wire batteries up

Step 22:  Wire batteries up.  These being expensive batteries I want to make sure they are protected from damage.  A battery management system (BMS) is employed.  A gracious EV-cohort donated an Elithion BMS needing only minimal additional components.  This BMS monitors voltage and temperature and disables the drive if a cell is in danger of being damaged.  It does the same during charge.  This BMS uses a small circuit board that attaches to each cell, these are daisy chained together and relay data to the BMS controller.  I've installed the BMS controller tucked up under the dash.  I will be able to view the status of the battery pack with my iPhone and a rs232 dongle.

front bank

rear bank, tucked into the back of the
trunk for good weight distribution

BMS controller, rat nests allowed

install batteries

Step 21:  Install batteries.  I picked up the cells and they look great.  They all have a listed capacity around 200Ah and an initial resistance reading around a quarter of a milliohm.  

The first task is to secure them in the car.  I'm simply using vinyl strapping to secure them to the plywood platforms already bolted in the car.  The 3rd picture is of the cells that will go in the trunk.

Tools acquired:  strapping tensioner and crimper

track batteries

Step 20:  Track batteries.  To save shipping costs I will pick the batteries up from the UPS freight terminal once they arrive.

order batteries

Step 19:  Order batteries.  This gets its own step.  A lot of the money in this car will be in its batteries.  I chose to order directly from CALB (China Aviation Lithium Battery) because they have a presence in California and my friend had met the salesman there a few years ago.  They had them in stock stateside and are packaging them up right now!  I'm getting 30 of the CA180FI cells.  It's going to be a very nice battery.

power cables

Step 18:  Make power cables.  I'm using 2/0 gauge.  The cables are orange, for easy identification.  To save money I painted black cable.  I'm going with the crimp-only crowd in the debate over the best way to make lug connections, copper to copper.  Adhesive lined shrink tubing is put over the cable-lug connection to keep it clean.  Anti oxidant grease is used when bolting lugs down.

Tools acquired: hammer crimper

There will be 8 cables:

• battery plus to main contactor
• main contactor to motor plus
• main contactor to motor controller plus (under car, in rear)
• mid-battery connection (under car)
• motor controller output to motor minus (under car)
• motor armature to motor field (pictured below)
• battery minus to emergency disconnect switch
• emergency disconnect switch to motor controller minus

battery mounts

Step 17:  Make platforms to mount batteries.  I'm going simple with 3/4" plywood.  In the front the plywood is secured to the motor mount and a horizontal brace, in the rear bolted through the floor of the trunk.  The only protection the batteries will have will be provided by the car and hood or trunk lid.  My idea is to use polyester strapping to strap the batteries to the plywood.  It will be about 200 pounds of batteries for each location.

There will be 14 batteries in the front and 16 in the rear.

air conditioning

Step 16:  Achieve refrigeration.  This part needed to be worked out before putting a large battery in the way.  Route the A/C hoses tucked away, a large battery is going to go in here.  The A/C ports will be accessible with the battery in place, and the compressor serviceable from underneath.  The high side port, pictured (red), is tucked under the dryer.  The low side port is up against the firewall.  

The jumper cables are for running the compressor on 12V while filling and testing.  The traction motor draws roughly 600W idling at 12V.  The air conditioning system increases power draw by roughly 700W.  

The battery may look like this box.  So I want to work the kinks out of the air conditioning before being encumbered with it.

Evacuated and filled with R134a.  Ice-cold!



Well, it was ice-cold then the compressor made noises and seized up. I learned that a refrigerant compressor has to be mounted right-side-up.  There is an oil plug on the body which has to be within 90 degrees of up.  It probably ran for 30 minutes upside down - don't do that!  

New compressor installed.  Air conditioning complete.

Tools acquired: AC gauges and cheapy vacuum pump from Harbor Freight