Extending the Range:

In my home-made, all electric pickup truck, I have been able to get about 35 miles per charge driving around town. On the freeway, I am hard pressed to get 28 miles. This is discouraging considering my daily commute is 20 miles each way, 75% of which is driving on the freeway. I could ask if my place of employment would allow me to plug in and charge the batteries while at work, but that really doesn’t align well with my goal of self sufficiency and independence. Besides, my calculations show that I should be getting 50-75 miles per charge. What’s going on here?

After doing more reading online, I learned that I was not charging the battery pack all the way. My pack is 120 volts. 100% charge is 127 volts. I was charging it up to about 129 volts and calling it good. Come to find out, that is only about 80% charged. To fully charge a 12 volt lead acid battery, you need to get the voltage up to about 14.5 or 15.5 volts. Duh!  For my 120 volt pack, I shouldn’t stop at 129 volts. I need to go all the way up to 150 volts or higher. I guess I knew this all along but hearing 1200 lbs of lead acid batteries bubbling as they entered the gassing stage made me a little nervous.  Turns out, that is a normal part of charging lead acid batteries to 100%. 

Charging all the way up to full made a huge improvement in my range, buying me an extra 8-10 miles. But a range of 36-38 miles still isn’t good enough.
Initially, I thought I may have a bad battery or maybe even Costco batteries are pieces of junk (The Jury is still out on that one). After not finding anything conclusive, I decided to take a different approach. Eliminate all sources of friction! REDUCE DRIVETRAIN, ROAD AND AIR RESISTANCE.

It’s all about the bearings:
I started by replacing the front wheel bearings because they are easy to do on a RWD truck. To my surprise, they extend the max range to over 40 miles. I actually drove 46 highway miles. That about killed the pack and it’s pretty scary driving on a busy interstate when you realize you can no longer go 55mph anymore.  55, 50, 45, 40 mph.  Why must there be a hill before my exit?  Move over onto the shoulder. 35 mph, 30. Somehow I made it to my exit and onto the last main road before I arrived to my neighborhood. I pulled over to let the voltage in the battery pack recover. If you let a dead battery sit for several minutes, it will recover slightly and allow you to drive a couple more miles.

I managed to drive the truck over one last hill before rolling over the other side and into my neighborhood. Home at last. I don’t ever want to do that again and neither does my battery pack. At least now I know the limitations.

After giving the truck’s battery pack a very thorough charge overnight, I drove it to the tire store and had them replace the original tires with low rolling resistance variety. After I got the tires, I took the truck for a freeway speed test. My old speed record was 70 mph. I have tried to exceed 70 mph a few other times but each time, that is all she will do.  With the new tires, I can drive 85 mph. Wow! A 15mph improvement. At first I didn’t believe it, thinking the tires were smaller and throwing off the speedometer or something. A second run with a GPS confirmed my new speed record was accurate. 

Real Wheel Bearings:
Try as I might, I could not get the rear wheel bearings out.  After 232,000 miles, metal on metal tend to meld into one piece.  Even after over 100 attempts of using the redneck mechanic removal method (throwing down the axle shaft on some wood on the concrete as hard as you can), the bearings would not come out.  I took the truck to Big-O Tires but sadly, they couldn’t get the rear wheel bearings out either. After a day of soaking the bearings in a corrosion blocker solution, they finally got them out, replacing them with bran new ones.

New distance record:
After charging the truck’s battery pack up to 100%, I drove it into work. Amazingly, this time, the 20 mile commute only depleted the battery pack to 80% state of charge. After sitting in the hot sun all day without charging, then driving 5 miles around running errands and then driving 20 miles to home at 55 mph, I pulled into my driveway with the battery pack at 40% state of charge. If I can drive 45 freeway miles with only using 60% of the battery, then maybe the battery would carry it further still. I estimate my max range is 50 miles but I don't want to confirm it lest I shorten the lifespan of my battery pack significantly.


Not Good Enough:
50 miles is fine for now but what happens when it gets really cold outside and the batteries have a 30% reduced capacity?  Eventually I want to install a heater. Running a 1100 watt heater during my commute will reduce my range by another 3 miles.

If this truck is going to be my reliable commuter vehicle all year around, it needs to have a 70 mile range or better. That would also extend the life of my battery pack significantly on the days I only drive 40 miles depleting the pack to only 60%.  So now what?
One word!  AEROMODS!

Take it from my sexy Electric Truck's ugly sister the Tesla, Aerodynamics give you excellent range.   Tesla has almost twice the battery capacity as my truck but over 4 times the range, (200 miles).

Electric Truck: Working out all the bugs

I have now driven over 600 miles in my home-modified electric truck. I have made quite a few enhancements in some areas and am still at square one in others.  I am still scratching my head why my range is not as good as I had hoped. I should be getting at least 50 miles per charge but I am only getting 28 highway miles per charge.


Costco batteries have a 75 amp rating of 115 minutes. When I am cruising on the highway at 50mph, my sustained current draw is about 120 amps. If I were to conservatively assume that my batteries will only last 60 minutes while pulling 120 amps, I should still be able to go 50 miles before they are discharged. For some reason, I am killing them early. Perhaps it's the periods when I am pulling more amps (like going up a hill or accelerating to freeway speed). But then there are also times when I am coasting down a hill or using the breaks where I am consuming no power. Hmmm.

I found one of my batteries had a lot lower voltage than the others.  Even after equalizing all of them, when the truck was discharged to 30%, this one battery still showed very low voltage.
I also found several batteries had loose connections.  While tightening them up, one of the posts ripped out of one of the batteries.  I returned both batteries to Costco and got replacement ones.  I also bought a battery load tester at Harbor Freight so I could determine if any more batteries were dead. 

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I replaced my clutch plate, disk and thrust bearing. Now I have a working clutch. It is possible to shift without a clutch but with an electric motor, you have to be patient while the it spins down to a low enough RPM for the shifter to fall into the next higher gear. Now with a working clutch, I can shift nearly as fast as in a normal gas car.

I built a better motor mount after my first one broke at the welds. This 2nd mount uses a wide piece of flat steel to carry the weight of the motor and a Tee shaped piece of steel fastened to the firewall to keep the motor from twisting under high torque. This tee mount held the motor great but caused lots of transmission noise to resonate into the cab of the truck. I removed the tee and replaced it with a light weight, 1” wide metal strap screwed into the truck frame. No more resonance but now the strap is causing an annoying squeaking sound every time the motor tries to twist under torque, I learned that the twisting force on the motor is quite high and after 50 miles, it snapped a spot weld off of the strap.
Onto plan “D”. I welded 2 pieces of flat metal from the flat metal motor strap to the motor itself. Bingo! No more squeak and no more resonance.  So far so good.

More recently, my flywheel has started making a lot of vibration at higher rpm's.  It's kind of annoying and detracts from the quiet ride of the electric truck.  I am waiting for the weekend to pull the engine back apart to have a look inside.  That's the good thing about EVs.  They are super easy to work on.  One hour of work and the whole motor is out.  90 minutes later and everything is back together again.  No oily grease, no seals to worry about, no fluids to drain, no filters, no fuss. 

I replaced the 6 pack of large 50uF capacitors (that looked like a 6-pack of soda) with 4 smaller footprint 200uF capacitors. 

This allowed me to have a lightweight on-board battery charger with higher charge current (7-19 Amps depending on the batteries state of charge) and smaller footprint size.  They get kind of hot when the batteries are charging at the fastest 19Amp rate.  I may have to install a small fan on them so they don't dry out.  

I built a nice battery box to cover up all the batteries in the truck bed.  It looks very unassuming until you peek inside.

Installing the Controller and Wiring

A friend of mine gave me an old broken Curtis motor controller. I spent about $70 in parts and a couple hours replacing a dozen burnt out MOSFETs and power diodes. Sadly when I powered it on, it was still not operational.  Oh well, it was worth the gamble.  I forked over the money to buy a bran new one.   

I proved out a concept that I read about on line where you modify a standard ATX computer power supply to take in 120 volts direct current and it will put out 12VDC.  This will come in handy for powering all the 12 volt systems on the truck, (headlights, horn, radio, signals, relays, etc) without needing an extra 12 volt battery and additional charger. 

I found a nice metal box at NPS for $8 to hold all the electrical parts. I drilled some holes, primed it, painted it white and mounted things up.  Here it is being assembled in the mad science lab in my basement. 

Here is the white box of parts that makes an electric truck tick.  The big yellow thing that looks like a bomb is actually a capacitor array that I am using in a circuit for an experimental quick charger. 

Trying It All Out:
On Friday Sept 2nd, 2011, I took the truck out for its maiden voyage.  Initially, it drove great.  I got it up to 40mph in 2nd gear.  You can watch the video here.
There were a few bugs that I still needed to work out.

• The welded motor mounts broke and had to be redesigned and rebuilt.   
• The motor speed controller needs a larger heat-sink.  It overheated after 10 miles. 
• The clutch still doesn't work well, although it isn't needed in an EV.  
• The controller is a little sluggish at take off.  I need to adjust it so I get more power while accelerating.  

The next day, I came up with a better motor mount design where a metal strap supports the motor.  You can see a day-time 2nd run here.  

For more info on my electric truck, click here. 

My electric truck can go up to 40mph in 2nd gear and up to 70mph in 3rd gear.  It's range is still limited by the battery pack to about 40 miles.  Before I can use it as a commuter truck, I need to break in the motor and the pack.  I hope to have a 70 mile range by the time I finish tweaking everything. 
To date, I have driven the truck over 120 miles.  That's pretty cool considering all my electricity is generated by the power of the sun.  In effect, this makes the truck solar powered. 

Mounting The Batteries

I needed a good way to hold 20 batteries securely in the truck without them bouncing all around.

I recently acquired a 230Amp welder off of ksl for $120. It even came with 40 lbs of welding rod and a welding hood. Nice!

I bought some angled and flat pieces of steel and starting cutting them up to make a battery tray that would hold 4 golf cart batteries in the front of the engine compartment.

I welded the pieces together, grinded them smooth, primed them and painted them. The angled edges hold the batteries fairly securely and prevent them from shifting around. A foam piece pressed against the hood of the truck finishes off the mount.  Here's a video of me cutting and welding the battery tray. 

I made two more battery trays, each can hold 8 batteries.

These larger trays mount in the front of the truck bed close to the cab.

I went to Costco to price out golf cart batteries. You can buy Trojan batteries for $149 each plus core charge. Costco had an equivalent capacity battery for only $79. I bought 14 of them on the spot and another 6 a week later.  I found a 50 foot length of 00 welding cable on Ebay for $155, and built up all the cables needed to connect all 20 golf cart batteries in series.