Valet Switch

[Lock]

One very great pleasure over the years has been handing over my little EV to folks for them to take it for a trip around the neighbourhood.

Seeing those big grins.

I'm comfortable handing over a vehicle rated at 350w to a newbie, less comfortable at 600w.

So I'd like to implement a "valet switch" that'd let me "de-power" the vehicle for demonstration rides...

This an option built into some controllers, but not that I have seen yet in smaller controllers.

Assuming a 0-5k pot arrangement for accelerator, it occurs to me that I might wire in an extra resistor that can be switched in/out of the pot/accelerator circuit, to vary the range that the controller "sees" from the pot... maybe 0-3k, instead of 0-5k...

Does this sound like a workable approach? Any other ways to "de-power" easily? Splitting a pack and switching from series to parallel by contactor (exchanging amps for volts)? This'd depend on whether the controller can handle the range of voltages, but would have other advantages besides just demo trips?

A separate switch, a resistor and a bit of wire seems easiest, if this works?

Tks

Lock

 

[Toorbough ULL-Zeveigh]

That's where a pot for the <A HREF="http://endless-sphere.com/forums/viewtopic.php?t=915">adjustable current limit mod</A> comes in.
Limiting the current limits the power, but only indirectly speed on the flat.

 

[Ypedal]

The new DB( CycleAnalyst i beleive it's now officially called ) has a feature to restrict power on controllers equipped with the right conector.

I have my battery packs conected via Andersons so i can easily unplug a pack and alow 36v operation.. instead of 72.

I have sent quite a few dozen riders of all levels on my Norco !

Heck.. i sent my 57 year old mother on my 72v bike ! hehe.

I have a nice open space for testing in front of my house so it's traffic free for the most part... and i don't let anyone ride without a Helmet.

 

[fechter]

The crudest way to do it would be to insert a resistor in series with the throttle signal. The value of the resistor will determine the maximum throttle. Since the controller input has a high input resistance, the limiting resistor will need to be in the ballpark of 150k. The exact value depends on the controller and throttle, so some experimentation may be required.

You could use something like a 250k trimmer pot and make it adjustable. When the switch is closed, the resistor is bypassed and things go back to normal.

I usually call this a "dork switch". Valet switch sounds much more refined.