# Need to loose some weight!



## ZeroGasoline (Jul 30, 2008)

First let me thank everyone on the forums for all of their hard work and their time contributing to the forum - it's a great resource.

I've been trying to find some ways to increase the range in my EV. I can't pry much more money out of the wife right now so the big ticket upgrades like batteries and tires/wheels are probably out of the picture.

Currently, I drive about 9 miles per day to work, charge, then return the 8.8 miles home. There is one rather large hill on the way to work, and by the time I'm rolling in the car is is sometimes very sluggish. I'd like to add the additional range just to take some stress off of my batteries.
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That leaves me with reducing the weight of the car. 

The car is a '94 Tercel. The car was 1950lbs with the ICE in it, and I estimate that it's pretty close to that now. My conversion overall is pretty textbook.

The wall that I'm running up against is how to cut the weight out of the car. It's pretty light as is but I'm not naturally a car guy so I'm hoping I've overlooked something. I've got access to a full auto shop so I can try just about anything.

If anyone has any suggestions I would be very grateful.

Thanks


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## TheSGC (Nov 15, 2007)

What are your battery specs? (I'm curious on the Ah ratings) 

What is your Tire Pressure? I noticed a huge difference going from the stock 30 PSI to 40 PSI. (20% range improvement according to my recorded data.)

I also found that adding a blower to cool the little 6.7" motor did WONDERS to my EV. My motor would overheat going up a 12% grade hill and my speed would drop to 12 MPH. With the blower I could hold the 25 MPH speed limit, and my range increased significantly because less AMPs were being wasted as heat through my motor. (Another 16% range increase)

Some other things are ditching the spare tire and tools, remove floor mats, clean out glove compartment etc.


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## ZeroGasoline (Jul 30, 2008)

I have 6x 12v 105aH batteries from NAPA. I know they are definitely on the lower end of the spectrum, but I wanted my first pack to be "disposable" to account for my lack of experience.

I've done roughly the same as you have with tire pressure. They are rated for 30psi and I have them at 40 or 41psi. I've been terrible ensuring they are consistently at this pressure - that is one of my goals for the summer.

I've read where a few other people have advocated blowers to cool the motor. What kind of blower is this exactly? I'll admit that I haven't looked into it that much but that definitely interests me. By the time I had finished my build last year it was begining to get pretty cold so motor cooling hadn't really crossed my mind. Do you have a website or evalbum page where I could take a look at yours?

***correction, I couldn't see the links in your signature when I was writing the reply***

I've removed the spare, and anything else non-essential from the car. I did leave one 40 piece socket set in the car as an emergency tool set, but it doesn't weigh much more than 2 or 3 pounds.


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## rctous (Jun 18, 2008)

I know this is the other way but have ya considered adding a couple more batteries to get the voltage up? More voltage less amp draw more range and power???

Brian


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## DavidDymaxion (Dec 1, 2008)

Random ideas:


Find lightweight racing seats from a wrecked car.
Replace rear windows with plastic.
Replace bumper structure with foam.
Remove right rear view mirror (if legal)



ZeroGasoline said:


> First let me thank everyone on the forums for all of their hard work and their time contributing to the forum - it's a great resource.
> 
> I've been trying to find some ways to increase the range in my EV. I can't pry much more money out of the wife right now so the big ticket upgrades like batteries and tires/wheels are probably out of the picture.
> 
> ...


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## madderscience (Jun 28, 2008)

if you are getting nearly 20 miles out of six 105Ah batteries I dare say you are doing pretty well. Since it would be rather expensive to go higher voltage (you would have to upgrade the charger and controller at a minimum) I would repeat the suggestion of trying to find a bigger (more AH, same voltage) battery pack next time around. Trojan T-1275's are 12v x 150AH or so, and Trojan T-875's are 8V x 175AH. Interstate makes equivalent batteries that are a bit cheaper than the trojans and work well too. either configuration should easily give that car more like 30 miles of range under similar conditions to what you are doing now, and still keep the car under GVW.

In the meantime, if you haven't had the alignment checked, it might help to have that done. Unless you need it, take the back seat out. there's 30 or 40 pounds right there. Removing carpeting might help too. If you really like hard work, you can strip out some of the asphalt sound deadening material that you will probably find under the carpets on the floorboards. a propane torch or a heat gun and a plastic scraper can accomplish this but don't get things too hot or you will mess up the paint and the undercoating. you can probably scrape 30 or 40 pounds of it out if you get all of it, but its a lot of work. I removed only a little bit of it out of my car because it got to be too much of a pain.

Go to some racing websites/forums and see what people do to prepare cars like yours for racing. There might be some other weight reduction tricks there.


Good Luck.


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## mattW (Sep 14, 2007)

Also don't overlook the weight reduction thread on the wiki, just follow the blue hyperlink.


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## ZeroGasoline (Jul 30, 2008)

madderscience said:


> if you are getting nearly 20 miles out of six 105Ah batteries I dare say you are doing pretty well.


I got 20 miles only once - by the time I got home I was barely rolling in at about 25mph. I haven't taken them that low since. Usually now, I'm getting closer to a safe 10 miles than the 20.



mattW said:


> Also don't overlook the weight reduction thread on the wiki, just follow the blue hyperlink.


I'll admit I overlooked the wiki - I never even knew it was there. There's a lot of good information in there though, thank you.

I think I'm going to take a hard look at component cooling (motor & controller). I went on a very light (no more than 100 amp draw) 5 mile ride the other day and both components got uncomfortably warm. I don't have a proper thermometer so I can't tell you the exact temp, but it was difficult to keep your hand on them for long. The front grill is completely blocked off right now to protect the front 4 batteries, so I think heat buildup is a major problem right now.

I'll post back once I make some changes and let you know how I made out. Thanks again.


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## TheSGC (Nov 15, 2007)

I just looked at your website and noticed that your Alltrax isn't on a heat sink. It needs a decent sized heatsink to work properly, and I would not be surprised that part of your bad performance was due to the controller overheating and going into thermal protection and slowing down considerably.

I have a 96 volt 400 AMP Kelly with a massive 3/4 inch aluminum plate as a heatsink and after driving 10 miles with 100+ AMPs its pretty much stone cold. The plate is warm, and the controller has never gone into thermal shutdown/slow down.


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## ZeroGasoline (Jul 30, 2008)

TheSGC said:


> I just looked at your website and noticed that your Alltrax isn't on a heat sink. It needs a decent sized heatsink to work properly, and I would not be surprised that part of your bad performance was due to the controller overheating and going into thermal protection and slowing down considerably.


I completely agree. The controller doesn't seem to get nearly as warm as the motor, but I think it does overheat some (especially when I have to climb one particular hill).

There's a noticeable difference in performance between 50 degrees F and 85 degrees F. The car seems to perform much better when the temp is down near 50F - so I agree cooling is part of my issue.

TheSCG, does your controller sit on top of or underneath your aluminum plate?


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## TheSGC (Nov 15, 2007)

My Controller sits on top of the heatsink. I found it worked out best because it was also a splash guard for the systems.


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## ZeroGasoline (Jul 30, 2008)

TheSGC said:


> My Controller sits on top of the heatsink. I found it worked out best because it was also a splash guard for the systems.


Thanks. I'll keep my eye out for a piece of aluminum that I could bolt in there with the rest of everything. I'm sure (like you said) that alone will provide plenty of cooling for my controller. If I can get the motor cooled as well, I think I'll be in business.


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