30A 125V Socket

Hey everyone new to the forum here.

Just picked up a 2018 i3 REx yesterday and I have a small question, I have a 30A 125V socket on the side of the house, I'm guessing the previous owner had an RV.

I was just wondering if it was OK to use this socket with an adapter to charge my i3 faster than a normal wall charge.

Also any suggestions on what kind of adapter to get?

Here's a picture:

Thanks

First, verify what circuit breaker is powering that receptacle. It may not be 30A, or actually 120vac.

You'll have a hard time trying to find a 30A (well, the largest that you could use would be 24A if that is a 30A circuit because of the 80% rule), 120vac device. Once you get over 12A, most of them are 240vac devices. There are a few 16A, 120vac EVSEs, but not that many, and they would require a 20A receptacle (looks sort of like a normal 120vac one, with one blade having a T-shape).

Note that the EVSE must be matched to the supplied power available. It (most, anyways) cannot autodetect. Once powered, it sends a signal to the car announcing how much power it can supply. If that exceeds the actual supply, and the car can use it, it will try to draw that amount, and would then trip the circuit breaker or blow the fuse.

So, short answer...yes, if you can find one, and that circuit is actually 120vac, 30A (which I sort of doubt).

The amount of power you supply in watts = volts * amps, so the higher you can make either one, up to the capacity of the device and/or vehicle, the faster you'll charge the vehicle.

First, verify what circuit breaker is powering that receptacle. It may not be 30A, or actually 120vac.

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Might as well start somewhere.

How do I verify the circuit breaker and how will I know it's right?

And I can't just use this?
https://m.harborfreight.com/30-amp-male-to-15-amp-female-rv-pigtail-power-adapter-69282.html?utm_referrer=direct%2Fnot%20provided

Just like you can plug a 60W lamp into a receptacle that could supply 120vac*15A, or 1800W, that doesn't mean that the 60W light bulb will use more.

To test that circuit, you'd either need to plug something into it, or use a meter to see which breaker turns it off. Once you've identified that, the breaker will indicate its size.

First, what EVSE do you want to use? That will dictate how much power can be supplied and would dictate the size of the circuit required to power it. For example, if that circuit really is 120vac, 30A, you could plug up to a 120vac, 24A EVSE into it, assuming you could find one (and I don't think you will!). That's assuming that the wiring in that adapter can handle 30A, which it almost certainly can't - it would be sized for the 15A device that would plug into the other end, not the 30A plug.

FWIW, depending on the gauge wire going to that receptacle and whether it is a dedicated circuit or not, you could change it over to 240vac by putting in a double breaker and moving the neutral lead to the second breaker of the dual. You'd then be able to swap the receptacle to something else, as it's not rated for 240vac. Doubling the voltage (with a compatible device) means twice the potential power available (P=V*A). You'd want to identify each end of that neutral wire as being hot by marking it with either black tape, paint, or marker.

I think I see where I am getting confused.

I wanted to use the stock cable that came with the i3 (Delphi I believe it's called?) to adapt to the RV outlet on the side of the house to charge faster, but if I use the stock cord the i3 came with the power would step down to the speed of the Delphi.

Right..?

The EVSE is designed to be able to output a specific maximum, and must be plugged or wired into a power supply that is at least as big (using the 80% rule, or the circuit must be able to supply 125% of what the EVSE can handle).

What happens is that the EVSE will send a signal to the EV indicating how much power it has available, and then, the EV will use up to that maximum amount, assuming it can. About the largest EVSE you'll find today is a 40A unit, which would require a 50A circuit. Much more common are 30-32A units, that require a 40A circuit to power them.

The unit you have, assuming it is designed with a standard 120vac, 15A plug, wouldn't be certified or adjusted to announce it has more than 12A, since that's what the plug design is capable of, and is the most common receptacle available in the typical USA home. A 20A receptacle is also available, and if you had a device that could utilize it, it would have a different power plug on it, only allowing it to be plugged into that 20A receptacle.

So, the EVSE is first the limiting factor, then, to be safe, the place it is powered from must also match what the thing can output. There are a few EVSEs that have an adjustable output so that they won't overload whatever they're plugged into, but that's kind of rare.

Per Wiki, that is a NEMA TT-30:

• Top pin - ground
• Left lower - hot
• Right lower - neutral

The EVSE that comes with the BMW i3 is limit to 12A. An adapter to a NEMA 5-20, all weather adapter mounted to the side of the house would be trivial using parts available at local hardware stores. Also, http://www.EVSEadapters.com may have a flexible adapter already available BUT they are not designed for rain exposure.

To draw a safe, 24A (80% of 30A), you'll need a 3d party EVSE like a "Khons, 12-32 A, 120-240 VAC", ~$400. It comes with a NEMA 14-50 plug but they sell a wide range of adapters.

I would suggest having an electrician look at the circuit, wire, and circuit breaker. The wire should be good enough to support 30 A at 240 VAC using a NEMA 14-30. Doubling the voltage does two very good things:

• doubles rate of charge
• balances the electrical load on the two legs

Best of all, you won't need an adapter with the Khons EVSE. I would also recommend getting a 'cheap' Volt Ohm Meter (VOM) at a hardware store to measure real metrics and not guesses.

GOOD LUCK!
Bob Wilson

bwilson4web said:

The EVSE that comes with the BMW i3 is limit to 12A.

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The one that came with my 2018 i3s is even lower than that - only 10a. Also got the 120/240V TurboCord, but that's a mere 16a. Both are so slow compared to my ChargePoint Home 240v/32a system I doubt I'll ever use either.

The NEMA TT-30 plugs are pretty rare. I don't think I've seen any EVSEs that will fit it natively, and the Khons is the first I've heard of that's dual voltage and can do 24a. But I wouldn't be real keen on that since using a 32a charger would require setting the car for a 24a limit so that the 30a breaker doesn't trip. This could be very inconvenient if you're planning to visit 30/32a L2 stations.

An alternate idea - convert it to a hardwired EVSE like the Clipper Creek ACS-25, or simply swap the outlet for something more common like a NEMA 5-20 and then get a used TurboCord for cheap ($380 on eBay). The latter is a pretty easy DIY job - just make sure to flip off the breaker before messing with the outlet, obviously. To be honest that outlet looks so old I'd want to replace it regardless.

The bigger question is if 120V is going to be adequate for your needs. At 120V you're looking at between 1.9 and 2.88 kW depending on amperage. At those rates, a 2017/2018 i3 will take over 12 hours to go from 0 to 100% and that may be too long for some people based on commutes and off-peak electricity hours. If this is the case, I'd second the above advice of having an electrician come out and and see if it can be changed to 240V

One thing to be particularly aware of, especially on older, high current receptacles, is that they DO wear out. Throw in the possibility of a loose or corroded connection, and it is a recipe for overheating, and damaging things...worst case, start a fire.

While it won't verify loose internal wire connections, if, when you plug something in, it is loose, don't use it, replace it. It needs to be somewhat tight when inserting the plug to minimize any resistance and make a good connection that won't heat up excessively.

I'd call an electrician and see if he can upgrade to 240v. 240v uses the same gauge wire as 120 v so the upgrade could be relatively inexpensive if you don't need to pull new wires. In most cases, pulling the wire is the most labor intensive and expensive part of an EVSE installation, so using existing wire will save you $$$.

He'll check the wire gauge and the number of wires. If you have 10 gauge 4 wire romex to your outside outlet, the upgrade to 220v 30amp would involve swapping the outdoor outlet for a 6-30 or 14-30 outlet and installing 30amp double pole breakers in your electric service panel.

Once you have a 220v 30amp plug, you can charge at up to 24amps (about 4 times faster than with the 120v 10amp EVSE which now comes with the i3).

bwilson4web said:

Per Wiki, that is a NEMA TT-30:

• Top pin - ground
• Left lower - hot
• Right lower - neutral

The EVSE that comes with the BMW i3 is limit to 12A. An adapter to a NEMA 5-20, all weather adapter mounted to the side of the house would be trivial using parts available at local hardware stores. Also, http://www.EVSEadapters.com may have a flexible adapter already available BUT they are not designed for rain exposure.

To draw a safe, 24A (80% of 30A), you'll need a 3d party EVSE like a "Khons, 12-32 A, 120-240 VAC", ~$400. It comes with a NEMA 14-50 plug but they sell a wide range of adapters.

I would suggest having an electrician look at the circuit, wire, and circuit breaker. The wire should be good enough to support 30 A at 240 VAC using a NEMA 14-30. Doubling the voltage does two very good things:

• doubles rate of charge
• balances the electrical load on the two legs

Best of all, you won't need an adapter with the Khons EVSE. I would also recommend getting a 'cheap' Volt Ohm Meter (VOM) at a hardware store to measure real metrics and not guesses.

GOOD LUCK!
Bob Wilson

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I second this !

Nyken said:

240v uses the same gauge wire as 120 v so the upgrade could be relatively inexpensive if you don't need to pull new wires.

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Ah that's good to know. I would absolutely say change it to 240V then and go with a 14-50, 14-30, or 5-20 plug, higher the better, depending on what the panel can handle. 0 to 100 charge times would look like this:

50a circuit / 32a charging = 7.68 kW ~4 hrs
30a circuit / 24a charging = 5.76 kW ~6 hrs
20a circuit / 16a charging = 3.84 kW ~9 hrs

For EVSEs I really think it's worth it to pay the extra $100-200 for "Smart" ones like the ChargePoint and JuiceBox.

You haven't indicated what size circuit is really powering that socket. Assuming it is a 30A circuit, rewiring it for a 30A, 240vac one verses 120vac is pretty cheap and simple as I mentioned way back. But, on a 30A circuit, you should NOT install an EVSE that is over 24A (80% rule). An EVSE does not use a neutral wire, so all it needs is the two power leads and a safety ground, which you should already have there.

The fact that the socket could handle 30A doesn't mean that it is wired for 30A. The wiring to it could actually be sized for a larger circuit, and then, you could install a larger EVSE, but you won't know until you look. IOW, you need to see what gauge wire is feeding it now, and that will tell you the maximum it can handle. Note, the CB is to protect the wiring, not the device connected to it.

If the run isn't too long, you might be able to use the existing wires in the conduit to pull larger ones, but if there are a lot of turns without pulling covers, that won't happen as the friction would be too great.