How do I take advantage of a 480v outlet at work?

I've been searching but not really finding much info. there is a 480v plug at work that I would like the ability to charge my i3, hasn't come in yet, from. Is this feasible? I thought it was just a 240v, but turns out its 480v.

You might look into a CCS charging system, but it would still likely cost at least a couple of grand. Depending on the amperage available, you might find a decent, smaller, CCS unit. Since a power supply will always be more expensive than what amounts to a smart switch on an EVSE, you may not want to make that leap, but businesses may have some additional tax incentives not open to individuals. Course, that would be useless if your vehicle doesn't have the dc fast charge option.

A transformer big enough to get you a usable voltage would likely cost almost as much as a CCS unit.

is it a 3 phase supply if so just use one of the phases.

I don't think one leg of a 480v 3-phase will work. The EVSE looks for a 240 v. circuit with two 120v. legs and a center tap "neutral". You still have to get a transformer with a 0-240 v. primary and a 120v.-0-120v. secondary to get the EVSE to do the handshake.

ah ha i see i forgot you are in the USA what voltage do you have on each phase.

The level 2 input should still work down to 208vac or so. Your power company may not like it if you unbalance the load by more than some factor, but it probably would work. If you look at some of the installation instructions diagrams for EVSE, they show various possibilities that can work at other than the typical residential situation. There are a lot of EVSE's installed in commercial situations, and those can have all sorts of power inputs.

I was really hoping there would be a smallish EVSE already out there that could handle this, one that could possibly be used with both 220v and 480v. Darn. I had previously thought it was just a standard 220v. I've parked next to it in my e46 for the past 9 years and never realized it was 480v. When I'm at work, I'm alone most of the time. Thought it would be sweet to charge at work for free. I'm hunting for a 220v plug but I doubt we have one. I guess I could still use the OCU L1 at work. Surely I can charge the 2.2 miles it takes to get to work within an 8 hour shift, haha.

Thanks anyway!

imolazhp said:

Surely I can charge the 2.2 miles it takes to get to work within an 8 hour shift, haha.

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Definitely. I was charging my 22 mile (11 miles each way, charging only at work) commute in 8 hours.

120vac * 12amp = a max of 1440W. Most people average about 250W/mile or so. There's overhead, it's not perfectly efficient converting 120vac to around 400vdc, but still, you should see at least 3 miles/hour recharge rate, and probably more.

If that 480vac is three-phase, you might be able to make it work. If you can get somewhere between 200-250vac on one leg to neutral, you should be able to make it work. You must determine that, though, otherwise, you'd risk burning things up. Call the tech support of an EVSE supplier (Clipper Creek has a bunch of models), and tell them what you have, and they'll tell you if it will work.

jadnashuanh said:

120vac * 12amp = a max of 1440W. Most people average about 250W/mile or so. There's overhead, it's not perfectly efficient converting 120vac to around 400vdc, but still, you should see at least 3 miles/hour recharge rate, and probably more.

If that 480vac is three-phase, you might be able to make it work. If you can get somewhere between 200-250vac on one leg to neutral, you should be able to make it work. You must determine that, though, otherwise, you'd risk burning things up. Call the tech support of an EVSE supplier (Clipper Creek has a bunch of models), and tell them what you have, and they'll tell you if it will work.

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I guess it wouldn't hurt to give them a call. I'm not sure if I'll be able to answer the questions they ask about the outlet without having to consult our technician at work. This would tip him off that I intend to charge at work which might cause some unwanted issues/attention. Our monthly light gas and water bill is more than my yearly salary, you would't think charging my car would make much of an impact but some people at work are a bit odd about that kind of stuff.

Thanks for the help nonetheless!

If I was a co-worker who was buying gasoline to get to work and you were driving on free electricty from our employer, I would be a little annoyed too. Free fuel is quite a perk!

Folks, the BMW onboard charger(s) will not like to handle a single phase of 480 volts (277 volts).

The Tesla cars can use 277 volts because those same chargers that are in the car are also used in the Superchargers on 480 volts.

If you used a transformer to step down the 277 volts to below 264 volts, you should be ok (240 volts plus 10%).

WoodlandHills said:

If I was a co-worker who was buying gasoline to get to work and you were driving on free electricty from our employer, I would be a little annoyed too. Free fuel is quite a perk!

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He drives to work on free fuel in his brand new, nearly every option, f250 super duty company truck that gets about 10mpg. I'm sure he conveniently forgets to mention this on his taxes.

But yes, I will keep the charging at work private as to not ruffle any feathers.

TonyWilliams said:

Folks, the BMW onboard charger(s) will not like handle a single phase of 480 volts (277 volts).

The Tesla cars can use 277 volts because those same chargers that are in the car are also used in the Superchargers on 480 volts.

If you used a transformer to step down the 277 volts to below 264 volts, you should be ok (240 volts plus 10%).

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I am not sure how many phases it has. Here is a picture of the plug if this helps any.

IT may not happen. The i3 charging circuits, at least as sold in the USA, wants a ground and a single phase acv circuit. You'd probably need a fairly expensive transformer and maybe access to system ground, which may or may not be readily available, to make things both work and be safe.

Of course, ask an electrician, not an electrical engineer who does software, but from this web page, it looks like 480v single phase http://waterheatertimer.org/How-to-wire-3-phase-electric.html (towards the bottom).


You'd still need a step down transformer, and an electrician to do the job.

That's a CS8469, which would be a 50 amp 480 volt outlet.

TonyWilliams said:

The Tesla cars can use 277 volts because those same chargers that are in the car are also used in the Superchargers on 480 volts.

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Isn't a Tesla Supercharger DC? If so, would a Tesla use its AC charger during a Supercharger charging session? Would a Tesla AC charger expect to experience AC voltages greater than the AC chargers in any other EV?

alohart said:

TonyWilliams said:

The Tesla cars can use 277 volts because those same chargers that are in the car are also used in the Superchargers on 480 volts.

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Isn't a Tesla Supercharger DC? If so, would a Tesla use its AC charger during a Supercharger charging session? Would a Tesla AC charger expect to experience AC voltages greater than the AC chargers in any other EV?

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All "chargers" take AC and rectify it into DC. The difference between a Supercharger and the Tesla car (or Mercedes B-Class ED or Toyota RAV4 EV) is where the charger is attached.

In the Tesla cars, there can be one or two "10kW" chargers under the rear seat (and one 10kW charger under the hood for RAV4 and B-Class), and for Supercharger, there are 12 of them in a box sitting on the curb or nearby.

No matter what, the input is AC and the output is DC. The acceptable input voltages are 100 to 277 volts AC , single phase, and output is 250-430 volts DC.

Because each of the chargers are single phase, there are four 10kW chargers per each of the three phases in a Supercharger.

Now, your probably asking, 12 multiplied by 10kW only equals 120kW (previously they were 90kW... three chargers on each of three phases). How do they get 135kW now?

Tesla limits the input amperage above 250 volts to maintain 10kW in the cars, so that at 277 volts, it's only 36 amps. In the Superchargers, they leave them at 40 amps each to make 11kW at 277 volts.

12 chargers * 11kW = almost 135kW

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The onboard charger use normally wouldn't be allowed with DC charging. That's not to say it can't... it just won't.

Like any DC power supply, it is designed with certain input limitations - some with more than others. The i3 is designed for lower acv than a 480acv source. Trying to input less or more than the supply was designed for can lead to damages and failure.

You really need to understand and not perpetuate the notion that an EVSE is a power supply...it is a fancy on/off switch with some safety controls built in...the charging circuit is in the vehicle and in the case of the i3, limited to a max of 7.4Kw and a specific voltage input range which does not include 480vac at this time (not that it couldn't, but it doesn't). It accepts the more common acv supply voltages available to most residences and businesses where it is being sold, though.

When it comes to DC fast charging, that moves the power supply outside of the vehicle, and for the most part, the internal charging circuit is bypassed. Both the DC fast charging circuit and the car must communicate to adjust the device's output to match the needs of the vehicle at any particular state of charge and internal requirements, but that is taken care of by following a specific standard. The i3 uses one defined by J1772, Tesla uses their own, as does Chademo. They are not directly compatible, but you could build a converter (and some are out there). That does not mean that they are as efficient or commonly available, but that they are technically possible. Try plugging in a 240vac iron into the USA typical plug, plug converter aside, it just doesn't work well. Try it the other way, and things burn up! IOW, if it isn't designed for it, it is unlikely to work.

You can't play a BluRay disk in a CD player, but it's not hard to go the other way. It's not as simple with power supplies and protocols. It is what it is.