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evnow
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Re: Level 2 Charger Confusion

Fri Jul 09, 2010 9:33 pm

pgrovetom wrote:By the way, the Level 1 EVSE doesn't have an inexpensive EVSE and also requires a dedicated new circuit. So even if you fall back on the 115V Level 1 EVSE, you still need a a newly installed dedicated 20A circuit installed just for the EVSE but it does just plug into a standard outlet. That installation won't be much cheaper. The only savings is the EVSE is a little simpler and it can be wired with a 20A breaker and Romex but from a labor point of view, that will still take some time from an electrician. It's not free.


But, since it can be plugged in anywhere - people are going to do just that. L-1 EVSE needs to handle that, right ...
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AndyH
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Re: Level 2 Charger Confusion

Fri Jul 09, 2010 10:11 pm

pgrovetom wrote:By the way, the Level 1 EVSE doesn't have an inexpensive EVSE and also requires a dedicated new circuit. So even if you fall back on the 115V Level 1 EVSE, you still need a a newly installed dedicated 20A circuit installed just for the EVSE but it does just plug into a standard outlet. That installation won't be much cheaper. The only savings is the EVSE is a little simpler and it can be wired with a 20A breaker and Romex but from a labor point of view, that will still take some time from an electrician. It's not free.


Please explain why you believe any of us will need to plug the L1 EVSE into a specially installed 20A 120V outlet. Please?

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garygid
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Re: Level 2 Charger Confusion

Fri Jul 09, 2010 10:27 pm

I suspect the "included" 120v EVSE will have a 12 amp "max" setting, so that it will be "legal" to use from a typical existing socket on a 15-amp breaker.

The AV "assessment" guy just wanted to see an existing "nearby" 120v outlet (for testing the LEAF with the non-AV 120v EVSE). He did not even suggest a dedicated 20-amp 120v circuit.

He suggested using a GFI socket there (even though the 120v EVSE should contain one, he said).

Of course, the 12-amp charging load, on a circuit shared with other ON loads, could still "blow" the breaker.

Presumably, L1 charging could be done at (at least) 15 amps, but a 20-amp breaker should then be used, to be legal.
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Re: Level 2 Charger Confusion

Fri Jul 09, 2010 11:56 pm

pgrovetom wrote:I looked at the NEC rules for sub panel loading and if anyone needs to upgrade their panel, this could be expensive.

Can you say more about this? My panel is maxed out, but my meter with main line switch is only a couple of feet from where I want the EVSE, and my solar system also ties in there. I am hoping I can install a sub panel connected behind the main line switch, either in parallel with the main panel or feeding through to it. Taking my solar system into account I am nowhere close to being maxed out at the meter.
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garygid
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Re: Level 2 Charger Confusion

Sat Jul 10, 2010 9:13 am

Perhaps others can benefit from my PV experience, and even give me some suggestions on adding EV support:

I had a meter wired directly to a 150 amp "main" breaker in the immediately adjacent (connected) 150-amp rated breaker panel.

I was told that SDG&E requires trenching, conduit (24" deep), and new feed wires (to replace the 32-year old "buried" service feed wires) if ANY service panel "upgrade" is done.

I was adding 7050 watts (SunnyBoy 7000 inverter, max just over 29 amps of AC) of Solar Generation required adding a 40-amp dual breaker for the PV "feed-in".

I was told (apparently incorrectly) that I would have to reduce the size of the main feed breaker by 40 amps to avoid the theoretical possibility of over-driving the 150-amp buss. So, we replaced the 150-amp main breaker with a 110-amp breaker, and added the 40-amp "PV" braker, thereby avoiding the expensive panel upgrade and trenching.

Apparently the "correct" buss loading calculation for PV feeds is: one is allowed to "over-rate" a panel by 20% when adding a PV feed-in. So, my 150 amp panel should have been treated like a 180-amp panel. Then, adding the 40-amp breaker would have only required reducing the main breaker from 150 to 140 amps. But, a 140-amp breaker seems very difficult to find. I suppose that a case could be made that the PV "feed" could never exceed 30 amps, and using the original 150-amp breaker should be OK, but I doubt that an inspector would go for that argumenr, because of the 40-amp PV breaker.

Now, faced with an almost full breaker panel, and wanting to add a dual 40-amp breaker (or two, the second for a future 2nd PHEV) for EV charging (and possibly one or two dedicated 20-amp breakers for Level 1 EV charging).

Since it is a GE panel that already uses "narrow" breakers, I cannot gain space by replacing pairs of 15 (or pairs of 20) amp breakers with the 2-in-1 type breakers, to free up a few slots. I will have to open it up to see if any of the remaining (two single and one double) knockouts will take breakers. I think the PV electrician said that some contact "tabs" were either missing or broken, and the associated spaces could not be used.

So, I might need to add a subpanel on the inside of the garage wall (right in back of the main panel that is IN the wall, facing outwards).

Perhaps I could then move some of the existing loads to the sub-panel and have the new EV-charging breakers conveniently located (within line-of-sight of the future EVSE) in the interior sub-panel.

When one has PV generation, a two-meter solution does not allow running both meters "backward". So, it would seem that some one-meter solution (Tariff) would be "best", even "required" to offset both the house consumption and the EV charging.

Further complication: If one has EV-TOU metering, the generation will all be in the daytime, in the high-rate or mid-rate time slots. There, I over-generate at least 9 months of the year, and A/C usage spikes usage in at least August and September so that there is perhaps 300 to 600 kWh net usage in those months. But, for the year, there is net generation. The night-charging time slot will never get any generation, so it would always show net usage (EV charging), perhaps of 200 to 600 kWh a month. Within one month's billing, does the over-geberation in the daytime time slots offset the net usage in the night slot? If it does, is it kWh for hWh, or datyime power rate offsetting nightime total (power plus distribution) billing?

Thanks for any help.
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Re: Level 2 Charger Confusion

Sat Jul 10, 2010 9:28 am

garygid wrote:Further complication: If one has EV-TOU metering, the generation will all be in the daytime, in the high-rate or mid-rate time slots. There, I over-generate at least 9 months of the year, and A/C usage spikes usage in at least August and September so that there is perhaps 300 to 600 kWh net usage in those months. But, for the year, there is net generation. The night-charging time slot will never get any generation, so it would always show net usage (EV charging), perhaps of 200 to 600 kWh a month. Within one month's billing, does the over-geberation in the daytime time slots offset the net usage in the night slot? If it does, is it kWh for hWh, or datyime power rate offsetting nightime total (power plus distribution) billing?

Thanks for any help.


I think we all need that kind of help from the math whizzes amongst us - to try and figure out how what we have to buy at the TOU super off-peak and off-peak rates is affected by the surpluses we generate at TOU peak rates.
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planet4ever
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Re: Level 2 Charger Confusion

Sat Jul 10, 2010 10:54 am

garygid wrote:Further complication: If one has EV-TOU metering, the generation will all be in the daytime, in the high-rate or mid-rate time slots. There, I over-generate at least 9 months of the year, and A/C usage spikes usage in at least August and September so that there is perhaps 300 to 600 kWh net usage in those months. But, for the year, there is net generation. The night-charging time slot will never get any generation, so it would always show net usage (EV charging), perhaps of 200 to 600 kWh a month. Within one month's billing, does the over-geberation in the daytime time slots offset the net usage in the night slot? If it does, is it kWh for hWh, or datyime power rate offsetting nightime total (power plus distribution) billing?

This sounds like something best discussed on the SDG&E thread. I can say that for PG&E we are assigned one tier for the month based on our total usage (night +/- day), but PG&E doesn't break out distribution separately, so SDG&E calculations are going to be different.

It does sound like you may have a similar sub panel need to mine, so I hope pgrovetom can provide some wisdom here.
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Re: Level 2 Charger Confusion

Sat Jul 10, 2010 11:24 am

I've just done some figures in the Edison area. Don't blast me for incorrect conclusions...I am NOT a math whizz by any stretch of the imagination. But I'll take constructive commentary on-board!

viewtopic.php?f=25&t=666&p=10304#p10304
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2015 pack on 12/30/15
Tinted windows
Bridgestone Ecopia 422+ tires
L1 EVSE upgrade
FIAMM horns
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2013 sun visors
LED shifter
Heated seats
GT-R map lamp lenses
Altima illuminated door switches

pgrovetom
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Re: Level 2 Charger Confusion

Sun Jul 11, 2010 11:34 am

But, since it can be plugged in anywhere - people are going to do just that. L-1 EVSE needs to handle that, right ...


Yes that is true and it will usually just work. With 16A as the specified maximum for Level 1, a real charger probably won't pull the maximum. That means it probably won't even pop a 15A breaker unless its got some other significant load on it. The building department, if one actually applies for a permit, would require a dedicated 20A circuit since 16A x 1.25 = 19A which is pushing even a 20 circuit close to the edge. That being said, the NEC and code requirements are very conservative so what is required and what will happen in the real world are different. I suspect someone who just plugs into an outlet in their garage will probably get a 20A circuit and it probably won't have anything else on it since its a garage. If they are unlucky enough to be charging and plug an electric drill into the same circuit, then it could pop the breaker. When that happens, you will know it as the drill will stop, then you just check it out, reset the breaker and put the Level 1 charger on an outlet where non of the other outlets get used typically and it will never be a problem.

It interesting they chose 16A given 15A and 20A are the standard breakers and circuits. They probably took the 20A, subtracted 1A for other loads and new 1.25 x 16 = 19 + 1 = 20A. So its probably built into their 16A choice so it typically just works in most outlets without popping the breaker. So yes it will only be an issue if one chooses to get a permit. I presume if one signs that waiver, Nissan will just give you the Level 1 chord and it will become the users problem.
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Re: Level 2 Charger Confusion

Sun Jul 11, 2010 12:07 pm

16x1.25=20 in my "calculator" (not the "magic 19" :) you "found"). And that's the proper limit (16A) to be pulled per NEC625 (80% of breaker rating for continuous loads). Unfortunately L1 EVSE will probably only pull 12A (assuming a 12x1.25=15A breaker).

(5/4 = inverse of 4/5, or 1.25 = inverse or 0.8)
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