# Motor matching 200bhp engine anyone??



## Amberwolf (May 29, 2009)

Before you worry about the motor, what batteries are you going to use to deliver that power, and where will they go? 
________
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## Bowser330 (Jun 15, 2008)

Amberwolf said:


> Before you worry about the motor, what batteries are you going to use to deliver that power, and where will they go?


+1

Jlrj, its important to keep in mind all the three major components...

(1) A motor that can handle a certain amount of voltage and amps continuously...as you mentioned. in the examples below I am mentioning 300V, I know a Kostov 11" can probably handle that but to handle 500A continuously (for 30 mins) is a touch requirement....What you could do is get the internals beefed up and then it could work...total cost of built-Kostov-11" would be probably 3000$ (MSRP is 2000$+1000 buildup)

(2) A controller that can deliver a strong amperage continuously...For example from what i hear the Curtis 144V 500A controller can only supply 200A continuously, however the soon to be released EVnetics controller can supply something like 500A..I think...Big difference...(Say you had a 300V system...thats 150kw = 200hp...) estimated cost...probably...2000$

(3) as AW mentioned, you also have to consider having a battery pack that can continuously supply that amount of current...most continuous ratings for lifepo4s are 3C, so If you had a 90AH cell (that would deliver 270A continuously) But at 3.2V you would need 100 of them to get to 320V, they cost about 100$, so thats 10K$ right there....they also weigh about 5 lbs I would assume so thats 500lbs of batteries...

By the estimate above...15K$... and you could have a powertrain that would deliver close to what you are looking for...

Also you have to understand that a road racing ICE with 200hp is not getting 200hp all the time, only when they are up around the higher peak RPMs, and how often is that, really...

you know what would be cool, is if you could get some type of data logging from these 200hp road-racing ICE engines to see in the 30min race, what gear the car was in and what RPM they were in for the entire race...that way you could actually see how often they are really using the peak 200hp...


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## Qer (May 7, 2008)

Bowser330 said:


> (1) A motor that can handle a certain amount of voltage and amps continuously...as you mentioned. in the examples below I am mentioning 300V, I know a Kostov 11" can probably handle that but to handle 500A continuously (for 30 mins) is a touch requirement....


The Kostov 11" can handle up to 250 Ampere for 60 minutes, don't think it will be much higher for 30 minutes though. But what matters is probably peak rather than continuously and that can be much higher...



Bowser330 said:


> however the soon to be released EVnetics controller can supply something like 500A..I think...


No comment as of now... 



Bowser330 said:


> (3) as AW mentioned, you also have to consider having a battery pack that can continuously supply that amount of current...most continuous ratings for lifepo4s are 3C, so If you had a 90AH cell (that would deliver 270A continuously) But at 3.2V you would need 100 of them to get to 320V, they cost about 100$, so thats 10K$ right there....they also weigh about 5 lbs I would assume so thats 500lbs of batteries...


However, a Kostov 11" is specified to 185 Volt and if you have a pack that can give 320 Volt, 270 Ampere that means you get 470 Ampere motor current for 3C from the batteries. At lower RPMs you can easily max out 1000 Ampere from the controller since the voltage over the motor will be much lower than 185 Volt.

Of course, most controllers can't handle 320 Volt...


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## jlrj87 (Jun 30, 2009)

Thanks for the replies!

The kostov does sound like a possibility, I was originally looking at the WarP 13s, but theyre max voltage is lower at 170V. Where supplies Kostov motors, so I can have a look at them. 

Might be a stupid question, but i know when u add 2 batteries you add the voltages, but do you add the Amphours as well? I'm guessing not... So two 12v batteries of 10Ah, would be 24v but still 10Ah right? Or wrong?


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## Bowser330 (Jun 15, 2008)

jlrj87 said:


> Thanks for the replies!
> 
> The kostov does sound like a possibility, I was originally looking at the WarP 13s, but theyre max voltage is lower at 170V. Where supplies Kostov motors, so I can have a look at them.
> 
> Might be a stupid question, but i know when u add 2 batteries you add the voltages, but do you add the Amphours as well? I'm guessing not... So two 12v batteries of 10Ah, would be 24v but still 10Ah right? Or wrong?


http://kostov-motors.com/tractionmotors/kostovlineofevmotors/

Series adds voltage, parallel adds Amps

12V 10AH, 2 in series = 24V 10AH

2 in parallel = 12V 20AH


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## Qer (May 7, 2008)

jlrj87 said:


> The kostov does sound like a possibility, I was originally looking at the WarP 13s, but theyre max voltage is lower at 170V. Where supplies Kostov motors, so I can have a look at them.


Just remember that voltage isn't everything. There are many factors in selecting an appropriate motor so the 170 versus 185 Volt might not be that much of an improvement after all. And bigger isn't always better as well, a 13" will give you more torque/Ampere but it will also give you less rpm and the total effect out won't change much. It's probably better to pick two small(er) motors, say 9", turn them into a Siamese dual motor and wire them up with a controller that can do parallel/serial-shifting. I even think Kostov can mate two motors for you directly from factory, CroDriver here in the forum ordered a custom made one for his car.

That said, I'm personally considering a Kostov 11" as well rather than a WarP, but my EV-building plans has gotten a bit derailed due to lack of time because of the controller project. On the other hand, what I've learned during that time will definitely mean that when I, eventually, start building the result will be VERY different compared to my initial plans thanks to all that new information I've got.


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## Bowser330 (Jun 15, 2008)

Qer said:


> Just remember that voltage isn't everything. There are many factors in selecting an appropriate motor so the 170 versus 185 Volt might not be that much of an improvement after all. And bigger isn't always better as well, a 13" will give you more torque/Ampere but it will also give you less rpm and the total effect out won't change much. It's probably better to pick two small(er) motors, say 9", turn them into a Siamese dual motor and wire them up with a controller that can do parallel/serial-shifting. I even think Kostov can mate two motors for you directly from factory, CroDriver here in the forum ordered a custom made one for his car.
> 
> That said, I'm personally considering a Kostov 11" as well rather than a WarP, but my EV-building plans has gotten a bit derailed due to lack of time because of the controller project. On the other hand, what I've learned during that time will definitely mean that when I, eventually, start building the result will be VERY different compared to my initial plans thanks to all that new information I've got.


I know its still in development and all that but will the EVnetics controller have Series/Parallel shifting abilities?

I think the idea of two built-for-high-voltage (300V) 9" kostovs with an EVnetics cotnroller would be a strong competitor for even the 25K$ (not available to the consumer) AC-propulsion package!


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## major (Apr 4, 2008)

jlrj87 said:


> Being a race car it would need to be able to have 200bhp all the time, not just every now and then so would need to be able to cope without burning itself out.
> 
> Would probably race for about 30mins a time.
> 
> Any suggestions guys?


Hi there jlrj,

Suggestions? Get real 

200 hp all the time for 30 minutes? What are you racing? 150 mph big oval track? To do that off batteries you'd need like a 100 kW-hr pack. See what that would weigh and cost.

And 200 hp all the time for 30 minutes would require another $100,000 in motor and controller.

This can be done, but would take very deep pockets. Pretty much the equivalent of 3 Tesla Raodsters.

Dream on,

major


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## joseph3354 (Apr 2, 2008)

check these out:

http://www.calmotors.com/products.ph...ts&page=medium


major is right,you will need a lot of battery capacity  .


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## Qer (May 7, 2008)

Bowser330 said:


> I know its still in development and all that but will the EVnetics controller have Series/Parallel shifting abilities?


You think we'd build a controller aiming for 4 digit current without adding support for series/parallel shifting? 

Of course it will be capable of handling that! That is, eventually. It will, however, not have it from day one due to two simple reasons:



There's more important things that has to be implemented and since I'm the software department (and have a daytime job to pay bills) it might unfortunately take a while until we get to that point on the wish list. However, when it becomes available it will be available even for the controllers that initially has been sold without the support.
At the moment we have no way of testing it in real life. We simply need to sell some controllers to be able to invest in the stuff used to test this feature thoroughly.
But we'll get there...


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## jlrj87 (Jun 30, 2009)

major said:


> Hi there jlrj,
> 
> Suggestions? Get real
> 
> ...


 
Ok its not an oval racer, thats for pansies,  but it is track racer so no it won't technically need 200bhp solidly for 30mins, but will need to be able to cope with hard acceleration out of corners and along straights, so this should allow for some down time in the motor.

I had heard about possibly putting two motors together someone else suggested two Warp 9s. What kind of advantages are there for using two smaller motors as apposed to one big one. I take it the higher rpms give you higher HP? What else is involved in linking two motors together?

Thanks to everyones replies, they have been very useful!


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## Qer (May 7, 2008)

jlrj87 said:


> I had heard about possibly putting two motors together someone else suggested two Warp 9s. What kind of advantages are there for using two smaller motors as apposed to one big one.


When a motor runs at low rpm the voltage over it is proportionally low which means that the amount of power out from the motor is low as well. By having two motors you can have them connected (electrically) in series at low rpms and in parallel at high rpms. At high rpms you won't notice any difference in power from the motors, but at low rpms you'll get twice the power than you'd get otherwise (provided the batteries can take it, of course).

EDIT: And of course I forgot about back-EMF in the parallel case. Dang. As long as you can push max current through the controller you won't notice any difference in performance from the motors in parallel mode, but when back-EMF starts to cut down the current, you'll get twice the current compared to a single motor. So at low AND high rpm you'll notice a performance gain, but in the mid range (where back-EMF is too high for serially connected motors to be effective but back-EMF hasn't started to cut down current for parallel motors) it will be the same as for a single motor.

Here's some good reading about it from a drag racing perspective:

http://www.plasmaboyracing.com/reviews.php



jlrj87 said:


> I take it the higher rpms give you higher HP?


Nope, or maybe, or, uh...

A motor that gives high rpm also gives lower torque. Watt (power) is Voltage multiplied with Ampere, or torque multiplied with speed (insert fitting scaling constant depending of favourite units). So if you increase rpm and keep the torque power goes up, but if you change motor but keep voltage and current you might get higher rpm but since power is the same, torque will drop as a result.

Your HP will be Volt times Ampere (minus losses, of course) no matter what motor you choose.

I hope I managed to make some sense here...


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## dreamer (Feb 28, 2009)

joseph3354 said:


> check these out:
> 
> http://www.calmotors.com/products.ph...ts&page=medium













Oooooh, Preeetttty ! I suppose the blue paint is a $1,000 option ?


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## Amberwolf (May 29, 2009)

dreamer said:


> Oooooh, Preeetttty ! I suppose the blue paint is a $1,000 option ?


No, it comes free with all their computer-generated pictures. 
________
Philippine girl live


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## major (Apr 4, 2008)

jlrj87 said:


> Ok its not an oval racer, thats for pansies,  but it is track racer so no it won't technically need 200bhp solidly for 30mins, but will need to be able to cope with hard acceleration out of corners and along straights,


Hey jlrj,

I doubt you will get DC motors to live, even using 2. For this type of racing you need pretty high continuous power rated motors (and controllers). AC drives with cooling systems are the way to go. See the Electric IMP at http://www.proev.com/ 

Regards,

major


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## jlrj87 (Jun 30, 2009)

major said:


> Hey jlrj,
> 
> I doubt you will get DC motors to live, even using 2. For this type of racing you need pretty high continuous power rated motors (and controllers). AC drives with cooling systems are the way to go. See the Electric IMP at http://www.proev.com/
> 
> ...


Yeah I spotted this the other day, and scared me a bit when I worked out how much they'd spent on Li batteries, we have nothing like that kind of budget, so it's not looking very good so far...


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