Naïve idea: how about a "Quick 440 system"?

[Yanquetino]

The discussions in other threads about the Quick 220 System got me thinking. How possible would it be for an intrepid engineer to invent a similar "Quick 440 System"?

If, say, one had two 240V outlets on separate breakers, perhaps one could plug them both into such a "box" to produce 480V for the QC port...?

Of course, the challenge would not be simple --or cheap! Besides adding the volts together, the system would also need an inverter to convert the AC input to DC output. And I would imagine that, unlike with the LEAF's onboard 240V charger, the box would also need the hardware and firmware to generate, monitor, and control the charge, as well as one of those huge plugs --just like a CHAdeMO station.

Still... wouldn't that be a great accessory? Perhaps one could take it to any RV park, plug into the outlets from two Milbank panels, and charge to 80% in under a half hour.

If, of course, one could afford such a device! :shock:

 

[EVDRIVER]

I am working on one from 36.6 12v DC cigarette plugs wired in series for a fast 440 charge, stay tuned.

 

[smkettner]

Quick 440 will not work the same way as the 220. You will need a transformer.

 

[GeekEV]

I am working on one from 36.6 12v DC cigarette plugs wired in series for a fast 440 charge, stay tuned.

I'll take one when you get it ready. :roll: (he's kidding folks)

Seriously though, Yanquetino, I don't think such a system world work. Even if you had two breakers, it seems likely to me that both would be feeding from the same source wiring and, thus, would have the same electrical potential. I think you'd still get 240v, not 480v (despite the often cited but incorrect 110/220/440). You MAY be able to do it if you had two feeds from two different utility sources. Perhaps one of our EE bretheren here can say for sure?

 

[planet4ever]

To answer more directly, the reason Quick 220 works is because nearly all houses are wired for 240v. Some 120v legs are connected at the breaker box between hot #1 and neutral, while the others are connected between hot #2 and neutral. If you pick the right pair of 120v outlets you can see the 240v voltage difference between hot #1 and hot #2. All 240v outlets are already connected between hot #1 and hot #2, so you can never see more than 240v no matter how you mix and match them.

Ray

 

[Yanquetino]

To answer more directly, the reason Quick 220 works is because nearly all houses are wired for 240v. Some 120v legs are connected at the breaker box between hot #1 and neutral, while the others are connected between hot #2 and neutral. If you pick the right pair of 120v outlets you can see the 240v voltage difference between hot #1 and hot #2. All 240v outlets are already connected between hot #1 and hot #2, so you can never see more than 240v no matter how you mix and match them.

This is why I put "naïve" in the thread's title. I obviously do not understand how our electric dryer and oven and steam shower can all be working at the same time, all of them pulling 240V at the same time. Yet the house is only "wired for 240V". :?: Same thing at an RV Park with its multiple 240V 50A breakers. Weird, you've gotta admit :!:

 

[TEG]

...All 240v outlets are already connected between hot #1 and hot #2, so you can never see more than 240v no matter how you mix and match them.
Ray

A while back I asked what would happen if you put a Quick220 into outlets on different houses...
If they were on different transformers would it be possible to end up with 440/480V?

Typically the cords aren't long enough to do such a thing, but I could imagine it might be possible somewhere.

 

[jwallace3]

You could use a transformer and step voltage up from 220 to 440 volts, however that's not the issue. The reason why you need 3 phase 480 is not the voltage really. Yes, once it's rectified and smoothed out by some caps it would be around 400 VDC. The main reason you need 3 phase is the constant power that's available. With residential voltage the "2" phases are 180 degrees out of phase. Residential voltage is really only a single phase 240 circuit, but they center tap the distribution transformer to give 120 circuits in addition to 240 circuits. Single phase voltage does not have constant power and is one of the reasons why single phase motors require starting caps to get them going.

So long story short, it's not the voltage that is needed for DC fast charging it's the availability of constant power. You could pull it off on single phase 240 but no residential transformer could handle the current. DC fast chargins is meant to deliver up to 62.5kW and most residential transformers are rated at 15kva or 25kva with a few having a 35kva if they have a 400 amp service. They run these oil filled transformers at almost 200% of their rating, but for most of us 62.5kw would throw the main breaker of 200 amps or less. 62500watts/240 volts = 260.4 amps!

 

[planet4ever]

I obviously do not understand how our electric dryer and oven and steam shower can all be working at the same time, all of them pulling 240V at the same time. Yet the house is only "wired for 240V". :?: Same thing at an RV Park with its multiple 240V 50A breakers. Weird, you've gotta admit :!:

Think of a water analogy. Imagine you aren't connected to a city water supply, but have a water tank up in the air beside the house. The higher the tank, the more water pressure you get. That's analogous to the voltage. At a given height, the size of the pipe leading to the house limits how fast the water can come in. That is analogous to the amperage. If you have a big enough main pipe you can feed off to several faucets running at the same time, no problem.

Put another way, you are not "pulling" 240 volts, that is what your utility is pushing. That is how "high" (not literally) the transformer is. What you are pulling is 5 amps or 12 amps or 16 amps or whatever. That is how wide open you have the "faucet", and is limited by the size of the electrical wire.

Ray

 

[TEG]

...All 240v outlets are already connected between hot #1 and hot #2, so you can never see more than 240v no matter how you mix and match them.
Ray

A while back I asked what would happen if you put a Quick220 into outlets on different houses...
If they were on different transformers would it be possible to end up with 440/480V?

Typically the cords aren't long enough to do such a thing, but I could imagine it might be possible somewhere.

I still don't think anyone is answering this question.
It isn't that I was asking for or needing 480V. Not asking about amps either.

Just asking if it could happen that the Quick 220 could accidentally deliver 480V (which would probably fry the EVSE) if you plugged it into two different outlets that are on different transformers?

I think the working assumption is that the Quick 220 will be plugged into the two different 'hots' of a 240V split-phase household supply.
Lets say for instance, someone found a yard lighting outlet at one house, and then another in a yard of the house across the street on a different transformer. What might happen with the Quick220 output? 0V? 120V? 240V? 480V?

 

[jwallace3]

Depends on what phase of the 3 phase distribution system each transformer was on. If they were on different phases, no matter how you hooked them up you would be causing a fault. On the same phase you would either connect 220 to 220 180 degrees out of phase (direct fault) or in phase in which case you have paralleled the transformers and still have 220 just twice the capacity (assuming the transformers are the same size. Chances are even if you pulled that off there would be some circulating current because of differences in voltage levels and transformer impedances.

If you could find 3 neighbors on 3 seperate phases in close proximity you could Y them up, use a step up transformer to go from 240 to 277 and then Y up those step up transformers and viola! You have 480 phase to phase 3 phase voltage. Now you can cause a small brown out at all 3 houses by using Level 3 charging.

 

[TEG]

OK, thanks.

 

[greenleaf]

According to the Wiki article

http://en.wikipedia.org/wiki/Charging_station

level 3 charging is at 62.5kW. The 200A service, typical of a new home, supplies a maximum of 48kW.

 

[TEG]

But if you found 3 homes on different phases...

 

[smkettner]

I still don't think anyone is answering this question.
It isn't that I was asking for or needing 480V. Not asking about amps either.

Just asking if it could happen that the Quick 220 could accidentally deliver 480V (which would probably fry the EVSE) if you plugged it into two different outlets that are on different transformers?

I think the working assumption is that the Quick 220 will be plugged into the two different 'hots' of a 240V split-phase household supply.
Lets say for instance, someone found a yard lighting outlet at one house, and then another in a yard of the house across the street on a different transformer. What might happen with the Quick220 output? 0V? 120V? 240V? 480V?

You will never ever ever get anything except 120 or 240 volts. This is the supply voltage and it will never be any higher. It does not matter if supplied by different transformers or even different utility companies. In phase or out of phase does not matter you still get no more than 240 volts period. Even if you somehow tied ten homes together you only get 240 max.

You cannot put alternating current in series like a stack of dry cell batteries.

You will need a step up transformer to get 480 volts. With a transformer you can have any voltage you like.

 

[tps]

If you could find 3 neighbors on 3 seperate phases in close proximity you could Y them up, use a step up transformer to go from 240 to 277 and then Y up those step up transformers and viola! You have 480 phase to phase 3 phase voltage. Now you can cause a small brown out at all 3 houses by using Level 3 charging.

It seems unlikely you'd find houses on 3 different phases in close proximity. At least in my area, they seem to put entire subdivisions on a single phase, even though almost all power poles along the road have all 3 phases.

Anyway, assuming you did find nearby houses with all 3 phases, the best you could do is a "Quick WYE". All houses would have their center-tap neutral connected to a common ground. (Electrical distribution systems are usually required to have a metalic ground from the generator to the load.) The best you could get by picking wires from different phases would by 208V 3-phase WYE. So far as transformers, we've got a bunch of 480/277 to 208/120 3-phase transformers in the electrical rooms at my office building. For example, one connected to a 50 amp 3-pole 480 breaker supplying a 100 amo 3-pole 208 breaker is the size of a small table!