EVSE Home Assessment Reports

[EVDRIVER]

evnow,

Yes, I would think the level 1 charge capability might have multiple uses. Whenever is is used, the amount of power it consumes from the 20A circuit will be significant.

Steve

Folks can install whatever they desire in their garages, and are free to over-install. I understand that completely - I ran heavier wire for the 220 circuit when I wired my garage just in case I upgraded my MIG welder at some point.

But there is no reason to allow for more than 12A for the Leaf because that's all the EVSE will allow to car to use. Basic L1 charge: 12A. L1 charge and run the AC to precool the cabin: 12A. L1 charge and turn the heater on full: 12A.

Sure - if one wanted to have a 20A circuit in the garage (air compressor? huge beer fridge? hacked EVSE to draw 16A?) they can - but let's make that clear that we're choosing to overspec so that new folks don't read that as 'the Leaf needs a super-circuit'...

Andy

If the Leaf is going to pre-heat the cabin on 120 it will have to shut the charger completely off, on low the heater will need to pull at least 1500 watts, I would expect the Leaf heater to be at least 4kw on high.

 

[muus]

but let's make that clear that we're choosing to overspec so that new folks don't read that as 'the Leaf needs a super-circuit'...

Exactly! I'm sure Aerovironment is suggesting a 20A dedicated circuit because it doesn't cost much more than a 15A circuit and the plug looks slightly different (the neutral is a sideways 'T'). It will avoid the chance that the breaker trips if people try to power something else from the same plug (which will happen). Don't forget, the car can be charging for 19 hours so if there is something else on the same circuit, chances are, at some point that other appliance will be turned on and then "click" goes the breaker. Think of it this way, you plug-in your car when you get home at 5:00 pm expecting your car to get a 14 hour charge so the battery is toped up for 7:00 am. During the night the dehumidifier, which is on the same circuit, turned on and the breaker tripped. You get up the next day and the battery doesn't have a sufficient charge to get you to work.

That is why Nissan is recommending a dedicated circuit and to be safe, make it 20A. It is not a necessity nor a legal requirement. I personally agree with the overspec point of view, which is why I ran a 3 gauge wire to my garage (I only needed 10 feet). I’ll be able to charge two cars from that. If I were running a new dedicated 120v circuit, I would make it 20A, but I wouldn't bother unless that would be the only way I could charge the car. Remember, most times you'll be using the EVSE.

Again, lets try to make this clear, ANY 120v plug can be used to charge the Leaf IF nothing else is on the same circuit. If you are plan on running a new 120v circuit, spend an extra few bucks and make it 20 amps.

 

[mitch672]

evnow,

Yes, I would think the level 1 charge capability might have multiple uses. Whenever is is used, the amount of power it consumes from the 20A circuit will be significant.

Steve

Folks can install whatever they desire in their garages, and are free to over-install. I understand that completely - I ran heavier wire for the 220 circuit when I wired my garage just in case I upgraded my MIG welder at some point.

But there is no reason to allow for more than 12A for the Leaf because that's all the EVSE will allow to car to use. Basic L1 charge: 12A. L1 charge and run the AC to precool the cabin: 12A. L1 charge and turn the heater on full: 12A.

Sure - if one wanted to have a 20A circuit in the garage (air compressor? huge beer fridge? hacked EVSE to draw 16A?) they can - but let's make that clear that we're choosing to overspec so that new folks don't read that as 'the Leaf needs a super-circuit'...

Andy

If the Leaf is going to pre-heat the cabin on 120 it will have to shut the charger completely off, on low the heater will need to pull at least 1500 watts, I would expect the Leaf heater to be at least 4kw on high.

I doubt it, it will just be "drawing down" the battery pack charge, no need to stop the charging.
This is why I say Nissan won't recomend preheat/precool unless you have the 240 L2 EVSE, and even then, you will still be drawing down the battery a bit.

 

[steveD]

Muus,
You are right on. I did not mean to be agreeing with Andy's comment that 20a is unnecessary, but that I wanted to learn where he got info about the consumption of the level 1 charger. My sources tell me it is higher than 12a.
Steve

 

[garygid]

Steve,
A Level 1 EVSE can be made to "offer" 16 amps, but it should not be used on a 15-amp circuit.

The Nissan L1 EVSE will PROBABLY offer just 12 amps, so it can be legally used on a 15-amp (or a 20-amp) circuit.

What additional "info" does your source provide, please?

 

[LEAFer]

I personally agree with the overspec point of view, which is why I ran a 3 gauge wire to my garage (I only needed 10 feet). I’ll be able to charge two cars from that. If I were running a new dedicated 120v circuit, I would make it 20A, but I wouldn't bother unless that would be the only way I could charge the car. Remember, most times you'll be using the EVSE.

Yes, but that "extra" dedicated 20A circuit might still be a good idea. It provides your "Plan B" in case the EVSE fails and can't be repaired quickly enough. If there's already an existing 15A or 20A available ... then that's your "Plan B". But for newbies that don't have a L1 120V outlet nearby ... they should install one. ( I am assuming an enclosed garage and no use of an extension cord for Plan B. )

 

[muus]

Yes, but that "extra" dedicated 20A circuit might still be a good idea. It provides your "Plan B" in case the EVSE fails and can't be repaired quickly enough. If there's already an existing 15A or 20A available ... then that's your "Plan B". But for newbies that don't have a L1 120V outlet nearby ... they should install one. ( I am assuming an enclosed garage and no use of an extension cord for Plan B. )

Fully agree with you, but who doesn't have a 120v plug in their garage? Also, since the electrician is already there, it wouldn't cost much more to add a new 120v 20A circuit. The only time I would avoid doing so is if you know you already have a good 120v circuit (like I do) or if there is no more space in your pannel. I wouldn't upgrade your breaker pannel just to add a new 120v circuit.

 

[muus]

My sources tell me it is higher than 12a.

I would also be interested in knowing where this information comes from. Everything I've read up to now indicates that the Leaf will only draw 12A with the emergency cable. I've done some searching but all I could find is the following, supposedly obtained from Mark Perry of Nissan.

In an average situation, a standard household outlet is rated at 110 volts/15 amps, although most people won’t get more than 10-12 amps out of that outlet. So, what that means is that the outlet will put out about 1.1 kW of power and it would take about 22 hours to get the LEAF battery from 0% to 100% full; clearly not a realistic daily charging situation. “So that’s why we think the Level 1 really is just there for that emergency,” said Perry. “In an hour under level 1 charging you might see 4 or 5 miles of additional range added to the battery pack.”

http://gas2.org/2010/05/27/nissan-leaf-will-include-fast-charge-capability-and-emergency-charging-cable-at-launch/

 

[AndyH]

evnow,

Yes, I would think the level 1 charge capability might have multiple uses. Whenever is is used, the amount of power it consumes from the 20A circuit will be significant.

Steve

Folks can install whatever they desire in their garages, and are free to over-install. I understand that completely - I ran heavier wire for the 220 circuit when I wired my garage just in case I upgraded my MIG welder at some point.

But there is no reason to allow for more than 12A for the Leaf because that's all the EVSE will allow to car to use. Basic L1 charge: 12A. L1 charge and run the AC to precool the cabin: 12A. L1 charge and turn the heater on full: 12A.

Sure - if one wanted to have a 20A circuit in the garage (air compressor? huge beer fridge? hacked EVSE to draw 16A?) they can - but let's make that clear that we're choosing to overspec so that new folks don't read that as 'the Leaf needs a super-circuit'...

Andy

If the Leaf is going to pre-heat the cabin on 120 it will have to shut the charger completely off, on low the heater will need to pull at least 1500 watts, I would expect the Leaf heater to be at least 4kw on high.

You're assuming that it'll try to pull full power for the heater from the 120V line, aren't you? Did you forget about the 24kWh battery pack?

The ability to preheat or precool from the pack has already been demonstrated in another thread.

Sorry!

 

[AndyH]

Andy,

Good info, can you tell me where you got your numbers. We are going by Aerovironment information regarding circuit needs.

Steve

Steve,

Are you quoting info direct from AV on what their L1 device draws, or what they recommend for a dedicated circuit, or what the rep and/or electrician recommended? Three different cases.

The two data points I have for L1 EVSE come from Nissan's statements that the included L1 device can be used in any normal household outlet. That's pulling 12A from a 15A circuit. The second comes from the Clipper Creek L1 device referenced here: http://www.mynissanleaf.com/viewtopic.php?p=10500#p10500 This is also designed to pull a max 12A from a normal 15A outlet.

Universal and/or emergency use is severely limited if the devices will only work when connected to a 20A outlet.

The benefit of a 20A outlet - dedicated or not - is absolutely there and already covered beautifully. We'll have to use a standard outlet for the EVSE, though, or use the EVSE with an adapter...

Andy

 

[AndyH]

but let's make that clear that we're choosing to overspec so that new folks don't read that as 'the Leaf needs a super-circuit'...

Exactly! I'm sure Aerovironment is suggesting a 20A dedicated circuit because it doesn't cost much more than a 15A circuit and the plug looks slightly different (the neutral is a sideways 'T'). It will avoid the chance that the breaker trips if people try to power something else from the same plug (which will happen). Don't forget, the car can be charging for 19 hours so if there is something else on the same circuit, chances are, at some point that other appliance will be turned on and then "click" goes the breaker. Think of it this way, you plug-in your car when you get home at 5:00 pm expecting your car to get a 14 hour charge so the battery is toped up for 7:00 am. During the night the dehumidifier, which is on the same circuit, turned on and the breaker tripped. You get up the next day and the battery doesn't have a sufficient charge to get you to work.

That is why Nissan is recommending a dedicated circuit and to be safe, make it 20A. It is not a necessity nor a legal requirement. I personally agree with the overspec point of view, which is why I ran a 3 gauge wire to my garage (I only needed 10 feet). I’ll be able to charge two cars from that. If I were running a new dedicated 120v circuit, I would make it 20A, but I wouldn't bother unless that would be the only way I could charge the car. Remember, most times you'll be using the EVSE.

Again, lets try to make this clear, ANY 120v plug can be used to charge the Leaf IF nothing else is on the same circuit. If you are plan on running a new 120v circuit, spend an extra few bucks and make it 20 amps.

Hmmm...what's the possibility that we're mixing things up here? Nissan's recommendations for 20A and/or 40A are for the Level 2 unit - not the 120V level 1 EVSE.

 

[evnow]

Andy,

Good info, can you tell me where you got your numbers. We are going by Aerovironment information regarding circuit needs.

Steve

Steve,

Are you quoting info direct from AV on what their L1 device draws, or what they recommend for a dedicated circuit, or what the rep and/or electrician recommended? Three different cases.

If I read correctly, Steve is an assessor/installer for AV ...

 

[AndyH]

If I read correctly, Steve is an assessor/installer for AV ...

That's fine - I mean no disrespect.

I'm raising the BS flag on the dedicated 20A thing, then.

Dedicated 20A 240V circuit for hard-wired Level 2 EVSE to support the on-board 3.3kW charger: Yes!
Dedicated 40A 240V circuit for hard-wired Level 2 EVSE to support future guess 6.6kW charger: Yes!
Requirement for a dedicated 120V 20A circuit for the L1 connection: No way.


Edit: added L2 clarification

 

[Dav]

He didnt' say it was a requirement, legally or to code.

All he said is that that is what AV is telling him he is supposed to do as their subcontractor. Quite a difference.

 

[AndyH]

Absolutely - which is why I asked the clarifying question.

 

[garygid]

20-amp breaker for Level 1, this useful way:

Since the LEAF will accept 15 (or maybe 16) amps at 240v (Level 2) it is easy to suspect that it MIGHT also accept the same currents (if offered) when doing 120v (Level 1) charging.

So, if SOME Level 1 EVSE had a 12/16 switch on it (Nissan's probably not, but easily could), or there was a 16-amp model, the 20-amp circuit would be quite useful, with 33% faster Level 1 charging.

 

[AndyH]

20-amp breaker for Level 1, this useful way:

Since the LEAF will accept 15 (or maybe 16) amps at 240v (Level 2) it is easy to suspect that it MIGHT also accept the same currents (if offered) when doing 120v (Level 1) charging.

So, if SOME Level 1 EVSE had a 12/16 switch on it (Nissan's probably not, but easily could), or there was a 16-amp model, the 20-amp circuit would be quite useful, with 33% faster Level 1 charging.

I appreciate this 'what if' Gary, but the facts we have so far are that the standard units will not have a switch or a user-operated 16A draw from a 20A circuit option. Clipper Creek, for example, has a L1 12A device in UL testing now. They CAN make a 16A version if there's sufficient demand, but it'll be a separate unit hard-coded for 16A.

We have ZERO info that any L1 product on the market or planned for the near term will draw more than 12A.

Andy

 

[DaveEV]

We have ZERO info that any L1 product on the market or planned for the near term will draw more than 12A.

Uh, see your earlier post:

http://www.mynissanleaf.com/viewtopic.php?p=10500#p10500

According to you, CC is working on a L1 20A EVSE.

 

[garygid]

If one is trying to specify (or suggest) a circuit that will support ANY J1772-defined Level 1 EVSE (both the 12 and 16 amp-max models), then a 20-amp breaker would be "required".

I cannot see the future, but I an not bound by "today".

If useful and allowed by the standards (and a max-amp selector "switch" is allowed), it is POSSIBLE (I suspect likely) that somebody will build it.

 

[LEAFer]

I think the 20A dedicated circuit suggestion/requirement/whatever is for 120V, not 240V. It is to be used for either backup ("Plan B" in case AV installed L2 EVSE fails) or simple verification in conjunction with the Nissan provided emergency L1 EVSE.
(The only reason the suggestion is made to be 1] dedicated and 2] 20A breaker, even though only 12A will be drawn, is "For Dummies" ... to distinguish it (isolate its purpose), and to prevent circuit breaker "popping" (no other loads).