Battery Trailer

[Mike Chancey]

Hi folks,

Has anyone worked out the math involved with battery
trailers?  Basically, some idea of how much additional power is going
to be required due to the added load?

Thanks,

Mike Chancey,
'88 Civic EV
Kansas City, Missouri
EV Photo Album at: http://evalbum.com
My Electric Car at: http://www.geocities.com/electric_honda
Mid-America EAA chapter at: http://maeaa.org
Join the EV List at: http://www.madkatz.com/ev/evlist.html

In medio stat virtus - Virtue is in the moderate, not the extreme
position. (Horace)

_______________________________________________
For subscription options, see
http://lists.sjsu.edu/mailman/listinfo/ev

[Roland Wiench]

Hello Mike,

I have calculated what the range of my EV would be with 2 strings of 30
T-145's for two 180 volt battery packs that would be either all onboard or
in a trailer.

If you use a trailer, then you must add the weight of the trailer and
connections devices.  This becomes about 2200 lbs for the batteries and
about 500 lbs for a trailer which is addition 2700 lbs which makes the total
battery pack of 4900 lbs.

I use Uve's Electric Vehicle Calculator which gave me a total weight of 5700
lbs for one string and 8400 lbs for two strings plus additional 500 lb
trailer for a S10 type pickup.   The range for a one string of batteries is
about 39 miles at 60 mph at 50% DOD and for the addition battery and trailer
it becomes 65 miles at 60 mph at 50% DOD.

It takes 7 to 10 additional hp and will loss about 10 mph in top speed.

If you leave the standard transmission and differential stock gears in
place, it becomes more worst then this.  I am running a modified
transmission and differential that's gives me a starting 19.5:1 gear ratio
and reduces to 5.57:1 in final drive.  This is more then double then the
standard gearing.

Roland






----- Original Message -----
From: "Mike Chancey" <[hidden email]>
To: <[hidden email]>
Sent: Sunday, October 07, 2007 6:25 AM
Subject: [EVDL] Battery Trailer

> Hi folks,
>
> Has anyone worked out the math involved with battery
> trailers?  Basically, some idea of how much additional power is going
> to be required due to the added load?
>
> Thanks,
>
> Mike Chancey,
> '88 Civic EV
> Kansas City, Missouri
> EV Photo Album at: http://evalbum.com
> My Electric Car at: http://www.geocities.com/electric_honda
> Mid-America EAA chapter at: http://maeaa.org
> Join the EV List at: http://www.madkatz.com/ev/evlist.html
>
> In medio stat virtus - Virtue is in the moderate, not the extreme
> position. (Horace)
>
> _______________________________________________
> For subscription options, see
> http://lists.sjsu.edu/mailman/listinfo/ev
>

_______________________________________________
For subscription options, see
http://lists.sjsu.edu/mailman/listinfo/ev

[Morgan LaMoore]

Roland's calculations look good, except that I don't see any air drag
calculations.

For a big vehicle like a van or pickup, the trailer should be pulled
along inside the turbulence that's normally created on the vehicle, so
it probably wouldn't add that much to air drag. For a small,
aerodynamic vehicle, it would probably have a much larger effect.

That said, I don't think there's any numbers available that will let
you see what an arbitrary trailer will do to the aerodynamics of an
arbitrary vehicle. The best way to find out would be to hook up the
trailer and do a roll-down test.

-Morgan LaMoore

_______________________________________________
For subscription options, see
http://lists.sjsu.edu/mailman/listinfo/ev

[mperry]

> It takes 7 to 10 additional hp and will loss about 10 mph in top speed.
>
> Roland

Yes, but in the real world your mileage *will* vary. With 2 of my small
rigs, I found a slight increase in range.

_______________________________________________
For subscription options, see
http://lists.sjsu.edu/mailman/listinfo/ev

[mperry]

> That said, I don't think there's any numbers available that will let
> you see what an arbitrary trailer will do to the aerodynamics of an
> arbitrary vehicle. The best way to find out would be to hook up the
> trailer and do a roll-down test.
>
> -Morgan LaMoore

True... and then test it against the same rig w/ that same extra weight
thrown in.

In my case, I used a trailer because the vehicle was not adaptable to all
that extra weight. (It was a no-choice "option", the only choice being
whether to carry extra batts or not.)


_______________________________________________
For subscription options, see
http://lists.sjsu.edu/mailman/listinfo/ev

[David Nelson-5]

I know of someone who had a motor home. When they decided to tow a
small car with them their mileage increased about 2mpg. It had to do
with breaking up the turbulence behind the motor home and thus
decreasing drag. Maybe that is what happened with your two rigs.

On 10/8/07, [hidden email] <[hidden email]> wrote:

> > It takes 7 to 10 additional hp and will loss about 10 mph in top speed.
> >
> > Roland
>
> Yes, but in the real world your mileage *will* vary. With 2 of my small
> rigs, I found a slight increase in range.
>
> _______________________________________________
> For subscription options, see
> http://lists.sjsu.edu/mailman/listinfo/ev
>

--
David D. Nelson

http://www.austinev.org/evalbum/1328

_______________________________________________
For subscription options, see
http://lists.sjsu.edu/mailman/listinfo/ev

[Arak Leatham]

So what are the relative merits of this idea.
 
Have a tractor kind of vehicle with only supercaps and hub motors in all wheels. Then a side car or trailer with all the required batteries for your shorter trip. The trailer would all have these same hub motors. Let's say DC for ease of design for the controller.
 
Then you could exchange the trailer at home for a new pack or for the hybrid trailer if you take a longer trip.
 
Having so many hub motors means they can be lighter on each wheel. I would consider using a 3wheel car with inline seating for two. Then the trailer is a side car(s) kind of thing tied to the front and back and not extending the vehicle length any.



Arak Leatham - Web and Desktop Systems Developer




_________________________________________________________________
Boo! Scare away worms, viruses and so much more! Try Windows Live OneCare!
http://onecare.live.com/standard/en-us/purchase/trial.aspx?s_cid=wl_hotmailnews
_______________________________________________
For subscription options, see
http://lists.sjsu.edu/mailman/listinfo/ev

[Lee Hart]

From: Arak Leatham
> So what are the relative merits of this idea.
> Have a tractor kind of vehicle with only supercaps and hub motors
> in all wheels. Then a side car or trailer with all the required
> batteries for your shorter trip. The trailer would all have these
> same hub motors... Then you could exchange the trailer at home for
> a new pack or for the hybrid trailer if you take a longer trip.

It's an interesting idea. Like all innovative ideas, a lot depends on the details. Badly done, it's a failure. Well done, it could be great!

Here's an example of a somewhat similar approach.
http://www.geocities.com/conceptcarcentralusa/keslingyare

The Yare was basically a 3-wheeler, with one front and two rear wheels. It was an ultra-light, ultra-streamlined teadrop. But it also had a trailer which contained the power plant (which could be a gasoline engine or electric drive). The trailer was completely contained inside the vehicle, so it had no effect aerodynamics; sort of like cutting out the floor of a conventional car and fitting a trailer inside the hole!

I saw the prototype in 1978. As I recall, the electric trailer connected to the car with two trailer hitches, and had two closely spaced wheels, which steered with the one front wheel with a mechanical linkage. This way he could back up with no problems.

--
"Excellence does not require perfection." -- Henry James
--
Lee A. Hart, 814 8th Ave N, Sartell MN 56377, leeahart-at-earthlink.net

_______________________________________________
For subscription options, see
http://lists.sjsu.edu/mailman/listinfo/ev

[mperry]

That's one I hadn't heard before... but makes sense.

No, mine was because I pulled the power off the rig and put it onto a
trailer. The one was a bike.

I never figured out why it happened. I only put the batts in the trailer
because it was more convenient than having the bike fall over all the time.
<g> It *could* have been that I used bigger wiring, or maybe I had a bad
connection when they were on the bike... or maybe because the trailer was in
the air some times? <g> (It had a suspension and would bounce around pretty
good on the bike trails.)
----- Original Message -----
From: "David Nelson" <[hidden email]>
To: "Electric Vehicle Discussion List" <[hidden email]>
Sent: Monday, October 08, 2007 7:13 PM
Subject: Re: [EVDL] Battery Trailer


> I know of someone who had a motor home. When they decided to tow a
> small car with them their mileage increased about 2mpg. It had to do
> with breaking up the turbulence behind the motor home and thus
> decreasing drag. Maybe that is what happened with your two rigs.

_______________________________________________
For subscription options, see
http://lists.sjsu.edu/mailman/listinfo/ev

[Mike Willmon]

I built a tapered tonnoeu cover for my Ranger a while back it it gave me a +2 mpg increase onto the 20mpg mileage.  I wonder if
you built a trailer that picked up the lines on the back of the truck and continued to slope down to complete the wedge what taht
would do to mileage.  You'll take a hit with the extra rolling resistance but I suppose you would more than make up for it at
higher speeds.

Mike W.

> -----Original Message-----
> From: [hidden email] [mailto:[hidden email]]On
> Behalf Of David Nelson
> Sent: Monday, October 08, 2007 6:14 PM
> To: Electric Vehicle Discussion List
> Subject: Re: [EVDL] Battery Trailer
>
>
> I know of someone who had a motor home. When they decided to tow a
> small car with them their mileage increased about 2mpg. It had to do
> with breaking up the turbulence behind the motor home and thus
> decreasing drag. Maybe that is what happened with your two rigs.

_______________________________________________
For subscription options, see
http://lists.sjsu.edu/mailman/listinfo/ev

[Darin at- forkenswift.com]

MIKE WILLMON wrote:

I wonder if you built a trailer that picked up the lines on the back of the truck and continued to slope down to complete the wedge what taht
would do to mileage.

Food for thought:

DIY aero-modder extraordinaire Phil Knox made an aero trailer to pull behind his CRX (ICE), and claimed the car's fuel consumption was unaffected when towing it at highway speeds, despite the added weight & rolling resistance.

He boat-tailed the trailer carefully enough to improve the overall Cd of the CRX+trailer package vs. the CRX on its own. I guess the aero improvement more or less equalled the weight+RR penalties.

photo: http://metrompg.com/offsite/crx-trailer.jpg

Darin

[Arak Leatham]

Cross Post From [ElectricVehicles] Sorry if this is old news.
>>>From Travis
 
Here's a very interesting article putting 5 different LiFePo batteriesagainst eachother in charge and discharge tests. Good data, lots ofgraphs, cost effectiveness, cost per Ah, cost per cell..... etc. Goodread.
http://zeva.com.au/tech/LiFePO4.php
Found on Hackaday.com
regards,Travis Gintz1986 Honda VFR AC conversionHttp://blog.evfr.net>>>



Arak Leatham - Web and Desktop Systems Developer
_________________________________________________________________
Climb to the top of the charts!  Play Star Shuffle:  the word scramble challenge with star power.
http://club.live.com/star_shuffle.aspx?icid=starshuffle_wlmailtextlink_oct
_______________________________________________
For subscription options, see
http://lists.sjsu.edu/mailman/listinfo/ev

[Arak Leatham]

Cross Post From [ElectricVehicles] Sorry if this is old news.
>>>From Travis
 
Here's a very interesting article putting 5 different LiFePo batteriesagainst eachother in charge and discharge tests. Good data, lots ofgraphs, cost effectiveness, cost per Ah, cost per cell..... etc. Goodread.
http://zeva.com.au/tech/LiFePO4.php
Found on Hackaday.com
regards,Travis Gintz1986 Honda VFR AC conversionHttp://blog.evfr.net>>>



Arak Leatham - Web and Desktop Systems Developer
_________________________________________________________________
Boo! Scare away worms, viruses and so much more! Try Windows Live OneCare!
http://onecare.live.com/standard/en-us/purchase/trial.aspx?s_cid=wl_hotmailnews
_______________________________________________
For subscription options, see
http://lists.sjsu.edu/mailman/listinfo/ev

[Dan Frederiksen-2]

it was posted here a few days ago and Ian (zeva) is a member of this
list : )

Arak Leatham wrote:

>Here's a very interesting article putting 5 different LiFePo batteriesagainst eachother in charge and discharge tests. Good data, lots ofgraphs, cost effectiveness, cost per Ah, cost per cell..... etc. Goodread.
>http://zeva.com.au/tech/LiFePO4.php
>Found on Hackaday.com
>regards,Travis Gintz1986 Honda VFR AC conversionHttp://blog.evfr.net>>>
>  
>

_______________________________________________
For subscription options, see
http://lists.sjsu.edu/mailman/listinfo/ev

[tgintz]

I thought it was a good read anyway :)

Some guy on another list (Doug Korthof, Electric vehicles for sale)
thought the data was innacurate, and when I asked him to point out
"WHY" he didn't respond. I'm still curious why he thought the data was
full of error. I'm not saying its 100% dead nuts on, but its very
close. I worked at GE testing tons of stuff (power supplies, IGBT's,
controllers) and It looked like it was set up pretty well.

On 10/12/07, Dan Frederiksen <[hidden email]> wrote:

> it was posted here a few days ago and Ian (zeva) is a member of this
> list : )
>
> Arak Leatham wrote:
>
> >Here's a very interesting article putting 5 different LiFePo batteriesagainst eachother in charge and discharge tests. Good data, lots ofgraphs, cost effectiveness, cost per Ah, cost per cell..... etc. Goodread.
> >http://zeva.com.au/tech/LiFePO4.php
> >Found on Hackaday.com
> >regards,Travis Gintz1986 Honda VFR AC conversionHttp://blog.evfr.net>>>
> >
> >
>
> _______________________________________________
> For subscription options, see
> http://lists.sjsu.edu/mailman/listinfo/ev
>

--

regards,
Travis Gintz
1986 Honda VFR AC conversion
Http://blog.evfr.net/

_______________________________________________
For subscription options, see
http://lists.sjsu.edu/mailman/listinfo/ev

[Ian Hooper-2]

The page has been accessed almost 4000 times now - makes it all  
worthwhile :)

My test rig was a little "grass roots" I admit :) but hopefully  
people will realise this and won't take the results for gospel. I  
like to think that at the very least testing a variety of cells on  
the same rig gives useful qualitative/comparative results.

-Ian

On 13/10/2007, at 12:53 AM, Travis Gintz wrote:

> I thought it was a good read anyway :)
>
> Some guy on another list (Doug Korthof, Electric vehicles for sale)
> thought the data was innacurate, and when I asked him to point out
> "WHY" he didn't respond. I'm still curious why he thought the data was
> full of error. I'm not saying its 100% dead nuts on, but its very
> close. I worked at GE testing tons of stuff (power supplies, IGBT's,
> controllers) and It looked like it was set up pretty well.
>
> On 10/12/07, Dan Frederiksen <[hidden email]> wrote:
>> it was posted here a few days ago and Ian (zeva) is a member of this
>> list : )
>>
>> Arak Leatham wrote:
>>
>>> Here's a very interesting article putting 5 different LiFePo  
>>> batteriesagainst eachother in charge and discharge tests. Good  
>>> data, lots ofgraphs, cost effectiveness, cost per Ah, cost per  
>>> cell..... etc. Goodread.
>>> http://zeva.com.au/tech/LiFePO4.php
>>> Found on Hackaday.com
>>> regards,Travis Gintz1986 Honda VFR AC conversionHttp://
>>> blog.evfr.net>>>
>>>
>>>
>>
>> _______________________________________________
>> For subscription options, see
>> http://lists.sjsu.edu/mailman/listinfo/ev
>>
>
>
> --
>
> regards,
> Travis Gintz
> 1986 Honda VFR AC conversion
> Http://blog.evfr.net/
>
> _______________________________________________
> For subscription options, see
> http://lists.sjsu.edu/mailman/listinfo/ev
>

_______________________________________________
For subscription options, see
http://lists.sjsu.edu/mailman/listinfo/ev