Hybrid home conversion with rear hub motors

[Intrigued]

Have you all checked into the Poulsen link that Darin put above? They add about 35 pounds per wheel, make something like 7 hp per wheel, are 72 volt, have regen, are fairly portable (attachment bar diffs), and would be easy to install. The company is personally wanting a member of their "dealer network" to install them at present...

The control system is a little simple, and begs some hypermiling mods. I personally would put a microswitch in the switch circuit to key off of the throttle, only coming in when off-idle.

Since I'm not going to be driving my Intrigue like Mario (Andretti), I'll just put in stouter springs to handle the batteries, and rear struts if the old ones are worn out. There's enough built-in variablility to handle the extra wheel weight. (IMHO, anyway... )

[MazdaMatt]

Metromizer, we're on the same page... i obsess about this stuff daily

Christ, that's an EXCELLENT point about the brakes!! Rotors may not weigh much but calipers certainly do! Plus, your are replacing the hub(heavy) and axel(not too heavy).

I know that in ontario, and likely the rest of north america, a car must have two braking systems (i'm sure there are exceptions). There is no specification of what they must be, or how many wheels they must control. So you can have your regen brakes on the back and your ebrake on the front... although the opposite would be safer, but then you get into steering your drive hubs.

[Clev]

Originally Posted by MazdaMatt

Metromizer, we're on the same page... i obsess about this stuff daily

Christ, that's an EXCELLENT point about the brakes!! Rotors may not weigh much but calipers certainly do! Plus, your are replacing the hub(heavy) and axel(not too heavy).

I know that in ontario, and likely the rest of north america, a car must have two braking systems (i'm sure there are exceptions). There is no specification of what they must be, or how many wheels they must control. So you can have your regen brakes on the back and your ebrake on the front... although the opposite would be safer, but then you get into steering your drive hubs.

Regen is NOT a braking system--it's a speed reduction system. Regen doesn't have the ability to stop the car in a safe distance.

[MazdaMatt]

Are you sure that i can't BE a braking system? If it can slow the car, what limitation is there from slowing the car harder?

[Christ]

reverse polarity as a braking system. Regen can be employed with it. I'm pretty sure most motors are designed with this capability.

[Clev]

Originally Posted by MazdaMatt

Are you sure that i can't BE a braking system? If it can slow the car, what limitation is there from slowing the car harder?

The amperage-handling capability of the motor/controller, and a place to stick the generated electricity. A motor and controller can only regen the amount of power that it puts out (i.e. 500 amps at 48 volts), and you'll have the same heat issues as if you were powering the motor at that amperage. 500 amps at 48 volts = 24kW or 32 hp. Essentially, you'll decelerate at the same rate that 32 hp would accelerate the car.

Again, then you'll need a resistor grid (like diesel-electric locomotives) to bleed off the excess amps as heat so you don't overcharge the batteries if they're almost full.

[Clev]

Originally Posted by Christ

reverse polarity as a braking system. Regen can be employed with it. I'm pretty sure most motors are designed with this capability.

You're talking about "plug braking", which burns up the momentum as heat in the motor. You can do one or the other, but that heat still has to go somewhere. Plug braking is only possible for very short distances (some forklifts use it, and you probably have seen how slowly a forklift decelerates.)

[almightybmw]

Plug braking is a bad idea for general traffic. For short distance low speed EVs its relatively safe. All the E-lifts I used the brake pedal controlled the motor this way, there was only an e-brake for parking, not general slow downs. If I turned the key off, steering was out the window (try steering 5000lbs with a 12 inch wheel and 3:1 ratios, not easy) and braking disappeared completely. It became a rolling brick with no brakes, as the e-brake was mostly worthless on these rigs (my experience, others might maintain their equipment better).

Friction is reason things work. (I'm over-simplifying this) Friction allows us to accelerate and negatively accelerate (never like the term decelerate). Relying on magnetism for acceleration and braking shouldn't be the first and only line of defense.
Example: Maglev trains. They use magnetism for movement right? But as a backup should that fail, they have standard rollers and rails with friction brakes for emergecies.

Nothing wrong with magnetism for braking. But safety (and the law) says a friction brake that can be modulated should always be there.

[MetroMPG]

Almighty, did your forklifts also have a mechanical/friction seat brake? A drum on the motor's tailshaft? The one we bought to scavenge for the ForkenSwift had both plug braking and the safety/seat brake.

(And I had to steer it after removing the power steering pump [and everything else], while it was being winched onto the flatbed truck that took it away - that was a bit of wrestling with the wheel.)

[metromizer]

Have you all checked into the Poulsen link that Darin put above?

The Poulsen drive hubs don't eliminate the OEM brakes