Spare Mobile Connector a waste?

[slcasner]

I'm having a small problem with one particular 120-volt outlet at my workplace. I plug in the Spare Mobile Connector, and everything looks fine, but somewhere about an hour (more or less) into charging the ground fault interrupter built into the connector trips.

My advice: remove the GFI from the connector and replace it with a heavy duty plug such as the Leviton ProGrade Nylon 15A 125V 5-15P plug (No. 5266-C), about 8 bucks at OSH or Home Depot. No cutting or stripping of wires is needed; the GFI can be removed with a screwdriver, and the new plug installed with a screwdriver. The wires are already the right length to slide into the terminals of the new plug. The one I mention is straight. Don't get the right-angle variant because it can't hold the cord.

 

[S-2000 Roadster]

I'm wondering if there is a problem using a cheapo two-prong adapter to pass the current through while leaving the ground prong unattached? (This is just a less permanent version of sawing off the ground prong...)

Never do that. The ground contact is there only to save human lives. It has no electrical purpose other than safety. If you saw it off or defeat it temporarily, then you're just asking for death when the inevitable failure occurs and you're about to be electrocuted.

In any case, removing the ground is most likely to make any existing GFI problems worse, rather than better.

 

[hcsharp]

My advice: remove the GFI from the connector and replace it with a heavy duty plug such as the Leviton ProGrade Nylon 15A 125V 5-15P plug (No. 5266-C), about 8 bucks at OSH or Home Depot. No cutting or stripping of wires is needed; the GFI can be removed with a screwdriver, and the new plug installed with a screwdriver. The wires are already the right length to slide into the terminals of the new plug. The one I mention is straight. Don't get the right-angle variant because it can't hold the cord.

That plug you mention is under-rated for the application. It needs to be rated for at least 20A.

ggr you should really find out what's causing the ground fault. If it's only happening on one outlet then there is a leak somewhere that should be investigated. If it's happening on most 120v outlets then there may be something wrong with your car, the GFI, the cable, the plug, or the building wiring. Not helpful, I know...

 

[smorgasbord]

That plug you mention is under-rated for the application. It needs to be rated for at least 20A.

Well, you ain't gonna find a 5-15 plug officially rated at 20 amps. If you look at the construction of the plug slcasner recommends and it's 5-20 version, I think you'll satisfy yourself that it'll be fine.

 

[slcasner]

Well, you ain't gonna find a 5-15 plug officially rated at 20 amps. If you look at the construction of the plug slcasner recommends and it's 5-20 version, I think you'll satisfy yourself that it'll be fine.

Right. If you compare them, you'll find the only difference is that one of the prongs is rotated 90 degrees.

 

[S-2000 Roadster]

Right. If you compare them, you'll find the only difference is that one of the prongs is rotated 90 degrees.

Well, that, and one is made of compounds physically capable of withstanding 20 amps of continuous current, while the other one might not be. In other words, there isn't only one difference.

 

[slcasner]

As I said, I invite you to actually compare them in your hands. I have.

 

[S-2000 Roadster]

As I said, I invite you to actually compare them in your hands. I have.

Yes, so have I. I went to the hardware store and purchased a great deal of electrical equipment, some of it vastly overrated because I thought the 50-amp charger would actually be pulling 50 A and not just 40 A. I haven't installed the 20 A stuff, but I took a good look at it.

Anyway, I saw many brands and many differences between 5-15 and 5-20. No doubt, some companies save money on the economic theory of economies of scale by overrating their 5-15 plugs so they can use the same parts for both and get a bigger volume discount on materials. Other companies might actually make the 5-15 plugs to a lower rating such that orientation is not the only difference. In other words, they can be the same, but they're not guaranteed to always be the same. If your plug is rated 5-15 then it's not guaranteed to live up to 20 A use. I'm just sayin'...

 

[doug]

I went to the hardware store and purchased a great deal of electrical equipment, some of it vastly overrated because I thought the 50-amp charger would actually be pulling 50 A and not just 40 A.

ironic

 

[btown]

My Spare Mobile Connector

After hijacking the Tesla connector off my MC240 in order to make a J1772 adapter, I saw what Scott had done to his Spare Mobile Connector and thought it was a great idea. Instead of making a new pilot board for this use, I decided to scavenge the pilot board from the MC240 (since I was no longer using it for anything). I had trouble finding a case that would fit the pilot board, so I decided to go with a 2" PVC tube. I think I like it even better then if I would have found a box, as it seems pretty natural to have something round in line with the cable.

Here's what it looks like inside:

And here's what it looks like all closed up (but not yet sealed)

I sealed it up with silicone stretch tape. It's really neat tape that sticks to itself and actually cures for a water tight seal.


I'll be using this to charge at 16A at 240V using a 120V dual circuit combiner box I previously made (before I realized that the standard spare mobile connector wouldn't allow charging at 240V due to no pilot signal). I will also carry around the Nema 14-50 plug in case I ever need to rewire the end to charge at an RV park.

 

[TEG]

Doesn't that MC240 pilot generator box put out a 24A or 30A pilot signal? You wouldn't want the Roadster to pull that much current through that thin gauge wire I think.

Also, you could buy an "off the shelf" joiner like this:
220 240 Volts from 110 120 Volt Outlets - Catalog & Pricing
And put an L6-20 plug on your hacked cable...

Your mechanism to get 240V off of two 120Vs should have safety relays so that the stray plug end doesn't have power until both sides are plugged in.

 

[hcsharp]

After hijacking the Tesla connector off my MC240 in order to make a J1772 adapter, I saw what Scott had done to his Spare Mobile Connector and thought it was a great idea. Instead of making a new pilot board for this use, I decided to scavenge the pilot board from the MC240 (since I was no longer using it for anything). I had trouble finding a case that would fit the pilot board, so I decided to go with a 2" PVC tube. I think I like it even better then if I would have found a box, as it seems pretty natural to have something round in line with the cable.
I sealed it up with silicone stretch tape. It's really neat tape that sticks to itself and actually cures for a water tight seal.

I'll be using this to charge at 16A at 240V using a 120V dual circuit combiner box I previously made (before I realized that the standard spare mobile connector wouldn't allow charging at 240V due to no pilot signal). I will also carry around the Nema 14-50 plug in case I ever need to rewire the end to charge at an RV park.

Nice work! A few words of caution: As TEG pointed out, you will start a fire if you try to charge from a NEMA 14-50 unless you are very careful to always limit the amps to 16. The spare mobile conn cable is only 12 gauge. You could probably get away with 24A considering the cable is rated for 105C but I don't recommend that. It's much more useful to replace the cable with #4 or #6 gauge, but of course a lot of work because then you have to take the connector apart, bore and tap the end for a 1" strain relief, bore and re-crimp the sleeves. Or build your own Tesla connector from scratch like I did. I've done both. Toss up which is easier.

The PVC pipe is a cool idea for a simple waterproof housing but again requires caution. Although the cable is rated 105C, the PVC will melt at that temp. I also recommend that you put the pilot generator near the plug end of the cable instead of the car end. PVC will scratch your car more than the cable will, so better to keep it farther from the car. I realize that means you have to run the extra conductor farther. My pilot generator has a switch that allows me to manually select the amps. It's better to have such a switch near the source of power because that's usually what determines the amps.

When I built my dual-120 to 240 solution I mounted a small volt meter display in the box to make it easier to know when you have opposing phases. A little more elegant but of course the LED solution works too if you know how to wire it.

Good luck.

 

[btown]

Doesn't that MC240 pilot generator box put out a 24A or 30A pilot signal? You wouldn't want the Roadster to pull that much current through that thin gauge wire I think.

Also, you could buy an "off the shelf" joiner like this:
220 240 Volts from 110 120 Volt Outlets - Catalog & Pricing
And put an L6-20 plug on your hacked cable...

Your mechanism to get 240V off of two 120Vs should have safety relays so that the stray plug end doesn't have power until both sides are plugged in.

I guess you could say I've subscribed to the Scott451 school of thought in that I must make the proper decisions and settings on the car (ie. set the current properly before starting). In terms of the current draw, Scott451 has regularly used the spare mobile connector at 30A and possibly even higher. It becomes a matter of how long you do it, what the ambient temperature you are operating in, etc. Wire ratings are made based on max ambient temperature and constant use. Defintely need to be careful in this area though for sure. My primary use will be at 16A, 240V for which the wires are already rated. I don't plan on ever needing to go the 30A RV park route, as I now have a J1772 adapter and those chargers are becoming increasingly available in much more desireable/usable locations (stores, shopping malls, restaurants, etc) then I've found RV parks to be.

I made my own joiner and I am not using a relay. There is no risk of shock at the stray plug as long as the mobile connector is NOT plugged in. Each "line" leg of the 120V goes to just one side of the L6-20 plug, so there is no risk until the mobile connector is plugged in.

 

[hcsharp]

...
Your mechanism to get 240V off of two 120Vs should have safety relays so that the stray plug end doesn't have power until both sides are plugged in.

Really? When I plug in one cord the other one remains dead and I don't have any safety relays. Am I missing something?

 

[TEG]

You can read about the safety relays in these threads:
My Nissan Leaf Forum View topic - Do It Yourself: 240v from two 120v sources
My Nissan Leaf Forum View topic - 120-to-240 Adapter Kit (Rev 1)
I think the short answer is that power could flow from the one plugged in end, through the "device" (EVSE), through the spade on the uplugged end, through you, and to the ground. So there could be a shock hazard unless you are careful. The scenario described is that a kid comes up, unplugs one of your cables and touches the bare end while the EVSE and car are still plugged in.
There isn't supposed to be power coming out of the male end of a NEMA plug.

 

[btown]

You can read about the safety relays in these threads:
My Nissan Leaf Forum View topic - Do It Yourself: 240v from two 120v sources
My Nissan Leaf Forum View topic - 120-to-240 Adapter Kit (Rev 1)
I think the short answer is that power could flow from the one plugged in end, through the "device" (EVSE), through the spade on the uplugged end, through you, and to the ground. So there could be a shock hazard unless you are careful. The scenario described is that a kid comes up, unplugs one of your cables and touches the bare end while the EVSE and car are still plugged in.
There isn't supposed to be power coming out of the male end of a NEMA plug.

TEG is of course 100% correct. There is no chance of shock as long as nothing is plugged into the 120V-240V adapter, but as soon as you plug ANYTHING into it then you have a completed circuit which represents a hazard. Even if the EV isn't charging, the pilot generator completes the circuit with plenty of current capability for a hazard.


Thank you hcsharp for pointing out the temperature as it relates to the PVC, as I hadn't really thought about it melting! It's not very likely that I'll actually ever need to use it at 30A, but if I ever do I'll probably want to do a good amount of testing or monitoring it. I wouldn't feel good about letting the cable get much more than a nice warm level (ie. nowhere near hot).

 

[btown]

After hijacking the Tesla connector off my MC240 in order to make a J1772 adapter, I saw what Scott had done to his Spare Mobile Connector and thought it was a great idea. Instead of making a new pilot board for this use, I decided to scavenge the pilot board from the MC240 (since I was no longer using it for anything). I had trouble finding a case that would fit the pilot board, so I decided to go with a 2" PVC tube. I think I like it even better then if I would have found a box, as it seems pretty natural to have something round in line with the cable.

Here's what it looks like inside:
View attachment 3234

And here's what it looks like all closed up (but not yet sealed)
View attachment 3233

I sealed it up with silicone stretch tape. It's really neat tape that sticks to itself and actually cures for a water tight seal.


I'll be using this to charge at 16A at 240V using a 120V dual circuit combiner box I previously made (before I realized that the standard spare mobile connector wouldn't allow charging at 240V due to no pilot signal). I will also carry around the Nema 14-50 plug in case I ever need to rewire the end to charge at an RV park.

I have an update for those of you who expressed concern about the fact the MC240 pilot board outputs a 30A pilot, which is way too much for when I'm plugged into a standard 15A or 20A 120V circuit. Although I can control this at the car, it is a bit of a hassle. So I decided to do a bit of PIC programming to solve this issue. Basically, I added a UI to the programming on the MC240 pilot board. Here's how it works:

This interface allows the user to change the amperage setting output by the
pilot tone. The steps to using this interface are:

1. Plug the charger into 120V or 240V
2. Connect the Tesla connector to the EV (do not turn the pilot switch on)
   If the EV is connected and the pilot switch is on, normal operation will
   begin as soon as the AC is plugged in (so a power failure will resume
   charging once power is restored). Step 3 will not occur
3. The LEDs will blink out the current charge setting/index using orange blinks
   If you slide the pilot switch on and leave it for 5 seconds, normal operation will
   resume (you will not enter the UI)
4. Toggle the pilot switch 2 times
   You are now in the UI
5. Toggling the pilot switch will now decrement the index (per toggle)
   If you want to abort and make no changes, simply unplug the charger
6. Sliding the pilot switch forward for 5 seconds will store the new setting
   After the setting is permanently stored, the charger resume normal
   operation. It will go through the normal startup blinks and start the pilot

So now I can set my charging cable to output whatever amperage I want. I currently have it programmed for 6 different possible amperages. Took a bit of time to reverse engineer the original code in order to override the stock duty cycle and then another good amount of time to develop the UI, but what fun!

 

[smorgasbord]

I'm temporarily staying at a house that has a 20 amp one-plug dedicated circuit. My car defaults to 15 amps when I use the Spare Mobile Connector (Guess it wasn't a waste after all!). When I tried setting the amperage higher via OVMS, the car stayed at 15 amps. I'll try the VDS tonight, but I thought I'd ask if anyone has successfully pulled more than 15 amps through the stock Spare Mobile Connector, and how did you do it?

 

[wiztecy]

I believe 15 amps is the most you'll pull on 110 with the mobile charger. Most I believe you can pull using a generic appliance from a given 20 amp breaker is 16 amps. (80% pull by code)

I'm curious if the mobile charger (UMC) would pull off the 110v line if you ran a 110v to 30AMP (14-30) adapter, and from there connecting to the UMC (with the right adapter such as a 14-30 to 14-50). Possibly the UMC only wants to see 220v and this won't work at all. Would love to ditch the 110v mobile charger if I can on trips.

 

[hcsharp]

I'm temporarily staying at a house that has a 20 amp one-plug dedicated circuit. My car defaults to 15 amps when I use the Spare Mobile Connector (Guess it wasn't a waste after all!). When I tried setting the amperage higher via OVMS, the car stayed at 15 amps. I'll try the VDS tonight, but I thought I'd ask if anyone has successfully pulled more than 15 amps through the stock Spare Mobile Connector, and how did you do it?

wiztecy is right you need a pilot signal to charge at more than 15A on a 120v outlet. We discussed this to some degree in your other thread how-can-SPC-get-away-without-the-box. You would have to make a pilot signal generator and set it for 16A. The other thread has more details.

@wiztecy I'm pretty sure Tesla made a TT-30 adapter for the Roadster UMC which charged at 24A on 120v.