# [EVDL] Lightweight Most Efficient Conversion



## EVDL List (Jul 27, 2007)

Hi Folk's,

I was thinking (it can happen) about taking my 10kwh worth of Thundersky batts ($5k 32ea 100ah) out of the E-Cat www.evalbum.com/2749 , selling my E-Porsche www.evalbum.com/1273 ,$7k and putting the 200lb battery pack LiFePO4 3.3V x 32 = 106V (wire in series instead of buddy pairs) into a 1700 lb Karman Ghia (maybe Honda Del-Sol if same weight), finish weight 1900lb. I have an E-Tek RT 72V PM motor, curious how that would do in an EV, maybe to small. But that would be a peppy lightweight conversion. Not sure if the LiFePO4 batteries will go less than 80% dod and the max current 200A have to check with Thundersky (or Dave Kois from evcomponents where I bought but I think they fizzled.) I figure at 330whr per mile (measured on the AC side) on my 2800lb Porsche 914 should be 1900/2800 x 330 = 224 whr per mile in a lighter Ghia-etc. So at 80% dod 80ah x 3.3V x 32 = 8448 whr / 224 = 37 miles range, maybe that's wishful thinking on a 200lb lightweight pack, I dunno but looks g!
ood on paper 

I finished putting in all the fusible links between the batteries, 4 sizes smaller (#12) than the main (#8) with hypalon fireproof insulation but normal copper wire inside (in E-Cat), 150A main breaker. I noticed that the wire lengths have to be "tuned" to the same length between the buddy pairs, the previous 60A buddy pair fuses were darkenned (probably getting ready to pop) on the shorter wires of non tuned buddy pairs. So this time I was careful to make the buddy pair wires the same length even if one terminal was closer to the next battery than the other. This current upgrade was for converting a Johnson 9.9hp 1gph sailmaster to electric with the Etek-RT motor but now I'm thinking of maybe going over to the "dark side" and just using it as gas since I'm hitting that little laws of physics thingy: hull speed mph = 1.5 x sqr-root of hull length (18') or 6.4mph so above 4hp it ramps up exponentially, need a 25hp to go twice as fast (my kid wants to go faster, kneeboard/s!
ki). Then I would free up the lithium stuff for a lightweight conversion, no more overweight lead sleds with 16-20 Trojans for me with poor braking/handling.

Have a renewable energy day,
mark
www.reevadiy.org community service RE & EV's
The 3 leg stool is solar,wind & EV's 
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## EVDL List (Jul 27, 2007)

Mark

One comment about the motor. Often people will try and put the
smallest motor in trying to save money. In your case, you are using
one you already have. But I think it's false economy to use a small
motor.

First, you are running the motor closer to it's limits and closer to
blowing it up. You have to do more for cooling, it will be critical.
You will also wear out brushes faster, not to mention shorter bearing
life. 5 years instead of 10, maybe not that big a deal. But I still
don't like planning on running a motor on or near it's limit.

Second, it's not necessarily going to be more efficient. In fact it
might be less efficient than a larger motor. A larger motor won't have
to work as hard, less heat, less wear and tear. This isn't like a
gasser. If you swap out a 4 cylinder for a big block V8, you'll have
plenty of power. But you'll never get anywhere near the fuel economy.
Ever. But a 9" motor can be just as efficient as a 6.7".

Third, a larger motor will do more if you need it. If you drive on
city streets all the time, you'll never need the extra power. But if
you have to drive on the highway, if you live in a hilly area, if you
want to drive with 4 passengers in a 4 passenger car, if you want to
have some fun (PODC) once in a while ....

And a larger motor isn't that much more weight relative to the car.
What's an 6.7" ADC, 75 lbs? A 9" ADC is 150. So you have a 75lb
penalty, less than 4% of the car. I think it's worth it.

Just my opinion. Worth everything you paid.

DAC

PS I'm jealous, you have much better toys than I do.


On Tue, Oct 19, 2010 at 8:44 AM, Mark Hanson <[email protected]> wro=
te:
>
> Hi Folk's,
>
> I was thinking (it can happen) about taking my 10kwh worth of Thundersky =
batts ($5k 32ea 100ah) out of the E-Cat www.evalbum.com/2749 , selling my E=
-Porsche www.evalbum.com/1273 ,$7k and putting the 200lb battery pack LiFeP=
O4 3.3V x 32 =3D 106V (wire in series instead of buddy pairs) into a 1700 l=
b Karman Ghia (maybe Honda Del-Sol if same weight), finish weight 1900lb. =
I have an E-Tek RT 72V PM motor, curious how that would do in an EV, may=
be to small. But that would be a peppy lightweight conversion. Not su=
re if the LiFePO4 batteries will go less than 80% dod and the max current 2=
00A have to check with Thundersky (or Dave Kois from evcomponents where I b=
ought but I think they fizzled.) I figure at 330whr per mile (measured o=
n the AC side) on my 2800lb Porsche 914 should be 1900/2800 x 330 =3D 224 w=
hr per mile in a lighter Ghia-etc. So at 80% dod 80ah x 3.3V x 32 =3D 8448 =
whr / 224 =3D 37 miles range, maybe that's wishful thinking on a 200lb ligh=
tweight pack, I dunno but looks g!
> ood on paper 
>
> I finished putting in all the fusible links between the batteries, 4 size=
s smaller (#12) than the main (#8) with hypalon fireproof insulation but no=
rmal copper wire inside (in E-Cat), 150A main breaker. I noticed that th=
e wire lengths have to be "tuned" to the same length between the buddy pair=
s, the previous 60A buddy pair fuses were darkenned (probably getting ready=
to pop) on the shorter wires of non tuned buddy pairs. So this time I w=
as careful to make the buddy pair wires the same length even if one termina=
l was closer to the next battery than the other. This current upgrade wa=
s for converting a Johnson 9.9hp 1gph sailmaster to electric with the Etek-=
RT motor but now I'm thinking of maybe going over to the "dark side" and ju=
st using it as gas since I'm hitting that little laws of physics thingy: hu=
ll speed mph =3D 1.5 x sqr-root of hull length (18') or 6.4mph so above 4hp=
it ramps up exponentially, need a 25hp to go twice as fast (my kid wants t=
o go faster, kneeboard/s!
> ki). Then I would free up the lithium stuff for a lightweight conve=
rsion, no more overweight lead sleds with 16-20 Trojans for me with poor br=
aking/handling.
>
> Have a renewable energy day,
> mark
> www.reevadiy.org community service RE & EV's
> The 3 leg stool is solar,wind & EV's
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>



-- =

http://www.evalbum.com/2149

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## EVDL List (Jul 27, 2007)

I think your idea of using a Ghia is great. I'm kinda biased here but my Ghia
with 16 flooded LA batteries and only 96 volts would giddy up to 85 mph
given a bit of time. Jumped up to 65 no problem. No speed demon but nice.
Now if you could give it 120 or so volts and a controller able to output 600
or more amps then I think you will be doing very well. The Ghia can hold
quite a few batteries. You may loose the back seat area but since you drive
a 914 who cares, right? They are light weight and agile and given that
LIFEPO batteries are considerably lighter it would be much more fun to
drive. No more lead sled. 

You might be hard pressed to get $7k for your 914 in this economy. Hope the
best for that. 

Pete 

http://greenev.zapto.org/electricvw
http://greenev.zapto.org/63ev

-----
If you don't understand, be patient, you will. Now I understand. 
-- 
View this message in context: http://electric-vehicle-discussion-list.413529.n4.nabble.com/Lightweight-Most-Efficient-Conversion-tp3002052p3002188.html
Sent from the Electric Vehicle Discussion List mailing list archive at Nabble.com.

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## EVDL List (Jul 27, 2007)

> gottdi wrote:
> 
> >
> > I think your idea of using a Ghia is great. I'm kinda biased here
> ...


----------



## EVDL List (Jul 27, 2007)

> Mark Hanson wrote:
> > thinking about...
> > selling my E-Porsche www.evalbum.com/1273, $7k
> 
> ...


----------



## EVDL List (Jul 27, 2007)

> On 19 Oct 2010 at 8:44, Mark Hanson wrote:
> 
> > I figure at 330whr per mile (measured on the AC side) on my 2800lb
> > Porsche 914 should be 1900/2800 x 330 = 224 whr per mile in a lighter
> ...


----------



## EVDL List (Jul 27, 2007)

Rolling resistance is directly proportional to weight -- double the weight 
double the drag. The nonlinear terms are very small and safely neglected. This 
translates directly for low speeds, so for a city speeds a lighter car is 
definitely better, and the Whr/mi will directly scale. At highway speeds about 
1/2 your drag is air resistance, in that case weight is less of an effect.


For Mark at low speeds it will drop from 330 whr / mi to 224 whr / mi, but at 
highway speeds the drop might be just something like 330 to 280 Whr/mi (or 
better or worse depending on speed). Of course this assume tires with the same 
rolling resistance, equally well aligned suspensions, etc.



________________________________
From: EVDL Administrator <[email protected]>
To: Electric Vehicle Discussion List <[email protected]>
Sent: Tue, October 19, 2010 11:12:54 AM
Subject: Re: [EVDL] Lightweight Most Efficient Conversion



> On 19 Oct 2010 at 8:44, Mark Hanson wrote:
> 
> > I figure at 330whr per mile (measured on the AC side) on my 2800lb
> > Porsche 914 should be 1900/2800 x 330 = 224 whr per mile in a lighter
> ...


----------



## EVDL List (Jul 27, 2007)

Eh, not entirely.

The *tire* drag may be somewhat related to weight
but (especially at higher speeds) the aero drag
is completely unrelated except where weight
translates into a bigger car (more frontal area)
or worse Cd or the ride height changes and this
affects aero drag, but other than those secondary
effect, higher weight will have only two immediate effects:
- increase tire rolling resistance (larger deflection)
- increase kinetic energy (more mass to accelerate)
so acceleration will be slower and/or consume more
energy to achieve the same speed.
With regen braking you can roughly re-capture half
the kinetic energy back into the battery pack, to 
be re-used for your next acceleration....
In case no re-gen is present, all kinetic energy will
be lost at your next stop, so this also turns a higher
weight into higher losses.

Hope this clarifies,

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 David Dymaxion
Sent: Tuesday, October 19, 2010 11:26 PM
To: Electric Vehicle Discussion List
Subject: Re: [EVDL] Lightweight Most Efficient Conversion

Rolling resistance is directly proportional to weight -- double the
weight double the drag. The nonlinear terms are very small and safely
neglected. This translates directly for low speeds, so for a city speeds
a lighter car is definitely better, and the Whr/mi will directly scale.
At highway speeds about
1/2 your drag is air resistance, in that case weight is less of an
effect.


For Mark at low speeds it will drop from 330 whr / mi to 224 whr / mi,
but at highway speeds the drop might be just something like 330 to 280
Whr/mi (or better or worse depending on speed). Of course this assume
tires with the same rolling resistance, equally well aligned
suspensions, etc.



________________________________
From: EVDL Administrator <[email protected]>
To: Electric Vehicle Discussion List <[email protected]>
Sent: Tue, October 19, 2010 11:12:54 AM
Subject: Re: [EVDL] Lightweight Most Efficient Conversion



> On 19 Oct 2010 at 8:44, Mark Hanson wrote:
> 
> > I figure at 330whr per mile (measured on the AC side) on my 2800lb
> > Porsche 914 should be 1900/2800 x 330 = 224 whr per mile in a lighter
> ...


----------



## EVDL List (Jul 27, 2007)

Oops,
Should not be answering email after midnight.
I missed where you specifically said Rolling resistance.
Note however that it may have a non-linear relation...
(So, twice the weight is not exactly twice the drag...)

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: Cor van de Water 
Sent: Wednesday, October 20, 2010 12:10 AM
To: 'Electric Vehicle Discussion List'
Subject: RE: [EVDL] Lightweight Most Efficient Conversion

Eh, not entirely.

The *tire* drag may be somewhat related to weight but (especially at
higher speeds) the aero drag is completely unrelated except where weight
translates into a bigger car (more frontal area) or worse Cd or the ride
height changes and this affects aero drag, but other than those
secondary effect, higher weight will have only two immediate effects:
- increase tire rolling resistance (larger deflection)
- increase kinetic energy (more mass to accelerate)
so acceleration will be slower and/or consume more
energy to achieve the same speed.
With regen braking you can roughly re-capture half the kinetic energy
back into the battery pack, to be re-used for your next acceleration....
In case no re-gen is present, all kinetic energy will be lost at your
next stop, so this also turns a higher weight into higher losses.

Hope this clarifies,

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 David Dymaxion
Sent: Tuesday, October 19, 2010 11:26 PM
To: Electric Vehicle Discussion List
Subject: Re: [EVDL] Lightweight Most Efficient Conversion

Rolling resistance is directly proportional to weight -- double the
weight double the drag. The nonlinear terms are very small and safely
neglected. This translates directly for low speeds, so for a city speeds
a lighter car is definitely better, and the Whr/mi will directly scale.
At highway speeds about
1/2 your drag is air resistance, in that case weight is less of an
effect.


For Mark at low speeds it will drop from 330 whr / mi to 224 whr / mi,
but at highway speeds the drop might be just something like 330 to 280
Whr/mi (or better or worse depending on speed). Of course this assume
tires with the same rolling resistance, equally well aligned
suspensions, etc.



________________________________
From: EVDL Administrator <[email protected]>
To: Electric Vehicle Discussion List <[email protected]>
Sent: Tue, October 19, 2010 11:12:54 AM
Subject: Re: [EVDL] Lightweight Most Efficient Conversion



> On 19 Oct 2010 at 8:44, Mark Hanson wrote:
> 
> > I figure at 330whr per mile (measured on the AC side) on my 2800lb
> > Porsche 914 should be 1900/2800 x 330 = 224 whr per mile in a lighter
> ...


----------



## EVDL List (Jul 27, 2007)

Hi Lee, Mark and All,

It's the low cost of gas plus the bad
economy that has dropped EV prices, sales for conversions. 
Hang on to them until late next yr when gas prices hit
$4.50-5/gal then they will just like last time gas prices
rose, start selling well for much better prices.

On Mark's idea, the Ghia is an
excellent glider as John Bryan's got 100wthrs/mile on his
after some serious drag reduction. As the lithium's weigh
less it should help that. It's fairly aero and low frontal
area. Add low drag tranny fluid like Redline, LRR tires,
etc and should work well.

On the Etek I wouldn't do that as they
don't handle high power well or starting torque
requirements. On my E Woody at 1000 lbs I replaced my GE
Citi-car motor with an Etek and the etek burned out trying
to start up a slight hill/driveway. I put the GE back in and
no problem even though it was 3.5hp vs the etek's 9hp
rating.

For Mark in more hilly areas I'd go with
a D+D Sep-Ex motor, controller in their largest size,
12-16hp depending on batt voltage. Their prices are very
reasonable and having a sale at the moment on 6.7" motors,
controllers they sell, same motor in series as the
Killacycle uses.

Jerry Dycus.

----- Original Message Follows -----
From: Lee Hart <[email protected]>
To: Electric Vehicle Discussion List <[email protected]>
Subject: Re: [EVDL] Lightweight Most Efficient Conversion
Date: Tue, 19 Oct 2010 11:53:48 -0500



> >Mark Hanson wrote:
> >> thinking about...
> >> selling my E-Porsche www.evalbum.com/1273, $7k
> >
> ...


----------



## EVDL List (Jul 27, 2007)

Hi folks,



> > On 19 Oct 2010 at 8:44, Mark Hanson wrote:
> >
> >> I figure at 330whr per mile (measured on the AC side) on my 2800lb
> >> Porsche 914 should be 1900/2800 x 330 = 224 whr per mile in a lighter
> ...


----------



## EVDL List (Jul 27, 2007)

Aerodynamic drag is a subset of overall drag. I meant that tire drag = rolling 
resistance. Rolling resistance is a form of drag (as would be brake drag from 
dragging brakes).


Side note, even though I wasn't talking about it before, tires do also exhibit 
aerodynamic drag. I met a guy on the Salt Flats that could go 130 mph with 
aerodynamic skinnies. He switched back to his twice as wide autocross tires and 
went 120 mph, 10 mph slower. Tire aerodynamic drag is a big effect at those 
speeds, but not much of an effect at typical commute speeds. Tire drag due to 
rolling resistance, however, is a big effect and directly proportional to 
weight.



________________________________
From: Cor van de Water <[email protected]>
To: Electric Vehicle Discussion List <[email protected]>
Sent: Tue, October 19, 2010 12:40:14 PM
Subject: Re: [EVDL] Lightweight Most Efficient Conversion

Eh, not entirely.

The *tire* drag may be somewhat related to weight
but (especially at higher speeds) the aero drag
is completely unrelated except where weight
translates into a bigger car (more frontal area)
or worse Cd or the ride height changes and this
affects aero drag, but other than those secondary
effect, higher weight will have only two immediate effects:
- increase tire rolling resistance (larger deflection)
- increase kinetic energy (more mass to accelerate)
so acceleration will be slower and/or consume more
energy to achieve the same speed.
With regen braking you can roughly re-capture half
the kinetic energy back into the battery pack, to 
be re-used for your next acceleration....
In case no re-gen is present, all kinetic energy will
be lost at your next stop, so this also turns a higher
weight into higher losses.

Hope this clarifies,

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 David Dymaxion
Sent: Tuesday, October 19, 2010 11:26 PM
To: Electric Vehicle Discussion List
Subject: Re: [EVDL] Lightweight Most Efficient Conversion

Rolling resistance is directly proportional to weight -- double the
weight double the drag. The nonlinear terms are very small and safely
neglected. This translates directly for low speeds, so for a city speeds
a lighter car is definitely better, and the Whr/mi will directly scale.
At highway speeds about
1/2 your drag is air resistance, in that case weight is less of an
effect.


For Mark at low speeds it will drop from 330 whr / mi to 224 whr / mi,
but at highway speeds the drop might be just something like 330 to 280
Whr/mi (or better or worse depending on speed). Of course this assume
tires with the same rolling resistance, equally well aligned
suspensions, etc.



________________________________
From: EVDL Administrator <[email protected]>
To: Electric Vehicle Discussion List <[email protected]>
Sent: Tue, October 19, 2010 11:12:54 AM
Subject: Re: [EVDL] Lightweight Most Efficient Conversion



> On 19 Oct 2010 at 8:44, Mark Hanson wrote:
> 
> > I figure at 330whr per mile (measured on the AC side) on my 2800lb
> > Porsche 914 should be 1900/2800 x 330 = 224 whr per mile in a lighter
> ...


----------



## EVDL List (Jul 27, 2007)

Steven Ciciora suggested:
> If you have some pulse train that is proportional to velocity

Ha! finally a good reason to hack into your ABS sensor(s) besides
detecting low tire pressure from difference in circumference, now
you can also use it to measure your drag!

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

_______________________________________________
| REPLYING: address your message to [email protected] only.
| Multiple-address or CCed messages may be rejected.
| UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub
| OTHER HELP: http://evdl.org/help/
| OPTIONS: http://lists.sjsu.edu/mailman/listinfo/ev


----------



## EVDL List (Jul 27, 2007)

PS



> I wrote:
> 
> > It will be interesting to see how the Edison2 Very Light Car electric version will do. Oliver Kuttner has mentioned he hopes it to weight 1,300 pounds (or less) and have a 12-16kWh lithium pack. If any car can get >100Wh/mile, the VLCe will. (I'm hoping my CarBEN EV will, too!)
> >
> ...


----------



## EVDL List (Jul 27, 2007)

Hi Mark,

I actually have a 1993 Honda del Sol that was converted with an ADC 9"
motor, Kelly KDHD controller, 14 KWh of Thundersky cells (45 100Ah cells).
If you want to chat to compare notes, let me know!

The bad news is that the del Sol is quite a bit heavier than you could have
imagined. Most web sources put its stock curb weight around 2300 pounds.
It also isn't very aerodynamic. The blunt back of the cab makes a really
cool convertible with a roll-bar feel, but it also causes quite a bit of
drag. My Mazda 626 has a lower Cd than the del Sol.

However, the good news is that I'm getting around 225-250 Wh/mile from it.
(Mix of driving with 60 mph highway and stop&go city on a 25 mile one-way
commute.) I actually think I should do better because the del Sol isn't
coasting very well right now. I've noticed the wheels are hard to turn by
hand, so I'm going to check the bearings. The del Sol coasts down much
faster than my 626 out of gear. I don't think the aerodynamics account for
all of that.

With some issues in my battery pack with balance, I achieved 50 miles range.
I think 60 miles is the top end of range with my setup. Performance isn't
great, but it's almost impressive. I don't think anybody on the road knows
it's electric from the performance. The controller isn't high performance
(pretty much wimps out after 200A for any period of time, but that's about
all the batteries would like to provide anyway.)

I didn't do the original conversion, but I'm fairly familiar with it and I'm
still in contact with the original owner. The trunk can fit 20 cells and
still have room to mount the removable hard top roof. You still have about
1/2 the trunk space too.

If you want to see pictures, the original converter had a blog page with
good details. It is http://mt-ev.blogspot.com
The car is also in evalbum at: http://www.evalbum.com/2778

Mike

-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf
Of Mark Hanson
Sent: Tuesday, October 19, 2010 6:45 AM
To: [email protected]
Subject: [EVDL] Lightweight Most Efficient Conversion


Hi Folk's,

I was thinking (it can happen) about taking my 10kwh worth of Thundersky
batts ($5k 32ea 100ah) out of the E-Cat www.evalbum.com/2749 , selling my
E-Porsche www.evalbum.com/1273 ,$7k and putting the 200lb battery pack
LiFePO4 3.3V x 32 = 106V (wire in series instead of buddy pairs) into a 1700
lb Karman Ghia (maybe Honda Del-Sol if same weight), finish weight 1900lb.
I have an E-Tek RT 72V PM motor, curious how that would do in an EV, maybe
to small. But that would be a peppy lightweight conversion. Not sure if
the LiFePO4 batteries will go less than 80% dod and the max current 200A
have to check with Thundersky (or Dave Kois from evcomponents where I bought
but I think they fizzled.) I figure at 330whr per mile (measured on the AC
side) on my 2800lb Porsche 914 should be 1900/2800 x 330 = 224 whr per mile
in a lighter Ghia-etc. So at 80% dod 80ah x 3.3V x 32 = 8448 whr / 224 = 37
miles range, maybe that's wishful thinking on a 200lb lightweight pack, I
dunno but looks g!
ood on paper 

I finished putting in all the fusible links between the batteries, 4 sizes
smaller (#12) than the main (#8) with hypalon fireproof insulation but
normal copper wire inside (in E-Cat), 150A main breaker. I noticed that the
wire lengths have to be "tuned" to the same length between the buddy pairs,
the previous 60A buddy pair fuses were darkenned (probably getting ready to
pop) on the shorter wires of non tuned buddy pairs. So this time I was
careful to make the buddy pair wires the same length even if one terminal
was closer to the next battery than the other. This current upgrade was for
converting a Johnson 9.9hp 1gph sailmaster to electric with the Etek-RT
motor but now I'm thinking of maybe going over to the "dark side" and just
using it as gas since I'm hitting that little laws of physics thingy: hull
speed mph = 1.5 x sqr-root of hull length (18') or 6.4mph so above 4hp it
ramps up exponentially, need a 25hp to go twice as fast (my kid wants to go
faster, kneeboard/s!
ki). Then I would free up the lithium stuff for a lightweight conversion,
no more overweight lead sleds with 16-20 Trojans for me with poor
braking/handling.

Have a renewable energy day,
mark
www.reevadiy.org community service RE & EV's
The 3 leg stool is solar,wind & EV's 
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## EVDL List (Jul 27, 2007)

Mike,
That sounds like some serious drag, probably by the brakes.
What I am used to is not whether you can turn a wheel by hand
but how many turns will it complete after you stop pushing
the wheel around....
If it stops (almost) instantly no matter how hard you turn it,
then you need to look at brake drag (pry something between the
brake shoes and move them away from the disk, or with drum
brakes, make sure the shoes move freely and do not jam against
the drum for some reason. Indeed the other reason may be the
bearing, but you can have pretty bad bearings and still drive
fine (with only a little extra noise).

The driven wheels can have additional drag from the gearbox
(thick/cold oil) and since an EV barely has time to warm up
the oil in the gearbox, it makes sense to put lighter weight
oil in there to reduce drag.

I presume you do this test when in Neutral, so we do not have 
to account for the drivetrain upstream of the gearbox.

In pickup trucks and vans an additional loss source is the 
differential in the rear axle - also there it makes sense to
use a lighter oil.

Success,

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 Mike Nickerson
Sent: Wednesday, October 20, 2010 10:40 AM
To: 'Electric Vehicle Discussion List'
Subject: Re: [EVDL] Lightweight Most Efficient Conversion

Hi Mark,

I actually have a 1993 Honda del Sol that was converted with an ADC 9"
motor, Kelly KDHD controller, 14 KWh of Thundersky cells (45 100Ah
cells).
If you want to chat to compare notes, let me know!

The bad news is that the del Sol is quite a bit heavier than you could
have imagined. Most web sources put its stock curb weight around 2300
pounds.
It also isn't very aerodynamic. The blunt back of the cab makes a
really cool convertible with a roll-bar feel, but it also causes quite a
bit of drag. My Mazda 626 has a lower Cd than the del Sol.

However, the good news is that I'm getting around 225-250 Wh/mile from
it.
(Mix of driving with 60 mph highway and stop&go city on a 25 mile
one-way
commute.) I actually think I should do better because the del Sol isn't
coasting very well right now. I've noticed the wheels are hard to turn
by hand, so I'm going to check the bearings. The del Sol coasts down
much faster than my 626 out of gear. I don't think the aerodynamics
account for all of that.

With some issues in my battery pack with balance, I achieved 50 miles
range.
I think 60 miles is the top end of range with my setup. Performance
isn't great, but it's almost impressive. I don't think anybody on the
road knows it's electric from the performance. The controller isn't
high performance (pretty much wimps out after 200A for any period of
time, but that's about all the batteries would like to provide anyway.)

I didn't do the original conversion, but I'm fairly familiar with it and
I'm still in contact with the original owner. The trunk can fit 20
cells and still have room to mount the removable hard top roof. You
still have about
1/2 the trunk space too.

If you want to see pictures, the original converter had a blog page with
good details. It is http://mt-ev.blogspot.com The car is also in
evalbum at: http://www.evalbum.com/2778

Mike

-----Original Message-----
From: [email protected] [mailto:[email protected]] On
Behalf Of Mark Hanson
Sent: Tuesday, October 19, 2010 6:45 AM
To: [email protected]
Subject: [EVDL] Lightweight Most Efficient Conversion


Hi Folk's,

I was thinking (it can happen) about taking my 10kwh worth of Thundersky
batts ($5k 32ea 100ah) out of the E-Cat www.evalbum.com/2749 , selling
my E-Porsche www.evalbum.com/1273 ,$7k and putting the 200lb battery
pack
LiFePO4 3.3V x 32 = 106V (wire in series instead of buddy pairs) into a
1700 lb Karman Ghia (maybe Honda Del-Sol if same weight), finish weight
1900lb.
I have an E-Tek RT 72V PM motor, curious how that would do in an EV,
maybe to small. But that would be a peppy lightweight conversion. Not
sure if the LiFePO4 batteries will go less than 80% dod and the max
current 200A have to check with Thundersky (or Dave Kois from
evcomponents where I bought but I think they fizzled.) I figure at
330whr per mile (measured on the AC
side) on my 2800lb Porsche 914 should be 1900/2800 x 330 = 224 whr per
mile in a lighter Ghia-etc. So at 80% dod 80ah x 3.3V x 32 = 8448 whr /
224 = 37 miles range, maybe that's wishful thinking on a 200lb
lightweight pack, I dunno but looks g!
ood on paper 

I finished putting in all the fusible links between the batteries, 4
sizes smaller (#12) than the main (#8) with hypalon fireproof insulation
but normal copper wire inside (in E-Cat), 150A main breaker. I noticed
that the wire lengths have to be "tuned" to the same length between the
buddy pairs, the previous 60A buddy pair fuses were darkenned (probably
getting ready to
pop) on the shorter wires of non tuned buddy pairs. So this time I was
careful to make the buddy pair wires the same length even if one
terminal was closer to the next battery than the other. This current
upgrade was for converting a Johnson 9.9hp 1gph sailmaster to electric
with the Etek-RT motor but now I'm thinking of maybe going over to the
"dark side" and just using it as gas since I'm hitting that little laws
of physics thingy: hull speed mph = 1.5 x sqr-root of hull length (18')
or 6.4mph so above 4hp it ramps up exponentially, need a 25hp to go
twice as fast (my kid wants to go faster, kneeboard/s!
ki). Then I would free up the lithium stuff for a lightweight
conversion, no more overweight lead sleds with 16-20 Trojans for me with
poor braking/handling.

Have a renewable energy day,
mark
www.reevadiy.org community service RE & EV's
The 3 leg stool is solar,wind & EV's

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## EVDL List (Jul 27, 2007)

I'm not sure that weight is a secondary factor. Not much driving is done at
constant speed on level ground. Here in Nova Scotia, there is little level
roadway, steady state throttle is nearly impossible. Acceleration takes
place frequently so weight is important.

When I raced stock outboard boats, one of the national champions tested
every variable. He added weight past the minimum just to see. He claimed an
extra 15 lbs. cost an mph. This may be due to constant acceleration from one
corner to the next, but in a limited performance envelope ( 15 cu in, 60mph
) I think a boat peaks part way down the straight and is steady state until
the next turn.

I'm importing a Suzuki Carry ( street legal in Canada) to convert. It has
reasonably low frontal area but I can't find the cx. The thing that
attracted me was the 1500 lb. weight. That means 1200 before adding motor,
controller, wire and batteries. I'm shooting for 1900lb done. You 'need
lots of rpms for the 6:20 diff so I bought an aircraft generator. I plan to
start with a 45 mph local driver at 48 volts and see if I need to go higher.
98 volts ( maybe 2 packs) is optimal to integrate with the battery bank for
my wind turbine. The truck should serve as an extra emergency power source.
120 volts of solar panels going on the roof next spring should give me a
free drive to the beer store once a week.

About the boat. Am I remembering correctly ; a 16x16 prop. This seems pretty
big to me. A smaller prop may produce better performance. An A Stock Hydro
with a 15hp engine, 330lb and 7200 rpm would run 63mph in competition with
good acceleration using a 6X9 prop.

John McManus






> Cor van de Water <[email protected]> wrote:
> 
> > Mike,
> > That sounds like some serious drag, probably by the brakes.
> ...


----------



## EVDL List (Jul 27, 2007)

You can take the TS cells to more than 80% DoD, but only if you are willing
to significantly reduce their cycle life. Staying above 20% SOC is
recommended, and above 30% gives longer life according to the manufacturer's
spec. I have a Suzuki Swift, curb weight about 1990 lb, finished ev weight
about 2250 lb with 36 180Ah CALB cells. Drag coeff. 0.32, area ~18 square
ft area. HPEVS AC50 motor with regen. I get about 190 to 215 Wh/mile in
mixed highway (60 mph)/secondary road (35-40 mph) driving. At the low end
in summer, high end in winter (with heater). For example, a few days ago I
drove 58 miles, about half on highways at 55 -65 mph, and half at 35 - 45
mph, and used 204.8 Wh/mile from the wall (measured with EKM meter at AC
input to the charger). Assuming around 94% charger efficiency (Manzanita
PFC30), that would be around 193 Wh/mile. I think the Del Sol is heavier
than you think, and it also has a higher drag coeff due to turbulence at
that abrupt rear window. Dave has his own company now, currentev.
-- 
View this message in context: http://electric-vehicle-discussion-list.413529.n4.nabble.com/Lightweight-Most-Efficient-Conversion-tp3002052p3003881.html
Sent from the Electric Vehicle Discussion List mailing list archive at Nabble.com.

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## EVDL List (Jul 27, 2007)

> John McManus wrote:
> > I'm not sure that weight is a secondary factor. Not much driving is done at
> > constant speed on level ground. Here in Nova Scotia, there is little level
> > roadway, steady state throttle is nearly impossible. Acceleration takes
> ...


----------



## EVDL List (Jul 27, 2007)

Willie:
I use a lot of throttle ( gas engine) to climb a hill and then , if
coasting with no throttle - sometimes out of gear-) lose speed all the way
down due to aero and mechanical drive. Wouldn't regeneration slow the
vehicle further needing ever more energy to climb the next hill.



> Willie McKemie <[email protected]> wrote:
> 
> > On Wed, Oct 20, 2010 at 10:42:12AM -0300, John McManus wrote:
> > > I'm not sure that weight is a secondary factor. Not much driving is done
> ...


----------



## EVDL List (Jul 27, 2007)

> John McManus wrote:
> > Willie:
> > I use a lot of throttle ( gas engine) to climb a hill and then , if
> > coasting with no throttle - sometimes out of gear-) lose speed all the way
> ...


----------



## EVDL List (Jul 27, 2007)

Depends on how steep the hill is, and how much loss is in the aerodynamics
and other losses and what the relative weight of the vehicle is to overcome
them whether you still need to touch the throttle a little while coming down
the hill, or whether you need to tap the brakes a little.



> John McManus <[email protected]> wrote:
> 
> > Willie:
> > I use a lot of throttle ( gas engine) to climb a hill and then , if
> ...


----------



## EVDL List (Jul 27, 2007)

The fact of the matter is, it's hard not to use friction brakes, at least in
the city. If you coast gently up to a stop sign, you will annoy drivers
behind you. If you see a green light ahead that turns red, you have a
choice to use friction brakes or brake the law. If you travel down a steep
hill, you may exceed the speed limit without using brakes. Etc.

On the other hand, if you're concerned about driving a rural, hilly road at
speeds around 50mph, then I agree with others: the weight probably doesn't
matter so much. 

Peri

-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf
Of Zeke Yewdall
Sent: 20 October, 2010 9:46 AM
To: Electric Vehicle Discussion List
Subject: Re: [EVDL] Lightweight Most Efficient Conversion

Depends on how steep the hill is, and how much loss is in the aerodynamics
and other losses and what the relative weight of the vehicle is to overcome
them whether you still need to touch the throttle a little while coming down
the hill, or whether you need to tap the brakes a little.



> John McManus <[email protected]> wrote:
> 
> > Willie:
> > I use a lot of throttle ( gas engine) to climb a hill and then , if
> ...


----------



## EVDL List (Jul 27, 2007)

John,
What grade is that way down?
If it is more than a few percent I would
expect that you maintain speed or even pick up
speed if you have a low drag vehicle (no brake
drag, high tire pressure and so on)


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 John McManus
Sent: Wednesday, October 20, 2010 9:14 PM
To: Electric Vehicle Discussion List
Subject: Re: [EVDL] Lightweight Most Efficient Conversion

Willie:
I use a lot of throttle ( gas engine) to climb a hill and then , if
coasting with no throttle - sometimes out of gear-) lose speed all the
way down due to aero and mechanical drive. Wouldn't regeneration slow
the vehicle further needing ever more energy to climb the next hill.

On Wed, Oct 20, 2010 at 1:14 PM, Willie McKemie <[email protected]>
wrote:

>


> John McManus wrote:
> > > I'm not sure that weight is a secondary factor. Not much driving is
> > > done
> > at
> ...


----------



## EVDL List (Jul 27, 2007)

Hi Peri,

> The fact of the matter is, it's hard not to use friction brakes, at least in
> the city. If you coast gently up to a stop sign, you will annoy drivers
> behind you.

Let 'em get mad -- doing this actually *helps* traffic flow faster. Regenerative brakes can be used, all except the last few mph. Coasting is actually even better than regen, and driving smoothly without jackrabbit starts and sudden stops really improves traffic flow -- look at any scientific traffic study.

> If you see a green light ahead that turns red, you have a
> choice to use friction brakes or [break] the law. If you travel down a steep
> hill, you may exceed the speed limit without using brakes. Etc.

Again, regenerative brakes can/should be used to stay safe and within the law.

> On the other hand, if you're concerned about driving a rural, hilly road at
> speeds around 50mph, then I agree with others: the weight probably doesn't
> matter so much. 

Yes, weight matters most in stop and go driving, but helps in coasting, and it matters only a little in constant speed driving (going up hill). Aerodynamic drag swamps all the other losses about 40-45MPH, and even matters some at 30-35MPH.

Sincerely, Neil
http://neilblanchard.blogspot.com/


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## EVDL List (Jul 27, 2007)

> Neil Blanchard wrote:
> 
> > Yes, weight matters most in stop and go driving, but helps in coasting, and it matters only a little in constant speed driving (going up hill). Aerodynamic drag swamps all the other losses about 40-45MPH, and even matters some at 30-35MPH.
> 
> ...


----------



## EVDL List (Jul 27, 2007)

Hi John,

> I use a lot of throttle ( gas engine) to climb a hill and then , if
> coasting with no throttle - sometimes out of gear-) lose speed all the way
> down due to aero and mechanical drive. Wouldn't regeneration slow the
> vehicle further needing ever more energy to climb the next hill.


Weight matters for acceleration and going up hills, yes. But once you are moving, weight gives you momentum for coasting, and you can use regenerative braking if you need to slow down faster. So, unless you have to use friction brakes, the energy you add in because of weight -- is always partially recoverable.

Aerodynamic drag is always a loss -- you cannot ever recover any of it. Same goes for rolling drag -- you heat up your tires, your brakes, your bearings, and wear out your tires if the alignment is off or wheels are out of true/round, and dragging brakes are obviously a problem. Rolling drag is nearly linear, no matter what speed you are going, while aerodynamic drag goes up with the square of the speed. So, because aero drag is a total loss and it increases so rapidly as the speed goes up, it has to be the biggest drag overall.

Drivetrain efficiency is the most important thing.
Aerodynamic drag is second most important.
Weight is next most important.
Rolling resistance is important, but not quite as critical as the three factors above.

I am basing this on data from the X-Prize, and vehicles like the early Apteras and Dave Cloud's Dolphin: http://neilblanchard.blogspot.com/2010/09/x-prize-knockout-round-cont.html

The average EV in the X-Prize Knockout Round (there were 12 of 'em, including the FVT eVaro which never used it's series hybrid genset) was ~134.7MPGe -- so drivetrain efficiency trumps all other factors.
The highest efficiency of any given motor type were the ones with the lowest aerodynamic drag -- this is about half the drag at 35-40MPH and about two thirds at 55MPH and three quarters of the drag at 75MPH.
If weight was the most important, the Spira and the Edison2 would have had the best efficiency, but they averaged about ~90.8MPGe, which is much less than the EV's, but much better than the hybrids (~61.3MPGe), which were heavier.
Any vehicle that cannot roll well can't do well, but while the Edison2 was tops on rolling resistance, it also has the best aero drag (though the Aptera is in the same ballpark, and the Li-ion Wave II, as well.

Dave Cloud's Dolphin confirms this: it is as heavy as any of the X-Prize cars, and it has world class aerodynamics -- it may be the lowest drag street car ever made. The frontal area is just 17.3 sq ft and the Cd is probably below 0.13, and may be even lower than that -- this beats the Edison2 VLC which is ~18.4 sq ft and 0.145 (by the old method -- new SAE Cd is 0.161). His Wh/mile is a little better than the E-Tracer, if I am not mistaken. When Edison2 does the electric version of the Very Light Car, they could go below 100Wh/mile, because they will be using very efficient TW4XP battery pack and A/C motor, which is ~85% efficient plug-to-wheels; which is probably better than the Dolphin's DC motors and lead acid pack, without regen. They estimate the Edison2 VLCe will weigh just 1,300 pounds, which is about 60% lighter than the Dolphin, as well.

So, saving nearly a ton of weight matters, but so does 10-20% drivetrain efficiency gain.

Sincerely, Neil
http://neilblanchard.blogspot.com/


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## EVDL List (Jul 27, 2007)

No, it matters a lot! For low speed (little aerodynamic drag), it is directly 
proportional. Double the weight, double the power needed to maintain speed, even 
on level ground. Quick test: Push vehicles of different weights. I can push my 
bike with one finger. I can push my lightweight EV with one arm. It takes two 
arms to push the twice as heavy gasser. I can't even budge a full sized truck.

Here's another thought experiment. Your effective frontal area is between about 
1/3 to 1/2 of the actual frontal area. Recall how hard the car was to push. For 
a small aerodynamic car (4 ft x 5 ft x 0.33 Cd) you need to hold up a small 
square board about 2.6 feet on an edge to match the aerodynamic drag. You'll be 
going around 50 mph when aero drag equals rolling resistance drag (depends on 
how heavy the car was and how good the rolling resistance ratio is for the 
tires, and how well it is aligned).

The accurate way to do this is as Lee Hart suggested, fit an a0 + a1*v + a2*v*v 
curve to coast down data, and you can calculate what percentage of your total 
drag is due to aerodynamic effects as a function of speed.




________________________________
Quote: ... [weight] matters only a little in constant speed driving ...



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## EVDL List (Jul 27, 2007)

This is all great stuff.Where do you guys find the cx numbers? All I get
when I google is Honda cx etc. I know the Suzuki Carry is a bit of a brick
but it is only about 20 sq.ft.

An aside. When I was running really well, I would add weight to the boat , a
bit every weekend. After 3 or 4 weeks I'd ask the inspectors ( I won) to
weigh the boat exactly. I'd be up to 25 lbs over . This was a moral deflater
to the competition. You never know when an edge might come in handy.

John McManus



> David Dymaxion <[email protected]>wrote:
> 
> > No, it matters a lot! For low speed (little aerodynamic drag), it is
> > directly
> ...


----------



## EVDL List (Jul 27, 2007)

"John,
What grade is that way down?
If it is more than a few percent I would
expect that you maintain speed or even pick up
speed if you have a low drag vehicle (no brake
drag, high tire pressure and so on)"

Dropping about 4500 ft in elevation down an average grade of 4.5% I got back
about 16% of the charge it took to get up the grade, as measured with a TBS
ExpertPro gauge. I don't have a gauge for energy, and the average pack
voltage is quite different on the way up versus down, so hard to say the
energy proportion gained going down. Motors likely vary in their regen
efficiency, but I don't think it is all that great in general. The
proportion also depends greatly on how fast you went up the grade. I went
up at 40-45 mph. Even on a 3% grade I hold the car back with regen to
maintain the speed limit. 
-- 
View this message in context: http://electric-vehicle-discussion-list.413529.n4.nabble.com/Lightweight-Most-Efficient-Conversion-tp3002052p3004962.html
Sent from the Electric Vehicle Discussion List mailing list archive at Nabble.com.

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## EVDL List (Jul 27, 2007)

> David Dymaxion wrote:
> 
> > No, it matters a lot! For low speed (little aerodynamic drag), it is
> > directly
> ...


----------



## EVDL List (Jul 27, 2007)

That's an apple-to-oranges comparison, so I'd be careful. For instance, front 
wheel drive cars have toe-out, it's diesel to gas, etc. Also please note the 
directly proportional to weight thing is at low speed -- 40 mph for a truck 
doesn't qualify.

A better test would be to compare your truck's mpg with a heavy load or trailer 
and without. Or better yet, do some coast down tests -- I can help with the math 
on that if you'd like.




________________________________
From: Roger Heuckeroth <[email protected]>
To: Electric Vehicle Discussion List <[email protected]>
Sent: Thu, October 21, 2010 8:53:09 AM
Subject: Re: [EVDL] Lightweight Most Efficient Conversion

Sometimes intuition can be deceiving. Here's another anecdotal example:

We have some friends that live about 1.5 miles away, up hill from 
where we live. We have two gas vehicles (EV still under 
construction). One is a 6000 lb 2010 Toyota Tundra, and the other is 
a 3500 lb 2010 VW Jetta TDI. The Tundra gets about 16-18 MPG on the 
highway, while the TDI gets 40+ MPG. That's cruising at about 75 
MPH. Now one thing I like to do just for kicks is when I leave my 
friends house I accelerate to about 40 MPH and throw it into Neutral. 
With the truck I'm still going 30+ MPH when I get to my driveway, and 
have to hit the brakes once when going through a hill that step and 
has an S turn. With the Jetta, I don't have to hit the brakes because 
I'm not going fast enough to require it, and I'm barely going 10 MPH 
when I get to our driveway.

Intuitively, I would expect the TDI with its .31 drag coefficient and 
low rolling resistance tires to come out in front. But the truck 
starts out with a higher potential energy, and it blows the Jetta away 
in this test.

In real world driving the TDI blows the truck away on fuel economy, 
but I don't think rolling resistance has much to do with it. 


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