVs with true regen.

What a daft idea. Back to work. Image

iMiEV MY12     105,131km in pure Electric and loving it !

Canberra32
Groupie
Posts: 238
Joined: Wed, 13 Jun 2012, 04:25
Real Name: Damian butcher
Location: Canberra

Raising the subject of range extending trailers

Post by Canberra32 » Tue, 22 Jan 2013, 11:11

Lol I actually thing better putting an ice in your car and go hybrid coz guys I'm not so down in wind tunnel tests but I'm guessing dragging a ton shaped like a brick is a fail.

User avatar
acmotor
Senior Member
Posts: 3595
Joined: Thu, 26 Apr 2007, 03:30
Real Name: Tuarn
Location: Perth,Australia

Raising the subject of range extending trailers

Post by acmotor » Tue, 22 Jan 2013, 22:18

......And you can't leave the ICE behind when you don't use it (90% of the time according to statistics).Image

This probably is just as important as wind resistance.
But point taken that care must be taken with aerodynamics as these may indeed cause a fail.

I would expect a 300kg aerodynamic trailer with low COG etc.

The whole EV range issue will be ancient history soon enough as battery packs improve. Image   
iMiEV MY12     105,131km in pure Electric and loving it !

Rattrap
Groupie
Posts: 120
Joined: Sat, 24 May 2008, 15:01
Real Name: John
Location: Tasmania

Raising the subject of range extending trailers

Post by Rattrap » Wed, 23 Jan 2013, 00:09

I was looking at lightweight generators yesterday, 6.5kw weighed in at just 115kg.

User avatar
Richo
Senior Member
Posts: 3737
Joined: Mon, 16 Jun 2008, 00:19
Real Name: Richard
Location: Perth, WA

Raising the subject of range extending trailers

Post by Richo » Wed, 23 Jan 2013, 20:33

I bet a 110cc motorbike engine + Etek-RT is like half that weight with more power.

So the short answer is NO but the long answer is YES.
Help prevent road rage - get outta my way!

User avatar
BigMouse
Senior Member
Posts: 600
Joined: Thu, 28 Oct 2010, 02:39
Real Name: Vincent Tannahill
Location: Silicon Valley
Contact:

Raising the subject of range extending trailers

Post by BigMouse » Wed, 20 Nov 2013, 16:34

Renault Zoe range extending trailer: http://llewblog.squarespace.com/electri ... l-you.html

User avatar
offgridQLD
Senior Member
Posts: 1825
Joined: Tue, 23 Jul 2013, 16:05
Real Name: Kurt
Location: Fleurieu Peninsula, SA

Raising the subject of range extending trailers

Post by offgridQLD » Wed, 20 Nov 2013, 20:28

Unless your going to bring 10kw of PV (I have 8kw spread out over a 350m2 house and 120m2 workshop and it takes up a good portion of that roof space)Traditional glass front PV is roughly 15kg - 200w so 10kw of pv is 750KG! Yes Thin flexible PV is available at 1/3 the weight and higher cost. So unless the trailer is going to sit all day charging from a much smaller on board PV array bringing enough with you to drive and hold charge at the same time is a big ask.

A small car like the Imeve can sit at 100km with only 10kw or so (ideal conditions flat road, no wind) So Ac motors idea of the 10kw e motor driving the push trailer sounds good to me. Though it's really just a complexity (warranty) cop out for not using the same addition trailer battery's to power/charge the car directly.

My thinking (for imeiv) is 20kw of lithium battery's 16 cell 48v config in a trailer . Motorbike style/size trailer sub 100kg + battery weight (perhaps 300 total). The sleek shaped fiberglass/plastic box perhaps 1000mm long by 600mm wide by 450mm high box sleek shape just big enough for the battery and a 3.2kw continuous inverter to mount in. Use the stock on board charger when stationary. Imiev example at 3kw charge rate you might add 25km range for every hr of charging. Total range of the car could be extended from a safe 100km stock to perhaps 200-250km combined

As for cost. Perhaps use something like 16 x 400AH grey Calb cells $10,000 including BMS, connections and shipping for the 20kw of cells. A good pure sine wave 2nd hand 5kw ups can be salvaged for around $200 and would work great. I payed $100 for a working 48v genuine 3.0kw continuous UPS to use with stock 10A charge cable. (E Jerry can or trailer project in mind)Image

The trailer its self could be built and registered to a very nice spec and overall Finnish for under $1000 if you made it your self.For the Imiev example You would then need a EVSE that takes advantage of the full 3kw output of the on board charger. Perhaps another $700?

So I would say its about a $12,000 investment to build your self a 20kw range extending trailer that could double the range of a small ev like the Imiev.

Being 48v and having its own 5kw pure sine wave inverter it could dock to your house and be used with stationary PV array and charge controller as off grid power or remote power trailer.

It boils down to the how often would I use it question. If it can have double duty (like the off grid example)then the its more viable investment. Otherwise just hire a car for long trips.

Just out of interest I think we worked out that charging our Imiev from a generator (we have a 8kw kubota diesel - stationary unit 250kg!) worked out to around 5lt -100km there is a lot of inefficiency in the proses but it's still not bad comparing it to a typical ICE car consumption.

Kurt
Last edited by offgridQLD on Wed, 20 Nov 2013, 09:38, edited 1 time in total.

User avatar
Richo
Senior Member
Posts: 3737
Joined: Mon, 16 Jun 2008, 00:19
Real Name: Richard
Location: Perth, WA

Raising the subject of range extending trailers

Post by Richo » Wed, 20 Nov 2013, 20:43

LlewBlog wrote:EP Tender ... Bloody clever stuff
It looks like it does the job.
luckily he didn't say who was clever as it is just a copy of what other people have done.

I still think it would have been good if it was a bit bigger to fit some luggage.
So the short answer is NO but the long answer is YES.
Help prevent road rage - get outta my way!

User avatar
Adverse Effects
Senior Member
Posts: 1082
Joined: Sat, 01 Jan 2011, 03:30
Real Name: Adverse Effects
Location: Brisbane

Raising the subject of range extending trailers

Post by Adverse Effects » Wed, 20 Nov 2013, 22:59

Richo wrote:I still think it would have been good if it was a bit bigger to fit some luggage.


so put a roof-rack on it

unheardofinstruments
Groupie
Posts: 86
Joined: Tue, 26 Jun 2012, 15:08
Real Name: ron Berry
Location: Nimbin
Contact:

Raising the subject of range extending trailers

Post by unheardofinstruments » Thu, 21 Nov 2013, 01:08

I had no idea a ups could be so little, seems a good way to regulate charge, I figured a rectified pmg such as from a wind turbine is very light for the output, coupled with a small motor with peltier generator units on the exhaust to charge the car up dc directly and for regeneration have it driven via a magnetic clutch on a belt to the wheel (although a gear pump/accumulator hydraulic regen is twice as efficient but why not both?) Drive from the trailer would be great, streamlining it with the car using lycra bendy bus style would help a lot too. Seems silly to go from genset to 240 and back down through the charger to dc. Why is the buck converter for regen not part of the charger? Could we make such a beast? Charge regulation for solar could be a good option too. That would make the trailer(+sleeper?) much cheaper and not heavy and full of batteries. The generator would run primarily as a source of heat and if it ran on algal biodiesel or ethanol/hydrogen...makes more room for panels...

User avatar
acmotor
Senior Member
Posts: 3595
Joined: Thu, 26 Apr 2007, 03:30
Real Name: Tuarn
Location: Perth,Australia

Raising the subject of range extending trailers

Post by acmotor » Thu, 21 Nov 2013, 07:01

Kurt, as usual I like your thinking.

Dual use trailer, house storage/load level and range extender.
Maybe 24kWh ?

It seems that CHAdeMO and higher voltage battery pack (switcheable 48V or 480V would be a better way to get it into the EV since inverter + charger losses could be 30-40% overall ?
e.g. 160 x 40Ah cells at 1C would happily supply 20kW rate via CHAdeMO.

If you could feed 48V pack voltage via a DC-DC into CHAdeMO at say 5kW that would still be useful and more efficient than going DC-AC-DC via the J1772 path.

Direct suppliment on line to battery pack while driving would be the most useful and perhaps highest efficiency but would probably not keep Mitsubishi happy.

iMiEV MY12     105,131km in pure Electric and loving it !

User avatar
offgridQLD
Senior Member
Posts: 1825
Joined: Tue, 23 Jul 2013, 16:05
Real Name: Kurt
Location: Fleurieu Peninsula, SA

Raising the subject of range extending trailers

Post by offgridQLD » Thu, 21 Nov 2013, 15:45

Yes about 22kw for 16s 400AH config, though you wouldn't use more that 18-20kw from it.

Yes there are losses with all the DC-AC-DC and so on. The main concern was cost what dose a chademo cost? Considering the simple approach is already topping $12,000- 10k of it being the additional battery's.Given you can purchase a 2010 Imiev for $18,000 if you start adding a chademo to the equation your could just buy a second Imiev and double the range Image

Personally to make it viable I would have to tie it in with the replacement of my 63kw lead acid house battery in a few years. I will defiantly be replacing it with a 48v 16 x 400AH calb (or similar) cells. So If I have already committed that 10k to lithium cells that have a purpose most of the time at home. The idea was rather than just sit them on a shelf in the power room permanently hard wired to the house inverter. Perhaps if they were just docked there in the tiny motorbike trailer instead then they could be removed and taken with me on the odd rare long trip. The issue is whats going to power my base loads, fridge, security system, modem and so on while I'm away on a long trip with the house bank behind the Imiev. I would then need a small 48v fill in bank to cover the loads and keep the home system ticking along aver the few hrs to potentially day or two I am away.

Kurt.
Last edited by offgridQLD on Thu, 21 Nov 2013, 04:53, edited 1 time in total.

User avatar
acmotor
Senior Member
Posts: 3595
Joined: Thu, 26 Apr 2007, 03:30
Real Name: Tuarn
Location: Perth,Australia

Raising the subject of range extending trailers

Post by acmotor » Thu, 21 Nov 2013, 16:36

At first I pondered how the second iMiEV was going to double the range (of the first one) Image and then I returned to the spare iMiEV as a battery pack hack thought.

I'd still not consider the CHAdeMO connection as expensive or complicated.
First, need to be able to buy a connector. Sub $200 surely.
Next, complete the hardware and CAN handshakes. Hardly complex when you get there.
Third, a controllable buck or boost or DC-DC interface should see 95%+ efficiency compared to as poor as 60% for the DC-AC-DC path. I think it would be worth the effort.

Have you seen any progress on DIY CHAdeMO yet ? Can't be too far away.
iMiEV MY12     105,131km in pure Electric and loving it !

User avatar
Johny
Senior Member
Posts: 3729
Joined: Mon, 23 Jun 2008, 16:26
Real Name: John Wright
Location: Melbourne
Contact:

Raising the subject of range extending trailers

Post by Johny » Thu, 21 Nov 2013, 17:30

I would think that a DIY CHAdeMO with direct connections to the pack would certainly be a warranty concern. Then again, charging while driving is a no-no with the standard iMiev as well.

User avatar
offgridQLD
Senior Member
Posts: 1825
Joined: Tue, 23 Jul 2013, 16:05
Real Name: Kurt
Location: Fleurieu Peninsula, SA

Raising the subject of range extending trailers

Post by offgridQLD » Thu, 21 Nov 2013, 19:46

Ok if a Chadimo charger was available for a reasonable price then sure direct DC is the way to go.

I don't think I would bother though just to keep the battery simple for my off grid purposes. Then again I really don't think I would bother towing a trailer with me just to get a 100km + 100km return travel distance as there is nothing within that range that I am hanging out to drive to. I think its easier just to pay for AC-DC charging from the grid if you have to at each end rather than tow it all with you.

Just the interest alone one the $12,000 taken from the bank to build the thing is $600 pa at a modest 5% interest. That could be used to encourage a lot of people to let you charge at there location.

Just for kicks and ideas. How about a small trailer with two tiny tandem wheels. One set of wheels left right say 12 inch is just there to support the trailer itself. The second set of wheel dosn't even make contact with the road say a 10 inch wheel spaced very close to the larger wheel. The 10 inch wheel are driven by a electric motor can even be at a fixed from a battery bank nothing fancy .It Can just be a simple dc motor. You reverse your imiev onto the rollers and strap it down and jack the trailer up so both wheels are off the ground. It gets the Imievs wheel turning at a slow speed (equivalent to say 35 - 40kmh road speed) I have easily seen up to 10kw rolling down a gentle little dip at slow speeds. How would the car know if its reging down a hill or having it's rear wheels were being driven? Not that I would bother but the Regen is very effective on the Imiev. Then again why not just have the trailer push you along while its in tow.

Kurt

Last edited by offgridQLD on Thu, 21 Nov 2013, 08:50, edited 1 time in total.

User avatar
Richo
Senior Member
Posts: 3737
Joined: Mon, 16 Jun 2008, 00:19
Real Name: Richard
Location: Perth, WA

Raising the subject of range extending trailers

Post by Richo » Thu, 21 Nov 2013, 20:49

Adverse Effects wrote:so put a roof-rack on it


A foot extra at the end of the trailer would mean I wouldn't need a roof rack to hold a few extra bags.
No extra drag, no extra fittings.
Just throw them in and go.
acmotor wrote: Direct suppliment on line to battery pack while driving would be the most useful and perhaps highest efficiency but would probably not keep Mitsubishi happy.


Joys of an off the shelf eV Image

I can see one day someone will be driving down the road with the plug in and cord going to a trailer.
It won't be pretty. Image
So the short answer is NO but the long answer is YES.
Help prevent road rage - get outta my way!

Post Reply