I visted Synkromotive two days ago to look into becoming a Beta tester of their new motor controller. It handles 600 amps and has a really nice user interface through a laptop to configure several controller parameters like the DMOC445 that I have on the AC 914EV. Other than the Zilla, I haven't seen a controller out there with this much programmable flexibility. It has inputs for over RPM, battery under-voltage and temperature as well.
During our discussions, they told me about their history with the Deka group 31 series of batteries, which I'm seriously considering using for the Civic-EV project. It turns out that, up until last year, all the public buses for Oregon and Washington used four Deka group 31 batteries in them. The bus companies were very frustrated because the batteries kept dying after 10-12 months of operation. Synkromotive worked with these companies and found out that the Deka batteries only have a 12 month warranty and only have 150 full discharge cycles of lifetime. All the buses in both states now use Odyssey group 31 batteries and have not had any issues.
It looks like the amp-hour and amperage rating for the Dekas isn't too bad, but the lifetime is horrible. The Odyssey batteries are twice as much but last three times as long and have even better amperage ratings. John Wayland uses Odyssey batteries in his EVs. Northwest Battery here in portland highly recommended Discover EV31a-a and FullRiver group 31 batteries over the Dekas as well, but they also cost more. The ZAP cars have a Discover EV31a-a upgrade, so they appear to like them too.
While I'm still sticking with group-31 batteries, I'm going to have to re-open the battery decision since I don't want to invest $2000 every 12 months in the electric vehicle. Hopefully this information will help others using group 31 batteries as well.
On a brighter note, I attended the Meeting of the Minds conference over the past two days and Oregon Governor Kulongowski announced a long term plan for supporting plug-in vehicles through a charging infrastructure and fleet purchases. I love this town. I took notes on the conference in case people want to see a huge list of factoids.
Cheers,
Tim
Thursday, July 31, 2008
Wednesday, July 23, 2008
Processing the Engine Wire Harness
This evening, I took apart the engine harness that we looked at back here.
After taking the harness apart, I'm left with a bunch of rotten electrical tape (top center in picture), the leftover wires (on the right) and what I really care about (on the left). The white wire is the alternator wire to the main battery, so I'll probably use that with the DC-DC converter to drive the main battery. The remaining wire harness has a few connectors to drive the reverse lights, the speedometer, and several of the dashboard instruments.
I'm a bit held up right now waiting for parts (what's new...) and thinking about how best to protect the steel for the battery racks. I'll be calling several powder-coating places tomorrow to get pricing, but one person highly recommends using POR-15 rust protector instead of powder-coating. The POR-15 etcher and paint will run me about $80 and will be a big mess in my driveway. I'll see what happens after I get some powder-coating quotes.
I'm also hesitant to design the battery hold-downs right now because all I have is foam-core mock-ups instead of the real thing. If I can get some real Deka 9A31 batteries, I can design the hold-downs more effectively.
After taking the harness apart, I'm left with a bunch of rotten electrical tape (top center in picture), the leftover wires (on the right) and what I really care about (on the left). The white wire is the alternator wire to the main battery, so I'll probably use that with the DC-DC converter to drive the main battery. The remaining wire harness has a few connectors to drive the reverse lights, the speedometer, and several of the dashboard instruments.
I'm a bit held up right now waiting for parts (what's new...) and thinking about how best to protect the steel for the battery racks. I'll be calling several powder-coating places tomorrow to get pricing, but one person highly recommends using POR-15 rust protector instead of powder-coating. The POR-15 etcher and paint will run me about $80 and will be a big mess in my driveway. I'll see what happens after I get some powder-coating quotes.
I'm also hesitant to design the battery hold-downs right now because all I have is foam-core mock-ups instead of the real thing. If I can get some real Deka 9A31 batteries, I can design the hold-downs more effectively.
Tuesday, July 22, 2008
Doing Sketchup of the Adapter
I took a few hours last night to learn more about Google Sketchup. It's quite a powerful tool for visualization, but I realize now that, unless you buy the expensive "Pro" edition, don't bother trying to export any valuable information from it.
I took the adapter plate into a precision measurement shop to get all the hole locations for the Civic transmission bell housing. Here is the picture on the measurement table at the shop.
The spacer ring behind the adapter plate is much simpler. I simply took measurements with a caliper and a steel ruler to generate the above.
Some numbers:
Here is a partial drawing of the adapter hub for the motor shaft into the rear of the flywheel. I didn't draw the taper-lock on the bottom end due to its complexity. There's actually a depression in the center of the hub above but, due to limitations in Sketchup, I wasn't able to delete all the facets correctly, so it looks like a circle drawn on the top.
Some numbers:
Here is a hacked drawing of the adapter plate. All the hole locations are correct because I typed them in from the precision measurement shop. The outline is just a quick hand drawing. Note that it doesn't have the cutout in the lower left corner for the CV joint shaft.
Here are the numbers for the hole locations I got from the CMM shop. I had a royal pain of a time getting a table into this blog, so you'll just have to click on this photo instead.
DISCLAIMER: With the exception of the precision hole measurements, all numbers are subject to my human error with a steel ruler and digital calipers. I do NOT recommend using these numbers to fabricate your own hub or adapter plate since there are probably slight errors in the numbers.
LICENSE RELEASE: This adapter plate and hub are proprietary designs from Electro Automotive and are not licensed under the TAPR Open Hardware License for this project. I'm including dimensions here as an academic exercise.
I took the adapter plate into a precision measurement shop to get all the hole locations for the Civic transmission bell housing. Here is the picture on the measurement table at the shop.
The spacer ring behind the adapter plate is much simpler. I simply took measurements with a caliper and a steel ruler to generate the above.
Some numbers:
- Overall spacer diameter: 9.25" (not critical)
- Internal hole diameter: 4" (not critical)
- Total thickness: 2 3/8"
- Outer diameter of raised ring: 8.5"
- Inner diameter of raised ring: 6" (not critical)
- Thickness of raised ring: 3/16" (not critical if over 3/16")
- The recessed holes are 3/8" holes that hold bolts for the Warp9/ADC9" motor face
- The sinks for the recessed holes are 19/32" diameter and .7" deep (approximate)
- The threaded holes have 1/2"-13 threads and are 1.4" deep
- The threaded holes have centers on a 7.25" diameter circle
- The depression inside the raised ring is 5/16" deep
Here is a partial drawing of the adapter hub for the motor shaft into the rear of the flywheel. I didn't draw the taper-lock on the bottom end due to its complexity. There's actually a depression in the center of the hub above but, due to limitations in Sketchup, I wasn't able to delete all the facets correctly, so it looks like a circle drawn on the top.
Some numbers:
- The six outer holes have 12mm threads and are 25mm deep
- The outer holes are evenly spaced at 60 degrees and have centers on a 63mm diameter circle
- The outer diameter of the hub is 80mm
- The top part of the hub is 33.5mm thick
- The overall height of the hub is 59mm thick
- The bottom end of the hub is 2.25" in diameter
- The depression in the top for the pilot bearing is 33mm in diameter and 2.5mm deep
- The holes for the bolts to pull in the taper lock are evenly spaced with centers on a 33mm circle.
- The central hole through the hub is 19mm in diameter
Here is a hacked drawing of the adapter plate. All the hole locations are correct because I typed them in from the precision measurement shop. The outline is just a quick hand drawing. Note that it doesn't have the cutout in the lower left corner for the CV joint shaft.
Here are the numbers for the hole locations I got from the CMM shop. I had a royal pain of a time getting a table into this blog, so you'll just have to click on this photo instead.
DISCLAIMER: With the exception of the precision hole measurements, all numbers are subject to my human error with a steel ruler and digital calipers. I do NOT recommend using these numbers to fabricate your own hub or adapter plate since there are probably slight errors in the numbers.
LICENSE RELEASE: This adapter plate and hub are proprietary designs from Electro Automotive and are not licensed under the TAPR Open Hardware License for this project. I'm including dimensions here as an academic exercise.
Saturday, July 19, 2008
Reusing the Power Steering Reservoir
Remember how we talked about making the power-steering into manual awhile ago? We still have some hydraulic tubes coming out of the power steering valve that need something done with them.
Based on my internet research, it's best to have a closed system where the output power steering fluid tubes feed back into the input fluid tube, but with a reservoir in between to handle expansion from heat. There's a solution online but it's for an Acura which only has one outlet and one inlet. I spent a few hours trying to figure out if I could use the existing power steering reservoir and tubing to get the same function.
Here's our power steering reservoir from the original gasoline engine with tubes attached.
In order to get this to fit (jump forward to the last picture to see what I'm shooting for), I cut the output hose from the reservoir and turned it around so that the cut end is attached to the reservoir.
As far as the grey-green hydraulic lines coming out of the power steering valve, I unscrewed them and hack sawed them short (see ruler for scale).
For the black hydraulic line going into the power steering valve, I had already hack sawed it earlier. This is the line before I bent it.
Here is the same hydraulic line after I bent it to get the pipe in the right place.
Here is the setup I'm trying to shoot for. The power steering reservoir is now under the firewall battery rack and close to the power steering valve. I'm going to add an "L" bracket to the large bolt in the lower left corner of the picture (behind my hand) to attach to the gold bracket holding the reservoir I've rotated the input and output hydraulic lines so that they mostly line up with the hoses coming out of the reservoir. I had to cut the flexible tubing more so that things lined up correctly.
The flexible tubes were already matched with the gray-green output hydraulic lines. The black input hydraulic line clearly doesn't match the size of the output tube from the reservoir, so I'll probably have to get a pipe adapter or intermediate tubing to bridge the gap. I hope this will keep the system mostly closed to keep dirt out but still allow a little breathing in case of expansion due to heat or cold.
What a day. Good night. Cheers, Tim.
Based on my internet research, it's best to have a closed system where the output power steering fluid tubes feed back into the input fluid tube, but with a reservoir in between to handle expansion from heat. There's a solution online but it's for an Acura which only has one outlet and one inlet. I spent a few hours trying to figure out if I could use the existing power steering reservoir and tubing to get the same function.
Here's our power steering reservoir from the original gasoline engine with tubes attached.
In order to get this to fit (jump forward to the last picture to see what I'm shooting for), I cut the output hose from the reservoir and turned it around so that the cut end is attached to the reservoir.
As far as the grey-green hydraulic lines coming out of the power steering valve, I unscrewed them and hack sawed them short (see ruler for scale).
For the black hydraulic line going into the power steering valve, I had already hack sawed it earlier. This is the line before I bent it.
Here is the same hydraulic line after I bent it to get the pipe in the right place.
Here is the setup I'm trying to shoot for. The power steering reservoir is now under the firewall battery rack and close to the power steering valve. I'm going to add an "L" bracket to the large bolt in the lower left corner of the picture (behind my hand) to attach to the gold bracket holding the reservoir I've rotated the input and output hydraulic lines so that they mostly line up with the hoses coming out of the reservoir. I had to cut the flexible tubing more so that things lined up correctly.
The flexible tubes were already matched with the gray-green output hydraulic lines. The black input hydraulic line clearly doesn't match the size of the output tube from the reservoir, so I'll probably have to get a pipe adapter or intermediate tubing to bridge the gap. I hope this will keep the system mostly closed to keep dirt out but still allow a little breathing in case of expansion due to heat or cold.
What a day. Good night. Cheers, Tim.
Finishing the Firewall Rack Base
Of all the battery racks, the firewall rack is the most complex with the most interferences. I'm going to try and capture all the problems I ran into today while trying to get the firewall rack base installed.
I re-installed the transmission while ago to make sure that I would get the proper spacing with the firewall rack. Since the mounts for the transmission are rubber, they flex, so I needed to use a floor jack to raise the transmission back to its working height to get the proper spacing. As shown in a prior post, the proper height is correct when the bottom of the transmission is level with the bottom of the front bumper, at least in my case.
Initially I had two 2" pieces of angle iron (1/8" thick) for the left and right supports, but I found out that they were too big and interfered with a bunch of brake lines. I reverted back to 1.5" angle iron. In order to properly bolt into the 8mm holes at the rear of the engine compartment, I needed to take off 1.5" of vertical wall from the ends to allow the bolt head to fit.
The piece on the left is 15" long and fits on the driver side. The piece on the right is 24" long and fits on the passenger side. The ends with the 1.5" missing vertical wall goes towards the rear end of the car.
To prepare for mounting, I drilled a 21/64" hole (just over 8mm) 1" in from the rear end and 3/8" in from the edge where the vertical wall was removed. I also drilled two 3/8" holes (center-punch, pilot hole, final drill) 5 3/8" and 10 3/8" in from the rear end up on the vertical walls to bolt into the shock-tower bars.
This is a picture after all the drilling has been done and the 3/8" bolts have been installed.
The vertical bars attached to the shock towers have 6mm holes drilled in them and I used 6mmx20mm bolts with lock washers to hold them in. The vertical bars are 1.25" wide and 6" long. The bottom holes in the vertical bars will be drilled after aligning the left and right support bars of the battery rack.
The rear end of each support bar is 2 3/4" above the chassis and is currently supported by 8mm all-thread with nuts that fits nicely into the 8mm hole. I'm going to replace this in the short-term future by adding a 8mm by 90mm bolt that goes through the hole in the support bar, through a 2 3/4" pipe and screws directly into the 8mm threaded hole in the chassis.
With the rear end of the bar at the right height, the front end of the bar needs to be raised so the bar is level. I used small clamps to attach the side bars to the vertical straps on the shock towers so I could verify placement before drilling any holes.
Here's a look at the right support bar holding up the rear support bar. I had to cut out a triangle of metal to prevent any of these bars from rubbing against the brake lines.
With the rear ends of the left and right support bars in place. We clamp them to the vertical straps on the shock towers after raising the front end so its level with the rear end. Remember the 3/8" holes we drilled in the vertical walls of the left/right support bars? These should line up with the vertical straps on the shock towers, so we can draw a circle on the vertical bars for later drilling.
The front and rear support bars (1.5" angle iron, 1/8" thick) are 31.25" long and have 3/8" holes drilled in them 1/2" from each end. The front-most face of the front support bar needs to be 15" from the rear end of the left/right support bars. After placing the front support bar, the rear support bar should be placed so that there is 31 1/8" of inside distance between them to support the group-31 batteries. With the two bars placed properly, you can draw circles on the left/right support bars through the 3/8" holes for later drilling.
Getting the firewall rack right is difficult due to the tight clearance between the top of the transmission and the underside of the hood. With the rear of the rack 2.75" above the 8mm threaded holes in the chassis, the front support bar should just barely clear the top edge of the transmission. I've used a piece of wood here to make sure the rack is level before marking any holes for drilling.
Alas, even with very little clearance above the transmission, the group-31 foam-core battery interferes with the underside of the hood. If you click on this picture to zoom in, you'll see that I've marked a section on this diagonal support on the underside of the hood that needs to be removed in order to let the hood close without battery interference. I'll have more pictures of that later.
With all the holes drilled and 3/8"-16 by 3/4" long bolts installed in all the holes, the base of the firewall rack is mostly done. I can stand on this and shake quite violently and nothing seems to move. It better not, since it has to hold 280 pounds of batteries.
Since the clearance with the underside of the hood is so tight, I'm going to have to replace the 3/8"-16 x 3/4" bolts on the left support with countersunk bolts so I don't raise the batteries any further. There's simply no room left. Ugh.
Next up: trying to get the power steering reservoir in place...
I re-installed the transmission while ago to make sure that I would get the proper spacing with the firewall rack. Since the mounts for the transmission are rubber, they flex, so I needed to use a floor jack to raise the transmission back to its working height to get the proper spacing. As shown in a prior post, the proper height is correct when the bottom of the transmission is level with the bottom of the front bumper, at least in my case.
Initially I had two 2" pieces of angle iron (1/8" thick) for the left and right supports, but I found out that they were too big and interfered with a bunch of brake lines. I reverted back to 1.5" angle iron. In order to properly bolt into the 8mm holes at the rear of the engine compartment, I needed to take off 1.5" of vertical wall from the ends to allow the bolt head to fit.
The piece on the left is 15" long and fits on the driver side. The piece on the right is 24" long and fits on the passenger side. The ends with the 1.5" missing vertical wall goes towards the rear end of the car.
To prepare for mounting, I drilled a 21/64" hole (just over 8mm) 1" in from the rear end and 3/8" in from the edge where the vertical wall was removed. I also drilled two 3/8" holes (center-punch, pilot hole, final drill) 5 3/8" and 10 3/8" in from the rear end up on the vertical walls to bolt into the shock-tower bars.
This is a picture after all the drilling has been done and the 3/8" bolts have been installed.
The vertical bars attached to the shock towers have 6mm holes drilled in them and I used 6mmx20mm bolts with lock washers to hold them in. The vertical bars are 1.25" wide and 6" long. The bottom holes in the vertical bars will be drilled after aligning the left and right support bars of the battery rack.
The rear end of each support bar is 2 3/4" above the chassis and is currently supported by 8mm all-thread with nuts that fits nicely into the 8mm hole. I'm going to replace this in the short-term future by adding a 8mm by 90mm bolt that goes through the hole in the support bar, through a 2 3/4" pipe and screws directly into the 8mm threaded hole in the chassis.
With the rear end of the bar at the right height, the front end of the bar needs to be raised so the bar is level. I used small clamps to attach the side bars to the vertical straps on the shock towers so I could verify placement before drilling any holes.
Here's a look at the right support bar holding up the rear support bar. I had to cut out a triangle of metal to prevent any of these bars from rubbing against the brake lines.
With the rear ends of the left and right support bars in place. We clamp them to the vertical straps on the shock towers after raising the front end so its level with the rear end. Remember the 3/8" holes we drilled in the vertical walls of the left/right support bars? These should line up with the vertical straps on the shock towers, so we can draw a circle on the vertical bars for later drilling.
The front and rear support bars (1.5" angle iron, 1/8" thick) are 31.25" long and have 3/8" holes drilled in them 1/2" from each end. The front-most face of the front support bar needs to be 15" from the rear end of the left/right support bars. After placing the front support bar, the rear support bar should be placed so that there is 31 1/8" of inside distance between them to support the group-31 batteries. With the two bars placed properly, you can draw circles on the left/right support bars through the 3/8" holes for later drilling.
Getting the firewall rack right is difficult due to the tight clearance between the top of the transmission and the underside of the hood. With the rear of the rack 2.75" above the 8mm threaded holes in the chassis, the front support bar should just barely clear the top edge of the transmission. I've used a piece of wood here to make sure the rack is level before marking any holes for drilling.
Alas, even with very little clearance above the transmission, the group-31 foam-core battery interferes with the underside of the hood. If you click on this picture to zoom in, you'll see that I've marked a section on this diagonal support on the underside of the hood that needs to be removed in order to let the hood close without battery interference. I'll have more pictures of that later.
With all the holes drilled and 3/8"-16 by 3/4" long bolts installed in all the holes, the base of the firewall rack is mostly done. I can stand on this and shake quite violently and nothing seems to move. It better not, since it has to hold 280 pounds of batteries.
Since the clearance with the underside of the hood is so tight, I'm going to have to replace the 3/8"-16 x 3/4" bolts on the left support with countersunk bolts so I don't raise the batteries any further. There's simply no room left. Ugh.
Next up: trying to get the power steering reservoir in place...
Rear Trunk Battery Rack
Today was busy, so you should see a few posts. This first one is all the work I did installing the rear trunk battery rack base. As I mentioned before some of this will be verbose as I'm trying not to lose all the finer details.
A few posts ago, I cut some 1.5"x1.5" square tubing 18" long (1/8" wall) and drilled a 3/8" hole in each end, 5/8" from the end. After laying these down in the trunk where I wanted to put them, I realized that there is a manufacturing "bump" on either side of the trunk. I got out my handy sledge hammer and flattened out the inner edge of the bump (under the head of the hammer in the picture above) to remove the interference.
Here is my attempt at finding a good place to drill a 3/8" hole to install the square pipe. My first attempt missed going through and ended up inside a support beam. The second attempt (upper hole was much more successful. This picture shows the passenger side of the trunk right up at the front just behind the rear seat, which is folded down.
There's a plastic plug to help us find a good place. I drew a horizontal line from the center of the plastic plug to the side of the car. I measured 1.25" toward the rear of the car and put another horizontal line. I then drew a line that "connected the dots" of the spot welds for the main support. After that, I drew a parallel line to that 3/16" towards the center of the car. The intersection of the second parallel line and the horizontal line 1.25" rear of the plastic plug is where you want to put the hole.
As I've mentioned before, start with a center punch, then drill a small hole (around 1/8") and then go for the larger 3/8" hole to prevent the drill from skidding around.
Here is the hole that I drilled in the previous picture from below. It goes through two pieces of metal so it should hold well.
I dropped a 3/8"-16 by 2.5" bolt down through the square tube and into the hole. To get the 3/8" nylock nut (and washer) to grab on the bottom, I needed to dangle a box wrench on the bolt head above. If you have two people this isn't an issue because one person can hold the bolt on top while the other person tightens it from the bottom. I still have to powdercoat the metal pieces, so I didn't actually tighten down the nuts, but let the bolt sit in the hole so I could drill an accurate hole at the other end.
The next step was to "connect-the-dots" again for the spot welds just under the rear end of the square tube. I drew a second line, parallel to the "connect-the-dots" line 3/16" towards the center of the car. I centered the hole in the rear end of the square tube on this second line and drew a circle with a pen through the hole. After rotating the rear end of the square tube away, I could then drill a 3/8" hole after center-punching the circle and drilling a 1/8" pilot hole.
Here's the driver-side front measurements being done. Again, the hole point is 1.25" rearward of the center of the plastic plug and 3/16" toward the center of the car from the "connect-the-dots" line from the spot welds.
This hole was a little less successful since I hit the edge of the double layers of metal that were spot welded together. I don't think this will be an issue, but I'll make sure to put an extra large washer underneath the car on the 3/8" bolt to spread the load out.
I drilled a hole for the rear end of the driver-side square tube the same way I did for the passenger side. Align the rear hole up with a line 3/16" inside of the "connect-the-dots" line for the spot welds.
After installing the two square pipes, I installed the two pieces of 1.5" (1/8" thick) angle iron to support the front and rear edges of the batteries. Both pieces of 1.5" angle iron are 36" long. The front piece has 3/8" holes drilled in it 3 3/8" from each end, centered between the longer edges (that is 3/4" from each edge). The rear piece has 3/8" holes drilled in it 2 1/2" from each end, again centered between the long edges.
This picture shows how to align the inside vertical edge of the front bar with the seam on the chassis in front of the shock tower. After trying several places with the foam-core batteries, this seemed like a reasonable place that keeps the batteries far enough forward but still gives a bit of breathing room behind the rear seat.
With the front bar aligned, I drew two circles onto the square tubes through the 3/8" holes. After removing the front bar, I center-punched, pilot-drilled and then drilled two 3/8" holes in the square tubes to match those on the front bar.
Here is the front bar in place with two 3/8"-16 by 3/4" long bolts. Since I still have to powder-coat everything, I haven't added the nylock nuts. The nylock nuts will have to be added by taping them inside a box wrench and inserting the box wrench end into the square tube to line up with the bolt being inserted from above. I'll have pictures of this later.
With the front bar in place, we now align the rear bar so that the inside edges of the vertical metal are 13 1/8" apart to allow for the batteries and a bit of expansion. After the rear bar is placed and centered right-to-left, I drew circles in the 3/8" holes I had drilled earlier in the rear bar (2.5" from the ends) onto the square tubing. I drilled 3/8" holes in the square tubing (again, center-punch, pilot-hole, final drill) and dropped 3/8-16 by 3/4" bolts into the holes to complete the base of the rear trunk battery rack.
Things that still need to be done for the rear rack are adding the 3/4" angle iron for the hold-downs, drilling all the needed holes for the hold-downs and powder-coating everything to protect it from rust and battery acid fumes.
Next up: The firewall battery rack
A few posts ago, I cut some 1.5"x1.5" square tubing 18" long (1/8" wall) and drilled a 3/8" hole in each end, 5/8" from the end. After laying these down in the trunk where I wanted to put them, I realized that there is a manufacturing "bump" on either side of the trunk. I got out my handy sledge hammer and flattened out the inner edge of the bump (under the head of the hammer in the picture above) to remove the interference.
Here is my attempt at finding a good place to drill a 3/8" hole to install the square pipe. My first attempt missed going through and ended up inside a support beam. The second attempt (upper hole was much more successful. This picture shows the passenger side of the trunk right up at the front just behind the rear seat, which is folded down.
There's a plastic plug to help us find a good place. I drew a horizontal line from the center of the plastic plug to the side of the car. I measured 1.25" toward the rear of the car and put another horizontal line. I then drew a line that "connected the dots" of the spot welds for the main support. After that, I drew a parallel line to that 3/16" towards the center of the car. The intersection of the second parallel line and the horizontal line 1.25" rear of the plastic plug is where you want to put the hole.
As I've mentioned before, start with a center punch, then drill a small hole (around 1/8") and then go for the larger 3/8" hole to prevent the drill from skidding around.
Here is the hole that I drilled in the previous picture from below. It goes through two pieces of metal so it should hold well.
I dropped a 3/8"-16 by 2.5" bolt down through the square tube and into the hole. To get the 3/8" nylock nut (and washer) to grab on the bottom, I needed to dangle a box wrench on the bolt head above. If you have two people this isn't an issue because one person can hold the bolt on top while the other person tightens it from the bottom. I still have to powdercoat the metal pieces, so I didn't actually tighten down the nuts, but let the bolt sit in the hole so I could drill an accurate hole at the other end.
The next step was to "connect-the-dots" again for the spot welds just under the rear end of the square tube. I drew a second line, parallel to the "connect-the-dots" line 3/16" towards the center of the car. I centered the hole in the rear end of the square tube on this second line and drew a circle with a pen through the hole. After rotating the rear end of the square tube away, I could then drill a 3/8" hole after center-punching the circle and drilling a 1/8" pilot hole.
Here's the driver-side front measurements being done. Again, the hole point is 1.25" rearward of the center of the plastic plug and 3/16" toward the center of the car from the "connect-the-dots" line from the spot welds.
This hole was a little less successful since I hit the edge of the double layers of metal that were spot welded together. I don't think this will be an issue, but I'll make sure to put an extra large washer underneath the car on the 3/8" bolt to spread the load out.
I drilled a hole for the rear end of the driver-side square tube the same way I did for the passenger side. Align the rear hole up with a line 3/16" inside of the "connect-the-dots" line for the spot welds.
After installing the two square pipes, I installed the two pieces of 1.5" (1/8" thick) angle iron to support the front and rear edges of the batteries. Both pieces of 1.5" angle iron are 36" long. The front piece has 3/8" holes drilled in it 3 3/8" from each end, centered between the longer edges (that is 3/4" from each edge). The rear piece has 3/8" holes drilled in it 2 1/2" from each end, again centered between the long edges.
This picture shows how to align the inside vertical edge of the front bar with the seam on the chassis in front of the shock tower. After trying several places with the foam-core batteries, this seemed like a reasonable place that keeps the batteries far enough forward but still gives a bit of breathing room behind the rear seat.
With the front bar aligned, I drew two circles onto the square tubes through the 3/8" holes. After removing the front bar, I center-punched, pilot-drilled and then drilled two 3/8" holes in the square tubes to match those on the front bar.
Here is the front bar in place with two 3/8"-16 by 3/4" long bolts. Since I still have to powder-coat everything, I haven't added the nylock nuts. The nylock nuts will have to be added by taping them inside a box wrench and inserting the box wrench end into the square tube to line up with the bolt being inserted from above. I'll have pictures of this later.
With the front bar in place, we now align the rear bar so that the inside edges of the vertical metal are 13 1/8" apart to allow for the batteries and a bit of expansion. After the rear bar is placed and centered right-to-left, I drew circles in the 3/8" holes I had drilled earlier in the rear bar (2.5" from the ends) onto the square tubing. I drilled 3/8" holes in the square tubing (again, center-punch, pilot-hole, final drill) and dropped 3/8-16 by 3/4" bolts into the holes to complete the base of the rear trunk battery rack.
Things that still need to be done for the rear rack are adding the 3/4" angle iron for the hold-downs, drilling all the needed holes for the hold-downs and powder-coating everything to protect it from rust and battery acid fumes.
Next up: The firewall battery rack
Sunday, July 13, 2008
Battery Racks, Continued
I did some more work on the battery racks over the past few days. The biggest challenge is getting everything to fit properly without hitting any blockages. At this point, I think I have all of the metal pieces cut, but I don't have the bolt holes drilled.
Note: the following descriptions are a bit verbose because I'm trying to keep track of all the detailed measurements as I go.
Here is a closeup of the front battery rack on the driver side. For the moment, the racks are only held in by the two beefy bolts from the towing bracket in the lower-right corner of the picture. I added a piece of 2" angle iron and a 10" support piece (1.25" wide and 3/16" thick) on the left side of the picture to support the back edge of the rack. I've already drilled the top hole and put in a 3/8" bolt and nylock nut. I have the bottom end clamped so I can drill an accurate hole through both pieces to insert the bottom 3/8" bolt. Of course, I actually drilled two 3/8" holes in the 10" support piece first 1" from each end, and then used those holes as guides to drill the holes in the bracket that I attached to.
Here's the front battery rack again, but on the passenger side of the vehicle. I'm using an already existing 6mm bolt on the side of the chassis support to hold the top end of the 10" support strut. This picture doesn't show it, but I'll eventually drill a hole through the bottom end of the diagonal support strut into the horizontal 2" angle iron and add a 3/8" bolt with nylock nut.
Moving onto the firewall battery rack. I'm using the existing 6mm bolts on the side of the shock towers to hold up four 6"x1.25"x3/16" steel flat bars which will support the base of the battery rack. I drilled 15/64" holes into these bars 5/8" from the end for the 6mm bolts.
I have two pieces of 2" angle iron 14" long clamped to the vertical bars to support the longer 1.5"horizontal angle iron (31.25" long) for the batteries. It turns out that 14" wasn't long enough (you can see the front horizontal angle iron teetering on the front edge of the 2" angle iron).
Here is a zoomed out view of the firewall battery rack mockup that I've clamped together. Again, the two pieces of 2" angle iron on the left and right are just about 1/2" too short to properly support the horizontal pieces of 1.5" angle iron. After contemplating this further, I decided to make the right side of 2" angle iron 15" long and the left side 24" long. This extends the left side forward so that I can add more supports and put in a platform for the motor controller and charger/dc-dc converter above the transmission.
To keep the system stable, I wanted to utilize these 8mm threaded holes near the back of the engine compartment. By extending the 2" angle iron to towards the back of the car, I can use 8mm metric threaded rod to bolt into the angle iron for support. This is a picture just behind the passenger side shock tower in the engine compartment where the original 12V battery used to be bolted into. I purchased a piece of 8mm all-thread to bolt into this. I expect to drill an 8mm hole 1" from the end of the angle iron and 1/2" in from the side to allow the use of the all-thread.
One more important thing to consider is the interference with the driver-side engine mount. The 2" angle iron can't come forward too far or it will interfere with the mount. I put a piece of
wood under the engine mount to raise it into it's final position to properly see the clearance.
The power steering reservoir is still underneath. I haven't figured out a good way to mount this under the firewall battery rack yet and allow the fluids to flow in and out of it. That will be another engineering project.
Moving to the rear batter rack, I've just placed the pieces of 1.5" square tubing and 1.5" angle iron to make sure the batteries fit (with foam-core model). While this design puts the batteries at a higher center of gravity, it allows us to keep the spare tire and avoids having the installer cut through the trunk floor, possibly compromising frame integrity. Two pieces of 1.5" square steel tubing (1/8" walls) are 18" long. The 1.5" angle iron pieces (1/8" wall) are 36" long.
Just a quick note about drilling holes: After drilling larger holes (like the 15/64" and 3/8" holes needed here), there will probably be lots of burrs left on the exit hole where you drilled. I found that the largest drill in my set (1/2") can be used with a light touch with the drill to remove these burrs. You could also use a 1/2" countersink to take the burrs off.
In order to prove that I can do this project with simple hand tools, I'm cutting all the angle iron with a hacksaw and drilling the holes with a hand drill. Several colleagues have suggested that I get a miter saw (chop saw) with a grinder blade to cut all the steel pieces since it would go much faster. A drill press would also be helpful for all these holes. While I agree that it would be faster and more accurate, I still like knowing this project can be done with simple hand tools.
Cheers,
Tim
Note: the following descriptions are a bit verbose because I'm trying to keep track of all the detailed measurements as I go.
Here is a closeup of the front battery rack on the driver side. For the moment, the racks are only held in by the two beefy bolts from the towing bracket in the lower-right corner of the picture. I added a piece of 2" angle iron and a 10" support piece (1.25" wide and 3/16" thick) on the left side of the picture to support the back edge of the rack. I've already drilled the top hole and put in a 3/8" bolt and nylock nut. I have the bottom end clamped so I can drill an accurate hole through both pieces to insert the bottom 3/8" bolt. Of course, I actually drilled two 3/8" holes in the 10" support piece first 1" from each end, and then used those holes as guides to drill the holes in the bracket that I attached to.
Here's the front battery rack again, but on the passenger side of the vehicle. I'm using an already existing 6mm bolt on the side of the chassis support to hold the top end of the 10" support strut. This picture doesn't show it, but I'll eventually drill a hole through the bottom end of the diagonal support strut into the horizontal 2" angle iron and add a 3/8" bolt with nylock nut.
Moving onto the firewall battery rack. I'm using the existing 6mm bolts on the side of the shock towers to hold up four 6"x1.25"x3/16" steel flat bars which will support the base of the battery rack. I drilled 15/64" holes into these bars 5/8" from the end for the 6mm bolts.
I have two pieces of 2" angle iron 14" long clamped to the vertical bars to support the longer 1.5"horizontal angle iron (31.25" long) for the batteries. It turns out that 14" wasn't long enough (you can see the front horizontal angle iron teetering on the front edge of the 2" angle iron).
Here is a zoomed out view of the firewall battery rack mockup that I've clamped together. Again, the two pieces of 2" angle iron on the left and right are just about 1/2" too short to properly support the horizontal pieces of 1.5" angle iron. After contemplating this further, I decided to make the right side of 2" angle iron 15" long and the left side 24" long. This extends the left side forward so that I can add more supports and put in a platform for the motor controller and charger/dc-dc converter above the transmission.
To keep the system stable, I wanted to utilize these 8mm threaded holes near the back of the engine compartment. By extending the 2" angle iron to towards the back of the car, I can use 8mm metric threaded rod to bolt into the angle iron for support. This is a picture just behind the passenger side shock tower in the engine compartment where the original 12V battery used to be bolted into. I purchased a piece of 8mm all-thread to bolt into this. I expect to drill an 8mm hole 1" from the end of the angle iron and 1/2" in from the side to allow the use of the all-thread.
One more important thing to consider is the interference with the driver-side engine mount. The 2" angle iron can't come forward too far or it will interfere with the mount. I put a piece of
wood under the engine mount to raise it into it's final position to properly see the clearance.
The power steering reservoir is still underneath. I haven't figured out a good way to mount this under the firewall battery rack yet and allow the fluids to flow in and out of it. That will be another engineering project.
Moving to the rear batter rack, I've just placed the pieces of 1.5" square tubing and 1.5" angle iron to make sure the batteries fit (with foam-core model). While this design puts the batteries at a higher center of gravity, it allows us to keep the spare tire and avoids having the installer cut through the trunk floor, possibly compromising frame integrity. Two pieces of 1.5" square steel tubing (1/8" walls) are 18" long. The 1.5" angle iron pieces (1/8" wall) are 36" long.
Just a quick note about drilling holes: After drilling larger holes (like the 15/64" and 3/8" holes needed here), there will probably be lots of burrs left on the exit hole where you drilled. I found that the largest drill in my set (1/2") can be used with a light touch with the drill to remove these burrs. You could also use a 1/2" countersink to take the burrs off.
In order to prove that I can do this project with simple hand tools, I'm cutting all the angle iron with a hacksaw and drilling the holes with a hand drill. Several colleagues have suggested that I get a miter saw (chop saw) with a grinder blade to cut all the steel pieces since it would go much faster. A drill press would also be helpful for all these holes. While I agree that it would be faster and more accurate, I still like knowing this project can be done with simple hand tools.
Cheers,
Tim
Strut Compressor Tool
I called a local suspension shop and asked if they would take the springs off of my strut assemblies. They gave me an estimate of $30 per strut. Against my better judgement, I looke at Harbor Freight and found a strut compressor tool that only cost $33, so I ordered it.
Here's what UPS delivered to my door.
After opening things up and assembling them, this is the final compressor tool. It's quite beefy and has safety pins and a safety ring to prevent the spring from "sproinging" while under compression. My strut assemblies are at a friends house now, but I hope to try this out when I get things back, or at least try it on the rear springs. More cool tools! (insert maniacal laugh here...)
Here's what UPS delivered to my door.
After opening things up and assembling them, this is the final compressor tool. It's quite beefy and has safety pins and a safety ring to prevent the spring from "sproinging" while under compression. My strut assemblies are at a friends house now, but I hope to try this out when I get things back, or at least try it on the rear springs. More cool tools! (insert maniacal laugh here...)
Rob Connelly's Front Battery Racks
"If I have seen farther than others it is because I have stood on the shoulders of giants"
Many other people have done Honda Civic EV conversions before this one, which is why my job is so easy. There's not much special about this project other than I'm trying to collect the information together into an open-source kit.
I'd like to thank Rob Connelly for providing 3D drawings of his front battery racks so people can see different ways of doing things.
Here's a picture captured from a .PDF that Rob put together.
Here is a picture of the front battery rack support that Rob C. used to support the rack above. Overall, this is a very clean installation that looks very professional.
I also received a note from David Harrington, who is converting a 6th gen Civic (1996) at civicity.blogspot.com and is making good progress.
Again, many thanks to everyone who is working on a Civic conversion and contributing to this open-source project.
Cheers,
Tim
Many other people have done Honda Civic EV conversions before this one, which is why my job is so easy. There's not much special about this project other than I'm trying to collect the information together into an open-source kit.
I'd like to thank Rob Connelly for providing 3D drawings of his front battery racks so people can see different ways of doing things.
Here's a picture captured from a .PDF that Rob put together.
Here is a picture of the front battery rack support that Rob C. used to support the rack above. Overall, this is a very clean installation that looks very professional.
I also received a note from David Harrington, who is converting a 6th gen Civic (1996) at civicity.blogspot.com and is making good progress.
Again, many thanks to everyone who is working on a Civic conversion and contributing to this open-source project.
Cheers,
Tim
Tuesday, July 8, 2008
Bolting Together the Front Battery Rack
I'm taking a different strategy from many EV installations in the hopes that people can more easily put together a kit for the Civic at home. Most folks weld together battery racks and then bolt them into the car (or sometimes weld them in). This strategy uses beefy angle iron pieces and 3/8" grade-8 bolts with nylock nuts to hold things together. I'll revisit whether this strategy is a good one or not after trying it out. Worst case, I take the bolted together frames and weld them.
Here are the main supports for the front battery rack and the rear trunk battery rack. We have two 10" long pieces of 2" angle iron for the front rack and two 18" long pieces of 1.5" square tubing (1/8" walls) to go in the trunk.
In order to bolt the main supports to the frame, we need to drill holes in them. Here I'm drilling 3/8" holes in 5/8" from the end of each square tube. I found that clamping the metal stock to the furniture dolly worked quite well for drilling since I could put my knees on the padded areas and there were several places to clamp onto.
Keep in mind when drilling holes that it's best to drill a "pilot" hole about 1/8" in diameter and then use the larger drill (3/8" in this example) to follow the pilot hole. Hole placement will be much more accurate and the large drill won't skip all over the place. Don't forget to wear your eye protection as well. Little bits of metal fly everywhere when drilling.
Hmm... It looks like the rattling from the drill shook the nuts off the furniture dolly casters! I found several nuts and washers lying on the floor that had nothing to do with the Civic and this is where they were coming from. I re-assembled the dolly and cranked down the caster mounting nuts tightly.
Remember the two 10" pieces of 2" angle iron? Here is the first one installed using the bolts from the towing bracket. The center of the holes are 15 mm from the top edge of the angle iron. The first hole is 20 mm in from the front end and the second hole is an additional 30 mm back. I only had english drills, so drilling 13/32" holes seemed to work fine.
Here's the main support bar installed on the driver's side tow-hook bolts. The hole placement is the same for the passenger side, but just mirrored.
With the two main supports in, I measured between the edges and took off a little for the curve at the corner of the angle iron. For this vehicle, cutting two 1.5" angle iron pieces 34 3/4" long worked quite well. In order to rotate the front angle iron piece into place, I had to remove the rear tow hook bolt.
Here I'm using the foam-core batteries to make sure I have enough clearance for the clutch slave cylinder. Things look pretty good.
The next step was to remove the 1.5" angle iron and drill 3/8" holes in each end. The holes were 1" from the end of each bar and 3/4" in from the edge (pretty much centered).
After putting the 1.5" horizontal angle iron bars back in, I pushed the front one as far forward into the front grille as possible and clamped down the ends to the main support (shown in picture) with small clamps. With the piece clamped in place, I could use a 3/8" drill to make a hole through the top piece into the main support. After this a 3/8" grade-8 bolt (3/4" long) with nylock nut was added to hold things together. I did this to both ends of the front bar.
After the front bar was bolted in, I measured 6 15/16" inside distance from the front bar to place the rear horizontal bar in and clamp that down with the small clamps. After drilling 3/8" holes and adding bolts with nylock nuts, the front rack base was complete.
Here's the completed front rack base. Keep in mind that this is only held in by two bolts on each end from the towing brackets. I plan to add vertical steel bars on each side to the extra 3" of angle iron protruding upwards in the picture. This is a good start, though. The foam-core batteries fit well and give good clearance to the clutch slave cylinder.
Again, after bolting this whole thing together, I'll revisit whether using heavy duty bolts and supports will be sufficient compared with welding. The intent is to make this kit easy to create and install.
Here are the main supports for the front battery rack and the rear trunk battery rack. We have two 10" long pieces of 2" angle iron for the front rack and two 18" long pieces of 1.5" square tubing (1/8" walls) to go in the trunk.
In order to bolt the main supports to the frame, we need to drill holes in them. Here I'm drilling 3/8" holes in 5/8" from the end of each square tube. I found that clamping the metal stock to the furniture dolly worked quite well for drilling since I could put my knees on the padded areas and there were several places to clamp onto.
Keep in mind when drilling holes that it's best to drill a "pilot" hole about 1/8" in diameter and then use the larger drill (3/8" in this example) to follow the pilot hole. Hole placement will be much more accurate and the large drill won't skip all over the place. Don't forget to wear your eye protection as well. Little bits of metal fly everywhere when drilling.
Hmm... It looks like the rattling from the drill shook the nuts off the furniture dolly casters! I found several nuts and washers lying on the floor that had nothing to do with the Civic and this is where they were coming from. I re-assembled the dolly and cranked down the caster mounting nuts tightly.
Remember the two 10" pieces of 2" angle iron? Here is the first one installed using the bolts from the towing bracket. The center of the holes are 15 mm from the top edge of the angle iron. The first hole is 20 mm in from the front end and the second hole is an additional 30 mm back. I only had english drills, so drilling 13/32" holes seemed to work fine.
Here's the main support bar installed on the driver's side tow-hook bolts. The hole placement is the same for the passenger side, but just mirrored.
With the two main supports in, I measured between the edges and took off a little for the curve at the corner of the angle iron. For this vehicle, cutting two 1.5" angle iron pieces 34 3/4" long worked quite well. In order to rotate the front angle iron piece into place, I had to remove the rear tow hook bolt.
Here I'm using the foam-core batteries to make sure I have enough clearance for the clutch slave cylinder. Things look pretty good.
The next step was to remove the 1.5" angle iron and drill 3/8" holes in each end. The holes were 1" from the end of each bar and 3/4" in from the edge (pretty much centered).
After putting the 1.5" horizontal angle iron bars back in, I pushed the front one as far forward into the front grille as possible and clamped down the ends to the main support (shown in picture) with small clamps. With the piece clamped in place, I could use a 3/8" drill to make a hole through the top piece into the main support. After this a 3/8" grade-8 bolt (3/4" long) with nylock nut was added to hold things together. I did this to both ends of the front bar.
After the front bar was bolted in, I measured 6 15/16" inside distance from the front bar to place the rear horizontal bar in and clamp that down with the small clamps. After drilling 3/8" holes and adding bolts with nylock nuts, the front rack base was complete.
Here's the completed front rack base. Keep in mind that this is only held in by two bolts on each end from the towing brackets. I plan to add vertical steel bars on each side to the extra 3" of angle iron protruding upwards in the picture. This is a good start, though. The foam-core batteries fit well and give good clearance to the clutch slave cylinder.
Again, after bolting this whole thing together, I'll revisit whether using heavy duty bolts and supports will be sufficient compared with welding. The intent is to make this kit easy to create and install.
Setting up KeepOut Areas
In preparation for designing the front and firewall battery racks, I wanted to make sure the engine compartment had several existing components in it so I could determine clearance more accurately.
Here my friend Rick and I are re-installing the transmission so I can properly figure out clearance on the front battery rack and placement for the firewall battery rack. This will be a bit tricky to fit the four firewall batteries and still close the hood. Although I can pick up the transmission by hand, it was far easier to use the engine hoist to slowly lower it in and bolt it back to the frame.
The rear support beam of the firewall battery rack will traverse the width of the engine compartment. In order to adequately bolt into the chassis, I had to bend (very carefully!) these brake lines back so that they wouldn't interfere with the battery rack.
Here is the brake line going into the driver side tire well. I had to carefully bend this down so that I could mount a vertical metal bar on the driver side shock tower that didn't interfere with the brake lines. I'm using this metal ruler as a straight-edge to determine interference with the brake line.
Next up: designing the front battery rack
Here my friend Rick and I are re-installing the transmission so I can properly figure out clearance on the front battery rack and placement for the firewall battery rack. This will be a bit tricky to fit the four firewall batteries and still close the hood. Although I can pick up the transmission by hand, it was far easier to use the engine hoist to slowly lower it in and bolt it back to the frame.
The rear support beam of the firewall battery rack will traverse the width of the engine compartment. In order to adequately bolt into the chassis, I had to bend (very carefully!) these brake lines back so that they wouldn't interfere with the battery rack.
Here is the brake line going into the driver side tire well. I had to carefully bend this down so that I could mount a vertical metal bar on the driver side shock tower that didn't interfere with the brake lines. I'm using this metal ruler as a straight-edge to determine interference with the brake line.
Next up: designing the front battery rack
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