# Idiot Protection - Preventing driving off while Plugged In



## ahambone (Jan 13, 2009)

Hello,

Today I had a humorous experience as I ran an errand in my EV over lunch. I manged to pull 15 feet out of the garage before realizing that my 120VAC extension cord was still plugged into the car. Fortunately I stopped before destroying the cable or any part of the car but it was a bit of a scare. Definitely an idiot moment - one I would not like to repeat. 

So here is my question to those with more EV experience: How do you prevent a car from starting and pulling out of the garage while still plugged in? Obviously the "just look" technology doesn't work for me  and I think it would fail the "wife test" too. It's particularly a problem since the power cord is on the far side of the car from the entrance to the garage - easily overlooked. 

Does anyone have a good example of a drive-logic duck circuit or other solution? My charger (Zivan NG-3) has some relays that click when the charger is running that I could use but the charger had long shut off and I think released the relays. I guess I need some kind of "120VAC is present on the charger supply line, light a 'AC Power' light on the dash and don't let the contactor engage" control. Before I haul off and design something, what's been done before?

Cheers,
--Adam


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## rankhornjp (Nov 26, 2007)

is there a way to put a door or is there a door over the plug, already (i.e. gas-cap door)? If so, you can put a limit switch or button that detects when the door is open and wont let the controller power up.

My .02

ETA: do you have a picture of your plug in on the car?


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## ahambone (Jan 13, 2009)

That's not a bad idea. In that case the new idiot light could say "Fuel Door" instead of "120VAC". I guess it could be a series interrupt to the key switch indicator on the controller as well. 

My car doesn't have a door over the gas cap - just a cylindrical cover that screws in. I may still be able to get a limit switch in it, however. Now I need to find the gas cap - I haven't put it back on since sticking the electrical wiring through the thing.

I don't have a close up photo of the fuel inlet (yet).

cheers,
--Adam E. Hampton


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## rankhornjp (Nov 26, 2007)

depending on how close your plug is to the side of the opening, you may be able to have the limit switch on the side so that the extension cord plug pushes against it while plugged in.


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## Jimdear2 (Oct 12, 2008)

A few suggestions,

*With On Board Charger;* Take your main contactor coil apply circuit and run it through the NC curcit of a suitable A/C relay that is powered up off the mains supply to your charger. With the charger powered, the relay is also powered and opens apply circuit and you cannot operate the main contactor circuit. Unplug the mains and the relay closes and you can now opeate the main contactor.

*With Off Board Charger;* A DC relay will interupt the main contactor circuit as above and will be operated by the input of the charger. The input lines from plug to batteries will have diodes downstream of the relay to prevent back feeding the relay.

*Mechanical Method;* Arrange you charging plug in so that driving away wil just disconnect the charging plug and cause no damage.

*Charge Port Cover Door Method;* Micro switch operates a relay to disconnect the main contactor operating coil circuit or the door switch itself opens the circuit.

Im sure there are a number of other methods and others will also chime in.

Edit Since you appear to have an onboard charger the first method would be best. you could also use the NO circuit of the relay to turn on a dash light incicating the 120 line is plugged in. end edit.


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## _GonZo_ (Mar 23, 2009)

Great ideas.

I am one of the candidates for destroying some charging leads due this issue. 

I am going to write it down so I do not forget to add it to the car.


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## jondoh (Sep 8, 2008)

my charging connector is just the regular 3 prong 120 ac plug (from my on-board charger) that's tied to the front bumper of my car. it's not fixed to the body of the car at the gas door as is the popular way to do it. I have backed out a few feet before realizing that I was still plugged in but even if i did completely forget, since my connection is just a wire to wire connection, it should just unplug without any harm. Even if i did break the plug, the charger cord is just your basic ac plug used in most desktop computers and I've got plenty of those in the basement.


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## michaelplogue (Jan 18, 2010)

Just put your charging plug smack dab in the middle of the driver's seat. That'll make you take it out......


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## EV-propulsion.com (Jun 1, 2009)

We have these available, wire it up so when the key is turned on the cord ejects 







or








We usually mount them without the cover shown, in the standard fuel fill hole.....
Mike
www.EV-propulsion.com


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## ahambone (Jan 13, 2009)

Thanks for the creative solutions, guys.



> With On Board Charger; Take your main contactor coil apply circuit and run it through the NC curcit of a suitable A/C relay that is powered up off the mains supply to your charger. With the charger powered, the relay is also powered and opens apply circuit and you cannot operate the main contactor circuit. Unplug the mains and the relay closes and you can now opeate the main contactor.


I think I like this option. Basically the "perfect" solution for me would be:


Idiot light on the dash labeled 120EV light up when plugged in
Cancels the main contactor until 120VAC is disconnected

I think doing it electrically is easier than a mechanical / limit switch since my plug is already assembled. It sounds like a 120v Double Pole Double Throw relay will work fine for me. One pole to engage the idiot light, the other for the main contactor control loop. I do find the self-ejecting plugs interesting - neat product.

Cheers,
--Adam


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## m38mike (Dec 27, 2008)

I like the idea of the DPDT relay controlling a warning light and the main contactor. I'll have to look at doing that as a backup, and to warn others who might drive the EV. 

I took a simpler route. I used a lighted extension cord and set my charger plug near the driver's door. That way I see the glow and the bright yellow cord every time I approach the EV. I also hung the cord from the ceiling along side of my EV parking spot. So when I unplug, the cord hangs free, but not on the floor. This also makes it convenient for plugging in power tools when I'm doing other work.


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## gor (Nov 25, 2009)

simple quick-fix method - simple extra joint on the cable - foot or two from the car - so if pulling out it would disconnect cable in this place (if other methods fail) - and you driving with foot of cable sticking out - no big deal
: ))))
happens a lot in gas stations - people pulling out with gas hose nozzle still in the tank ...
p.s. i know, nothing is fool-proof : )))


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## kchiangusa (Mar 28, 2012)

ahambone said:


> Hello,
> 
> Today I had a humorous experience as I ran an errand in my EV over lunch. I manged to pull 15 feet out of the garage before realizing that my 120VAC extension cord was still plugged into the car. Fortunately I stopped before destroying the cable or any part of the car but it was a bit of a scare. Definitely an idiot moment - one I would not like to repeat.
> 
> ...



I know this is an old thread, but same thing happened to me and my electric MR2 last week. 

I chose to build a solution using a magnetic reed switch, but haven't quite got it fully working yet.

http://blog.mr2ev.com/close-call-almost-drove-off-while-plugged-in/

Please comment if anyone has suggestions! Thanks!


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## Duncan (Dec 8, 2008)

Here in NZ you must have a physical system to stop the car being driven away still connected
Mine is simple
I have a rally type switch that disables the car - in front of the charger connection

You can't plug the charger in with the switch in position
You cant drive the car without the switch


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## mora (Nov 11, 2009)

My charge cord is short and once I drove couple of meters before I realized the cord was still plugged in. No damage done but now I know when to check if cord is still plugged.

I was thinking of reed switch too. I would not disengage main contactors but light a dash led and energize a buzzer when "fuel" door is open and someone turns the key. Or should alarm activate when driver door opens and charge port cover is open? Like some cars that warn you if you are about to leave headlights on when drivers door is open.

This doesn't actually prevent driving away though. It is just a warning. Same if driver decides to roll away by releasing handbrake first. There should be a way to physically lock gearbox to parking position or something like that. But then a simple alarm system doesn't cause problems if circuit decides to operate during drive. If magnet falls off or charge port opens a bit too much when driving over a bump you don't want your main contactors to open.


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