Electric Vehicles


Installing a trailer hitch on my Bolt

Installing a trailer hitch on my Bolt
After some research
I settled on a draw tite hitch from e-trailer
It is rated at 2000 lbs and max of 200 lb tongue weight
I don't expect my trailer to be anywhere near that but rugged is better than
Light weight when it comes to trailer hitches
The scariest part in the install is cutting out the slot in the Bolts rear bumper cover.
Note***
Instructions say 3.25" wide x 5" tall in the center
I assumed the 5" was measured vertically so my slot actually came in st
5.75" after putting it together it seems they mean
5" measured along the face of the rear cover
Pop two rear cover plastic retainers
Remove bottom two screws of the bumper mount
Place two rear attachment screws with anti rotation bars
And cool fish wire into the big hole in the cars frame
Lift whole hitch under the now loose rear bumper cover
And hang it from the two bumper studs .
Start the two nuts but don't tighten until the frame bolts have been passed through the big hitch stabilizer arms
Tighten the 4 bolts and the hitch is installed
Will work on the light kit today

Getting the lead out

Getting the lead out
culling out the good from the bad
I needed the big Trojan T105 batteries for the solar battery bank, so I needed to make a replacement.
Most of the yard buggy use is to move something from one part of the yard to the other, or to collect wood, so the buggy only needs enough battery to make a couple of trips around the yard, instead of the giant heavy lead batteries which pack 220AH, I decided to make up some prius packs equivalent to the 48V lead pack, but with only 15-20AH. They charge faster, and are much lighter.
Started by reconditioning the old gen one (288V) modules. These modules came from several sources, including two packs that were in tough shape, so it was not surprising to find very poor performance from more than half of the modules. The grid charger is a nice tool for this, and to prevent the distortion of the modules durng the gassing stage of the charge, I made some end plates with 3/4" plywood, and some long 1/4-20 threaded rods to compress the modules.
I made a special paralleling cable where I can plug the 48V modules into a common buss, and then plug both ends of the buss cables into the 50A Anderson connectors already on the buggy.
WOW! the NIMH internal resistance is much lower than the lead acid, so the voltage droop under full load is almost non existent, compared to the lead batteries. Can scrub out at will on any surface, so now the issue will be to get enough weight over the rear wheels, so I can pull my trailers. Will rig up a solar quick charger for the packs, but until then, my grid charger will do the job but more slowly.

New England Hybrid Festival 2013

New England Hybrid Festival 2013
first photos that I took
Another New England hybrid festival as come and went, so here are the photos that people have sent.

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Converting a telephone truck to electric

Converting a telephone truck to electric
Ful electric telephone truck
Old telephone trucks make a great tool for cleaning gutters, painting, siding and many other uses. I converter my 40 year old truck to full electric, this blog which starts at the page bottom follows the conversion process.
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More serious rake and vacuum attachment

More serious rake and vacuum attachment
Getting serious about raking
I needed a bigger faster raking and leaf pickup process, so I built a two axis arm for controlling the 8" diameter hose from the e-tek powered electric vacuum.
The arm is powered by some automotive electric window motors with actuators. One moves the hose out to the right and back, and the other tilts the hose up and down.
The control handle for this motorized hose assembly uses two radioshack DPDT 20A 12V spring return to center heavy duty switches. The one mounted in the handle controls the up and down motor, and the one in the rear section of the control handle is actuated when the handle is rotated out and in around the pivot. The window motors move fast, and by adjusting the attachment points and control arms I was able to get a fast stable control of the hose.
The rake frame took several tries to get right, with the most important aspect being the best rake angle to the ground. Straight down works best, which is equivalent to the rake passing right past your feet while manually raking. The weight of the raking frame is counter balanced by a large garage door spring attached to the control handle. The spring is tensioned with a come along that can be tuned to make the rake frame neutral, and slightly lifted off the ground. To rake, I push the rake frame control handle forward, then I back up the machine. The beauty of this approach is that the rake stroke can be quite long. After one or two passes with the rake to bring the leafs into a pile, the pile of leaf is sucked up with the robotic hose arm.
It works nicely, but I decided to build a large vacuum nozzle that will sit on the rake frame, and suck up the leafs as they are raked, so fewer passes will be required. I got the nozzle built, but the snow stopped my testing, so I will have to wait until spring to further refine the attachment.

Electric rake #1

Electric rake #1
Electric rake #1
Raking leaves when your property has a lot of oak and Maple trees can be a big chore each year. Several years ago, I made my first attempt at an electric raking machine.
Yes, yard blowers and vacuums are available, but most of them are gas powered, and they do not really rake the lawn which clears thatch.
I built this contraption from a surplus gearmotor, a drawer slide, a screen door spring, and some rope.
The rake is lifted when the motor crank starts moving up, as the drawer slide has an adjustable rope that limits the handle up travel. Once the gear motor crank starts the down stroke, the rake hits the ground, and the rear of the handle responds by stretching the adjustable screen door spring, which is adjusted for the correct raking down force.The gearmotor arm sweeps rearward for the raking stroke, then lifts the rake at the end of the rearward stroke.
It works pretty well, but is a bit slow and has a fairley short stroke, so while it is a cool electric raking machine concept, It needed a lot of work to make it be a time and labor saver.
Back to the drawing board.

Making a Cheap battery State Of Charge gauge more accurate

Making a Cheap battery State Of Charge gauge more accurate
Making the SOC meter more useable
I had to buy some speed controllers and other EV parts for my yard machine, so I took a chance and got what was supposed to be a 36 Volt system battery SOC gauge.
kelly controller SOC gauge

I took out a variable voltage power supply, and checked the led display's SOC against a Trojan battery company equivalent voltage chart, and found that it was not even close. I could not use it as it was, and the thing was glued together with no way to get inside.I took my band saw and cut the outer tube so the back could be removed. The circuit looks like a series of resistors that make up a voltage divider and some op amp comparators to turn on the leds when the voltage rises over the voltage divider taps. This type of comparator can be quite accurate, but it depends on voltage references and precision resistors,which this unit does not use. What was most interesting was that there is a potentiometer on the circuit that can adjust the divider current to make the whole scale move up or down. I set the power supply to the 100% SOC voltage according to the trojan chart, and then adjusted the pot so the 100% led just came on. I then adjusted the power supply down until each led went out, and noted where the 50% SOC was so I knew when to get to a charger. While this setting may be a bit temperature sensitive, it at least made the gauge usable.
To gain access to the pot, without cutting open the whole case, drill a hole in the indicated place on the back cover and you should be able to adjust the gauge without cutting it open. Of course one could calculate the precision resistor values required for accurate SOC throughout the range, and replace the 10% resistors that they used, but relative SOC is all I need so simply getting the 100% and 50% points will be sufficient accuracy for me.

creature comforts 1

creature comforts 1
Creature comforts
I have been saving a cool bucket seat that I picked up at least ten years ago so I cut off the mounting brackets welded on some angle iron and steel tube, and welded the whole assembly to the torque tube. The front to back adjustment was retained, so big and little people can drive the machine. The handle bars tube is pretty big, so rather than looking for some custom hand grips, I made my own. Some 1/8" buna -n closed cell foam with adhesive back was applied to the bare steel. The foam was carefully wrapped with black electrical tape, which was then painted with PVC pipe cement to hold it together.I covered the tape with a nylon braid to give some grip, and tucked the end into the tube end and tapped in a wooden plug to hold things together.Feels nice.

The yard machine takes shape

The yard machine takes shape
The yard machine starts to take shape
I have been collecting bits and pieces of electric golf carts for many years, and decided that it was time to put them to some use.
I took a rear end from a club car golf cart, and a front wheel with steering bearing from an ezgo.
The three wheels were attached to a welded square frame. I chose to eliminate the rear suspension to make the buggy more or less load independent.
I wanted a single front wheel so I could turn the long machine in a short radius.
The chassis was very easy to twist, and was not stable until I welded in the central torque tube and cross braces which stiffened things up nicely. I bent some steel tube into some handle bars, and mounted an old car seat. The brakes were fixed and adjusted, and a mechanical ratcheting brake from a golf cart was mounted and connected. now that I had some brakes I added a kelly controls PWM motor controller with reversing contactor and mounted it in a water proof aluminum box right behind the motor. The six golf cart batteries were split into two battery hangers and mounted low and just in front of the rear wheels.
Partners in crime Paul Provost and Troy Coverstone ran some test runs to confirm that the thing was fun to drive and reasonably safe.I added an instrument panel with what was supposed to be an led SOC meter. It was not very accurate until I hacked into it and figured out how to adjust it (see mikes tips).
We mounted the leaf vac next, with an e-tec motor and additional controller.

Battery current sensor

Battery current sensor
How it works inside?
If a larger capacity battery pack is used in the Insight, we must "fool" the BCM into allowing the full AH capacity of the new pack to be used.
I setup a BCM and junction board with current sensor, to determine the best way to fool the current sensor into thinking that only 1/10 of the actual current is passing through it. After a thorough analysis of the system, I determined that the Insight battery current sensor was outputting a current loop signal with ~.20mA/A, and since it is a current loop, a simple current dump resistor to BCM ground should do it.

weed whacker motor converted to bicycle motor

weed whacker motor converted to bicycle motor
Bicycle drive
About 12 years ago, I decided to build a powered bicycle, so I dismantled my seldom used weed whacker and built a three speed drive system that attached to the motor. I put it on the front wheel of a bike, with a hand shifter so I could move it through the gears. It worked pretty well as far as pushing the bike, with top speed being faster than I felt comfortable going. I could not stand the noise and fumes, so I removed it.
I just ran into the motor/drive when looking for something else, so I figured I would snap a few photos in case someone else wants to play with a similar concept.

Rebalancing the Insight battery?

Rebalancing the Insight battery?
Long term storage warning
A common problem with the MT Honda Insight, and to a lesser degree the Civic hybrids is a condition called recalibration. The most common version of this condition shows up as a rapid drop in the battery SOC gauge from some intermediate value to empty. The car goes into a forced charge to bring the SOC back up, which if it happens frequently, can take its toll on the MPG.
One of the possible reasons for this condition is an unbalanced SOC between the different cells in the pack.
The warning label from a civic battery pack warns to run the car for 30 minutes a month. It is likely that the self discharge characteristics of the cells is not predictable, so some subpacks will discharge to a lower level than others, and there does not seem to be a rebalancing mechanism in place to correct the imbalance once developed?
The civic hybrid battery packs made 2005 or before are a good source for replacement 6 cell subpacks with the PTC temperature strips attached.

Mikes Saturday Hybrid-Solar- Electric Workshop

Mikes Saturday Hybrid-Solar- Electric Workshop
batmobile
With the many projects I hope to work on, some extra hands are always welcome.
Check here to see if their will be a workshop if you want to come up and lend a hand.
Present project:
Design, build, and test an IMA-EV mod to give full electric mode to the gen 1 Insight

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Insight Battery pack turbo cooler

Insight Battery pack turbo cooler
Insight Battery Turbo Cooler
As any owner will tell you, when you are pumping charge in and out of the pack with MIMA, it can get hot, especially in summer. The battery is cooled with a two speed fan that draws air into the battery pack from behind the passenger seat inlet vent.MIMA will force the two fans on at full speed when the temperature of the battery gets over 95F.
I made a Turbo Cooler for my pack by ducting the passenger foot AC outlet to the battery pack input duct. I set the fan on high, and the duct to foot only. The driver side vent is ducttaped over, so that all the air comes out of the passenger side.
The increased air flow helps a lot, with mild MIMA use, but if you are really pushing the hybrid ratio to the electric side, the pack can still get into the 100 F range. Because of the large thermal mass of the heavy batteries, it takes a lot to cool them even a few degrees. To Turbo Cool the pack, I wait till I am going down hill, so the power is nearly free, and turn on the AC to full, set to 60 F. A long hill and you can cool the pack several degrees.

Battery pack monitoring

Battery pack monitoring
Battery pack monitoring system
Back in 2001 when I first started being active in the Insight on line community, I was concerned about the life of the battery pack, especially the issue of recalibrations. Our understanding of the reasons for the "recals" have not advanced much since then.
I designed a battery monitoring system that used relays for isolation to read each of the 14.4v monitoring points in the pack. The connection to the pack was accomplished with a special spring loaded back probe that just clipped onto the battery. A Labview based data acquisition card and software scanned the taps and recorded the voltage graphically.
I fully expected that my pack would eventually start having the recal issue and wanted to be ready. I am now nearly at 100K on my car, and still have not experienced a single recal. Honda says that gradually accumulating errors in the coulomb counting SOC software is the reason that recal's happen, but I ask what causes the errors? My intuition says that one cell in a subpack is of lower capacity, and since the pack is one long 120 cell series string, that one cell will cause the whole pack to have less capacity than the system expects. When the BCM senses the weak cell dropping voltage as it becomes depleted, the system stops assisting and starts charging to prevent the cell from becoming reverse charged which is instant death. A smart system would have the ability to balance the pack by charging that cell more than the others. Unfortunately since the cell is in a 6 cell subpack, that is not possible with either the Honda or Toyota systems.

The battery controller

The battery controller
The Prius and Insight BCM modules are quite different. The Insight one is not as complex. The main controller for both is painted over so the part numbers cannot be read.