# [EVDL] Pusher trailer (was: A Simple Series Hybrid Concept for the Nissan Leaf)



## EVDL List (Jul 27, 2007)

Probably the least expensive, least polluting, most efficient way to 
do this is a "pusher" trailer:

http://www.jstraubel.com/EVpusher/EVpusher2.htm

Proven concept. You can charge the car (EV) either with regen or via 
an upgrade alternator and an inverter on the pusher.

You only need to have it for the highway portion of your long trip. 
You can detach it quickly when you reach your destination, or when 
you return home. Thus, backing up is generally not as much of an issue.

To maintain highway speed, you need about a 10 kW generator capable 
of running continuously at 10kW. Not an inexpensive item. Also it is 
heavy. A "front clip" from a wrecked car is dirt cheap, however.

Bill D.

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## EVDL List (Jul 27, 2007)

I've always had issues with pusher trailers, especially when regen is to 
be used to charge the batteries at the same time (Causing more "drag"). 
While I can see them working perfectly well on the straight, the moment 
any kind of turn or curve is encountered, or any kind of snaking 
starting to happen, the pushing trailer will immediately try to 
jack-knife the vehicle, and of course the greater the turn the greater 
the force against the rear of the vehicle. The slightest turn would make 
for an automatic PIT manoeuvre. Also, as we're talking about EVs here, 
most drivers would add low-rolling-resistance tyres, which would give 
even less grip and exacerbate this problem.

If there was a system where the trailer was hard-joined to the vehicle, 
and correctly counter-steered (making the vehicle, in effect, a rigid 
6-wheeled vehicle with 4-wheel steering), this wouldn't be a problem, 
but all the pusher trailer systems I've seen are typically a "Lock the 
steering of a FWD car and stick a towing receiver on the front bumper" 
style.

However, something like taking a cheap industrial ACIM and joining it to 
a motorcycle engine (750-1000cc would probably do - something from a 
wrecked rice rocket, or the Diesel engine from a Smart car) with a 
rectifier would make for a cheap and efficient genset, with enough power 
to charge the batteries and drive the vehicle forward, and would have no 
mechanical complexity in joining it to the towing vehicle whatsoever 
(Just an extra cable to carry the power). Given that this could also be 
used for backup home power in case of outages and the like, it's a more 
appealing option. Buying an off-the-shelf generator (and large-enough 
sized charger) for this function would be prohibitively expensive, but 
then buying an off-the-shelf EV solution is also prohibitively 
expensive. It would probably be about as efficient as running a pusher 
trailer, too, given that in a pusher the ICE is running outside it's 
most efficient power band for 90% of the time, whereas the genset can 
keep the ICE at it's peak power band for 100% of the time, making up for 
the inefficiency of converting to electricity and piping (cabling?) it 
to the EV.

This is just my impression, though. IANAEE (Electrical Engineer), 
IANAICEM (Internal Combustion Engine Mechanic), YMMV, E&OE, Offer void 
where prohibited, No purchase necessary.

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## EVDL List (Jul 27, 2007)

Most vehicles (except special built, light EV-dedicated cars)
will take at least 250Wh per mile to stay on Freeway speeds,
say a moderate 60 MPH.
This calculates to 15 kWh per hour, or a continuous 15kW
sustained from a genset to keep the batteries at the same
charge level while doing constant 60.
This jives well with my experience that my S10 truck needed
around 50A at 312V to maintain 55 and this was a slightly
heavier vehicle than most EVs but driven slower. Speed is
very important as accelerating to 70 MPH caused the
consumption to double...
To put 15kW into your pack, your charger must receive more
and the generator must be spec'ed for even more as the
continuous output is usually derated.

Regards,

Cor van de Water
Director HW & Systems Architecture Group
Proxim Wireless Corporation http://www.proxim.com
Email: [email protected] Private: http://www.cvandewater.com
Skype: cor_van_de_water IM: [email protected]
Tel: +1 408 383 7626 VoIP: +31 20 3987567 FWD# 25925
Tel: +91 (040)23117400 x203 XoIP: +31877841130

-----Original Message-----
From: [email protected] [mailto:[email protected]] On
Behalf Of Bill Dube
Sent: Sunday, May 01, 2011 3:16 PM
To: Electric Vehicle Discussion List
Subject: [EVDL] Pusher trailer (was: A Simple Series Hybrid Concept for
the Nissan Leaf)

Probably the least expensive, least polluting, most efficient way to do
this is a "pusher" trailer:

http://www.jstraubel.com/EVpusher/EVpusher2.htm

Proven concept. You can charge the car (EV) either with regen or via an
upgrade alternator and an inverter on the pusher.

You only need to have it for the highway portion of your long trip. 
You can detach it quickly when you reach your destination, or when you
return home. Thus, backing up is generally not as much of an issue.

To maintain highway speed, you need about a 10 kW generator capable of
running continuously at 10kW. Not an inexpensive item. Also it is heavy.
A "front clip" from a wrecked car is dirt cheap, however.

Bill D.

_______________________________________________
| REPLYING: address your message to [email protected] only.
| Multiple-address or CCed messages may be rejected.
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| Multiple-address or CCed messages may be rejected.
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## EVDL List (Jul 27, 2007)

Robert,

Do you have direct experience with pusher trailers (I can't tell from
your post)?

It seems that this guy:
http://www.jstraubel.com/EVpusher/EVpusher2.htm has had no problem
with the oversteer conditions you are afraid of.

"I have still found it basically impossible to get into a condition of
oversteer. (This is where the car would want to turn into the
direction of the turn if you take your hand off the wheel, normaly if
you release the wheel a vehicle will straighten itself out of a turn)
Even in relatively tight turns with the trailer at nearly full power,
the car wants to straighten itself out. The shortened trailer also
drafts behind the EV much better further improving the mpg. "

Anyway, food for thought. It seems crazy to me too, but I haven't
heard of any problems from people that actually use them.
-D



> Robert Johnston <[email protected]> wrote:
> >
> > I've always had issues with pusher trailers, especially when regen is to
> > be used to charge the batteries at the same time (Causing more "drag").
> ...


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## EVDL List (Jul 27, 2007)

Here's another one, same experience:
http://www.mrsharkey.com/pusher.htm

"
Q: How do you control the trailer with a single-point hitch? Doesn't
it get all squirrelly
and make the car jackknife?
A: The trailer tracks behind the car perfectly. You can't even tell
that it's there. You can't hear it and you can't feel it. The EV
outweighs the trailer 3-to-1 and the hitch point is very close to the
rear axle. Having 1,000 pounds of batteries in the back of the car
helps a lot too, I'd guess.
"


On Mon, May 2, 2011 at 10:24 AM, Daniel Busby <[email protected]> wrot=
e:
> Robert,
>
> Do you have direct experience with pusher trailers (I can't tell from
> your post)?
>
> It seems that this guy:
> http://www.jstraubel.com/EVpusher/EVpusher2.htm has had no problem
> with the oversteer conditions you are afraid of.
>
> "I have still found it basically impossible to get into a condition of
> oversteer. (This is where the car would want to turn into the
> direction of the turn if you take your hand off the wheel, normaly if
> you release the wheel a vehicle will straighten itself out of a turn)
> Even in relatively tight turns with the trailer at nearly full power,
> the car wants to straighten itself out. The shortened trailer also
> drafts behind the EV much better further improving the mpg. "
>
> Anyway, food for thought. It seems crazy to me too, but I haven't
> heard of any problems from people that actually use them.
> -D
>
>


> Robert Johnston <[email protected]> wrote:
> >>
> >> I've always had issues with pusher trailers, especially when regen is to
> >> be used to charge the batteries at the same time (Causing more "drag").
> ...


----------



## EVDL List (Jul 27, 2007)

My concern would be more about the hitch that is used. A standard trailer
hitch like the one shown is meant to have tongue weight. In this use I would
have to think that under load the hitch is pulling up trying to remove
itself from the ball. =


Sincerely,
Mark Grasser
=



-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf
Of Peter Gabrielsson
Sent: Monday, May 02, 2011 1:40 PM
To: Electric Vehicle Discussion List
Subject: Re: [EVDL] Pusher trailer (was: A Simple Series Hybrid Concept for
the Nissan Leaf)

Here's another one, same experience:
http://www.mrsharkey.com/pusher.htm

"
Q: How do you control the trailer with a single-point hitch? Doesn't
it get all squirrelly
and make the car jackknife?
A: The trailer tracks behind the car perfectly. You can't even tell
that it's there. You can't hear it and you can't feel it. The EV
outweighs the trailer 3-to-1 and the hitch point is very close to the
rear axle. Having 1,000 pounds of batteries in the back of the car
helps a lot too, I'd guess.
"


On Mon, May 2, 2011 at 10:24 AM, Daniel Busby <[email protected]>
wrote:
> Robert,
>
> Do you have direct experience with pusher trailers (I can't tell from
> your post)?
>
> It seems that this guy:
> http://www.jstraubel.com/EVpusher/EVpusher2.htm has had no problem
> with the oversteer conditions you are afraid of.
>
> "I have still found it basically impossible to get into a condition of
> oversteer. (This is where the car would want to turn into the
> direction of the turn if you take your hand off the wheel, normaly if
> you release the wheel a vehicle will straighten itself out of a turn)
> Even in relatively tight turns with the trailer at nearly full power,
> the car wants to straighten itself out. The shortened trailer also
> drafts behind the EV much better further improving the mpg. "
>
> Anyway, food for thought. It seems crazy to me too, but I haven't
> heard of any problems from people that actually use them.
> -D
>
>


> Robert Johnston <[email protected]> wrote:
> >>
> >> I've always had issues with pusher trailers, especially when regen is to
> >> be used to charge the batteries at the same time (Causing more "drag").
> ...


----------

