leafme
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Battery Charging

Thu Apr 22, 2010 3:39 pm

Jessica,

I've heard varying things about charging and I'd like to have you put the issues to rest.


I understand there are 4 charge modes:
Level 1 - 120v, 15a
Level 2lo - 240v, 15a
Level 2hi - 240v, 30a
Level 3 - commercial 480v, 75kW

Are these correct? I'm questioning the first three currents only as I've already noted Nissan and the rest of the American general public don't recognize the NFPA National Electrical Code nominal voltages I've indicated here.

1. No wall charger is needed when charging at level 1. Simply plug a 120v, 15a rated extension cord into a standard 120v, 15a electrical receptacle. Right?

2. What is the charger on the wall doing if the charge electronics are in the leaf (level 2lo?). Am I even correct? Is the wall charger only needed for comms from my leaf to Nissan/AV if I only use level 2lo? Or again, am I in left field?

3. Will the DEC 2010 production leafs be able to be charged at level 2hi or am I stuck with the 8hr recharge time of level 2lo when I buy in DEC 2010?

4. If I can charge at home with level 2lo or level 2hi, is the level programmable by me by time? e.g. can I program it with my phone to charge the battery for 2 hrs at level 2hi and then back down to level 2lo for the balance of the charge (thinking conserving battery life here)? or maybe I have no choice since the DEC 2010 model won't do level 2hi.

Thanks
Malcolm, San Diego

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garygid
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Re: Battery Charging

Thu Apr 22, 2010 5:07 pm

I have seen no mention of the Level 2hi charging being available for the Leaf.

However, the AeroVironment charge station apparently can handle 35 amps when connected to a 40-amp breaker and "programmed" to offer the higher current to the attached vehicle.

Perhaps Nissan thinks it is of little benefit for most users to charge in 4 hours instead of 8.
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Dav
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Re: Battery Charging

Thu Apr 22, 2010 5:55 pm

garygid, what he calls level 2hi is, I believe, what you are talking about. We cannot make use of the 30+ amp capability until Nissan makes it available in 2012. Theoretically, ours will be (at our cost) upgradable when it becomes available.

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garygid
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Re: Battery Charging

Fri Apr 23, 2010 1:17 pm

Is the 120v charging at 15 amps, or lower, maybe 13 amps?
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mitch672
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Re: Battery Charging

Fri Apr 23, 2010 3:00 pm

I would not expect the 120V charging to draw more than 12AMPs from a standard 15A circuit, as any more and you would risk tripping the circuit breaker due to heating. %80 is usually the max draw from a circuit, to leave some margin for breaker heating.
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DaveEV
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Re: Battery Charging

Fri Apr 23, 2010 3:56 pm

To be clear NEC codes will only allow you to hard-wire appliances that draw no more than 80% of the rated circuit capacity.

As mitch672 says, if you draw any more than 80% of the circuits rating, the breaker should eventually trip.

So for a few standard circuit breaker sizes:

15A = 12A
20A = 16A
30A = 24A
40A = 32A
50A = 40A

If you want to draw 35A from a circuit continuously, that means you should have at least a 43.75A rated circuit. Since no-one makes a 43.75A circuit breaker, the next commonly found size is 50A.

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Re: Battery Charging

Fri Apr 23, 2010 4:11 pm

The RAV4-EV draws 27 amps when charging. For code purposes it had to be hard-wired with a 40 Amp breaker.

Speaking practically, most of us had a "portableized" charger that we would plug in to 30 Amp circuits at friends and relatives houses. No problems encountered, but not up to code.

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Re: Battery Charging

Fri Apr 23, 2010 6:10 pm

Level 1 goes up to 20A. It's unique in not requiring any special safety features over a standard NEMA outlet, because it basically *is* a standard NEMA outlet.
Level 2 J1772 goes up to 80A (19.2kW). But most chargers (both the offboard and onboard hardware) don't support currents that high, and that includes the Leaf. The Leaf is limited to 3.3kW, although there's been some talk of it possibly going to double that, perhaps as an option (that's an option I'd definitely take; it'll let you make good use of 50A RV sockets if you get a J1772 adapter).
Level 3 is 480VAC in, generally, and variable DC out, and since there's no standard for the US yet, there's no official upper bound, and level 3 chargers as powerful as 300kW have been built. The Leaf, however, is limited to 50kW.
Level 4 is even rarer than Level 3. An example is the 800V, 1000A Aerovironment (yes, 800kW!) charger they sold to TARDEC. No commercial EV that I have heard of, in service or proposed, will support this in the coming years. In the far future, I hope to see semis running off these.

The lower end of Level 3 can run straight off the grid, although utilities don't like it. The upper end of Level 3 and all of Level 4 should be run with a battery buffer, or you're going to have some very angry utilities (and their consumers). Level 3 and 4 chargers are large and quite pricey. A 250kW charger is the size of a vending machine, while the 800kW charger is the size of four vending machines shoved together. I've not seen any prices for the Nissan/Aerovironment 50kW chargers, but judging from historic prices, I'd expect them to run about $40k a pop. The price doesn't scale linearly; if I recall, a 250kW Level 3 charger will run you about $130k (w/o a battery bank). In an ideal future-charging scenario, each Level 3 or Level 4 "charging area" will share a common, large battery buffer and have half a dozen or so chargers. They'll probably do what Aerovironment currently does on a number of their chargers, which is having two or more charge connectors per charger, and if you have one vehicle, they charge at the max rating, while if you have multiple, the current gets split up between them.
Last edited by KarenRei on Thu Apr 29, 2010 6:01 pm, edited 2 times in total.

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LTLFTcomposite
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Re: Battery Charging

Fri Apr 23, 2010 6:17 pm

The description of the purchase process implied that the home assessment and charger installation would occur before the vehicle purchase. Do I *have* to get a 220V charging station? From what I've read the 120V should be sufficient for my needs, many days I only go 20-40 miles then the car is home for 12-14 hours.
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garygid
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Re: Battery Charging

Fri Apr 23, 2010 9:14 pm

When the Leaf's 240v charging station is hard-wired, certain electrical codes apply.

However, when one disconnects it from the hard-wire and simply wires it to an "extension cord" it becomes just a plug-in portable device (perhaps no longer J1772 standard). For safety, perhaps one should add an additional dual-breaker (240v 40a) in an in-line box right near the plug end of the "extension cord".

Then, when connected through a suitable "extension-cord" to a standard electric dryer plug, it seems that it could be used at any location with a suitable electric dryer socket, right?

If not, what prohibits such use?

Certainly, there is a safety issue, especially if the higher Level 2 currents were being used:
(But we are only using 15 (or maybe 30) amps!)

Unplugging it while charging is not a safe idea, just like unpluging a running dryer or an operating welding machine would not be a good idea. But one can plug them in.

But, charging overnight almost anywhere would then be relatively easy, right?
Last edited by garygid on Sun Apr 25, 2010 10:29 pm, edited 1 time in total.
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