Tuesday, December 29, 2009


Even though I'm not quite ready for them, I decided to go ahead and purchase the traction batteries.  It was a convenient time for me to get them (since I could borrow a friend's truck) and the battery distributor (Northeast Battery) gave me a nice price.  I bought 13 Trojan T-1275 Plus batteries with the low-profile universal terminal to provide the minimum 156 V recommended to power my AC-24LS motor.  The universal terminal is supposedly less inclined to loosen with vibration and over time and is the connection I've seen recommended the most by EV converter experts.  This image is from Trojan's product spec sheet for their "plus" line of batteries.

Funny thing happened, though, when I went to pick the batteries up.  I thought the left rear tire looked a little low when I got out at Northeast Battery's parking lot but didn't think too much about it.  Well, when they lowered the pallet of batteries onto the truck-bed I couldn't believe how much the back end dropped!  I looked at the left rear tire again and it was obvious now (with the weight added to the back end) that the tire was basically flat.  It didn't look like the front tires were in danger of losing traction because of the imbalance, but it didn't look that healthy, either.  Yikes!  So I limped to the nearest gas station (less than 1/4 mile away, fortunately) and filled up the rear tires.  Man, I was sitting there for a long time filling that left tire - I topped off the other one, too, while I was at it.  The truck was much more level now, and I felt much more comfortable driving it with the load.  So no worries getting back to my home town (just under a 50 mile drive).  The truck actually rode a lot nicer with the load in back, though I was careful to leave plenty of space in front of me for braking, and was ginger going around curves.

Here's the happy picture of the batteries in the back of the truck.

Even with the tires properly inflated, the back end of the truck was lower than I expected.  By my calculations there was a shade under 1100 lbs sitting there, which caused the back end to drop 3 inches.  It's a bit hard to see with the pictures below (I'm a horrible photographer) but these are loaded and unloaded pictures of the bed height.

Loaded.  (Don't ask me why I placed the yardstick upside down like that)  We're at 19 inches here.

Unloaded. We're at 16 inches here, 3 inches higher off the ground now.

With the help of a strong-backed friend, the batteries are now sitting on the pallet in the basement, waiting for me to get off my butt and finish the battery racks.

Tuesday, December 22, 2009

Battery layout and rack designs Pt 2

The rear battery boxes will be made with 1.5"x1.5"x.125"thk steel angle, welded into 2 boxes which will be bolted together and bolted to the car, either through the floor pan or directly to the frame.

To make sure they will actually fit in the car, we built the boxes in stages.  First, the base of the "lower" rear rack (the one that will hold 6 batteries side-by-side) was tacked together and placed in the car.

Hooray.  It fits.  As you can see by the second image, the left-to-right level is a bit off, but that's because we haven't yet set up the brackets that will anchor the rack in place.  As you can see below, we should be able to utilize the seat belt anchor to secure the rear corners of this box. (Hard to see in this image, but it's the rust-colored spot inside the red circle)

So, since things are looking ok at this point we proceeded to complete the frames.  Here's the lower rack tacked together.  The gap in one of the upper edges is where the opening to the upper box will be.

Here's the upper rack partially tacked together.  It's a more complicated design because it will contain 2 rows of batteries (1 row with 3 batteries end-to-end, 1 with 2 batteries end-to-end).

Here's the upper rack basically finished.

The next step is to put the racks in the car and fit brackets to them to secure them to the car and keep them level.  Our initial plan was bolt the two racks together in place, then bolt the racks to the car in 7 places: the front of the lower rack will be secured to the floor pan on either side of the "center hump" (the floor pan will be sandwiched between two 1/8" thick plates), the back corners of the lower rack will be secured to the seat belt anchors, the rear of the upper rack will be secured through the trunk floor, and the upper rack will be secured through the trunk floor near the rear wheel wells.  Here's a picture showing the lower rack.  You can see where the pedestal supports will sit on the floor.

This view shows where the upper rack will be attached to the trunk floor.

More to come.