# [EVDL] 12,000 miles and 5 controllers later



## EVDL List (Jul 27, 2007)

Hi Roland,
It looks like you need a lot less power to run up your hills. If your
battery pack is putting out 75 amps at 180 volts you are using only 13.5
Kilowatts of power. To get up some of the hills around here in Olympia Wa I
need about 24 kilowatts of power to the motor. Especially if I am starting
up hill at a stop light. 

My Nissan pickup with me in it weighs in at 4000 lbs. (I have 1400 lbs of
batteries - 20 6 volt golf cart)

So you power needs are much less than mine. That will definitely change the
equations. I did not change the gear ratios because that was a little beyond
my engineering skills for the conversion. 

Tom 

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## EVDL List (Jul 27, 2007)

I did some calculations using a relation between my EV which weighs 7000 lbs 
at 13.5 kw using a 5.57:1 ratio as to yours at 4000 lbs at 24 kw.

By weight:

(13.5 x 7000)/24 = 3935 lbs which is close enough to 4000 lbs


By differential gear ratio:

(5.57 x 4000)/7000 = 3.18:1 at 180 volts

Your EV at 120 volts:

(180 x 3.18)/120 = 4.77:1 differential gear ratio

Look up the ring and pinion gear set for your vehicle at jegs.com.
to see what the closes gear ratio that will be to 4.77:1. You can talk to 
the tech there to see which will work.

This gear change will decrease your motor and battery ampere. I have 
another car that is the same and style as the EV I have. It use to have a 
2.78:1 differential gear in it and got only 13 mpg city stop and go driving 
and 17 mpg highway. Replace the gear to a 3.90:1 and it increase it by 5 
mpg.

Roland








----- Original Message ----- 
From: "Tom H" <[email protected]>
To: <[email protected]>
Sent: Friday, May 27, 2011 2:47 PM
Subject: Re: [EVDL] 12,000 miles and 5 controllers later


> Hi Roland,
> It looks like you need a lot less power to run up your hills. If your
> battery pack is putting out 75 amps at 180 volts you are using only 13.5
> Kilowatts of power. To get up some of the hills around here in Olympia Wa 
> I
> need about 24 kilowatts of power to the motor. Especially if I am 
> starting
> up hill at a stop light.
>
> My Nissan pickup with me in it weighs in at 4000 lbs. (I have 1400 lbs of
> batteries - 20 6 volt golf cart)
>
> So you power needs are much less than mine. That will definitely change 
> the
> equations. I did not change the gear ratios because that was a little 
> beyond
> my engineering skills for the conversion.
>
> Tom
>
> --
> View this message in context: 
> http://electric-vehicle-discussion-list.413529.n4.nabble.com/12-000-miles-and-5-controllers-later-tp3556075p3556339.html
> Sent from the Electric Vehicle Discussion List mailing list archive at 
> Nabble.com.
>
> _______________________________________________
> | Moratorium on drag racing discussion is in effect.
> | Please take those discussions elsewhere. Thanks.
> |
> | REPLYING: address your message to [email protected] only.
> | Multiple-address or CCed messages may be rejected.
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> 

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## EVDL List (Jul 27, 2007)

> SLPinfo.org wrote:
> 
> > You have mentioned this "sweet spot" before. I have tried to find it for
> > my ADC 9", but have not been successful. I have found torque curves
> ...


----------



## EVDL List (Jul 27, 2007)

I wonder if there is something wrong with your motor. The controllers should 
be self protecting. See if you have a short in the armature or less likely 
the field winding. This can be done by setting up a video camera to look at 
the commutator (remove the screen around the commutator) & go for a drive. 
See if there is much sparking. You may also have an excessively advanced 
brush timing. I blew my reconditioned Raptor 1200A after only 60 miles. I 
dont think it is motor related though. The manual for the Raptor refers to a 
"wild ride" if you get a blown controller. My EV took off like a 911 Porsche 
with squealing wheels, clutch until the Mosfets burnt out. Lucky not to hit 
any body /things. David Sharpe

--------------------------------------------------
From: "Tom H" <[email protected]>
Sent: Saturday, May 28, 2011 4:46 AM
To: <[email protected]>
Subject: [EVDL] 12,000 miles and 5 controllers later

> After three years and 12,000 miles on my converted pick-up, I would like 
> to
> share some of my experiences with the discussion list. Maybe something I
> say here will help someone just starting to avoid some of the mistakes I
> have made.
>
> _______________________________________________
> | Moratorium on drag racing discussion is in effect.
> | Please take those discussions elsewhere. Thanks.
> |
> | 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/
> | CONFIGURE: http://lists.sjsu.edu/mailman/listinfo/ev
> 

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## EVDL List (Jul 27, 2007)

Roger,
First let me say that I really and truly do appreciate you taking the time
to compose your detailed response to me about Roland's "sweet spot". I
respect that your time is valuable and that you give of it freely.
However, such detailed explanations usually result in my eyes glazing over
and me mumbling to myself "what's the bottom line". I don't often read all
the long messages that show up sometimes beyond the first paragraph for that
reason. My EV is basic transportation to me - it's not a hobby. I just want
it to work efficiently. I don't have the time or the mental energy to work
through what for me are highly complex electrical, mechanical, or
engineering details. I realize that for many on this list those details are
inherently interesting but for me they are not. But I don't want anyone to
quit posting such messages for that reason. I can hit the delete button just
as easily as anyone else and I don't have a problem doing so.
Another point is that although I have a tach it doesn't work. Despite many,
many attempts using many different suggestions from the EV list I've never
been able to get it to work. I'm in the process of having my EV components
transferred from one vehicle to another, but I am not going to bother having
the tach installed. Notice that I said "having it installed". I can do some
really basic stuff on my EV, but I'm not an engineer or a mechanic so I have
to pay someone else to do it.
Roland's notion of a sweet spot was interesting to me because in waiting to
get my newer EV (97 S-10 instead of a 91 Plymouth Colt) I'm trying to figure
out optimum speeds for driving in each gear and shifting. I have formulae
for computing speeds from both Roland's posts and Mike Brown's Convert it
book, but the key number I've always been missing is RPM. No one has ever
told me what's the "optimum" rpm or the "maximum" rpm or the "shift point"
rpm that I should be aiming for. Without a tach I have to use my speedometer
(and yes my amp guage which I use to measure motor amps, not battery amps).
But the speedometer is most important because I want to avoid tickets and I
find that if I spend too much time staring at guages I'm not paying
attention to traffic like I should be. As basic transportation 90% of my EV
driving is done during rush hour.
It is interesting that Roland said 3600-3900 rpm would be the sweet spot
form my 9" ADC and you said the "rule of thumb" is 3000-4000 rpm. I had
never seen either of these sets of numbers before, so I have in fact learned
pretty much what I need to know. Bottom line - even though I couldn't follow
allow the details, YES your response was very helpful!
- Peter Flipsen Jr



> Roger Stockton <[email protected]>wrote:
> 
> > SLPinfo.org wrote:
> >
> ...


----------



## EVDL List (Jul 27, 2007)

Hello Peter,

The sweet spot data is what I received from NetGain for a 9 and 11 inch 
motor.

You can convert the speedometer to a rpm indicator using the following 
knowns:

Find the running circumference of the tire. It is known that the same type 
and diameter tire at the same air pressure will have a different running 
circumference on different vehicles at different weight and speeds.

I learn about this way back in the 50's when I was doing road rallies where 
you may drive a vehicles for 39.5 mph for 18.5 miles and then turn left. If 
there is no road to the left to turn on, then your calculations are off.

After the EV is built and the tires are air up to the pressure, but not 
exceeding the max psi air pressure at maximum load that is on the side of 
the tire, then you can find the running circumference.

On a smooth dried road surface, put a mark on the tire and on the road. 
Move the vehicle so the tire makes one turn until that tire mark is next to 
the road surface again. Then measure the distance between the two marks on 
the road.

Lets say its 85 inches which we call TC.

Now we have to find the overall gear ratio in each gear. This is easier 
with a electric motor then with a engine. While the motor and transmission 
is in the vehicle and the tires are off the ground, put a mark on the tire, 
so you can keep track of one turn of the tire.

If the motor has a input shaft on the front of the motor, then you can use 
the keyway position to keep track how many turns it takes for the motor 
turns while the tire turns one time.

If the motor does not have a input shaft, then remove the brush cover and 
put a piece of tape on the communtator to keep track of the number of 
rotations.

Now shift the transmission into 1st gear and rotate the tire by hand counter 
clock wise which would be the forward direction. If you rotate the tire one 
turn and the motor goes 10 turns, then your overall gear ratio is 10:1 in 
1st gear.

Now shift the transmission into 2nd gear and repeat the operation.

We then now know the two known, the tire running circumference or TC
and the overall gear ratios in each transmission gears or OR.

We now converter the MPH formula to a RPM formula:

MPH x OR x 1056
RPM = ----------------
TC

Now calculated the RPM for each 5 mph for increase of speed as for example 
in first gear at 5 mph with a overall gear ratio of 10:1 and a tire 
circumference of 85 inches becomes:


5 mph x 10 OA x 1056
RPM = --------------------- = 621 rpm
85 in.


At 621 rpm, the speedo will read 5 mph in first gear.

I then find the maximum mph indication at the maximum rated motor rpm and 
the mph for the sweet spot rpm.

Roland



----- Original Message ----- 
From: "SLPinfo.org" <[email protected]>
To: "Electric Vehicle Discussion List" <[email protected]>
Sent: Sunday, May 29, 2011 6:41 AM
Subject: Re: [EVDL] 12,000 miles and 5 controllers later


> Roger,
> First let me say that I really and truly do appreciate you taking the time
> to compose your detailed response to me about Roland's "sweet spot". I
> respect that your time is valuable and that you give of it freely.
> However, such detailed explanations usually result in my eyes glazing over
> and me mumbling to myself "what's the bottom line". I don't often read all
> the long messages that show up sometimes beyond the first paragraph for 
> that
> reason. My EV is basic transportation to me - it's not a hobby. I just 
> want
> it to work efficiently. I don't have the time or the mental energy to work
> through what for me are highly complex electrical, mechanical, or
> engineering details. I realize that for many on this list those details 
> are
> inherently interesting but for me they are not. But I don't want anyone to
> quit posting such messages for that reason. I can hit the delete button 
> just
> as easily as anyone else and I don't have a problem doing so.
> Another point is that although I have a tach it doesn't work. Despite 
> many,
> many attempts using many different suggestions from the EV list I've never
> been able to get it to work. I'm in the process of having my EV components
> transferred from one vehicle to another, but I am not going to bother 
> having
> the tach installed. Notice that I said "having it installed". I can do 
> some
> really basic stuff on my EV, but I'm not an engineer or a mechanic so I 
> have
> to pay someone else to do it.
> Roland's notion of a sweet spot was interesting to me because in waiting 
> to
> get my newer EV (97 S-10 instead of a 91 Plymouth Colt) I'm trying to 
> figure
> out optimum speeds for driving in each gear and shifting. I have formulae
> for computing speeds from both Roland's posts and Mike Brown's Convert it
> book, but the key number I've always been missing is RPM. No one has ever
> told me what's the "optimum" rpm or the "maximum" rpm or the "shift point"
> rpm that I should be aiming for. Without a tach I have to use my 
> speedometer
> (and yes my amp guage which I use to measure motor amps, not battery 
> amps).
> But the speedometer is most important because I want to avoid tickets and 
> I
> find that if I spend too much time staring at guages I'm not paying
> attention to traffic like I should be. As basic transportation 90% of my 
> EV
> driving is done during rush hour.
> It is interesting that Roland said 3600-3900 rpm would be the sweet spot
> form my 9" ADC and you said the "rule of thumb" is 3000-4000 rpm. I had
> never seen either of these sets of numbers before, so I have in fact 
> learned
> pretty much what I need to know. Bottom line - even though I couldn't 
> follow
> allow the details, YES your response was very helpful!
> - Peter Flipsen Jr
>
> On Fri, May 27, 2011 at 5:15 PM, Roger Stockton 


> > <[email protected]>wrote:
> >
> > > SLPinfo.org wrote:
> > >
> ...


----------



## EVDL List (Jul 27, 2007)

The Kelly and Logisystems controllers are well known for letting the
magic smoke out.


On Fri, May 27, 2011 at 6:22 PM, David Sharpe <[email protected]> wro=
te:
> I wonder if there is something wrong with your motor. The controllers sho=
uld
> be self protecting. See if you have a short in the armature or less likely
> the field winding. This can be done by setting up a video camera to look =
at
> the commutator (remove the screen around the commutator) & go for a drive.
> See if there is much sparking. You may also have an excessively advanced
> brush timing. I blew my reconditioned Raptor 1200A after only 60 miles. I
> dont think it is motor related though. The manual for the Raptor refers t=
o a
> "wild ride" if you get a blown controller. My EV took off like a 911 Pors=
che
> with squealing wheels, clutch until the Mosfets burnt out. Lucky not t=
o hit
> any body /things. David Sharpe
>
> --------------------------------------------------
> From: "Tom H" <[email protected]>
> Sent: Saturday, May 28, 2011 4:46 AM
> To: <[email protected]>
> Subject: [EVDL] 12,000 miles and 5 controllers later
>
>> After three years and 12,000 miles on my converted pick-up, I would like
>> to
>> share some of my experiences with the discussion list. Maybe somethin=
g I
>> say here will help someone just starting to avoid some of the mistakes I
>> have made.
>>
>> _______________________________________________
>> | Moratorium on drag racing discussion is in effect.
>> | Please take those discussions elsewhere. Thanks.
>> |
>> | 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/
>> | CONFIGURE: http://lists.sjsu.edu/mailman/listinfo/ev
>>
>
> _______________________________________________
> | Moratorium on drag racing discussion is in effect.
> | Please take those discussions elsewhere. Thanks.
> |
> | 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/
> | CONFIGURE: http://lists.sjsu.edu/mailman/listinfo/ev
>



-- =

www.electric-lemon.com

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## EVDL List (Jul 27, 2007)

> SLPinfo.org wrote:
> 
> > First let me say that I really and truly do appreciate you taking the time
> > to compose your detailed response to me about Roland's "sweet spot". I
> ...


----------



## EVDL List (Jul 27, 2007)

Roger

Thanks for the straightforward and rational response. Have now calculated
max speeds. With my previous EV I was able to keep the motor amps in the
100-150 range most of the time. Will be interesting to see how it goes with
a heavier and less aerodynamic vehicle.

Peter


> "Roger Stockton" <[email protected]> wrote:
> > SLPinfo.org wrote:
> >
> >> First let me say that I really and truly do appreciate you taking the
> ...


----------



## EVDL List (Jul 27, 2007)

Hello, 
As the one who started this thread I thought it was time to add some further
comments. 

This has been a fascinating discussion on motor power curves and other
interesting subjects. I am curious as to how we ever got onto this subject
from a simple history of my experiences with an EV and five controllers. 

Part of the discussion seems to stem from a perception that I was
complaining about the power of my motor. I have been quite satisfied with
the Warp Impulse 9 motor I have and it provides me with plenty of power as
long as the controller can output enough amps. 

I do not think my system has power problems. Here are some of the
calculation on total power usage I have made. The NetGain controller has an
add on option of an "Interface Module" that records the instaneous reading
of amps to motor, voltage at motor, battery current, battery voltage. This
is recorded on a disc that I can then download to a spreadsheet. Readings
can be recorded every second (or tenth of a second).

When I integrate the motor current x motor voltage every second over a 7
mile trip (to get power usage). I find that the controller has put about 250
watt-hours of energy into the motor for every mile I drive. (1.75
Kilowatt-hrs for the trip) This seems to fall right into the range that
others have reported. I do need about 24 K-watts of instantaneous power to
get up the hills around here at 35 mph, but overall power consumption per
mile is not that high.

The test of the "sweet" spot for the motor would be run the same measured
mile in different gears and record the power usage. That would then tell me
the most efficient motor rpms. I have done "rolling wheels vs motor turns"
test to get the gear ratios for the transmission so can get rpms per miles
per hour for each gear. This would be a "real life test" not based on power
curves provided by the manufacturers and I might do that soon. 

I expect in this case that the "sweet" spot might be at higher rpms than
plotted. The power loss from the controller is 2 watts per amp of current
going to the motor according to the designer of the controller (at
NetGains). If I am driving at 35 mph in fourth gear the controller has to
put 225-250 amps to the motor because the voltage at the motor is lower. In
third gear (higher motor rpms and higher voltage at the motor) the
controller is putting out only 150-180 amps to maintain the same speed (that
is power output). Remember that power = voltage x current. This means that
the power loss in the controller in third gear is only 300 watts (this is
not watt-hrs!) while in fourth gear it is 450 watts (2 watts per amp to the
motor x current to motor). Thus power loss in the controller calculates out
to about 9 watt-hrs/mile in third gear and 13 watt-hrs/mile in fourth gear. 
This needs to be added to the "efficiency" the motor at different rpms when
calculating the "sweet spot." 

When I measure the power actually going back into the batteries from the
wall outlet it averages out to about 400 watt-hours per mile. The
difference can be attributed to several factors:

1. The best chargers consume about 125-135% of the usable power actually put
back into the batteries. This is because they put in extra power to equalize
the batteries on every charge, and they are not 100% efficient. 
2. The battery pack also runs my 12 volts system through the DC-DC
converter. So I am consuming pack power to run my lights, fans, and
controller. 
3. In the winter time, when I am running my heater all the time the average
consumption of power increases to 500 watt-hrs per mile when calculated at
the wall outlet. 

So I don't think these numbers indicate I have problem with my motor or
controller. Power usage seems to be well within the recorded values out
there.

Tom H

--
View this message in context: http://electric-vehicle-discussion-list.413529.n4.nabble.com/12-000-miles-and-5-controllers-later-tp3556075p3564150.html
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