# Help with motor choice.



## ookamithewolf1 (Mar 22, 2018)

So i'm new to EV conversion and am slowly amassing all the info I need so that I can eventually convert my car. I have a 1968 Dodge Dart Sedan with a 6 cylinder engine. Luckily it's a 'compact' and weighs 2866 lbs, without the engine its just under 2400 lbs. My question is whether an AC-50 will work for this application, or if there is something better. My car shipped with 110 HP and 185 ft/lbs of torque, and the ac-50 is rated at 71hp and 120 ft/lbs. Now, I don't really care about performance since this is my commuter car. Will this be enough? What are your ideas?


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## PAXtss (Dec 16, 2017)

A couple of questions- Does it have a manual transmission? How much high speed driving will you be doing?

My answer is yes it will work particularly when you say you don't care that much about performance.. Others say it will be under powered. I put the 51 in an '86 Mazda pickup and used 1/2 of a Leaf battery pack at 96V. It meets our needs easily which is around town driving, some at 50mph and towing (short distance) and launching/ recovering our 32' trimaran sail boat. The truck weighs 3000 # with me in it.
We drive in economy mode all the time and get about 3 1/2+ miles per KWH. That is stop and go and up some hills.

I would recommend upping the voltage to at least 120 or 144. 120 could be made out of a full Leaf battery put in 3 sub packs in parallel- best is 3 modules in parallel and 16 sets of 3 in series. Each Leaf module has 4 cells in it and puts out 7.5 nominal so 16x 7.5= 120V
With batteries and motor you will add at least 600 #. 
There are other motor options but for me the AC 50 was a great first conversion- pretty much plug and play,


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## ookamithewolf1 (Mar 22, 2018)

PAXtss said:


> A couple of questions- Does it have a manual transmission? How much high speed driving will you be doing?


I plan on putting a Chrysler 3-speed manual transmission in. I would like to drive this car on the highway, as I like to travel a lot. I may also be towing a small 8' camper at times as well.


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## Kevin Sharpe (Jul 4, 2011)

ookamithewolf1 said:


> I would like to drive this car on the highway, as I like to travel a lot. I may also be towing a small 8' camper at times as well.


How far to you want to drive with and without the camper?


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## ookamithewolf1 (Mar 22, 2018)

Kevin Sharpe said:


> How far to you want to drive with and without the camper?


That's tough to say, but I would like to eventually visit all the national parks, so we're talking driving across the continent a few times. I would like to put a solid 100,000 miles on it as a electric car.


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## Kevin Sharpe (Jul 4, 2011)

ookamithewolf1 said:


> That's tough to say


Sorry, I was unclear... how far do you want to drive before stopping to charge? I'm trying to understand what size battery you'll need 

Can you also estimate the weight of the camper?



ookamithewolf1 said:


> I would like to eventually visit all the national parks, so we're talking driving across the continent a few times.


Where will you recharge the battery on these trips?


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## brian_ (Feb 7, 2017)

With the reduction in range due to towing, you will be restricted to some combination of these approaches:

staying on major routes with fast charge stations
using campsites with 50-amp power service to recharge overnight
using campsites with lower power service for extended stays to recharge over the stay
staying at places other than parks while the car charges
It seems like a major hassle to me. Camping in parks with a trailer and driving an EV long distances just don't seem very compatible. I hope you have a lot of time for travel.


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## electro wrks (Mar 5, 2012)

Brian is right. Even with a model X (the best stock tow vehicle available, even today), this couple was really pushing it range-wise in their long distance RV adventure: https://www.tesla.com/customer-stories/crossing-canada-modelx-towing-camping-trailer?redirect=no

Their range was cut way down by the trailer; and the lack of SC stations made for some anxious times. I'm sure there are more SC stations now, but it still would be tough to do. I think the next generation Teslas, with better battery energy densities, will be better suited for the task.

If you insist upon doing a conversion for a use like this, a better vehicle would be like what PAXtss has, a pickup or other fully framed, heavier duty suspension vehicle. These vehicles have greater carrying capacity and more room for the batteries needed. Be prepared for it to very expensive. Lotsa $ for batteries (you'll need them). 

The AC line of motors is not a good choice for this application.
1) Their voltage(max ~150) is too low to take advantage of the DC fast charging network. 200-250V seems to be the minimum needed. 300-400V would be better. Traveling as you intend, without fast charging, would be very slow indeed.
2) Limits imposed by the Curtis controllers typically used and lack of provisions for motor cooling, limits the power outputs of these motors compared to other OEM, EV motors that have become available in the last few years.

One local EVRVer I know is working on putting a large battery bank in their trailer. It would be a range extender for the tow vehicle and a power source for trailer use. Again, lotsa $ needed. 

Keep working on your idea. The EVRV (or should I say ERV?) world is not quite here yet, but will be soon if we keep pushing the limits!


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## brian_ (Feb 7, 2017)

ookamithewolf1 said:


> Now, I don't really care about performance since this is my commuter car.





ookamithewolf1 said:


> I would like to drive this car on the highway, as I like to travel a lot. I may also be towing a small 8' camper at times as well.





ookamithewolf1 said:


> ... I would like to eventually visit all the national parks, so we're talking driving across the continent a few times.


Commuter use and long distances towing a trailer on highways are very different scenarios. Even if you are patient, the power which is adequate for urban commuting probably won't be viable for climbing grades at highway speed with even a small trailer attached.

Whatever meets the travel requirements seems to me to likely work for commuting, but not the other way around.


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## PAXtss (Dec 16, 2017)

Now that you have thrown in more requirements I suspect that the AC50 will be marginal. unless you are willing to spend a lot of time charging at low voltage as electrowrks points out.

If you really want to travel that much under those circumstances the battery sizing is a major concern. 
Rule of thumb Total weight (including trailer) (in lbs) divided by 100 gives wh/mile.

For a 3000# car 3000/100= 300Wh/mile or .3KWH/mile so to drive 100 miles is .3*100= 30KWH - battery pack needs to be at least 1.15 times this - so you need at least 34.5 KWH battery pack 

If trailer and other things weigh 1000 lbs then total weight is 4000
then 4000/100 = 400 wh/mile .40KWH/mile so to drive 100 miles you need 40KWH * 1.15 =46KWH . 
Oh and as you increase the battery size you add more weight and decrease KWH/mile.
If you are going to get into the 200v plus range then you really have to pay attention to safety. Actually you should pay attention at lower voltages - these batteries are fun to work with but are definitely not toys and need total respect.


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## ookamithewolf1 (Mar 22, 2018)

Alright, Thanks everyone for your input. I guess I should have mentioned that I won't be doing this for another 5 years, so I wasn't really concerned with batteries and range since I'm waiting for the cost of batteries to fall and/or for solid state batteries to be invented. If I've interpreted what info I've been given it seems that the motor would be fine for daily driving but under-powered for towing (so basically the same as it is now). 

Can anyone link me to a more appropriate motor?


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## Duncan (Dec 8, 2008)

Hi
If you don't intend doing this for five years I suggest you don't waste your money buying a motor now

In five years time I suspect that you will be able to get a much better motor much cheaper!

The motor from a Nissan Leaf - or by then from a Tesla type 3
Or something else!


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