# Charger Interlock Method?



## coryrc (Aug 5, 2008)

omonoid said:


> I have my pack charger and 12v battery charger wired to the same plug so when the car is plugged in, both are on.
> 
> My goal is to have some sort of in dash led that is lit when the car is plugged in, and also have a relay that prevents me from starting the car when it is plugged in.
> 
> ...


You wouldn't be the first! That's better than a 120Vac relay as well, if you use a universal-input switching supply and end up switching to 240Vac/120Vac or even DC charging.

The only better plan is to put in a switch that opens when the charger door is open. Then it'll work even if the breaker opens.


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## Guest (Jul 4, 2011)

Why not just a microswitch that is connected to the potentiometer so you can't drive away. The micro switch can be located anywhere. I have loads of them. You could even have a micro switch on your ignition too if you wanted but you need to mount the switch so when your plugged in for charging the switch is activated. Wonderful little devices.


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## cruisin (Jun 3, 2009)

gottdi said:


> Why not just a microswitch that is connected to the potentiometer so you can't drive away. The micro switch can be located anywhere. I have loads of them. You could even have a micro switch on your ignition too if you wanted but you need to mount the switch so when your plugged in for charging the switch is activated. Wonderful little devices.


Not recommened to use a micro switch on the plug in door or anywhere else to prvent driving away while charging. If these switches fail and they all do sooner or later you will be starnded. In my conversions I use a NC relay on the input to the charger to switch something off like maybe the 12/24v to the controller or the 5v to the pot. The failure of the micro switch is like a failure of the 12/24v relay for the controller. No go. Just is bad is the use of the DC converters that are being used with a high failure rate. Used because they are cheap. Go solid state on the DC-Dc without the worries of being stranded.


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## Anaerin (Feb 4, 2009)

cruisin said:


> Not recommened to use a micro switch on the plug in door or anywhere else to prvent driving away while charging. If these switches fail and they all do sooner or later you will be starnded. In my conversions I use a NC relay on the input to the charger to switch something off like maybe the 12/24v to the controller or the 5v to the pot. The failure of the micro switch is like a failure of the 12/24v relay for the controller. No go. Just is bad is the use of the DC converters that are being used with a high failure rate. Used because they are cheap. Go solid state on the DC-Dc without the worries of being stranded.


Or use a cheap DC-DC, and include an aux battery too. Then if the DC-DC does die, you're not stranded as the battery will keep the voltage high enough to work from. That's good practise anyway, incidentally.


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## Guest (Jul 5, 2011)

All my micro switches are medical grade or industrial grade and all I have can be either NC or NO and none have ever failed me in any application. They are used with very low power so tend to last for just about forever. All electrical components can fail. So what makes using a quality micro switch any different than your solution? I don't use walmart crap. I also like easier and less overall cost but retain the quality.


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## EVfun (Mar 14, 2010)

cruisin said:


> Not recommened to use a micro switch on the plug in door or anywhere else to prvent driving away while charging. If these switches fail and they all do sooner or later you will be starnded. In my conversions I use a NC relay on the input to the charger to switch something off like maybe the 12/24v to the controller or the 5v to the pot. The failure of the micro switch is like a failure of the 12/24v relay for the controller. No go. Just is bad is the use of the DC converters that are being used with a high failure rate. Used because they are cheap. Go solid state on the DC-Dc without the worries of being stranded.


Not recommended to use a relay because if you blow the circuit breaker, trip the GFI, or the outlet goes dead for any other reason, you can drive off with the car still plugged in. If you are worried about the microswitch failing you can also add a discreetly located bypass switch. 

I recommend a sealed reed switch and a magnet attached to the charger door. This is common alarm type hardware with a reputation for being reliable. Because it is sealed it won't suffer from rain trying to corrode the switch contacts.


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## Guest (Jul 5, 2011)

What happens if the reed switch fails? Or the mercury switch? Or any switch for that matter. How many redundant systems do you need to be sure you don't drive off while charging? How many can fail? I have a real good system in the MG. My charge plug is under the hood. Lift the hood and plug in. Kinda hard to drive with the hood up. Kinda hard to shut the hood with the charging cables hanging out. Unplug and shut the hood. Then drive away.  

Fool proof? Not 100%. Nothing is.


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## Guest (Jul 5, 2011)

Actually the micro switch is connected to the 12 volt power of the vehicle. Not the AC system. So if I loose the 12 volt I can't drive off anyway because the controller won't turn on. Charger is on the AC system and if I loose AC power it just stops charging. Two separate systems.


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## EVfun (Mar 14, 2010)

gottdi said:


> What happens if the reed switch fails? Or the mercury switch? Or any switch for that matter. How many redundant systems do you need to be sure you don't drive off while charging? How many can fail? I have a real good system in the MG. My charge plug is under the hood. Lift the hood and plug in. Kinda hard to drive with the hood up. Kinda hard to shut the hood with the charging cables hanging out. Unplug and shut the hood. Then drive away.
> 
> Fool proof? Not 100%. Nothing is.


Honestly, reed switches are a lot more reliable than 120 vac being on the cord just because one end is plugged into the car. They are generally more reliable than the open contact type switches used in most car door jams to operate the dome light too. Mercury switches are not recommended because of the jostling when driving will cause many false trips. If the reed switch fails you don't drive anywhere until you bypass that safety system. 

On the VW Caddy and Datsun I used reed switches and magnets. The Buggy has no safety interlock. It used to be under the Corvette gas filler door on the hood. It would have been my own fault if I drove off with the crossed flags facing me in the drivers seat. Now the car is plugged in just in front of the rear tire. I would have to pretty much close my eyes while getting in to miss that.


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## coryrc (Aug 5, 2008)

gottdi said:


> Why not just a microswitch that is connected to the potentiometer so you can't drive away. The micro switch can be located anywhere. I have loads of them. You could even have a micro switch on your ignition too if you wanted but you need to mount the switch so when your plugged in for charging the switch is activated. Wonderful little devices.


If your charger door popped open while driving (say, because it wasn't closed all the way to begin with), you'd lose power for no good reason. Better to prevent the start signal no matter what technique you use (given you use a start signal, of course).


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## dtbaker (Jan 5, 2008)

depending on the charger you have, you may already HAVE a source that is either on/off when the charger is plugged in. Check your charger docs... then there are several ways you can use it.

Elcons for instance have a third wire that outputs nothing when charger is plugged into AC, and pack voltage when not plugged in... if you run this thru a fuse, to pot box ksi (which is a microswitch on accel!), then to controller ksi; you can't drive off whn plugged in, and have added NO parts that might break. 

some people object to running pack voltage thru pb-6 ksi, and to controller, but others have been doing it for a long time. the current pulled is so low, it doesn't seem to put much strain on anything.


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## Guest (Jul 6, 2011)

coryrc said:


> If your charger door popped open while driving (say, because it wasn't closed all the way to begin with), you'd lose power for no good reason. Better to prevent the start signal no matter what technique you use (given you use a start signal, of course).


Assuming of course if I have my switch connected to my fuel door flap.


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## omonoid (Aug 30, 2009)

never thought of usng a micro switch. But the only place i could put it is in the fuel door, which is already jam packed with the outlet, and it seems like after a few slams of the fuel door, the switch would bust.

I think in my case my original plan would work best because it depends on 120v ac being plugged in rather than a physical door or switch being pushed.


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## Guest (Jul 7, 2011)

Well since you already have a fuel door and if you set up the micro switch properly the switch will never break. Not even if you slam it because it depends upon being open not shut. So you don't really slam it open now do you. I'll stick with the micro switch thank you very much. 

Pete


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## omonoid (Aug 30, 2009)

it sounds like a cheaper alternative, so ill give it a shot then. So i would get a good quality NO one, wire it to the ignition, and mount it somewhere by the hinge?

I also wanted an led indicator to be on when the car is plugged in. So would i get another NC switch and mount it next to the NO one and have that power an led?


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## Guest (Jul 7, 2011)

Not sure about the LED. Want me to send you a microswitch? Send your address via PM and I will pitch one your way. Maybe even two.


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