David Roden wrote:
On 14 May 2009 at 13:35, Christopher Zach wrote:This is what GE did with the E15 and one of the main reasons why it is so bad.I have an E15 and I don't think it's "so bad" at all. It's a very reliable machine. Once I learned to come to a full stop before reversing, I quit having so much trouble with the reversing relay.
Sure. For the people who didn't and burned a bunch of relays it probably was a bad thing. Which might have led to people turning away from it. Why add the complexity and potential problems?
I think in later models they tried to use delays and other circuits to keep from toasting the relay, but those circuits blew up as well. More complexity.
It's a moot point now anyway as I no longer have a reversing relay. Now I have a nice smooth PWM controller to provide both relayless reversing and stepless acceleration. I can creep the tractor up to the bumper of the project car in the garage, moving less than a cm at a time.
True. However many Alltrax controllers died to give you that ability :-) More seriously, it did require some growing pains. And do you really need that ability to mow? Maybe. But it adds complexity.
If I'm crazy enough to do so, I can hit the reverse switch while moving forward. The tractor will come to a stop and then start backing up.
That is good.
I can (again if I'm being silly) also leave the controller on with the tractor on a slope and the brake not set. The controller will hold the tractor still for me. (I don't recommend this for long term use, as it's rough on the motor and wastes energy.)
That is bad. Expect to see a bunch of tractors returned with burned armatures and worn brushes (you can do this stunt on an AC motor that is water cooled like the Prizm. On a DC motor you will either burn out the armature or lift the commutator bars)
Addition of this feature=more returns.
No thanks. If it did that, I'd be buying a new gas tractor from Home Despot every 5 years, storing and burning gasoline, and breathing exhaust fumes.
What I meant was build your system to be like familiar things. Oddly enough this is why I like both the Prizm and the Volt: Both are more "normal" cars. The Prizm even uses regen to "fake" engine drag. For a car user this is comforting.
As I said, there's a place for simple conversions -- at the budget end of the line. But electric drive has significant advantages over ICEs. There should be room in the marketplace for a well designed electric machine that doesn't disregard those advantages, though that room is of necessity apt to be at the top end!
Ok, but everyone wants to make their EV thing the "Tesla" of the world. Look at how much money they blew on custom-made headlights. Look at how much GM blew on a super-one-off body for the EV1 versus dropping an electric system into a Prizm and a dull boring S10. Guess which one is easier to get parts for today and which one even *exists* now?
Look at the Electric Ox. Very expensive, but what does it do for the money that a simpler design won't do just as well?
GE had this thought out with the Elec-trak line. They had the E8-E12 as the basic bare-bones lawn mower and the E15-20 for the snow blowing and tilling. Most people need a doodle-bug maybe with a simple plow attachment at best. For that the E10 with a single-speed motor, belt clutch, mower deck in the middle, and a 3 speed transmission was perfect. Needed two contactors, a relay or two for the safety system and that was it.
Electric Ox built a super-cool system that cost way too much for anyone but the richest playboy. It's not a doodlebug, and it's not made now.
What I'm saying is I wish people would build things that people *use* as opposed to building engineering solutions for issues that may have nothing to do with what people need. I'm getting tired of seeing it in the EV market and waiing and waiting for the Elec-trak replacement and getting "oh we'll have the super-duper thing out next year" followed by the inevitable web site not found message.
Again. Chris Chris