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      01-19-2014, 05:43 PM   #1
hl0m4n
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Arrow ► i3 Charging FAQ

im confused as to charging methods for the i3 so can someone sum it up for me? do all of these need a professional electrician for install?

110v cord set- charge time from 0-100%- price to install

220v wall box- charge time from 0-100%- price to install

dc fast charge- 30 minutes- price to install
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      01-19-2014, 07:44 PM   #2
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For the 120vac, you just plug it into an existing (preferably 20A) receptacle...about 8-hours for full charge from min. Cost, probably nothing.

For 240vac, similar to a dryer, you need a special charging box wired to it, about 3-hours. Cost, depends, but with permit and wiring and hardware, around $1500.

For high voltage DC, you need the option in the car ($700), AND power you almost certainly won't have in a residential setting. 20-minutes to about 80%, a couple of hours to finish topping it off, but you can get near in 30-minutes. Cost, if you had the power, maybe $30K or so.

These are all from nearly depleated...less time for a part charge.
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      01-19-2014, 08:00 PM   #3
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^ thanks! so there are only 2 residential charging solutions with the dc charger being available at those public stations?

why is dc not available in residential setting? not enough voltage? can you provide a technical explanation on dc charging?
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      01-19-2014, 09:00 PM   #4
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The currently available DC chargers range from 50Kw to 100Kw output, and use 3-phase, high voltage power...not the 240vac a typical home has. So, if you really wanted it, you'd need to have access to commercial power, pay for it, then buy the charger and have it installed. The things are expensive, at least for now. At the upper end, that's likely in the order of 250A out, not counting losses in converting it to the high-voltage DC, so in reality, probably more like 300A, lots more than most homes have to power their entire house.
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      01-20-2014, 09:17 AM   #5
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^ thanks for the detailed explanation. on a final note, if the i3 doesn't have the optional dc option can the car still be charged at a dc charging station at 240v?

in other words, is dc charging stations backwards compatible?
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      01-20-2014, 04:01 PM   #6
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The i3 can always be recharged with the 120vac cable it comes with, or with the 240vac at a level 2 charger (IF it is the right plug and protocol - needs to be J1772). It will only be able to be recharged with a DC fast charger IF you bought that option. Now, whether a fast charger will also have the lower-powered connectors, I do not know...there aren't very many of them out there right now. There are lots more 240vac chargers out there, but some have CHAdeMO connectors (won't work on the i3). The connector used on the i3 is recently approved, and agreed to by many manufacturers, but not all. So, the existing chargers are a somewhat mixed bag.

The charger 'talks' to the car to agree on the proper charge rate and level, so it needs not only the right plug, but the right protocol. In the future, this may not be as big a deal, but right now, the largest electric fleet is of the Nissan Leaf, and it does not use the same plug...the Japanese haven't gone to the J1772 connector and protocol...time will tell.
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      01-20-2014, 06:43 PM   #7
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Quote:
Originally Posted by jadnashuanh View Post
The i3 can always be recharged with the 120vac cable it comes with, or with the 240vac at a level 2 charger (IF it is the right plug and protocol - needs to be J1772). It will only be able to be recharged with a DC fast charger IF you bought that option. Now, whether a fast charger will also have the lower-powered connectors, I do not know...there aren't very many of them out there right now. There are lots more 240vac chargers out there, but some have CHAdeMO connectors (won't work on the i3). The connector used on the i3 is recently approved, and agreed to by many manufacturers, but not all. So, the existing chargers are a somewhat mixed bag.

The charger 'talks' to the car to agree on the proper charge rate and level, so it needs not only the right plug, but the right protocol. In the future, this may not be as big a deal, but right now, the largest electric fleet is of the Nissan Leaf, and it does not use the same plug...the Japanese haven't gone to the J1772 connector and protocol...time will tell.
Can I ask please what would be your advice to someone who buys an i3 in San Francisco on whether or not to pay the $700 extra to get the DC (SAE) fast charging capability. Even here in California will there be enough i3 compatible DC charging stations available during the next three years to make this worth it?

Thanks in advance for any thoughts you have on this.
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      01-20-2014, 08:56 PM   #8
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I have no idea on where and how many DC fast chargers will show up...but, you can't easily retrofit that capability to the vehicle. Being CA, and a major city, you have a much better chance than many other places. Now, you have to decide if you really need it.
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      01-20-2014, 11:05 PM   #9
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Quote:
Originally Posted by tiburonh View Post
Can I ask please what would be your advice to someone who buys an i3 in San Francisco on whether or not to pay the $700 extra to get the DC (SAE) fast charging capability. Even here in California will there be enough i3 compatible DC charging stations available during the next three years to make this worth it?

Thanks in advance for any thoughts you have on this.
For only $700 I definitely recommend you get it. NRG is obligated to install 200 DC quick chargers in CA in the next few years and many will be CCS capable. You will regret not getting it when the chargers begin showing up in areas you like to travel to...
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      01-21-2014, 12:05 PM   #10
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Quote:
Originally Posted by tommolog View Post
For only $700 I definitely recommend you get it. NRG is obligated to install 200 DC quick chargers in CA in the next few years and many will be CCS capable. You will regret not getting it when the chargers begin showing up in areas you like to travel to...
Thanks Tom. Good to know. I'll go with the DC option.
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      01-25-2014, 10:14 PM   #11
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Quote:
Originally Posted by jadnashuanh View Post
For the 120vac, you just plug it into an existing (preferably 20A) receptacle...about 8-hours for full charge from min. Cost, probably nothing.

For 240vac, similar to a dryer, you need a special charging box wired to it, about 3-hours. Cost, depends, but with permit and wiring and hardware, around $1500.
For the 240 vac charge, why do you need a special charging box and not simply a 240 vac outlet, like for a clothes dryer?

Thanks,
Pat
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      01-25-2014, 11:50 PM   #12
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Quote:
Originally Posted by catpat8000 View Post
For the 240 vac charge, why do you need a special charging box and not simply a 240 vac outlet, like for a clothes dryer?

Thanks,
Pat
Not sure, but the vehicle has an onboard charger to bump the voltage up to the high voltage DC required to charge the batteries with a 120vac input...my guess is the cost to include another converter in the vehicle would have added more cost and weight and volume than they wanted to include in the vehicle...so, they use an external box to do that.

Higher current requires bigger components and the associated heat that comes with it.
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      01-26-2014, 05:52 PM   #13
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I did a little research since I was curious...

A level 2 charger is required when you want to charge faster than the 120vac cable that comes with the vehicle.

The L2 charger has various safety circuits built into it which include a proximity detector to ensure the cable is properly installed before applying the 240vac and it generates a 1KHz square wave to announce it is there and capable of providing power. The car responds by changing the height of the square wave (attenuates it) and the charger responds by energizing the relay to actually apply the power. This is simplified, but functionally accurate as I understand it. Part of that negotiation is an indication of the amount of power the vehicle can accept and what the charger can provide.

While the standard allows up to around 62A, most charging stations do not provide that much. Most are in the order of 30A or so. You'd need to match the circuit breaker and wiring size to the charger you buy...I do not remember the max the i3 can accept on its level 2 input.

DC fast charge could exceed 100A.
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      02-17-2014, 08:56 AM   #14
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FWIW, I installed a 30a level 2 charger in my garage for a leaf that I leased while I waited for the i3 to come out. It came out to about $600 + $30 in breaker and wire. pretty simple to install and alot of places don't require permits. Even if you do need to get a permit, you can do the work yourself. Homedepot.com for the charger. The only thing that would bring the cost up would be if you needed more wire. I managed to install it right under my breaker box. Hope this helps
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      02-17-2014, 11:20 AM   #15
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Quote:
Originally Posted by jadnashuanh View Post
...While the standard allows up to around 62A, most charging stations do not provide that much. Most are in the order of 30A or so. You'd need to match the circuit breaker and wiring size to the charger you buy...I do not remember the max the i3 can accept on its level 2 input...
The i3 charger is 7.4 kW, so you do not need an EVSE capable of more than 32 A (7,400w/240V=30.8A).
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      02-17-2014, 06:50 PM   #16
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Quote:
Originally Posted by ultraturtle View Post
The i3 charger is 7.4 kW, so you do not need an EVSE capable of more than 32 A (7,400w/240V=30.8A).
Very true, but who knows whether next year's model might have a more robust on-board charger capability, requiring a bigger supply to maximize the charging rates. You can plug a 10W light bulb into a 20A circuit, but a big spotlight would trip the breaker...so, bigger may or may not be worthwhile. The bottom line, the 240vac Level 2 charger will be faster than the 120-vac line cord, and the DCFC, if you opt for that option on the vehicle and can find a place to plug in, will be the fastest of the options available for now.
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      02-26-2014, 02:18 AM   #17
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Need to clarify a few things here.

For a 3.3kWh charger, a 30amp 240v circuit is fine.
For a 6.6kWh charger, you will want to go with at least a 40amp circuit.

Remember to go at least 10% over on the circuit capacity than your load.

Remember, whatever the actual charge is that is going into your battery, figure the charger will be taking about 10% more or so for inefficiency.

110v charging is the worst, You will loose more through inefficiency, as the voltage is having to go from 110v to probably 350-390 volts. They generally draw about 1300 watts or so, with only 1150 watts or so going into your battery. So to charge a 20kWh+ battery, it will literally take close to 20 hrs to charge. So not a very practical solution for most people.

I use the dryer outlet for my 3.3 kWh charger. And if I drive 50 miles in a day, it will still only take about 4 hrs to charge.

Most dryer outlets are good for only 30 amps, so it won't yield the power necessary for 6.6-7.2 kw charging.

Most Central AC circuits are set up for 50 amps though.
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