# Pondering Tercel/Paseo Conversion



## PhxVigo (May 25, 2009)

Hello all, 

I'll get the background bit out of the way first... 

Your skill level with auto mechanics and fabrication
Auto mechanics; Basic. I've changed oil, spark plugs, coil, alternator, radiator, heater core, etc on previous vehicles. 

Fabrication; Do Legos count?  No pratical experience. Looks fun though. 

The range you are hoping to get (how many miles/charge) 
I'd like an honest 30 mile range while keeping the DoD to a reasonable level. It's a 13 mile drive to work, then sit for 8 hours and a 13 mile drive home. 10 miles (20 round trip) is on the freeway with 65mph limit. I'd like to keep the freeway option open if possible. Also, I'm in Phoenix and really need to keep the air conditioning.

What level of performance you are hoping to get 
Keep up with traffic. 65mph on freeway speed if possible otherwise surface streets are 40-45mph limit. 

How much money you are willing to put into your project 
TBD. Maybe $7,000. 

What parts you've already considered, if any. 
HPGC AC31-01, 90's Tercel or Paseo. (Please see below)

I've been thinking about doing a conversion. I'm still in the planning phase, nothing has been purchased, so it's a blank slate. I do have some ideas though, and wanted some input from those more knowledgeable.

I'd like to do a small car. I'm thinking a mid 90's Toyota Tercel or Paseo. From my internet research, the Tercel has a curb weight of 1950 lbs and a gross weight of 2899 lbs. I'd like to remove the rear seat and put as many batteries as will fit in that area to help keep the load spread between the axles. For the Paseo I'd take the same approach, but it has a little higher starting weight (2070 curb, and 2975 gross) 

I was considering using a D&D ES-31B motor, but then I came across the HPGC AC31-01 (http://www.evparts.com/prod-MT5610.htm). I think an AC drive with regen would be cool, and while the price is a bit high, it's in the realm of possibility.

Okay, so there's the background. Now the questions... 

What sort of battery pack will I need to achieve my range goals? I'd like to stick with lead. I'm thinking 8V batteries would simplify wiring. 

Given the weight of lead, will the motor I've picked be adequate?

Thanks in advance!
-Bill


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## PhxVigo (May 25, 2009)

Replying to myself here... I hope this makes sense.

Using the recommendations from the Wiki and information from the three other completed Tercels in the EValbum, here are some thoughts on batteries...

There were two Tercel's with Wh/mile estimates. One says 253, the other says 300. Taking the worst, 30 mile range * 300 wh/m = 9,000w

9,000 w / 108v = 83.33 ah

83.33 ah * 1.25 (for 80% DoD) = 104.17 ah

104.17 ah * 1.8 (for peukert loss) = 187.5 ah

So, since the formula estimates for Peukert loss, I need to find something with at least 187.5ah at the 20 hour rate. Looking at the Trojan T-605 battery, it has 210ah at the 20 hour rate. It's 6v and weighs 58lbs. I'd need 18 of them, so 1,044lbs of batteries.

One of the Tercel conversions said it was about 1600lbs with ICE removed. So, glider weight plus batteries is about 2,650lbs. Motor is 46 lbs, I don't know the weight of the controller. Just to throw out a number, I'll say 300 lbs for battery box, controller and charger. Which comes out to just about 3,000 lbs. I've exceeded the gross weight without any cargo (like a driver for example).


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## madderscience (Jun 28, 2008)

Your battery calculations are about right though I'd go ahead and put in at least 20 batteries (120V with 6V batteries). Hey, what's another 120lbs among friends? Remember that your Air conditioning requirement is going to be about a 10% tax on your range due to the extra load. Sure you can't crack a window instead?

As for the motor, the D&D is a little small for a freeway capable car. Go for at least an 8" diameter motor such as this one from evparts:

http://www.evparts.com/prod-MT2116.htm

if you have any real hills, go for the 9" motor instead (many options at same site as above). Considerably more torque.

Note that if you DO want regen, there is a fairly reasonably priced AC option out there (finally), but it is limited to 96V:

http://www.evparts.com/prod-MT5610.htm (motor AND controller)

With this one you'd probably want to go with 250AH flooded golf cart batteries like the trojan T-145 to get enough capacity. This motor may not be quite powerful enough if you have any lengthy hills to climb though.

The 30 mile round trip range will be feasible unless you are climbing a mountain pass.

Many EV conversion (including mine) are several hundred pounds over GVW. we compensate by installing stiffer suspension components and bigger brakes. Stuff like this is available for many japanese cars to satisfy the hopped-up rice racer crowd.

Good luck.


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## PhxVigo (May 25, 2009)

madderscience said:


> Your battery calculations are about right though I'd go ahead and put in at least 20 batteries (120V with 6V batteries). Hey, what's another 120lbs among friends? Remember that your Air conditioning requirement is going to be about a 10% tax on your range due to the extra load. Sure you can't crack a window instead?


It's good to know I'm not totally off base. Regarding the air conditioning, I *can* open the window and I used to go that route back in the day. In Phoenix, we see 100+ temps in 5 months of the year. Driving around with no air gets old fast. I figure, if I'm going to spend the money, it makes sense to build a car I want to drive not one that's a chore. I was wondering how much it would cost me though. 10% range isn't too awful I suppose.



madderscience said:


> As for the motor, the D&D is a little small for a freeway capable car. Go for at least an 8" diameter motor such as this one from evparts:
> 
> http://www.evparts.com/prod-MT2116.htm
> 
> ...


I was originally thinking the D&D as the Tercel conversions on EV Album had used something similar and it seemed to work out well. I agree though, the 8" is probably a better choice.

The AC motor you linked to is exactly the one I was thinking about and the one my battery calculations were based on. The website lists it as 96v max, but there is a discussion about it here: http://www.diyelectriccar.com/forums/showthread.php?t=24498&highlight=AC31 where they come to the conclusion that 108v is the max nominal voltage for the controller. Thus I figured 108v was the way to go.



madderscience said:


> With this one you'd probably want to go with 250AH flooded golf cart batteries like the trojan T-145 to get enough capacity. This motor may not be quite powerful enough if you have any lengthy hills to climb though.


I redid the calcs with 96v, and the T-605's would be just enough with no air conditioning. At the 108v level though, including an extra 10% for air comes out to 206.25ah, so if I can do 108v, the T-605's should be enough. I realize of course this is all an estimation. I guess you don't really know until you start driving it.



madderscience said:


> The 30 mile round trip range will be feasible unless you are climbing a mountain pass.


Fortunately, there is only one hill on my route. I will guess that it's about twice as high as a typical freeway overpass. Nothing too severe. If it was a problem, I can change my route to avoid it without adding any additional mileage.



madderscience said:


> Many EV conversion (including mine) are several hundred pounds over GVW. we compensate by installing stiffer suspension components and bigger brakes. Stuff like this is available for many japanese cars to satisfy the hopped-up rice racer crowd.
> 
> Good luck.


I thought by choosing a smaller, lightweight car I could keep the weight down. I'm finding out that is quite difficult to do though. At some point I would like to go with LiPo's, which would be ideal, but the price isn't there for me yet.

Anyway, thanks for the reply. I think I'm on the right track, I'm just concerned with the weight I'm looking at, the little AC motor won't cut it. Is there some way to estimate what my top speed and acceleration would work out to?


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## madderscience (Jun 28, 2008)

"just enough" with the batteries means that as soon as the batteries start to degrade which they do over time, you will find just enough isn't enough anymore. Your calculation assumes you are cycling the batteries to 80%. FLA's can take several hundred cycles of that, but the car's performance will start to get noticeably more sluggish towards the bottom. I'd try to give myself some more margin there. It's as if you planned your driving with your ICE car to get to the next gas station with a completely empty tank. That's cuttiing it close.

For what it is worth, since you are in a nice warm area of the country you will benefit a bit from the heat in that the batteries will perform better. FLA batteries are rated at 80 degrees F. colder than that and there capacity drops. warmer than that and they perform better. One thing to keep in mind though is they can be damaged if they exceed 120 degrees F. (plate warping). So ensure that your batteries are ventilated. 

As another FWIW, your 300 wh/mile (battery-to-wheels) estimate is conservative for a small car, especially if you dial in the rolling resistance and such. You can probably get away with assuming 250wh/mile for the battery-to-wheel calculation.

The hill you describe is nothing to worry about.

You ARE keeping your weight down with a small car, relative to what it would be if you were converting a bigger vehicle, and you are benefiting from the aerodynamic advantages of the smaller vehicle, which of course aren't impacted by the extra battery weight. Unfortunately as you have noticed, getting enough lead in a small car for 40 miles of range will usually exceed the GVW as previously discussed. About the only way to go and stay under GVW with FLA is to convert a small pickup.

In a small car, top speed will probably be limited by either your pack voltage or your motor RPM limit. A DC powered, 120V small car with a decently sized motor should be able to get up to 70mph on the level but it isn't going to be a hot rod. I don't know how using the AC motor you were considering would affect that. My MR2 with 1250lbs of lead (3400lbs total curb weight), 126v and a 9" motor and the same curtis controller you are considering needs 20 to 25 seconds to do 0 to 60, and I have had it up to 70 though it wasn't quite wound out yet. Motor redline in my car is at 75 in the highest gear. So you aren't going to be building a hot rod, but you will be able to keep up with normal traffic. 

Good Luck.


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## dtbaker (Jan 5, 2008)

madderscience said:


> "just enough" with the batteries means that as soon as the batteries start to degrade which they do over time, you will find just enough isn't enough anymore. Your calculation assumes you are cycling the batteries to 80%. FLA's can take several hundred cycles of that, but the car's performance will start to get noticeably more sluggish towards the bottom.


I'll second that. I have 96v worth of 8v, and while my range is right around 40, that last 10 feels like a strain. My usual day is closer to 20, so its not a problem. If you have room, I'd suggest 120v worth (15 x 8v batteries FLA).... like the us battery usg8chcx and stick to simple 8" DC motor if you want to keep your cost down.


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## PhxVigo (May 25, 2009)

madderscience said:


> "just enough" with the batteries means that as soon as the batteries start to degrade which they do over time, you will find just enough isn't enough anymore. Your calculation assumes you are cycling the batteries to 80%. FLA's can take several hundred cycles of that, but the car's performance will start to get noticeably more sluggish towards the bottom. I'd try to give myself some more margin there. It's as if you planned your driving with your ICE car to get to the next gas station with a completely empty tank. That's cuttiing it close.


Understood. Is there a rule of thumb for what kind of extra capacity one should leave to allow for the ageing of the batteries? 10%? 20%? It would be nice if they would last at least a year and two would be better. My hope is that the price for Lipo's will continue to come down and I can reevaluate them when this pack reaches the end of its life.



madderscience said:


> For what it is worth, since you are in a nice warm area of the country you will benefit a bit from the heat in that the batteries will perform better. FLA batteries are rated at 80 degrees F. colder than that and there capacity drops. warmer than that and they perform better. One thing to keep in mind though is they can be damaged if they exceed 120 degrees F. (plate warping). So ensure that your batteries are ventilated.


That will be a problem. It's unavoidable for the batteries to spend time above 120. In the summer, ambient temperature will be 110+. While the car is parked, the temperature inside will be 150+. I had intended on putting the batteries in a ventilated box anyway so perhaps I can have the fan run all the time (solar cell?) or maybe have it temperature activated. That should help some. There are a ton of golf carts in Phoenix, so they must have some way of coping with the summer heat.


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## PhxVigo (May 25, 2009)

dtbaker said:


> I'll second that. I have 96v worth of 8v, and while my range is right around 40, that last 10 feels like a strain. My usual day is closer to 20, so its not a problem. If you have room, I'd suggest 120v worth (15 x 8v batteries FLA).... like the us battery usg8chcx and stick to simple 8" DC motor if you want to keep your cost down.


Is your 40 mile range down to 80% discharge? If I were to go with the ADC 8", then I agree, higher voltage is the way to go. With the particular AC motor I'm interested in though, I'm capped by the controller at 108v.

I'm still bouncing back and forth regarding what voltage battery to go with. I was originally considering an 8 volt very similar to the one you recommend. Then I was thinking it would be better to use 12 volt to minimize the number of batteries (less cables to make) and it would also be handy for the modular charging option (buy one 12v charger for each battery). They do make some 12v batteries with enough Ah's for my needs but those things are monsters... 80+ pounds each. I'd have a heck of a time getting them in the car.

I had a read through your website. Looks good! I liked the spreadsheet listing vehicle weights (and kbb prices). I notice there's no Tercel in there though.  I considered the Metro/Swift as a possibility, but the styling doesn't do it for me. Otherwise, it seems like an excellent EV platform.


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## Guest (Jun 2, 2009)

12 6 volt GC2 Golf cart batteries. Heavy is an understatement. I will be adding another 4 to up my pack to 96 volts. I should get the mileage I want then. Plus a bit of an extra pep boost too. My Ghia does real well in first and second and fair in 3rd and 4th. It will do just better than 65 mph now and it will do a solid 15 miles at 65 mph with out a hiccup or slow down. I may actually be able to reach my place of employment too if I try at maybe 55 mph. 22 miles from driveway to parking lot. We shall see. A bit more pep and the hill should be no problem. It is just the distance I am concerned about on the return trip after the large short hill. 

Pete


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## nheistand (Jun 2, 2009)

I am driving my 1990 Toyota Tercel with the DC kit from Electro Automotive. Since you have a 30mi commute, my conversion would be about right with 40mi range. AC components are more expensive and do not buy much for your commute. I am running an Impulse 9 motor and 12x8v golf cart batteries. I believe I can go 60mph but have not tested it. 

Going fast (65mph) shortens your range. You might consider running 15x8v batteries with a system like mine to get a little more speed and range. The easy way to do it would be to take out the back seat and put 10 batteries in the hatch and back seat area and 5 batteries up front. Or 3 batteries up front, 6 in a plastic marine battery box in the back seat, and 4 in another plastic marine box in the hatch area.

The DC kit from Electro Auto is $6000 and 8v batteries are $140 from Interstate. Sams club has 8v batteries for $80 or so but not the best type of terminal posts. Just some thoughts.

Norm


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## PhxVigo (May 25, 2009)

nheistand said:


> I am driving my 1990 Toyota Tercel with the DC kit from Electro Automotive. Since you have a 30mi commute, my conversion would be about right with 40mi range. AC components are more expensive and do not buy much for your commute. I am running an Impulse 9 motor and 12x8v golf cart batteries. I believe I can go 60mph but have not tested it.
> ...snip...
> Norm


Thanks! That's just the kind of info I am looking for... It seems like there are several Tercel's on EV album getting the kind of range I need with a lot fewer batteries than the calcs say I need. Perhaps the calcs are a bit conservative.

What DoD are you at after 40 miles?

Do you by chance have a web page or build thread? I'd love to read more... I found a couple pictures. It looks like you have the previous body style (from the one I was considering) with a hatchback. Do you by chance know your starting curb weight (Before you removed the ICE) and your ending weight (after EV conversion)?

Are you running the Curtis 1221 or 1231? How is your acceleration?

Sorry for all the questions... 

Recently I've been thinking I should "get my feet wet" with a bike conversion first. You can pick up kits cheap and I think I still have my old bike somewhere in my mom's garage. Hehe...


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## nheistand (Jun 2, 2009)

According to the registration, the vehicle was 2000 lb. It has a tag that says the carrying capacity is 775lbs. My rough weight estimates are:

300 lb: gas engine, radiator, exhaust, gas tank, etc. 
150 lb: electric motor (nice big 9in)
768 lb: 12x8v u8vgc batteries (12 x 64lb)

So 2000 - 300 = 1700, 1700 + 150 + 768 = 2618 lb
So if the original was 2000 + 775 = 2775 limit, I am allowed 157 lbs.
Guess I will need to lose some weight. 

Essentially the little car was designed to carry 4 adults so 180 x 4 = 720 lbs and another 55 lbs of groceries. As you can see I have replaced the other 3 adults and groceries with the weight of my batteries.

The main concerns with the extra weight are springs (rear in my case) and brakes. I plan to add a vacuum resevoir so the power brakes will work well and I have replaced all the pads and shoes. The rear of my car sets a little bit lower than the front so I would be nice to have some booster springs of some sort in the rear, or may just those cheap coil inserts that would make it ride a little higher.

I think my acceleration is fine but have not measured it. I do not know the numbers for my actual top speed and range yet. Data from other conversions give a fair estimate of what you get with a 9in motor, Curtiss 1221 controller, and 12x8v batteries. If I get actual 60+mph and 35+mi range with the battery pack down to 15% or something then I could consider adding 3 more batteries for 15x8v = 120v which is the limit for the Curtiss 1221. Then I would for sure need a little more rear springs and would get both more speed and/or more range. It is always a trade-off you know with speed versus range.

Just some ideas.


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