David Heacock's 1985 Avanti EV Conversion (In Process)

Battery Racks
Updated 4/14/10.

The building of the battery racks was not only a learning experience for me but also resulted in a lot of fun working with metal. As noted in references about building an EV, learning how to weld by building the battery racks is probably not a good idea. Up to this point I had experimented with the MIG welder and built a number of smaller items. Friends at a local welding shop were kind enough to take a look at some of my first welds and comment on what was wrong or could be done better. As they often say, practice, practice and more practice helps develop the skills. I'm still not a great welder but I figure if I can't break the parts apart using a large hammer the welds should hold in the long run. Again, ask for help and you can probably do a pretty good job.

The problem was to determine how many batteries could be installed and where. I decided I had enough room for nine batteries in the front and maybe more. I wanted to keep the batteries as low as possible but also have them accessible. A really good EV friend just happened to have 12 AGM batteries that worked nicely for testing purposes but would not be of much use for really getting very far once the project was complete. I used the dimensions of these batteries along with the cardboard boxes they came in to first determine if nine batteries would fit in front. Then as I always do, I designed the battery racks for slightly bigger batteries in the future. My main problem was I did not know how much added weight was necessary in the front of the Avanti to return the car to at least a level position using the unmodified Avanti front end.

I first decided to build a small battery box for the first three batteries in the very front of the engine compartment. The following pictures show this battery box as it was completed and placed in the car.

It is always a good idea to first tack weld the parts of the racks together and then make sure they fit the way they are supposed to. Another good idea is to remember that when welding, the extreme heat tends to warp things that are not clamped down. My welding bench consisted of an old steel clad door and a couple of metal saw horses as shown in the following picture.

The next battery rack in the center of the engine compartment was going to be a little more difficult. My goal with all these racks was to take advantage of existing holes in the frame and mounting bolt positions. I decided to use the holes that were originally used for the engine mounts realizing these were on a slanted portion of the frame. I first made a couple of plates for either side that could be bolted in place and then had to figure out how to connect the horizontal cross piece. As shown in the following picture I used a piece of wood to get the correct angles against the plates before I cut the metal crosspiece.

Once I had the center support figured out using the existing motor mount holes I then looked forward and backward to find existing frame mounting holes or bolts I could attach front and rear supports to. The following picture shows the completed rack with the angled plates that mount to the existing motor mount holes. The biggest part of getting this rack finished was lifting it in and out a number of times to make sure it fit correctly before I finished welding it.

The following pictures show the rack in position and all the nine batteries installed. Note that I welded small angle pieces to the various racks so that later they could be used to tie down the batteries.

After placing nine batteries in the front I found the front of the Avanti was still higher than the rear. So at this point I started looking to see where I could add the additional three batteries for my 144 volt system. As it turned out, because I had placed the motor in the rear, I had room under the rear top rack. I decided to make a rack that would be hinged on one end so it could be lowered under the car to access the batteries. Again I tried to use existing mounting bolts or holes. The following picture shows the lower battery rack before it was painted. At one end can be seen the large mounting bar that was positioned between the X frame on the Avanti and rested on the lower I-beam edge. This end has the hinge that I had a local shop weld to my battery rack as I wasn't confident I could get the hinge on correctly.

The following picture is of the lower rack after it was painted. The small "L" brackets were first bolted to the Avanti frame. After the rack was installed and raised into position two bolts were used to attach the front of the rack to the holes in the "L" brackets previously attached to the frame.

The last picture shows the lower rack in place in the down position, ready to load the batteries.

At this point I was starting to feel fairly good as I had just saved a lot of money building the racks myself and the electric part of the EV was starting to develop.

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