WARNING!  This writeup is not a "how-to" manual, but only a history of what I did to convert my truck to electric power.  From this point on, the hazards become very real.  120 volts DC is very dangerous and can be lethal!  If you decide to do similar things to what I did, be sure you understand the proper methods of dealing with high voltage and the possible consequences!  If you do not have a total understanding how to safely work with high voltage, DO NOT DO IT!
 

The arrival of my batteries yesterday allowed me to concentrate my efforts on their installation and inter-connections.  The batteries I chose are US Battery model US-145XC.  The local distributor for US Battery is Interstate Battery who sells the exact same battery as their part U-2400.  There are a number of deep cycle battery models with the same length and width.  The height varies with capacity.  This is a 251 Amp hour battery, and is the highest power battery available with this footprint. 

Battery Mounting and Wiring Requirements

I had several requirements for the batteries, their mounting, and their connection:

1.  The batteries had to be restrained!  I have seen writeups of a number of conversions where the batteries are just sitting loose in a box.  This is not satisfactory to me.  All my batteries are restrained.

2.  The battery boxes and their mounting had to be strong enough to survive an accident without tearing loose.  I ran some strength calculations and beefed up several members for added strength.

3.  The batteries had to be protected from road spray and debris.  All batteries are contained in boxes with solid liners, and a protective sheet of neoprene is positioned over each battery box.

4.  The batteries had to be arranged to prevent any two points that are close together from having any higher voltage than absolutely required.  Each of my battery boxes is physically separated from the others and each is arranged to keep the higher voltage potentials apart from each other.

5.  All connections that could be insulated would be insulated.  I use insulating boots over every battery terminal, and plan to do so as much as possible over every connection to other hardware.

6.  All cables in the battery system must have additional insulation and physical protection whenever they run from place to place in the chassis outside the battery boxes or the electronics mounting board.  All my exposed cables are enclosed in either heavy vinyl tubing or in split loom.

7.  All cables must be physically restrained by cable clamps or other means on all long runs.  I have included numerous cable clamps to assure the cables cannot move enough to be damaged or cause damage.

I think I have meet all these requirements in my implementation.
 
 
 

My batteries arrived! Here are 20  6 volt deep cycle batteries capable of supplying 120 volts at over 400 amps.  They have a total capacity of over 30 kilowatt hours! As the man from the battery company said when he delivered my batteries, "That's more capacity than many solar powered homes have."

Wiring Difficulties

I had specified "L" terminals on the batteries, as the general consensus is that they provide the most reliable high current connections as needed in an EV.  The orientation of these terminals caused me some real problems.  The connecting tabs of the terminals are pretty much in direct line with the end battery cap.  As I need access to all the caps to periodically check and add water, the cables must clear them.

I tried without success laying out the batteries several different ways to try to make clear wiring paths.

My final solution was to install the batteries in an alternating orientation (plus up, plus down, plus up, etc).  I really did not want to do this as keeping the batteries aligned is cleaner and less likely to cause errors.  However, with this alternating layout, the connections mostly run in straight lines along the battery edges.  By bending the terminal lugs about 25 degrees, I was able to keep the cables outside the area occupied by the caps.
 

This top  view of one of the batteries shows the "L" terminals.  This is supposedly the most capable type of connection for EV's  Unfortunately, the alignment of them leaves a lot to be desired. To run a cable from battery to battery, it is difficult to miss the battery caps, which need to be accessible for normal service.

My solution to the connection problem was to form the lugs to about a 25 degree angle, and to curve the cable both outward and upward.  This clears the caps adequately.  Even when the insulating boots are in place, there is adequate clearance.

Making the cables for all the high current interconnects is a somewhat tedious process.  First I need to score the insulation just slightly farther from the end than the depth of penetration into the lug.  This is about 1 inch.  Then I have to bend the end of the cable to pull apart the thin section of the insulation that is left.  This is preferable to cutting deeper and nicking some of the wire strands.

Next I coat the inside of the lug with Noalox.  This is an anti-corrosive, metal particle loaded cream.  I carefully place the lug over the stripped cable, being very careful not to catch any of the many very fine wire strands.  I rotate the lug to align it correctly for the application.  I then use the long handle crimper and place two crimps on each terminal.

Next I put a length of shrink sleeve over each end, being careful to put the red and black sleeves on the correct ends, if there is a difference.  I shrink these lengths of sleeving using a hot air gun.

Finally, I stretch the hole of a boot with a pair of long nose pliers, swab it with soapy water, and swab the shrink sleeve with the soapy water.  I then work the insulating boot over the end of the cable into place on the shrink sleeving.  It is a very tight fit.

When I have done these operations to each end of the cable, it is complete.
 

I use the massive crimpers to attach the lugs to the cable. This shows one of my reformed lugs crimped to a cable.  Note the two four sided crimps.  This makes a very secure "gas tight" joint.

Crimping Cross Sections
 

When I pulled cable through its protective vinyl tubing (see below), I used a couple of scrap lugs.  After I finished getting the cable into the tubing, I cut them from the cable. Here is one of those lugs.  This shows the end I cut from the cable, and shows the 1159 strands of wire that make up the 2/0 welding cable.

I then cut through one of the crimped areas and carefully sanded the end. For all you can see, it is a solid bar of copper.  The crimping does an excellent job of squeezing the many strands into a single mass.  This is why they call it a "gas tight" joint.  The copper strands are pressed so tightly together, that no air or corrosive gases can get in to tarnish the copper and increase its resistance.

After determining the exact length needed for the 12 connections which connect adjacent batteries, I made a "production run" of the 12 cables.  They are all identical except for the direction the boots are installed in relation to the bend of the lugs.  I needed 6 of each orientation. The balance of the cables will be custom fit on a case by case basis.

Battery Installation

My battery boxes consist of a welded angle frame which is lined with plywood, then with styrofoam.  This then is a snug fit around the batteries.  If the batteries swell with age, the styrofoam will absorb this.
 

I am lining the battery boxes with styrofoam insulation.  Here the large box is ready for batteries.

After lining all the under-bed boxes and preparing them for the battery hold downs, I installed 18 of my 20 batteries. There are two more batteries which will be housed under the hood.

When I purchased the truck, I was delighted that a previous owner had installed air shocks on the rear.  I had no idea of whether these would  provide enough lift to offset the added weight of so many batteries, but at least I had an option.

After installing the 18 rear batteries, the back of the truck sat quite low.  Pumping the air shocks to 130 psi. raised it about half way up to the unloaded level.  This would be marginally OK.  To correctly solve the problem, I ordered a set of rear airbags.

Before actually connecting any of the batteries, I bought two 1/2 inch combination wrenches at the local swap meet.  I insulated these by covering one end of each with shrink sleeving.  These are the only wrenches I will use when connecting or disconnecting cables to or from the batteries.
 
 

These are the 2 wrenches I insulated with shrink sleeving to make them safe to work on the battery terminals.

Battery Hold Down Brackets
 

The battery hold down bars are attached along one top edge of the batteries, and bolt to the angle structure.  In essence they clamp the top corner edge against the diagonally opposite bottom corner edge. On the batteries which are clamped along their ends, the lifting loops are too close to the edge, and would interfere with the bars.  To compensate, a 1/4 by 3/8 wood strip is attached to the bottom corner of the bar.  This holds the battery, but clears the loops without weakening the angle hold downs. Bars which clamp the long edge of the batteries do not need this spacer.

Here the 10 rear batteries are connected using the 2/0 welding cable, crimped ends, shrink sleeving, and insulating boots.. You can easily see the battery hold down bar along the front edge of the near two batteries.

Fusible Links
 

A fusible link is placed in each of the two cables which connect the rear 10 batteries to the front 8.  These are "disaster" protection against short circuits or a major system fault. This view also shows the vinyl tubing which is placed over the exposed lengths of cable to further protect it.

This is my progress through October 7, 2008
 

I finished connecting the 18 rear batteries, except for two cables intentionally left open.  I will not connect these two cables until I want to actually power up the system.
 

Here all 18 "under bed" batteries are connected.  The two cables in the forward boxes are not connected at one end each to make sure the system is not "hot".  When all the cables are installed throughout the system and I want to energize the system, these cables will be connected. The power from these rear batteries is carried forward by one cable from each of the forward boxes.

Long Cables along the Frame

After completing the battery interconnects, I measured for the cables going forward to the hood area and cut both cables and 1 inch vinyl. tubing to the correct lengths.  The vinyl tubing is for mechanical protection of the cables where they run through the truck chassis without other protection.

I had quite a time pulling the cable through the tubing.  The longer length was over 13 feet, and the vinyl cable insulation tends to stick to the vinyl tubing.  That, and the fact that the tubing was somewhat flattened by having spent most of its life rolled tightly on a reel, made it even more difficult.

Earlier, in trying to determine the best way to bend the lugs, and to see just how far I could bend them, I had spoiled several by opening cracks during forming.  I now utilized a couple of these scrap lugs.  After cutting them down somewhat for better clearance, I crimped one to each cable.  I ran a nylon cord through the vinyl tubing and tied it to the hole in the lug.  By clamping the cord in my vise, I was able to pull on the tubing and work it gradually over the cable.

I then installed a cable into each 4-battery box, connected them to the correct battery terminals, and ran them forward to the hood.  The vinyl tubing is a snug fit in the holes in the battery boxes.
 

This shows the negative cable exiting the driver side box.  It curves and crosses the driveshaft.

After crossing the driveshaft, where it is well anchored to the floor above, the cable proceeds to the right frame member where it joins the positive lead. The next few pictures show that I did not crawl under the truck to pressure wash the frame.  This picture shows just a short length that the pressure washer could reach from the rear of the cab.

The positive lead exits the passenger side box and joins the negative.

Both cables proceed forward along the frame, are clamped, then pass over the transmission cross member.

From there, they continue along the frame, are clamped again, and proceed up into the hood area. I will carefully cut a drain hole in the bottom of each vinyl tubing at the low spots to allow any condensation or other moisture to safely drain out.

I have now cut the drain holes. I tried several techniques on a scrap piece of vinyl tubing and had difficulty with all of them.  The problem was in cutting a neat hole through the 1/8 inch wall of the stiff tubing without scratching the insulation of the cable inside. My final solution was to thin the wall of the tubing using a small sanding drum in my Dremyl type grinding tool, running at a very low speed.  After the wall was thinned, it was a straight forward job to cut the hole in the remaining thin wall using a sharp pair of diagonal cutters.  This avoided any contact with the cable inside.

Here the cables enter the hood and are clamped again.  The negative will proceed to the battery box and the positive through a high current connector to the electronics board.

This is my progress through October 9, 2008
 

Closing the Fender Well Hole

Before I am ready to put the batteries in the front boxes, I must do something I have been very successfully putting off for several weeks- patching the hole in the fender well I made to allow more room for the driver side battery box.  It is a roughly triangular shape hole with the sharp corner of the box protruding.  I bought a formed steel fence post cap to cover this hole. 

I spaced the cap 3/4 inch out from the box with a small block and held the cap in the location I wanted.  I then marked a line around the cap 3/4 inch from the fender well.  After trimming the cap to these marks, it fit fairly well to the fender well contour.  I now found out how lousy a welder I am on thin sheet metal, working where I cannot see what I am doing and doing it over my head!  I managed to get several short beads around the cap to securely fasten it.  I then liberally applied caulking all around to seal all the remaining openings (and to try and hide the ugly welds I was able to get).
 
 

This is the 3 cornered cut through the fender well wall.  The corner of the battery box (shown here in a very early condition) pokes through the fender and will need to be protected from underneath.

The cap that closes off the hole is finally installed.  A combination of welding a few places around the edge and liberal amounts of caulk completed the job.  Of course a coat of paint makes it all look much better. The cap is located were it should just clear the tire on a hard right turn with the spring compressed to the snubber.  If it should contact the tire, it is a flat surface pretty much tangent to the tire, and should just rub harmlessly. There is plenty of clearance for all normal driving conditions.

I originally used 3/8- plywood for the side panels of the under-hood batteries, like all the other battery boxes.  As I had not yet decided to use the styrofoam insulation around my batteries at that time, it turned out that there was not enough room for it, so I redesigned the battery box panels.

I made all new side panels for the two front battery boxes.  Some of these were made of the same 3/8- plywood I used on all the other battery boxes, and some were 1/8 in fiberglass reinforced plastic panels.  I mixed and matched these to provide the proper inside dimensions for a snug fitting battery in each box after installing panels of styrofoam sheet inside the liners.

All the cables entering or exiting these boxes are protected by vinyl tubing.  Where the tubing enters through plywood, I just use the tightly fitting hole in the plywood to hold the vinyl sheath in place.  Where it passes through a plastic panel, I welded a clamp assembly to the exterior of the box frame to support the heavy, stiff tubing and cable.
 

The two front batteries are installed and wired.  The only cable remaining is from the negative terminal of the driver side battery to a high current connector which plugs into the electronics board.  I need to fabricate and install the battery hold down bars for these two batteries before the final cable can be installed.

This is one of the cable clamps I made to stabilize the vinyl tubing/cable assembly as it enters through the thin plastic wall.

The battery hold down bars have been made and installed and all the batteries are now wired.  The two loose cables would have my full 120 volt DC nominal (actually about 132 volts) potential if I were to connect the two cables in the back that I left open temporarily.

I cut the vinyl tubing and added a cable clamp to the positive cable.  This is the point where I will start using the split loom over the cable to maintain flexibility for plugging and unplugging this cable to the main board. I have some 3/4 inch split loom in both red and blue colors on order from an Ebay vendor.

This is my progress through October 13, 2008

Neoprene Battery Covers

Addendum of Friday October 17, 2008

I finished the battery project today by installing protective neoprene battery covers.

There are several possible occurances which could damage an unprotected battery.  Even though I used insulating boots on all the terminals, it is conceivable that a dropped tool could still contact the terminals under the boots.  Road debris and other contamination can cause an electrical leak causing the batteries to slowly discharge.  Road spray or other water can do the same.  A sheet of neoprene over the batteries will protect against all of these possibilities, and help keep the batteries clean.

In addition, the extra layer of neoprene will improve safety by limiting possible exposure to voltages any higher than occur in the single battery box that might be uncovered at any given time.

I purchased a 3 foot by 6 foot piece of sheet neoprene and made covers for all the battery boxes.  The batteries are still readily accessible by pulling the neoprene aside.  Each battery box has a separate piece attached along the front wall of the box liner.
 

As the front two batteries are pretty well protected by the hood, I cut the neoprene to stay inside the walls of the battery boxes.  This still provides good protection against accidental shorts and debris, but does not provide very good protection against liquids.

The rear battery boxes are more exposed to the elements, so I made the neoprene extend well over the edges of the boxes for better protection.

To access the batteries for service or inspection, the neoprene can be pulled forward to fully expose them.

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