C-car Group,
Looking for leads on replacement wheel lug nuts.? I 'happened' to sheer off four.? ok, the wheel was rust/welded on, so i cut off the lugs to get the wheel off.? I searched the archives but found no discovered stock numbers.? My local trailer and golf cart stores struck out.? Before i drive an hour to a big golf cart store, i thought i'd see if anyone solved the riddle on lug replacements.? ?Currently, working off three wheels!!? ?Happy New Year.

David Foy
GIZMO, 1980 Commuta car
Harwood, MD

¿ªÔÆÌåÓý

Hi,
good luck with your restoration.? I have an 80 commuta that i am upgrading; i'll hold on to the original parts, some may be of use to you
David Foy
"GIZMO" 1980 CommutaCar
?Harwood, MD

¿ªÔÆÌåÓý

¿ªÔÆÌåÓý

Dakota Lithium are good, but like 5x the cost?

¿ªÔÆÌåÓý

On 12/27/20 6:09 PM, David Schwartz wrote:

Does proportional control of the electric brake duplicate or have characteristics of the standard hydraulic brakes?

Yes.

John

On 12/27/20 10:57 AM, Tom Rymes wrote:

I?€?d say that, if it has the word ?€?trailer?€? in front of it, it?€?s a bad idea. Trailer brakes, trailer tires, etc.
Can they be made to work? Sure? Should they? No, if for no other reason than the fact that you?€?d lose brakes if something went wrong electrically (short, fuse, whatever).

Just like hydraulic brakes will fail if a line corrodes enough to leak. Had that happen to me in my '75 Datsun 280Z at about the 300,000 mile mark. Fortunately all modern cars have dual circuit brakes so only 2 wheels failed. The other two continued to work.

If I designed an electric brake system, I'd use the same dual redundant system as hydraulic systems. And I'd store enough energy within the controller to achieve at least a couple of stops if a fuse blew. Hopefully the engineer would use a self-resetting PolyFuse. Airbomb detonators do the same thing. I won't touch a modern car's yellow wiring (code for air bomb wiring) until the battery has been disconnected for at least a half hour.

Details like these are what separate engineers from great engineers. And they are what would make an electronic so complex to design and test on all 4 corners of possible failure.

John

On 12/27/20 12:58 PM, mrspeed700 via groups.io wrote:

No they won't work,? electric brakes are self energizing and won't modulate like hydraulic brakes would

Yes they will. A drum trailer brake consists of a backing plate, two shoes and a cam attached to an arm with an electromagnet on the end. The electromagnet is positioned to touch a smooth part of the side of the drum.

When current is applied to the magnet, it is attracted to the moving drum. The drum movement causes the arm to slide on the drum, the cam rotates and the brakes begin to be applied.

The more current applied, the stronger the drag and thus more braking. If full 12 volts is applied, most trailer brakes (unless the trailer is overloaded) can skid the wheels.

Old fashioned brake controllers consisted of a cylinder which was spliced into the vehicle's hydraulic brake plumbing. This cylinder pushed against a spring. Also attached to the cylinder was an arm that swept over a wirewound resistor element. The harder the brakes were applied, the further the arm was moved and more current was applied to the trailer brakes.

Modern controllers are electronic and contain an accelerometer.

After installation, the vehicle is parked on a level surface. A little lever or knob on the side is used to zero the accelerometer so that it detects no change in motion due to gravity. The controller is typically mounted at a 45 deg upward angle so the driver can see the display and can move the manual application lever to apply braking without pressing the brake pedal.

in operation, when the vehicle brakes are applied, the accelerometer detects the deceleration and applies current to the brakes. The embedded processor contains algorithms to compensate for braking on a hill. It contains a separate algorithm to relax the trailer brakes when the vehicle starts to move from a stop downhill. On a downhill, the accelerometer would detect apparent braking and continuously apply the trailer brakes, preventing the tow vehicle from moving, absent the hill compensation algorithm.

That said, designing a controller to operate electric brakes as the primary brakes would be a very complex project, one that I would not want to take on. Only one aspect is providing proportional pedal resistance as the brakes area applied just like hydraulic brakes. Absent proportional resistance, as you apply the brakes, the g force will push your leg forward, applying more braking in a positive feedback loop, locking up the wheels and maybe even standing the car on its nose, depending on where the batteries are located.

When I had to sell my car, I had identified an automotive axle that would replace the stock one with much better brakes. Faded memory can't recall the car model. Someone else had identified an automotive brake assembly which could be bolted to the existing axle. Pinto lingers in my memory but I'm not sure.

Yet a third option is to buy a hotrodder's universal brake assembly from some place like Scummit and make or have made an adapter plate. That would probably be the overall simplest option.

John

This is a used 1981 Commuta 72 volt postal van. I have a Florida title for the postal van in the name of the previous owner. ?It has a twelve horsepower GE motor to a three speed manual transmission. This is a used vehicle and can be considered a project car. Current mileage is 38.6 miles, so it has hardly been driven.

?

I have verified the drive train is in good working order by connecting batteries to the motor and running through all gears while the van was on jack stands.? You will need to add a full complement of new batteries and a control system. The postal van comes with Michelin radial tires with less than 2 miles on them. ?The postal van also comes with the original Lester Model 9840 battery charger.? Manuals for the vehicle are available on the C-Car group website or I can provide them on a USB stick.?

?

I have owned this car for about 12 years and realize I do not have the time and energy to do a proper restoration of the vehicle.? I have removed the postal service decals from the vehicle and repaired any damaged body work.? It has been completely repainted white.? Some body panels were removed or disassembled to properly paint the vehicle and these need to be reinstalled.

?

?If you would like photos or have questions please email Me ??The asking price is $1200.

?

If you would like to schedule an appointment to come view the car, arrangements can be made. I am located in Salisbury, NC, midway between Winston-Salem and Charlotte just minutes off of I-85.? This is a pick up item only or you arrange for shipment. ?I recommend using an enclosed trailer. ?Vehicle does not have warranty.?

¿ªÔÆÌåÓý

Good info posted here on batteries
Thanks, Bart

¿ªÔÆÌåÓý

Would Electric trailer brakes be suitable? for use on citi citicar??

dave@...