Going Over the Data

I have been pouring over all the data I have collected, such as range estimations, AMP draw at different speeds, top speed and all these hills. I them made a conclusion and took it to the electric vehicle teacher and he agreed: my controller is way underpowered.

Actually, I learned that my K99-4007 was actually quite fine for the Civic with the blower cooler and proper gear selection. It was my controller limiting the acceleration and AMP draw to the motor. Which makes sense because my controller couldn't provide the continuous power required to maintain hills, and I only need to higher AMPS for a few seconds.

So now I know it's the controller, it's on the top of my EV list of things to buy. I am still working on getting a plug at school, but I really need the upgrade controller before driving it there. I hope to have the new controller by the end of August, before the semester starts up again.

More Tweaking

This week was spent gathering more EV driving data by my dad. I adjusted the vacuum switch on the brake pump because the pump would not turn off. A quick adjust of the setting screw and it now stays off for a lot less of time, but still works just fine.

I also took another crack at figuring out the whole hill thing. I temporarily hooked up my current meter and took some AMP testings and then went off to the hill with the worst grade (5.6 %) and did a few runs, with momentum and one starting from a stop, after getting the controller warm.

I found that it would draw 200+ amps, then drop down to 182 AMPs and wouldn't go any higher, even if I floored it. This means that the controller is limiting the current due to heat.

So I found the most powerful CPU fan I could find and planted it on the Kelly controller. Man, what a difference! I have a heatsink for the bottom of the controller, but the top also needed some cooling. After a 5 mile run the controller was practically cold and usually it's quite warm. And it's 85 degrees F out today, and humid and it's probably closer to 120F under the hood and the controller will start to slow down at 125 F. The CPU fan was designed to cool Quad Core Xeon processors, so cooling the Kelly isn't too far out of it's design specs. And I can always add another one.

Now it has to go through some real testing but my dad driving it to work again and see if it's any better. The motor needs to see 215+ AMPs to hold the hills at 30 MPH, which means it needs to pull 215 from the batteries, which hopefully it can do now for longer than a few seconds. 20-30 seconds would be nice just to clear the hills.

Dilemma

After a few days of daily driving, we have decided that we need to upgrade the controller. The Kelly just won't make some of the hills, dipping down to 5 MPH because the continuous power of the controller is 160 AMPs and I need more like 250 AMPs.

I thought it would have been fine because the other controller that was recommended to me was a Curtis 1221c, which is similar to my Kelly with 400 AMPs peak, but instead only 150 AMPs continuous.

I was going to build the Open Source EV Controller, but I planned on taking my time slowly building it over a period of a few months to iron out any kinks and give it a thorough testing. So now I have to research production controllers and I am currently looking at either the Curtis 1231C, Logisystems and the new Synkromotive controller. Right now my eyes are set on the Synkromotive controller since it has the highest continuous current of 400 AMPs and a peak of 650, so it would be a HUGE performance increase.

I also have put up my spare parts for sale on Craigslist and DIY Electric Car Classifieds to fund this controller upgrade:

http://www.diyelectriccar.com/forums/showthread.php/ev-parts-lot-sale-33926.html

I am hoping anyone out there will pick up these parts since it's a great deal, and a great way to get started on an EV project.

Here are the links to the Open Source EV Controller:
http://ecomodder.com/wiki/index.php/ReVolt
And this is the Forum Post on Ecomodder, a good read and a must read for anyone wanting to learn about this controller: http://ecomodder.com/forum/showthread.php/paul-sabrinas-cheap-144v-motor-controller-6404.html

Battery Watering

Yesterday I checked the water level off all my batteries after getting the suggestion from my PakTrakr to "Check Water in Battery B1". I found that most of the batteries needed little to no water, which is excellent. Nothing was dangerously low , which is quite good after 230 miles of EV driving. I have read that watering is needed every 200 or so miles and it only takes about 15 minutes to check the levels and add new water if needed, so it might become a Friday night thing to do since the EV will be doing close to 200 miles a week, hopefully starting tomorrow.

Also, after my video run I checked my cables to see how they were and I noticed that one was quite warm so I removed it and found that is had high resistance. So I removed all the cables and gave them a good corrosion sanding. The resistance went from 0.4 ohms to 0.0 ohms after some instense cleaning, about 15 minutes per connection and I have 16 connections.... do the math... I watche Lord of the Rings: The Two Towers and I still wasn't done with the cables....

I haven't driven the EV since that, but I should expect cooler cables and possible an increase of power. Since that resistance was limiting me to 240 battery AMPs (V=IR) now I should be able to pull more, but I really don't want to in order to preserve battery life.

EV Driving Video

Well, here it is, the first driving video! Proof that one can make an EV with an automatic transmission.

There is no commentary by me because I was sort of tired and I did another whole commentary but the the camera fell over at the first corner and I didn't realize until partway through so I scrapped it.

Anyways, it's a 1.1 mile run around my neighborhood doing 25 MPH speeds. You can clearly hear the 12 volt Thomas brake pump and when that is off, the hum of the electric motor. I am going to get another video one of these days with a bit of 45 MPH highway, but that will have to wait until I can get a passenger to hold the camera for me.

Tweaks

I have about 75 miles on the EV now and I am getting ready so some tweaks. I am going to adjust the controller settings for a smoother start and I am researching a new suspension system. I am also looking at the pulley system for hooking up the AC and Power Steering, but the new suspension is on the top of my list. I think I have found a system I like

I am also development my own Battery Management System. While wet deep cycle batteries don't require it, I figure it would be a good system to caring for the batteries and making sure they are properly balanced and don't get overcharged. I do have the PakTrakr but it only monitors the batteries, but doesn't actually manage them or balance the batteries.

I still haven't made the EV driving video but I am hoping to do it this weekend if the weather ever lightens up.