# 1ph or 3ph chargers?



## Woodsmith (Jun 5, 2008)

While thinking about charging solutions I wondered about what the pros and cons and effects were of 240v single phase and 440v three phase charging were.

It would be easy to set up a 1ph charging point at home by putting in a suitable socket and cabling but I could also apply for a 3ph supply and use that instead. I think the college uses 3ph charging for its forklifts and I was wondering if there would be any benefit in suggesting to the college that I could use the same supply as the forklifts to save them installing a dedicated charging point in the carpark.

So, I assume there is a cost element to going 3ph. What other effects would it have? Reduced charge time - How would that affect the batteries (LiFePO4)? Cable size - Would the charge cable and plug be huge or smaller as there is less current? Dual voltage - Would a charger be able to operate on 240v 1ph and 440v 3ph? Charger size and weight - would the charger be too big and heavy?

Sorry if this is a bit abstract but it shows my overall ignorance of the charging side of EVs.


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## Coulomb (Apr 22, 2009)

Woodsmith said:


> Would the charge cable and plug be huge or smaller as there is less current?


3 phase connectors always seem to be huge. I guess the idea is that the only reason you want it is for high power, so they are capable of at least 30 A, so that's a substantial connector. In Australia, the plug is the size of a soup can, and cables are at least 15 mm thick. So that takes up a bit more space in your vehicle.


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## BMI/LiFeTech (Aug 12, 2009)

Woodsmith said:


> While thinking about charging solutions I wondered about what the pros and cons and effects were of 240v single phase and 440v three phase charging were.
> 
> It would be easy to set up a 1ph charging point at home by putting in a suitable socket and cabling but I could also apply for a 3ph supply and use that instead. I think the college uses 3ph charging for its forklifts and I was wondering if there would be any benefit in suggesting to the college that I could use the same supply as the forklifts to save them installing a dedicated charging point in the carpark.
> 
> ...


Three phase power allows for very fast charging (in as short as 15 minutes charging time to 90% capacity for some LiFePO4). The downside is the cost in terms of both having three phase power supplied to a residential/domestic installation as well as the cost of the charger itself. If a three phase outlet is already available that is of great benefit since you would only need to purchase a three phase charger. If a neutral connector/pin is available at the three phase outlet you could also charge by single phase charger from the same three phase outlet using a suitable adaptor cable and single phase charger. So there are distinct advantages to be had if three phase power is already available and you do not need to go to the expense of having it installed in your premises.


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## BMI/LiFeTech (Aug 12, 2009)

Coulomb said:


> 3 phase connectors always seem to be huge. I guess the idea is that the only reason you want it is for high power, so they are capable of at least 30 A, so that's a substantial connector. In Australia, the plug is the size of a soup can, and cables are at least 15 mm thick. So that takes up a bit more space in your vehicle.


Three phase connectors only seem large because they are usually rated at greater than 30amps per phase. This requires quite large mating conductors in the plug and socket so as to be able to carry the high current. Many much smaller three phase connectors are available for lower currents. It is the Clipsal brand of three phase plugs/socket outlets which give people the idea that all three phase connectors are large and the size of a "soup can" when there are many other manufacturers/brands of connectors available which are considerably smaller.


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## jaspersk (Jun 26, 2008)

As Lifetech said, getting 3 phase to your residence is extremely expensive. Frankly, there is no way to get three phase at a cost you would be willing to pay. Unless you live on a busy corridor, it is unlikely that the power company even has 3 phase available in front of your house. On top of that you need to think about all of the equipment required to get 3 phase into your house and pull off single phase for your normal house appliances. I really don't think this is feasible for a non-industrial location. I wouldn't be surprised if the local building codes took issue with installing 3 phase in a house.

All that said, you can certainly crank out a lot more power if you really need it and have the money to pay for a 3 phase charger. If you have 3 phase available where you work, you could charge a great deal faster.


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## Coulomb (Apr 22, 2009)

jaspersk said:


> As Lifetech said, getting 3 phase to your residence is extremely expensive.


? Maybe it depends where you live.



> Frankly, there is no way to get three phase at a cost you would be willing to pay.


Huh. In Australia, it's no big deal. People I know install 3-phase so they can run big lathes, air compressors, or welders.



> Unless you live on a busy corridor, it is unlikely that the power company even has 3 phase available in front of your house.


? Power is distributed in 3-phase. Even in the USA, am I right? So surely that's no issue.

Ah, in the US, every house has its own transformer; in Australia, there is a large 3-phase transformer at the end of the street that does a whole block of houses. Every third house gets the same phase usually, or you can connect to all three phases for a little extra. Your main switch has 3 poles instead of one, and your meter is a little more complex to measure power on three phases. The house load is split between the phases, except of course for the 3-phase outlet(s) which have all 3. In the US, you might need two extra transformers, or replace your single phase transformer with a 3-phase one. I guess that could get expensive. I think that's a legacy of the low 115 V US mains. Sharing a transformer amongst many houses would presumably result in too much line loss, or very fat and expensive cables.



> On top of that you need to think about all of the equipment required to get 3 phase into your house and pull off single phase for your normal house appliances. I really don't think this is feasible for a non-industrial location.


? In Australia, you just use neutral and one of the phases for single phase loads. No special equipment is required.



> I wouldn't be surprised if the local building codes took issue with installing 3 phase in a house.


Again, we have ordinary houses with 3-phase power here. Why would the buildings people care?


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## jaspersk (Jun 26, 2008)

Coulomb said:


> ? Maybe it depends where you live.
> 
> Huh. In Australia, it's no big deal. People I know install 3-phase so they can run big lathes, air compressors, or welders.


I missed that you lived in Australia. I should probably not be commenting since I am not familiar with your power system. Sorry about that.  Now I understand why you simply suggested you could apply for it. That didn't make sense when I read it.



Coulomb said:


> ? Power is distributed in 3-phase. Even in the USA, am I right? So surely that's no issue.
> 
> Ah, in the US, every house has its own transformer; in Australia, there is a large 3-phase transformer at the end of the street that does a whole block of houses. Every third house gets the same phase usually, or you can connect to all three phases for a little extra. Your main switch has 3 poles instead of one, and your meter is a little more complex to measure power on three phases. The house load is split between the phases, except of course for the 3-phase outlet(s) which have all 3. In the US, you might need two extra transformers, or replace your single phase transformer with a 3-phase one. I guess that could get expensive. I think that's a legacy of the low 115 V US mains. Sharing a transformer amongst many houses would presumably result in too much line loss, or very fat and expensive cables.
> 
> ...


That is interesting. I have learned something new. Power in the US is distributed in 3 phase, however, once you get into neighborhoods, they use split-phase electrical distribution. Someone here will correct me if I am wrong but I have never seen 3 phase in a house in the United States. Sometimes, the power company will feed more than one house off the same transformer but it is a single phase transformer feeding 240 single phase with a center tapped neutral. So each house gets 240V single phase plus a neutral so the 120V loads are fed from one of the 240V sides to neutral. It definitely is a big deal in the US to convert to three phase. When you look down most residential streets you will see only two wires on the poles. In fact, they recently built a school nearby my house and the power company had to run nearly a mile of additional wire to get the additional phases to it for the large HVAC loads. The way most tariffs are written in the US, the customer is responsible for the cost of all line extensions so that type of upgrade is very expensive unless you live on a larger street or industrial area where the 3-phase circuits already exist. But you can't go to the local hardware store and buy equipment for handling 3 phase power.

Once in a while, I hear about people wanting to run industrial equipment like a 3 phase lathe in their house and they are typically looking to buy a large and expensive phase converter to make that happen.


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## BMI/LiFeTech (Aug 12, 2009)

Thanks for the insight into the US power distribution system Jaspersk.
I am quite surprised that for such an advanced country as the USA you have such a backward power distribution system. 
I just assumed that all modern industrialised countries like USA, Canada and all of Europe had three phase power available in the street outside every house in every major city and large town in the country as is the case in Australia. 
Many houses in Australia have three phase already connected. The most common use or reason for having three phase connected being for whole house ducted air conditioning systems.

That raises the question how is power supplied to large airconditioners for houses in the USA if three phase is not available?

The main issue that the power companies in Australia are concerned about is the type of load which will be connected to three phase power if it is connected to a house that only has an existing single phase supply. They don't like to see loads which are unbalanced and thus make it difficult on the power distribution system and the power stations. This is why they don't like it when large welders are connected since many welders use only two of the three phases not to mention the widly fluctuating load while in use. Quite often the power company will refuse to connect three phase to your house if you say you want to run a large welder. 
They don't have a problem with connecting three phase power to houses if you are running a load which uses power from all three phases evenly such as running a compressor motor on an air conditioning system.
I am sure they also would have no objection to connecting three phase for the purpose of EV charging by means of a high power three phase charger since the charger load is evenly balanced across the phases.


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## Woodsmith (Jun 5, 2008)

Three phase wouldn't be difficult to get, it would just be money and a justification letter to the electrical supply company.

Almost all my neighbours have three phase as they are large houses converted to flats. I already have the supply ducting and distribution boards set up from when I was thinking of converting to flats too. I also have my wood workshop here so it would be good to be able to run three phase for the machinery too.

I just wasn't sure if it was worth it in terms of charging equipment and if the equipment will be the size and cost of my car.


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## SimonRafferty (Apr 13, 2009)

In the UK, the cost of 3 phase depends on where the local sub-station is in relation to your house. Unfortunately, for me, it's $9000 away! So I use a solid state phase converter which gives me near perfect 3 phase at 10 Hp - big enough for my CNC.

The only point of 3 phase so far as charging is concerned is the current that's available through it. At home, I'm limited to 80A single phase whereas at work I have 100A per phase 3 phase.

You are better off having a 30A (or more) spur connected to your fuse box and using that instead.

Si


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## Tesseract (Sep 27, 2008)

BMI/LiFeTech said:


> Thanks for the insight into the US power distribution system Jaspersk.
> I am quite surprised that for such an advanced country as the USA you have such a backward power distribution system.


Trying to make enemies right off the bat, huh? Please try to avoid making any divisive nationalistic comments, okay?

We have a "backward power distribution system" because we were the first to actually have one. American's invented the electrical grid, you know, and like anything else in life, a little practice is usually needed before things are done well. We are essentially cursed by legacy installations. Developing countries can skip all of that (note how cell phone service is becoming ubiquitous in Africa while landlines are still relatively rare).

Three phase power is available in virtually every residential neighborhood in the US, it's just not common for there to be anything but a single phase (more properly, a single phase to split phase) transformer feeding each house (or houses, at times). To get three phase power to your house you have to PAY for the utility company to exchange the single phase transformer with a three phase version. In my neck of the woods that typically costs $3,000-$4,000.

Air conditioners, and other large loads, do use single phase power in the US as a result, but the push is on more and more to include small VFDs, essentially, driving three phase motors in even household appliances over here. There are already window unit A/Cs and washing machines available with such and they generally achieve much better overall efficiency (and improve the power factor presented to the utility greatly).


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## BMI/LiFeTech (Aug 12, 2009)

I think the main point which most people miss is that even with single phase power availability in a house a high power charger can be used in most cases if a suitable power outlet is installed.

Most people think they are limited to the power available from a 10A or 15A outlet but this is simply not the case.
In Australia every new house where only single phase power is provided the main supply fuse owned by the power company is rated at 100A. 
That means that theoretically you have 100A at 240V to play with (assuming that no appliances are running). There is no reason why a single phase outlet rated at 32A, 40A or even 50A could not be installed. Especially at night when you are asleep and no appliances are consuming power. 
The only consideration is if electric hot water is used since this is often heated at night and the power companies like to heat water at night via off peak power as a load dump so they can stabilise the load at the generator station.

Even so, if only 40A is available for battery charging then 9.6kW allows for a pretty high power single phase charger to be used!


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## BMI/LiFeTech (Aug 12, 2009)

Tesseract said:


> Trying to make enemies right off the bat, huh? Please try to avoid making any divisive nationalistic comments, okay?


Sorry Tesseract I meant no offence by that comment. My sincere apologies. I was just stunned to hear that three phase power was not available in every street. 

I guess that when you are the pioneers or the first to introduce something new that mistakes will be made and those who come later will learn from those mistakes and not repeat them no matter whether it is an invention of something like a car, an appliance or the entire electrical distribution system in a country.


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## BMI/LiFeTech (Aug 12, 2009)

I understand that the single phase power supplied to houses in the USA is 115VAC 60Hz but there are quite a few places where 230VAC is also available or is that just in newer areas and houses?


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## Tesseract (Sep 27, 2008)

BMI/LiFeTech said:


> I understand that the single phase power supplied to houses in the USA is 115VAC 60Hz but there are quite a few places where 230VAC is also available or is that just in newer areas and houses?


Every house in the US is supplied with 240VAC center-tapped (hence the name "split phase"). That is, there is 120VAC from each phase leg to the center tap, called the neutral here, and which is bonded to ground (literally, as to a rod driven 2M into the ground).

The usual electrical service for a new construction residence in the US is a minimum of 240V/150A, which 200A being very common. My older house has a 125A main breaker and 100A can be found.

EDIT: also, the voltage spec varies a little bit depending on the age of the person specifying it.  110V/220V is common among older electricians/engineers with 115 or 117V and 230V (but not 234V, go figure) whereas the modern specification is 120V/240V.


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## Woodsmith (Jun 5, 2008)

SimonRafferty said:


> You are better off having a 30A (or more) spur connected to your fuse box and using that instead.
> 
> Si


Yes, the easy way is a 30+A supply to charge with at home. I can install that myself safely and effectively. I can also monitor the demand in the house to ensure that I don't over load the supply.

Unfortunately the supply to my house is old and was based on a 1ph 4x60amp fused intake to 4 meters, one for each of the bedsits that was in here. Converting to a single dwelling meant the supply company just removed three of the meters and fuses so I only have 60A to play within a 7 bed house!

I am figuring on upgrading the supply to either 100amp 1ph or going the whole hog and getting 3ph installed. One or the other will have to happen at some point as I renovate the house and start using more of it.


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## tomofreno (Mar 3, 2009)

> There is no reason why a single phase outlet rated at 32A, 40A or even 50A could not be installed.


 That is what I am doing. I had 125A service (US) but upgraded it to 200A when I installed solar panels to power my house and ev. I have space in an existing subpanel in the garage for a 240V breaker, so I am installing a 50A 240V GFCI breaker there to charge from with a Manzanita PFC30 (max current at 240V of about 35A). As far as advantage of 3ph, in this specific case you can get a bit higher charging current out of the PFC30 with 3ph compared to 240V "single phase".

Tom


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## Drew (Jul 26, 2009)

BMI/LiFeTech said:


> Sorry Tesseract I meant no offence by that comment. My sincere apologies. I was just stunned to hear that three phase power was not available in every street.
> 
> I guess that when you are the pioneers or the first to introduce something new that mistakes will be made and those who come later will learn from those mistakes and not repeat them no matter whether it is an invention of something like a car, an appliance or the entire electrical distribution system in a country.


+1

I'm surprised that three phase isn't available in American homes, every house I've ever lived in has had three phase.


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## jaspersk (Jun 26, 2008)

Woodsmith said:


> Three phase wouldn't be difficult to get, it would just be money and a justification letter to the electrical supply company.
> 
> Almost all my neighbours have three phase as they are large houses converted to flats. I already have the supply ducting and distribution boards set up from when I was thinking of converting to flats too. I also have my wood workshop here so it would be good to be able to run three phase for the machinery too.


You are providing your experience in the UK, right? When I look up and down the streets in a residential neighborhood where I live, most of what I see is two wires. It isn't unusual to see 4 wires out on the larger roads since those single phase circuits come from somewhere but it is unusual to see them in residential areas. I grew up on a dairy farm where 3 phase would have been more appropriate since we had a lot of 10-20HP loads for things like vacuum pumps, large refrigerated tanks, and silo unloaders. Thinking about infrastructure, most of the farm equipment was standard single phase despite the large size of the motors since that is all most farmers had available.

Unfortunately a justification letter to the power company wouldn't do us much here. They are regulated and the tariffs in the areas I am familiar with charge the customer for the entire cost of the "line extension." 

Consider yourself fortunate. I suppose you have a system of trains that will take you from city to city as well when you want to go somewhere outside the range limit of your EV....


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## Bentzon (Sep 5, 2009)

Hehe nice to live in a country where most huoses got 3 phase supply.

You could just connect 3 230V chargers together in parrallel and run them from a 16A 5 pole Cee plug 3x230V.

http://www.bmsbattery.com/product_info.php?products_id=111

3 of these and you got 50A at 144v and probably cheaper than any 3X400V charger you can find that can output 50A.


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## Drew (Jul 26, 2009)

I also forgot to mention, I don't know what its like in the UK or US, but in Aus petrol stations and the like have three phase to run pumps and freezers, I'd imagine that restaurants and the like have it too, so if you're out and about and you want a recharge then three phase might work very well, until there are enough people to wear out your welcome


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