Chapter 17 - Battery Box Bugaboos
Nothing has given me more headaches than the battery boxes. Where should they go? How big should they be? Lee thinks I should mount all the batteries right side up. He doubts that the sealed batteries are really leak proof. I wanted sealed batteries so I would be able to have more mounting options. The best plan I could come up with called for 7 batteries in the gas tank area, all standing on end in a "T" shaped box, along with the battery charger. The forward battery box would hold 4 batteries, also on end. The middle box would sit just forward and above the electric motor and hold the final 2 batteries. These batteries would each weight 60 pounds, giving me 780 pounds of power to drive a 3200 pound car. No, not ideal, but the Vette seemed to shrink every time I looked for battery space.
I set to work on the boxes. Trouble soon followed. The "T" box was difficult to make, and difficult to mount. Also, once in place, it was impossible to get any batteries into the box. Too much wishing and hoping and not enough careful planning.
Another problem. Switching from 60 lb. batteries to 70 lb. batteries meant all 3 boxes were just a tiny bit too small.
Back to square one. A new plan is needed. If I cut a big hole in the rear bulkhead I would have room for a simple square box that would hold 6 upright batteries, and lose only 6 inches of cargo space.
My angle grinder put too much fiberglass dust in the air, so I had to cut the bulkhead by hand, stopping every 3 inches to vacuum the fallen dust.
I decided to reinforce the new battery boxes with carbon fiber. A 50 foot roll, 3" wide, set me back about $170.
Carbon fiber is supposed to be very strong, so I decided to do a test. I cut off a 5" piece of cloth and laid it on some mat board. Next, I unraveled a few strands of the carbon and laid them at right angle to the other strands. After my coat of resin had dried, I discovered that just 3 strands of carbon fiber could hold 280 pounds with ease. Was I impressed? Yes!
The carbon cloth was stiffer than my fiberglass cloth and didn't lie down and soak up resin as easily, but I thought it was worth the trouble. I ran the carbon fiber down the sides and across the bottom of the rear battery box. Teflon slider disks were added to the bottom of the box, in the hope that this would make the box easier to slide into place.
Didn't work. So I tried another idea. Nylon rollers. If the box wouldn't slide, I would make it roll.
I started with 4 roller tracks, but I thought better of it and went with 6.
Before loading the box with batteries, electric heater strips were placed in the bottom.
Later on, the heater strips will be wired up so that they can warm the batteries when the temperature of the batteries drop below 60 degrees. The heaters need 110 volts, so they will operate only when the car is plugged in to a wall outlet.
The empty box moved smoothly, but, with a full load, it jammed. Oookay, maybe it's time to work on some other thing!