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.
Bucket truck kicks it's gas habit for good
First zero carbon test drive
I need amp and voltmeters before I get better data.
Don't need the 6:1, this configuration has more power than required for my around the yard moving of the machine.
The bucket has dual controls, one set in the bucket, a second on the end of a 20 foot cable so the boom can be used as a remote crane. The boom hydraulics run off a 36V golf cart motor. The 55V solar panel array will keep the battery's charged and ready to go.
It would be great to make a remote steering and motor control system in the bucket, so I could ride around up there. It would get pretty hairy with the boom at it's 25 foot level. The thing crawls at very low speed, so it would be possible in theory.
The hydraulic boom could let the solar array track the sun, bigger array?
Too many projects, not enough time.
For now,the EV telephone truck is ready to go to work.
E-Tek motor drive installed
A careful use of an angle iron and some clamps assured that we welded the motor bracket to the rest of the assembly with perfect chain alignment.
After tacking the parts in place, I had to remove the whole weldment to finish all the welds and check alignment. I used the 4:1 reduction,since the smaller 12 tooth sprocket which will yield a 6.6:1 reduction has not arrived yet.
I wired in the bucket hydraulics, and solar charging system, so my full electric solar recharged bucket truck is 100% operational YEA!
New batteries for EV 1
I removed the weaker modules and replaced them with more tested ones to again find the modules with the best capacity. Next I constructed 4 of the 7 module packs, and again tested them with a couple of cycles,I replaced the weakest modules, and finally got 4 reasonably matched and highest capacity packs.
I made up a paralleling buss that would accept up to 5 of the 48V packs .
Finally I need a 12V module to power the solenoid valves on the bucket, and I will be ready to roll.
New coupling shaft
The pulley was turned down with a precise cavity on the mounting end so the torque plate self centered when placed in the cavity. The 20 holes were used as guides for drilling and tapping 10-32 holes. Ready to mount the bearing.
Not enough torque
When all was said and done. I routed the master cylinder output directly to the front drivers disk brake assembly (the only one that worked). The first electric run was disappointing, as the motor running with the max 400A that the controller is capable of, was just able to push the truck on flat grass. Once I tried to climb even a slight hill, it just gave up.
Based on the amp/torque curves for the CM77 motor, I should have been producing about 37 Ft Lbs. The CM77 output shaft is not designed for side loading, so it is not a good option for a chain based torque magnifying system.
I purchased an 80 tooth chain sprocket, a 20 tooth, and 12 tooth smaller sprocket and a bearing so I can make an additional chain speed reducer.
The e-tek motor running at 200A produces ~19 ft lbs, so if I use the 12 tooth drive sprocket with the 80 tooth large sprocket, which is a 6.6:1 ratio, I should be in the 125 Ft lb range which I estimate should be sufficient to move the 8,000 lb truck around my yard.
I may be able to walk faster than it will move, but thats fine for around the house.
Why is it never easy?
I got some beefy battery terminals, and invested in the correct crimping tool for the big 2/0 wire that was used for the high current wiring. $4.75 a foot for the welding cable makes one very careful to use as short a wire as possible. The throttle pot and linkage is always an expensive item, so I decided to try a simpler cheaper way. The truck throttle cable was fed through an aluminum bracket, and then to a spring to pull the cable out and lift the throttle pedal.
The travel of the pedal/ cable was limited by a small aluminum bracket so the cable travel is the same as the 5K slide pot travel. I found a piece of thin spring steel with a slotted end, that with a bit of sanding fit nicely into the slot in the slide pot actuator. The slide pot was moved to the end of travel, and the throttle switch adjusted to open when at the end of travel. The spring steel actuator was first held with zip ties, then taped to the throttle cable sleeve with black electrical tape, which is carefully coated with PVC pipe cement to make it permanent.
It works quite well considering how simply it is made. The first powered test showed a non linear response, and sure enough the pot was an audio taper rather than linear. I mounted the pot so the taper gave smooth low speed operation, and a fast ramp up in speed at the full throttle end. The worlds first log throttle.
I turned a snug fitting steel alignment shaft that fit on the ID of both the clutch disk spline and the saw blade ID. This forced the two disk to be centered on each other. I clamped the two disk together, and drilled the tap drill holes through the blade. The blade holes were tapped to 1/4-28, and the clutch disk holes were opened to 1/4". The motor output shaft was welded to the saw blade, and the clutch plate was screwed to the saw blade to make the final adapter. The assembly was spun in a lathe to confirm that it runs true. Now the delicate and critical final step of mounting the motor to the bell housing exactly concentric with the tranny output shaft. Both the tranny output shaft, and the motor output have some degree of shaft misalignment compensation which should help.
The drive motor
Back in the 70's I got the bug to build an EV, and picked up a pretty beat 30V 400A 15 HP motor/generator from a surplus equipment company. This is a series wound motor that can take some serious power, so I decided I would use that instead. These motors have so much torque that the drive shaft can snap, so they use a torsion bar output shaft. The rear of the torsion shaft is driven by the rear female spline of the main motor shaft which is a tube.The output side of the motor has another external spline to drive the drive flange. The flange elongated slots engage the three raised post on the output end of the torsion shaft once the torque is high enough.A clever way to keep the output shaft from snapping under the high torque.
The drive spline will not be used on my coupling system so I cut it off with an air cut off wheel, since the shaft was too hard to cut with a bandsaw.
The mounting plate
I clamped the bell housing on my bridgeport table then indicated the round tranny locating hole on the bell housing to center the miller quill on the tranny mounting hole.Then I took the main motor mounting plate and with the indicator got that exactly concentric with the tranny hole. With the plate clamped to the bell housing I drilled two spring pin holes and drove in the spring pins to allow disassembly and re assembly with perfect alignment. I transfered the two 7/16-14 holes to the mounting plate and drilled clearance holes.
The final step was to determine the exact thickness spacer necessary to engage the clutch plate with the tranny spline with about 0.02" clearance between the two shafts.
With some help, the assembly was mounted. Next step battery holder.
The truck likes the new batteries
I cut out two shorter angles, and screwed them to the tranny mounting angle at both ends. I welded a nut on the rear of the short angles so the 3/8-16 bolts would have a real nut to screw through.The two small angles were then welded to the frame. The extra drive shaft was cut off to keep the electric motor from needing a thick spacer when mounted to the remaining screws in the bell housing. The clutch plate will be my final drive attachment to the motor shaft, so I needed a disk to make the final connection to the drive motor. I had some circular saw blanks, and will see if I can make it work with a bit of machining and welding.