Friday, January 29, 2010

Compressor Mount

Well, it took almost the whole day, but I finished the mounting bracket for the A/C compressor. No picture yet since it's not assembled. Parts of it needed to be painted. It will fit in the space nicely and will be adjustable to accommodate different size belts. It looks like I'm going to need a 31" belt, which I was able to find on Graingers web site.

I did manage to spend some time contemplating how I'm going to position the batteries so that I can connect them together the easiest. While fitting some of the batteries in place, I realized that I could make one small adjustment to improve placement. Yesterday I explained how I needed to put two of the batteries that I'd intended to put in the large box up front, in the back instead because they ran into the wiper washer nozzles. Well I figured out how to get at least one of them back into that front box. This will just free up a bit more space in the back and encourage even better airflow.

Thursday, January 28, 2010

Installing Batteries Part I

I've fallen a bit behind in posting what's going on, so let's catch up. I gotta warn you, this one's a bit long.

The copper straps, or interconnects, for the batteries arrived Wednesday. The suppliers found some in their warehouse after all, so they didn't have to come from China. They are composed of 5 strips of copper, held together with head shrink tubing and are a total of 3/32" thick.

I fit most of the batteries in the back box in the trunk, 12 across, with room above for up to 9 more. With all those batteries in there, it would be a very tight fit and almost impossible to route any sort of cooling air flow around them. I only need to fit 18 in that space, so I decided I'd better start playing with the spacing to help promote better air flow. Rather than 12 across in the back row, I decided to go with 11 and space them a bit. But since the interconnects are made to fit properly when the batteries are snug against each other, that meant I was going to have to make my own. I already had some 1/32" copper strap, so I simply cut, laminated and drilled a few that are about 1 centimeter longer than the others.

You can see I'd put one in place just to test the spacing. Once I fit the rest of the straps, there will be about 4 mm between each battery. Plenty of space for air flow. Above, there will be 7 more, two stacks of 2 and one of three at the far right side. In the midst of the 11 batteries I'll be putting a temperature switch that will turn the fan on when the temperature reaches 122 °F. Although I don't have any of it built yet, I know just how I'll be anchoring all those batteries to the box and the chassis so they don't fly around. Oh, and notice the larger black wire laying across the batteries at the bottom of the picture? That's for the XM Radio tuner that I've installed in the back. Gotta have music!

Today I spent time building out part of the system that will allow me to anchor the batteries in the larger tray that will go under the hood.

The strap in the middle of the box is bolted to the tray underneath. All of the rest of the bolts go through the box, through the tray and into the supports that my friend Tim and I welded to the chassis this last summer. The whole thing is as sturdy as a rock. This box will hold a total of 14 batteries (138 lbs for those of you keeping score). There will be two stacks of 4 laid flat in the front (bottom of the picture), and two stacks of 3 in the back. I had planned to stack 4 in the back as well, but I ran into a snag. One of those snags where if I had to build the car again, I would know to look out for it.

When Tim and I welded those supports to the frame, I specified more clearance over the motor than I needed. Only 3/4", but it turned out that I could have used that space. You can't see it in the picture, but when you close the hood, the two nozzles for the windshield wiper fluid come down right into the back corners of the boxes. They would interfere with closing the hood, but only just. How tight you ask? 1/4". That 3/4" clearance I left seems pretty silly now. It's not that big a deal, it just means 18 batteries in the back instead of 16.

Before I mount the two smaller boxes in front of the large one, I need to sort out two things. One is the rpm sensor mount and the other is the A/C compressor. The mount for the rpm sensor will be easy enough, but there's more to the story. Since there isn't enough room in the engine compartment to run the A/C compressor off of an auxiliary motor, I have to run it off the tail shaft of the main drive motor. I had purchased a rpm sensor that mounts to the end of the tail shaft, but if the pulley is in place it interferes with the sensor. It was beginning to look like I would have to choose one of the other.

Along came a new sensor that is designed specifically for the WarP motor I'm using. It mounts flush to the motor and I could use it and the pulley at the same time. The only problem is that no one is sure if it will work with the Zilla controller. The controller expects 4 pulses per revolution and this sensor can deliver that, but only testing it will tell for certain. So the bottom line is that I have to build a mount for the first sensor and test it out, and then mount the new one and test it to see if the Zilla interprets them the same. That will be part of the testing that I'll be doing before the car comes off the jack stands.

Either way, I need to have the compressor's mount built and ready to go in case I can use it. Other wise, I'd have to disassemble the battery boxes I would have installed by that point so that I could work in the space. Taking the compressor out if I can't use it, while the batteries are in place won't be difficult.

Speaking of the compressor, I'd been sweating one detail, and that was how to hook it up to the electrical system. There are three wires on it. Take a look...

Notice the big black harness at the top. That contains one wire, and the matching harness is on the car, so no problem there. But take a look at the side there, and you'll see two wires, one with a male the other with a female plug. There is no place to plug those in. No dangling wires left in the engine bay that might accept those to plugs. Baffled, I went to talk to the guys that took the engine out. They showed me that those two just plug into each other. Josh, the mechanic had a car on the lift and showed me. I'll be damned. I would have never thought that they'd build a compressor with an external wire that has a connector in it. The only reason I can guess for that is if you needed to pull it apart to do diagnostics on the unit.

Anyway, thanks to them, I've got all the wiring sorted for the A/C system. Now if I can just get it in the car, with a functioning rpm sensor...

Friday, January 22, 2010

Charger Plug Part II

Earlier I had mentioned that I was going to need to redo the charging port for the car. I found out the charger can draw up to 25 amps even though it's the 20 amp model. Well, that renders 20 amp plug I had used insufficient. After looking around for a good solution, I hit upon the same solution nearly everyone else that uses 220 for charging uses, an L6 30 amp plug. I was lucky enough to find a recessed receptacle online for a good price.

This type of plug is also a locking plug. Push it on and turn it and it won't come out accidentally. Of course I have a kill switch connected to the charging door so that I can't drive away with the car plugged in. The kill switch is under that ugly blue thing at the top of the door. I needed to put something over the switch to keep water off of it, and the best thing I could think of was a piece of a rubber glove. That's the thumb of a rubber glove. I used magic marker on the end of it, so you don't see a bright blue sliver under the gas door. Yeah, I know it's kind of cheesy, but it works.

Also, I found out that the battery guys don't have the right interconnect straps at the shop, so they are going to have to order them from China. Fortunately they will be shipped via standard package shipping, and not container ship transport. The said they'd give me an ETA as soon as they have one.

Wednesday, January 20, 2010

What a Week I'm Having!

If you read yesterday's post, you know that I got the long awaited batteries, only to find out that they sent the wrong interconnect straps. So I can't actually hook them together. That pretty much renders them very expensive paper weights.

Then later last night a storm rolled through town and dumped a lot of rain. And I mean a lot! Under normal circumstances that's nothing but a curiosity. After all, storms like that don't hit the desert that often. However, my current circumstance made this a bad thing. I had 25 feet of open trench in the front yard.

By 7:00 PM there was 8 inches of water in the trench and the storm had only been raging for an hour and a half. This morning I woke up and looked out to assess the damage and found that the trenches had completely collapsed. There were a couple sections with standing water and a the rest was just slop. In no place could you actually see the conduit, it was under 8 to 12 inches of slop. Now I wouldn't care, except the inspector hasn't seen the lines yet, and they generally want to see you've buried them deep enough before you go and re-bury them.

He pulled up while I was bailing out the trench. I explained what happened and asked him what I needed to do to pass inspection. He asked me a few questions and let me explain what we'd done to install the line. He looked at the work we did in the garage and said it all looked good, but then he saw the car and started asking me about it.

It's hard not to get too enthusiastic about it, especially when talking to someone who's interested. But he was totally into it and very impressed with the project. he then said "I've seen enough. It's clear you guys knew what you were doing and did a good job. You just ran into some bad luck." Then he signed off on the project. What a relief! Oddly enough, he's been doing all the inspections on an addition that my neighbor is putting on his house. I invited him to stop by anytime to check on the progress, and he said he would. And you know, I think he will.

Later in the day, I got a call from the battery folks. They think they have enough interconnects that will work for me, and they are going to pack them up and send them to me asap. I sure hope they do. What a roller coaster of a week, and it's only Wednesday.

Tuesday, January 19, 2010

The Batteries Have Arrived!

Here they are - 48 LiFePo4 Sky Energy 120 Amp/Hour batteries.

I popped the top off the first case to get a look at them and measure a few. They came along with a check list that states each battery checked out at 3.304 Volts. I threw the multi-meter on a few of them and found that they were each at 3.290 Volts. Not really a concern, especially since they were each the same. Later I'll number and measure each so that I can track any deviations.

Unfortunately it's not all good news. As I was looking through the other boxes I came across the interconnects that I need to tie all the batteries together. I was a bit alarmed when I saw that they were labeled "100 AH". The problem is that the 100 AH batteries are a different size from the 120's I have. I took one out to see if it would fit properly and found that it didn't.

So, at this point I have the batteries, but no way of connecting them to each other. *Sigh* I called the guys I ordered them from and they are going to work to get me the correct ones as soon as they can. Again *sigh*

Thursday, January 14, 2010

A Few Things Worth Mentioning

Today, my dad and I finished up the electric run from the service panel to the garage. I'm waiting on one part (the outlet) so that I can wire it to the box and then call the city for inspection.

Long ago I had chosen the form factor for the power plugs I would be using. Unfortunately, it was before I really understood what kind of power I would be drawing. I ended up choosing components that simply aren't up to the current I'll be sending through them.

I found out what I really need is something that can handle 240 Volts and up to 30 Amps. The best fittings for the job turn out to be NEMA L6-30. Since almost none of it is installed, it's no big deal, I just have to get the right parts and install them. Unfortunately, there is one bit that is installed, and that's the receptacle in the car. So, I'll be needing to take that apart and re-do it. The truth is, I'm kind of glad, because the new configuration will be sturdier and it will look way cooler. I'll include pictures once I'm done.

However, the best news for the day just came from FedEx. They called to arrange delivery for the batteries. Tuesday the 19th, between 2 PM and 6 PM, I will be losing some floor space in my garage to a palate of batteries. Joy!

Monday, January 11, 2010

Good News Everyone!

I've received word that the batteries have arrived in the country, Seattle to be specific. The company I ordered them from is going through the shipping container and portioning out everyone's order. I should have the batteries here within a couple weeks.

While I'm talking about batteries, it's occurred to me that I haven't really gone into too much detail about them, the range they should provide, and other such pieces of data. If you're interested in the nitty gritty numbers read on. Other wise... you've been warned.

I'm getting 48 of the Sky Energy SE120AHA batteries. They have a nominal voltage of 3.4 volts and provide 120 Amp/Hours. The batteries will be wired in series. This is just like the batteries in a normal TV remote are set up (positive to negative, positive to negative, etc). What that means is that all of the batteries become one big battery, and the voltage of that one big battery is the total of each added together. So, the math looks like this:

3.4 x 48 = 163.2 Volts

So that whole pack will have a nominal voltage of about 163 volts. Each battery offers 120 Amp/Hours of current, so to figure out the total number of Watts provided, you multiply the Volts by the amps:

163.2 x 120 = 19584 Watt/Hours Or roughly 19.6 kilowatt/hours.

Now, I don't want to draw all the current out of the batteries, because that will shorten the life. If I use only 80% of the power, or less, I'll extend the life of the batteries to upwards of 3000 cycles. So, if I want to leave at least 20% of the power in the battery, that means I'll get to use this much power:

19.6 kWh x .80 = 15.68 kWh

The car will likely use between 225 and 250 Watts/mile. Erring on the conservative side, lets say it will be 250. So then we figure out the range of the car, using only 80% of the current:

15680 / 250 = 62.7

So conservatively, I should have a range of 62 miles. Of course if I'm flooring it when I leave every stop light, that number goes down. If I'm on a freeway going 65 miles an hour, that number will go down. If I travel conservatively on a surface street, traveling no faster than 45, I should be able to extend that a bit. Or in the event I need to tap into that remaining 20% reserve energy for some reason, I could get as much as 16 more miles out the car.

You can see why people that drive EV's cringe at the question "How far can you go on a charge?" (Would you really want to explain that every time?) Or why the manufacturers that are just getting into the market of promoting EV's that they hope to build at some undetermined time in the future are reluctant to give out those numbers. Well that's not true of all manufacturers. Some promise 100 miles when practical experience or simple math like I've done above shows that the range would be more like 50.

To charge the car is simply a matter of how much electricity I can get a hold of and how fast I can dump it into the battery. The charger I have will run off of anything from 110 to 240. It has a dial that will allow me to limit the current (amps) it draws from the socket so that if I'm at a friend's house and they let me charge the car, I don't draw more than the outlet's breaker is rated for. The charger can only draw 20 amps off the service line which is probably the biggest limiting factor I face. But if the battery pack voltage is less than the outlet's, the charger modifies the power by decreasing the voltage to the battery pack, while at the same time increasing the amps it puts out to as much as 30. Such will be the case with the service line I'm running to the garage now.

For the sake of simplicity, lets assume I've drawn the battery pack down by 15 kWh's and the charger opeates at 100% efficiency (more on that in a moment). The charger will essentially be putting out 172.8 volts (the charge voltage for the battery pack) at 30 amps. Here's how it pans out:

172.8 volts x 30 amps = 5184 watts

15000 watt hours / 5184 watts = 2.9 hours

A 120 circuit is a different story. A 120 volt circuit putting out 20 amps equates to 2400 watts no matter how you cut it. The charger will modify that by raising the voltage to 172.8, but that means the amperage output will drop correspondingly to 13.8.

172.8 volts x 13.8 amps = 2400 watts

15000 watt hours / 2400 watts = 6.25 hours

As you can see a 120 volt outlet will take a while longer, but 6.25 hours is still quite acceptable. Now there is some loss when the charger is modifying the power from the wall and pushing it to the battery pack. It won't affect the time on the higher voltage charge, but the 120 volt charge time will likely go up by an hour or so.

So, there you go. Way more data than you ever wanted to know. When ever anyone asks me about range I'll simply refer them to this page. :-)

Wednesday, January 6, 2010

The Joys of Manual Labor

Happy New Year all! It's been a couple weeks since I've posted anything, but I haven't been sitting idle. Well that's not entirely true. But I have done some work.

I'm still waiting on batteries. And while there are still a few things I could be doing on the car before they arrive, I've been tackling a far more glamorous job. Trenching! We are the second owners of this house, and as astounding as it may be to believe, the owners that had the house built did not have any 22o Volt outlets installed in the garage. What sort of uncivilized cretin neglects to run a 22o Volt circuit to a garage!? That should be standard fare. The optional upgrade should be whether you want three phase power or not.

Anyway, if I want to charge the car in a reasonable amount of time, I need to feed it some 220. Running the power from the service panel (which, as Murphy would dictate, is on the opposite side of the house) to the garage has proved to be no small task. Running the line through the attic was simply not an option. It's sad to say that the best option left to me was to trench it in.

Code states that it must be 18" below ground in conduit. For those of you who don't live in Arizona, a 25 foot trench 18" deep is likely a days work. But here, we have this fantastic soil called caliche. For those of you unfamiliar with it, just imagine granite that's brown and dusty and you'd be close. It's actually soil in which the particles have been cemented together with lime. Swing a pick at it, and it bounces off.

Being that all of this work had to take place near existing power lines, phone lines, cable/internet lines and water lines, I just didn't feel using a jack hammer was a good plan. And yes, it's not uncommon to use a jack hammer on this stuff. So, pick and shovel it is. Here's shot of the trench coming from the service panel toward the front of the yard.

Then here's the trench running along the front of the house.

That palm tree to the left provided us with an astounding number of roots which made the work just that much more fun. Last, here's a shot of what will likely be the best part of the whole affair; the area where we have to go under the front walkway.

The walkway is 36" wide and we have to get the pipe under it while making sure that it remains at least 18" under ground. I got a garden auger bit for my drill that's 30" long. I'm hoping that the auger bit, plus an extension will get us there. If I'm lucky, there are no discarded roof tiles or chunks of concrete left under there by the workers that built the house.