Looking for a motor .. then will look at the battery pack

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reikiman
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Looking for a motor .. then will look at the battery pack

I'm looking right now for a better motor & battery pack for the Karmann Ghia. I know very well that "More" is a slippery slope. I started with an electric bicycle in 1995 and step by step have moved up the vehicle food chain to have a car. Anyway.. the car as it stands is not fast enough nor enough range. I've been driving it for two weeks and it will make it to 40 miles/hr (eventually) whereas I have a bit of driving on a 45+ miles/hr expressway that must be traversed to get to the office. Further the range tends to be less than 10 miles (and that's with a 150AH battery pack so I'm thinking there's a weakness in the battery pack maybe). Anyway.. "More".

From looking at the EV Album listings the 120+ volt range will give this car enough pep to be reasonable and even with lead acid the range is respectable. If I can afford it I'll be getting a lithium pack however. And as noted before I'm looking towards making this car "more" enough that it might be my primary vehicle for around the SF Bay Area trips.

I have access to a Netgain Impulse9 motor at a great price. One of the Karmann Ghia's has this motor paired with a 144v 1000a controller (!!!!) and claims an 85+ miles/hr speed. That sounds, um, adequate. Sheesh over 100kw peak.

..but.. Maybe I'm over analyzing but I'm interested in the options. All vendors are being added to the vendor directory as I go..

Some of the vehicles use this...
Advanced DC #FB1-4001A http://www.evparts.com/prod-MT2120.htm
At 144 VDC, 28.5 HP continuous, 30.4 HP for one hour, 48.8 HP for five min., 100 HP peak
Price $1750.00 (motor only.. controller would be $1000 or so)

This series of AC motors looks interesting. The biggest one (AC50) is more powerful than the Impulse9, AND more compact, AND more efficient. It runs at only 108 volts max. It's over $4000 for the motor and controller. Oofda.
AC Induction Motor and Controller Kits
http://www.electricmotorsport.com/store/ems_ev_parts_motors_ac-induction.php

Electro Automotive carries Azure Dynamics (Solectria) AC motor systems
http://electroauto.com/catalog/ackits.shtml
The AC24 is smaller than the AC50 above, less powerful, lower max amps, lower HP, and is a whole slew of parts that must be bought together at more $$$'s than the AC kit that EMS carries.

eva-michael
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Re: Looking for a motor .. then will look at the battery pack

Peak 144V 1000A! I'm sure this can move a truck! Also it will cost too much to have batteries which can provide 144V 1000Amp.
150Ah=10 miles? what voltage?

www.evassemble.com all for EVs
If you are finding ev parts, this will be a website deserves your visit.

reikiman
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Re: Looking for a motor .. then will look at the battery pack

That's with the specific controller and of course it won't be staying at peak current the whole drive. It's nice to know the motor has extra capacity. The motor in the car right now is too small for the car.

It's a 72 volt car right now. That's not enough for around these parts.

The batteries are flooded lead acid (Trojan J150) and the car had been sitting idle in a show room for a year. The guys said they turned on the charger every month or so. But I'm thinking it's likely the batteries suffered from sitting idle.

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Spaceangel
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Re: Looking for a motor .. then will look at the battery pack

I don't know how much room you have or can make for battery pack. Can you go with Yellow or Blue tops? Wire a lot of them in series to get a high voltage, low current? Maybe a 312 volt system? I tend to like AC but still a tad bit expensive but is there an adapter plate for the 9" ADC or Warp motors and the high voltage controllers are water cooled so it is small. I saw a cheap adapter plate on eBay but it was for a small motor and I already have a backward mounted motor on my bug with a belt. NEV and 36 volt with 48 volt pack. It tops out a 25 or 30 but in Maine it is good enough to get to store and back. I tend to agree if the batteries sit and charged without cycling them range is reduced and that is why I now take mine out and bring them home when the vehicle sits. I left then in for 4 months and charged them and again and again and got maybe the one year but when I actually used them in Dracut I got another two years on the pack. I believe it is called stratified? heavy H2SO4 sinks to bottom and water separates and floats to the top and makes the battery degrade faster not being stirred or cycled.I carry the Blue tops up to ME for it is light and have handles. I use eight of them.
Rusty

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Re: Looking for a motor .. then will look at the battery pack

Can you go with Yellow or Blue tops?

I'm planning to go LiFePO4/Thundersky ... but yeah if I wanted to stay with lead acid I'd be swapping for some sort of sealed battery. The car came with a hydrometer for testing battery condition and, y'know, that's an art I just don't want to learn. I'll do it but I want to get to modern technology as soon as possible.

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antiscab
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Re: Looking for a motor .. then will look at the battery pack

Further the range tends to be less than 10 miles (and that's with a 150AH battery pack so I'm thinking there's a weakness in the battery pack maybe).

nominal 150Ah 72v flooded lead acid is good for around 5.4kwh when brand new .

less than 10 miles at ~40mph would indeed indicate the battery has had it.

I would highly recommend installing some kind of Ah counter before upgrading to a newer battery, to see how much it actually uses now.

Matt

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eva-michael
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Re: Looking for a motor .. then will look at the battery pack

72V mostly is for electric motorbike or heavy scooter. 144V should be pretty good for a car!
I think that 72V batteries have dropped down largely from its original capacity otherwise should not be such a poor performance.

www.evassemble.com all for EVs
If you are finding ev parts, this will be a website deserves your visit.

antiscab
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Re: Looking for a motor .. then will look at the battery pack

indeed,

the other thing to keep in mind are the battery type limits.

for flooded lead acid, max discharge rates are:
0.3C continuous,
1C peak.

theres just about no way that car can stay within those limits with that battery pack, meaning service life will be rather short.
dont get more flooded lead acid.

if budget is a problem, get AGMs.

how much range do you really need?

going lithium costs more up front, but you do get more range, and the energy use measured at the power point per miles driven is much lower (~40% lower than flooded lead acid as the round trip efficiency is *much* higher).

Matt

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2007 Vectrix, modified with 42 x Thundersky 60Ah
Vectrix 60Ah Lithium Tyres Fuel Registration Insurance cycle analyst 2 x TC Charger & MC
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Spaceangel
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Re: Looking for a motor .. then will look at the battery pack

One thing that can increase efficiency and range is using a higher voltage system. The PWM "controller" can vary the speed of the motor while driving. But during the "off" times of the Pulse Width Modulator, the electromotive force "voltage" will go through the recovery diodes or flyback diodes and give sort of free electricity for one cycle. At 18 or so KHz that is some extra electrons. On my bug I tried 24 volts and got 10 to 12 miles range using 8 blue tops. When I used AXE-4865 I got double range. Still eight batteries at same speed. Reason being I drew 90 Amps vs a nearly continuous 250 amps. I peg the motor amps with a controller and do only 250 to 300 battery amps.
Rusty

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Re: Looking for a motor .. then will look at the battery pack

0.3C continuous, 1C peak.

Ah, that's definitely a problem here. The controller is 500A peak and hitting the throttle pretty hard from a stop can get it to 450A easily. However for routine driving I've been concentrating on keeping it 100A or below.

how much range do you really need?

I wrote a bit about that in another post - "More is a slippery slope". Given that, I'd like to have enough range/speed to be credible on the highway and do 90% or more of my driving in the electric car. Ideally the car will do enough that it would be practical to sell off my gas car because of disuse. That means a 100 mile range. While I typically don't drive that far the SF Bay Area geography makes a 100 mile trip (e.g. Berkeley and back) quite within the realm of possibility. Plus there is this mountain range separating me from the ocean and a trip to Santa Cruz is also within the realm of possibility.

The result is 120+ volts at 160AH ... Just have to deal with my eyeballs popping out of their sockets.

I just hooked up a spare Cycle Analyst that happens to be lying around the garage and took it for a spin. Unfortunately the shunt isn't calibrated properly in the C/A. It read 85A max while the analog meter in the dash read over 400A max. It said 4.5 AH used .. so, roughly speaking there is a 5x multiplication to get to correct units. That's 22.5AH used on a 5 mile trip, or 1620WH or 330 WH/mile. I was hitting the throttle pretty hard and also did a max speed test reaching approx 50 miles/hr by putting it into 4th gear (previously the fastest I'd gotten this car was 40 miles/hr in 3rd gear).

I think that usage is in reason. My motorcycle has a similar motor and would use around 10Ah on a similar trip.

But that's with a miscalibrated meter. Does anybody know the specifics of calibrating a C/A for a given shunt? The C/A manual doesn't say other than they're calibrated in mOHM but the shunt is not marked in mOHM.

The idea I have after the above research is - because I can get that Impulse9 motor so inexpensively (read: special deal) and because that motor is more than sufficient for my speed need - it will leave more room in my total budget than if I got the AC motor kit instead. The battery pack is probably more important than the motor, so long as the motor is sufficient.

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Spaceangel
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Re: Looking for a motor .. then will look at the battery pack

The Impulse9 is like the WarP9 motor? It is a 120 volt motor? Withstand 156 volt with a good controller? Nice motor for your car and lots of room for endless possibilities. If you can get a better controller you can get a lot more range especially with a Lithium pack. Then the 100 AH TS cells would be nice if you can get them at a deal. Operating a controller at higher voltages is low input on pot box or hall effect device will allow for more range through less current. Do you have a Cruising Equipment E-Meter on you VW now or just a battery ampere meter? I think it is called Xantrex meter now? Your J150 is better than my old 5SHP battery pack and a nice Peukert Exponent too. It is rated at 60 to 70 minutes at 75 Amperes. So if you kept speed to 75 Amp you would go as far as an hour maybe 20 miles. I always had to draw 100 amps to have any speed to keep up with light traffic, just to test range of battery pack. Don't use 4th speed for it makes any car SUCK AMPS. Does your car run NOW? As in do some more testing.
Can you put in two shunts? One for the battery pack and one in motor circuit. Also two meters and maybe right next to each other. You can see the motor current being maxed out with little input of pot box a lot of times. A nice way to get more range.

Antiscab said

the other thing to keep in mind are the battery type limits.

for flooded lead acid, max discharge rates are:
0.3C continuous,
1C peak.

Well Trojan is a rugged battery and I always did 2 or 3C and got 3 years on my set. T-125 though. Which campare favorably to J150 with same or almost same Peukert. What VOLTAGE pack Lithium are you thinking of? A T-125 has about 130 to 140 AH 20 Hour BCI and I always did close to 450 to 500 Amps so it can take it on your J150 you can do 250 to 300 Amperes. I think 120 AH for 5 hour rate?

Rusty

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reikiman
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Re: Looking for a motor .. then will look at the battery pack

The only meter is an Westach analog one.. it has its own shunt, and there's another shunt for the cycleanalyst. The C/A is there just temporarily for testing and unfortunately doesn't have a long-enough wire to get into the dashboard.

Interesting comparison of experience. I probably said - the car sat in a showroom for a year and I'd guess the pack suffered from that. I only did 4th today for a speed test, and was on a road I don't normally drive on that has higher speed. Normally I'm on regular streets and only 35-40 max in 3rd maybe.

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Spaceangel
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Re: Looking for a motor .. then will look at the battery pack

We both have the same meters Westach. I went a little over board and like the dual meters from them and meter every thing. I have a 2C-30 500 amp ammeter and and a 1000 Amp meter on motor side. Both gets pegged a lot at 48 volt pack. I have the 50 volt and 250 amp meter wired in too for battery voltage and special low speed driving, model number 2DC10-76 from Westberg. I have a Zener in there to read 50 when pack is 60 volts sort of like an expanded scale.
What Voltage are you aiming for? I only have experience in 20 AH TS cells. Maybe a little in V Power bike 48 volt pack. What speed can you go at 100 Amperes? Both 2nd and 3rd speed? 72 volt pack or what ever you have now? Maybe get a E-meter? They are so nice. Best device for real range.Almost dead on the monies accurate if you do it right. You can go real fast and try to kill battery pack and then go slow and it will redo drain accordingly. I went an extra 12 miles on a dead pack,maybe I did 5 MPH but current was low to keep pack voltage up to about 1.9v/c or 2.0 to prevent reverse cells.
Rusty

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antiscab
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Re: Looking for a motor .. then will look at the battery pack

0.3C continuous, 1C peak.

Ah, that's definitely a problem here. The controller is 500A peak and hitting the throttle pretty hard from a stop can get it to 450A easily. However for routine driving I've been concentrating on keeping it 100A or below.

how much range do you really need?

i suspect your amp meter is reading motor side amps.
from a 500A controller, you will only see 450A on the battery side for a momentary peak as motor voltage gets close to and reaches battery voltage.

motor amps = torque
battery amps = power

the peak power of a series dc motor is around mid-way along its max rpm.

But that's with a miscalibrated meter. Does anybody know the specifics of calibrating a C/A for a given shunt? The C/A manual doesn't say other than they're calibrated in mOHM but the shunt is not marked in mOHM.

The idea I have after the above research is - because I can get that Impulse9 motor so inexpensively (read: special deal) and because that motor is more than sufficient for my speed need - it will leave more room in my total budget than if I got the AC motor kit instead. The battery pack is probably more important than the motor, so long as the motor is sufficient.

meter calibration:

mOhm = rated mV / rated A

what rpm does your present motor do in top gear at ~60mph?

how much power does it pull to do 60mph?
your batteries won't like it, but they should be able to push the car to 60mph if you can full 450A from them.

Rusty - how long did your batteries last for, and what setup were you using?

Matt

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2007 Vectrix, modified with 42 x Thundersky 60Ah
Vectrix 60Ah Lithium Tyres Fuel Registration Insurance cycle analyst 2 x TC Charger & MC
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Spaceangel
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Re: Looking for a motor .. then will look at the battery pack

I used and still use contactor 24 volt and eight blue tops with AXE-4865 depending on how lazy I am. The motor is one I got on EV for sale list rated at 36 volts but use 48 volts with Damon's controller.I sort of like the instant power of contactor pulling in and squeaking tires for a foot or two. Range on 24 volt is 5 or 6 miles thru woods or dirt path to Corinaa from Stetson ME. I use the eight batteries wired in series parallel to give me 24 volts with enough current. But making two 48 volt packs using same batteries gives me 10 to 12 mile range easy and if I go slow 25 miles. I don't think a VW Bug is very efficient for the tranny. Makes a nice off road vehicle though. There is no electricity and I have to recharge using solar or gen set or even SUV and inverter to Iota DLS54.4-15 charger. That is why I use Blue tops for I can keep them dead for a couple of hours or so and even over the weekend. I usually just unplug Anderson Power poles and reconnect them to inverter in SUV to power HAM equipment. The Alltrax controller doesn't get how for the times I play rough but it is not like I push it 50 MPH down a road. It is a platform for me to play only. I bought a wrecked VX-1 and going to make it 208 volt three phase powered next week. I will be using a VFD by Hitachi to power it. Using a contactor to power a vehicle is like a Golf Cart. Fast off the line but still slowwwwww. And a waste of Amps.When the contactor is pulled in it always draws a lot of Amperes. At least a AXE-4865 you can be moving and draw 20 to 50 amps going slow. Oh BTW I just noticed two batteries weak so back up to Sam's club to get two new ones. They are only $177.50 for the Optima blue tops. If I wanted real range I would do like a member of out NEEAA here does with his Bug. Using some eight volters making a 120 volt pack. His name is Bill Glickman and a club member. Making a vehicle out of lead is old technology but cheap enough. If one can afford it NiFe, NiMH, or LiFePO4 is the way to go. What the heck, I ain't rich. I use what I can find now at a reasonable price. Also I got my controller from Damon set up like a Cursid controller I gived-ed to him to smoke test. It was a Inductor controller that allowed resistive to be used but around 9 K ohms to about three k ohms. So he traded mine for his and it too is now programmable thru RS-232 port to make it anything I want to.
Rusty

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Re: Looking for a motor .. then will look at the battery pack

The 450A peak is momentary, as you suggest. The shunt is in the middle of the pack so it's not measuring motor current.

mOhm = rated mV / rated A

As I recall (the car is 40 miles away at the moment) the shunt is rated for 500A and 50mV ... which is .1 mOhm. Given that the C/A appeared to be off by a factor of 5x and has a default shunt value of .5 mOhm ... I won't be able to test this until thursday however.

what rpm does your present motor do in top gear at ~60mph?

Oh, um, don't have a tach that I can use while driving. I have one that can be used if the wheels are off the ground. And in any case the max speed is 50ish m/h. I could calculate wheel RPM based on the wheel circumference. There might be a page somewhere that shows the gear ratios of the normal VW 4 speed transmission. That would be important for working out the speed potential/requirements, eh?

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Re: Looking for a motor .. then will look at the battery pack

what rpm does your present motor do in top gear at ~60mph?

Oh, um, don't have a tach that I can use while driving. I have one that can be used if the wheels are off the ground. And in any case the max speed is 50ish m/h. I could calculate wheel RPM based on the wheel circumference. There might be a page somewhere that shows the gear ratios of the normal VW 4 speed transmission. That would be important for working out the speed potential/requirements, eh?

i was hoping you would be able to measure two things:
power needed at 60mph, and of course rpm.

its the continuous power requirement that usually gets people in trouble.

how much power does the car use to hold 50mph?

i can use that to extrapolate.

Matt

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Re: Looking for a motor .. then will look at the battery pack

Here's the data .. sorry for the delay, it's been a hectic week.

The test run was 6.3 miles in length and the car was a bit pokey at the end. I was hitting the throttle more than I normally do. At the end of the run one of the batteries was much warmer than the others. The run started with approx 1.5 miles of 25 miles/hr on neighborhood streets until I got to the expressway. Then I did two passes on the expressway and got to 50 miles/hr both times however on the second pass 50 was only barely achieved.

pass 1: approx 330A to maintain 50 miles/hr, at approx 55 volts
pass 2: approx 290A to maintain 50 miles/hr, at less than 50 volts

Yes, the dashboard volt meter showed the pack voltage dipping below 50 volts under heavy load. On the second pass it barely maintained 50 miles/hr, obviously the pack was depleted by the first pass.

Total trip: 1562.4 Wh, 30.31 Ah, 415 Amax (these numbers are from the cycle analyst - it's been configured for .1000 mOHM shunt as per the calculation above -- the numbers above are approx from the analog gauge, unfortunately the cycle analyst is in the engine compartment and its wires aren't long enough so it can be on the dashboard to read while driving)

The motor was hot enough to be barely touchable. The controller was warm (an Alltrax 600A 72v controller). One battery was warm. I had seen one battery being warm some other time but thought it was a different battery than this time.

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Re: Looking for a motor .. then will look at the battery pack

Here's the data .. sorry for the delay, it's been a hectic week.

The test run was 6.3 miles in length and the car was a bit pokey at the end. I was hitting the throttle more than I normally do. At the end of the run one of the batteries was much warmer than the others. The run started with approx 1.5 miles of 25 miles/hr on neighborhood streets until I got to the expressway. Then I did two passes on the expressway and got to 50 miles/hr both times however on the second pass 50 was only barely achieved.

pass 1: approx 330A to maintain 50 miles/hr, at approx 55 volts
pass 2: approx 290A to maintain 50 miles/hr, at less than 50 volts

Yes, the dashboard volt meter showed the pack voltage dipping below 50 volts under heavy load. On the second pass it barely maintained 50 miles/hr, obviously the pack was depleted by the first pass.

Total trip: 1562.4 Wh, 30.31 Ah, 415 Amax (these numbers are from the cycle analyst - it's been configured for .1000 mOHM shunt as per the calculation above -- the numbers above are approx from the analog gauge, unfortunately the cycle analyst is in the engine compartment and its wires aren't long enough so it can be on the dashboard to read while driving)

The motor was hot enough to be barely touchable. The controller was warm (an Alltrax 600A 72v controller). One battery was warm. I had seen one battery being warm some other time but thought it was a different battery than this time.

my own posts tend to be a bit sparodic :)

ok, from those results you need ~17kw at the battery to do 50mph (there must have been a slight hill, because that is quite high).
that would mean ~29kw for 60mph.

some of that is to do with overloading the present motor. a bigger motor will be more efficient at that loading level.

try a coast down test.

accelerate to 50mph, and then coast down to 40mph.
time how long it takes to do that.

that will probably give a better indication of the power required at the motor.

Matt

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2007 Vectrix, modified with 42 x Thundersky 60Ah
Vectrix 60Ah Lithium Tyres Fuel Registration Insurance cycle analyst 2 x TC Charger & MC
conversion

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Re: Looking for a motor .. then will look at the battery pack

try a coast down test.

accelerate to 50mph, and then coast down to 40mph.
time how long it takes to do that.

that will probably give a better indication of the power required at the motor.

Matt

Reikiman does your karman have a clutch?
Was wondering if you pressed the clutch pedal to seperate any slowing caused by the motor/and controller?

As antiscab mentioned that your power readings maybe high. It would be good to know that the motor and controller aren't adding too much extra resistance to slowing the car during the coast test. As you might change the controller or motor.

Would be nice to know the time to 30mph,20,10 too. If its safe on the road.

Go over the well.
Ken

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Re: Looking for a motor .. then will look at the battery pack

I've done coast-down tests before .. see: http://visforvoltage.org/blog/reikiman/2927 .. interesting is that the karmann ghia seems to have a longer coast-down than my chevy tracker. Anyway here's the figures... the max amps were similar to above and the total trip consumed 33 Ah covering 9 miles or so total combining a grocery shopping trip with this coast-down test. BTW On my way to the test I decided to check the tire air pressure. The tires have been a bit bulgy and I wondered whether it was just the battery pack weight or what. Turns out the tires were at 25-30 psi and now they're at 40psi.

Pass one:

50 - 0 sec
45 - 10.5 sec
35 - 24 sec (came to an ever so slight rise)
30 - 33 sec
25 - 40.5 sec
20 - 48 sec (encountered a curve)
15 - 1:19 (on a ever so slight down)
10 - 1:50

Pass two

45 - 0 sec
40 - 12.5 sec
35 - 22.5 sec
30 - 31 sec (had seen an ever so slight rise)
25 - 39 sec
20 - 48 sec

Decided to start pass two at a lower speed due to pack condition and then cut it off early because I was getting to a serious curve and there was another car behind me.

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Re: Looking for a motor .. then will look at the battery pack

one thing i forgot to ask....
how much does your karmann ghia weigh, with you in it?

Matt

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Re: Looking for a motor .. then will look at the battery pack

...from above ...
Pass one:

50 - 0 sec
45 - 10.5 sec
35 - 24 sec (came to an ever so slight rise)
30 - 33 sec
25 - 40.5 sec
20 - 48 sec (encountered a curve)
15 - 1:19 (on a ever so slight down)
10 - 1:50

Pass two

45 - 0 sec
40 - 12.5 sec
35 - 22.5 sec
30 - 31 sec (had seen an ever so slight rise)
25 - 39 sec
20 - 48 sec

Had a look at this data in spreadsheet. Initial Dynamics look a bit slow to transition into steep decell.
Road slope air cushion etc are hard to model.

Questions:
1. Was the convertable up or down?
2. Do you want to be able to do 65mph with it down?
3. What do you think the Car weighs with the 6 x Trojan 12V 120Ah (say 1100kg)
The other Karmann Ghia's with bigger pack are 1300kgs. Mass effects this coast deceleration dramatically.
4. Are the Battery Racks holding the Cells Down, your Pics don't show it?

Slowdown-withEstimate-Curve.JPG

May as well let anyone check out my Spreadsheet with Curve V(t) from Cd, and Crr
Coast Calc Spread Sheet - Open Office
[Edit - File type not accepted on site - Sorry]
Not sure if calcs are spot on.

2.5 Frontal Area9m^2)......... (Expect it to be 1.87)
900.0 mass(kg) .............. (1200kg)
0.500 Cd ................... 0.45
0.0030 Crr ................... 0.001

So it been hard to get useful data to detiremine Power for 65 mph Top speed.
But worth learning process :)

Cheers

7circle
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Re: Looking for a motor .. then will look at the battery pack

Sun, 04/25/2010 - 00:44
#18
....
ok, from those results you need ~17kw at the battery to do 50mph (there must have been a slight hill, because that is quite high).
that would mean ~29kw for 60mph.

Matt

Just eleaborating, as I WAS assuming Power Max Proportioanl to Velocity Squared, but I was wrong.

This is based on Drag Force porportional to Velocity Squared Fd = Kd x V^2

But Power is proportional to F * V

So Power for new top speed is Pmax = Kd * V^3 (CUBED !)

So if P@50 = 17kw =( then Kd = 17 / 50^3 = 0.136 )

then P@60 = 17 / 50^3 x 60^3
= 29 kW (N.B. This is assuming P@50 of 17kW is what is Drag loss there also is Motor and Controller Losses)

Cheers and Thanks Mat for what prompted me to recheck it.

Some more thoughts to

On the link to similar eCar Nick Druin's Karmann
..... It draws just under 100A at 140V at 60mph: ~233Wh/m in cold weather.

So Nick Drouin's car
P@60 = 140 x 100 = 14kW for 60mph. That's less than yours at 50mph.

Suggests his P@50 = 14/60^3 x 50^3 = 8.1kW
So (Wiring + Battery Terminal + Controller + Motor) Losses in your (Reikman's) EV looks High.
If Losses (17 - 8.1 = 8.9 ) kW and if your voltage measurement doesn't include the Nominal voltage of 6 x 12V Batts of 72V.
You would think some stuff is getting HOT.
The Batteries are loosing 330A x (72 - 52)V = 6.6kW.

It would be nice for Reikman to have a Dyno next door where you could look around for voltage drops in the system at load.

Your controller Alltrax 7245, 500 A

Is can it really do 500A Continuous?

Spec says 200A, so 200A x 70V = 14kW to Motor and say double loss @100A of 0.11V on Spec Ploss = 22W (sounds low)

Anyway Looks like a lithium swap could just do the job, if wireing and motor are okay.

;) Have Fun.

reikiman
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Re: Looking for a motor .. then will look at the battery pack

Yes all my tests has been with the top up - I haven't tried taking the top down yet. I'd want to take it full speed with the top down but to be honest that's a secondary thing (nice-to-have rather than must-have)

Having relooked at that page of alltrax controllers it is the 8.5" model which does 72 volts. It's rated for 450A peak 300A continuous.

On my way in today I noticed I was able to cruise at 40mph with 100A don't remember the voltage at that point however. I'm thinking voltage at that point is in the neighborhood of 65 volts. It's interesting how 50mph required 3x the power. If I can I'll try 50mph on the drive home tonight.

You would think some stuff is getting HOT.

Well, the motor is often getting hot enough I can barely touch it - and one of the batteries is routinely hotter than the others, say about 130 F? The motor at barely touchable is likely 170F or more. Makes me wonder how much difference would come just from installing the Impulse9 motor and the same pack.

- David Herron, The Long Tail Pipe, davidherron.com, 7gen.com, What is Reiki
- Electrified Electra To

7circle
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Re: Looking for a motor .. then will look at the battery pack

I think the reduced voltage is what is maxing out the Motor RPM. (I'm sure Mat mentioned it above)

As the Batterys and maybe poor wiring is reducing the Voltage to the controller and onto the motor.

So the Back EMF from the motor at:
40mph in 3rd Gear at 55V
50mph in 4th Gear at 55V

So if the voltage was 68V then you could reach higher RPM. Now how much?

Can't easily get Data on D&D ES-15A Motor. Only compare to others.

If you went to LiFePO4 and charged cells to 3.75V Max.
24Cells x 3.70V = 88.8V

Discharge Hard at 3C for 3.0V x 24 Cells = 72V
Trojan J150 Plus are:
L x W x H (mm)
351 x 181 x 283 (18 litres) x 6 = 108 litres.

If you just replaced these with Lithium and minimal mechanical work your going to have a great EV.

Well I hope you suprise the forum with a System at 48V and AC Motor that you wont be worried about safety wise as much.
When show'n it off ;)

antiscab
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Re: Looking for a motor .. then will look at the battery pack

On my way in today I noticed I was able to cruise at 40mph with 100A don't remember the voltage at that point however. I'm thinking voltage at that point is in the neighborhood of 65 volts. It's interesting how 50mph required 3x the power. If I can I'll try 50mph on the drive home tonight.

increasing speed from 40mph to 50mph increases power to push the air out of the way by 1.95x (i tend to focus on that as thats where most of the energy goes)

however, that requires 1.95x current, which increases the motors resistance losses 3.81x.

i think that for above 40mph, that motor is way to small (though i guess we already knew that).

the max continuous current for both the warp 9 and the impulse 9 is ~200A (though they will take more than 1000A for a few seconds)

if you are planning on staying at 72v for a significant amount of time (ie for your next battery) than get the impulse 9.
otherwise, the warp 9 if you can fit it.
tricky thing is, the warp 9 has lots more back emf, so at ~3000rpm, the impulse 9 gives ~35hp whereas the warp 9 only gives ~18hp at 72v.

at 72v, those motors are fairly predictable, since thats all that netgains testing hardware can manage (the motors can take up to ~170v at load before arcing though).

the other thing is, before putting the motor in, if you are just going to run at 72v, return the brush timing to neutral.
it will improve the efficiency at the expense of performance at higher voltages (i will also reduce the max voltage to ~120v IIRC).

72v is a reasonably common system voltage for forklifts now, so it might be worth checking out forklift wreckers for second hand stuff rather than buying new.

Matt

Daily Ride:
2007 Vectrix, modified with 42 x Thundersky 60Ah
Vectrix 60Ah Lithium Tyres Fuel Registration Insurance cycle analyst 2 x TC Charger & MC
conversion

reikiman
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Re: Looking for a motor .. then will look at the battery pack

BTW - I bought the Impulse9. It's in the back section of my gas car at the moment and I don't quite know how to get it into the garage because the motor is heavier than any one person could carry. Anyway...

The plan is to install it in the car and initially use the alltrax controller already there to power the motor. Given that Netgain's website shows a power table @ 72 volts this motor will run fine on the existing pack. It'll be interesting to see what difference this makes (if any).

The motor came with a mounting plate & VW clutch that will let it hook directly to the transmission on this car. Should just be a simple swapout of the motor. Well, simple except for the matter of lifting this behemoth into place. There is a VW repair shop near me who I've been meaning to have a chat with, and mebbe they'll be interested in working with me on this. I do want them to look at the suspension and mebbe go over some of the other mechanicals. Or there's this guy down the street who also builds EV's who may be interested to help.

Also... I did one drive with the car going 14-15 miles where the usual drive is approx 7 miles. On every drive so far one of the batteries has ended up hotter than the others. At the end of that drive that one battery was very very hot, there was a bit of liquid pooled on top the battery, and I opened the battery cap nearest that pool and saw the battery fluid was BOILING. Obviously that battery has a weak cell and it should be replaced.

- David Herron, The Long Tail Pipe, davidherron.com, 7gen.com, What is Reiki
- Electrified Electra To

strawhistle
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Re: Looking for a motor .. then will look at the battery pack

Hi David, yes that battery should be replaced, it is shorted out ( the lead oxide has precipitated out and filled the bottom of the cell shorting out the plates) the heat generated is energy from the other cells-battery's ! LaTeR

thank GOD I wake up above ground !!!!

Cruisin
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Re: Looking for a motor .. then will look at the battery pack

I am driving a 70 VW beetle converted with a Impulse 9 motor and Li-ion batteries using 117vdc and can tell you this thing goes too fast. Using 2nd gear from 0 to 60mph workd well. To reduce the noise level I will sometimes use 3rd gear above 45mph. Range under favorable conditions is well over 50 miles, maybe 100 max. The car has been completly restored including 4 wheel disks with emergency brake. I am in Livermore if you are ever in the area.

Mik
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Re: Looking for a motor .. then will look at the battery pack

BTW - I bought the Impulse9. It's in the back section of my gas car at the moment and I don't quite know how to get it into the garage because the motor is heavier than any one person could carry. Anyway......
..
...

I often use a skateboard for such jobs!

This information may be used entirely at your own risk.

There is always a way if there is no other way!

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