Leaf Disclosure and trickle charging

[LeftieBiker]

...Finally as to inefficiencies and overhead, in our experience the trickle charge time actually needed is usually some 20% shorter than what our car computer says, so it's quite efficient for our needs.

:?: Why you consider the charging finishing a bit early to be "efficient" is a puzzle. Efficiency of charging has to do with how much of the power coming from the wall gets to the battery. Charging at 120 Volts, 12 Amps, is about 75% efficient. Charging at 240 Volts, 16 Amps is about 86% efficient. Charging a 2013 model at 27.5 Amps would be a bit more efficient than that, as will charging to 80%, as opposed to 100%. (The reason has to do with the fixed overhead to charging the car, involving pumps, cooling and the like. Shorter charging time, less overhead.)

If you want to make the argument that the cost of the electricity wasted with Level 1 charging is small compared to the cost of installing a Level 2 charge station, then few would disagree. The advantages of Level 2 charging have to do with speed and convenience. If you don't need much charge each day and don't need to preheat the car in a very cold climate, then trickle charging will suffice, as you have found.

In short, I'm quite satisfied with trickle, and would prefer Nissan not to pre-emptively define what gives me enjoyment. They should focus on tips and full disclosure on practices that increase battery and EVSE life, and of course driving range, and leave the specific consumer choices to the consumer.

Consider the possibility that some people buy the LEAF, expecting to use it for a 50+ mile commute using the supplied trickle charge EVSE (because that's what Nissan includes with the car, right?). How happy are they going to be when they find that they charge all the time and still can't seem to fill up the car? Nissan expected that LEAF drivers would use the Level 2 charging for which the car was designed and which was likely to provide a more satisfying user experience. The Level 1 EVSE was provided for opportunity charging where Level 2 was unavailable and Nissan didn't want new LEAF owners to assume that the very very slow trickle charge EVSE was the only way they could charge the car.

If you manage ok with Level 1 charging fine. But knocking Nissan for recommending against it, for quite valid reasons, seems unwarranted.

The problem with many of the above assertions is that they aren't true. I use 120 volt charging only, and have no trouble with my 45-50 mile commute three days a week. Some of you are instantly assuming that I start with a 100% "buffer" the first day and have less left every day, but nope, I get to my desired 90-95% charge on all three of those days, with about 5-6 hours left over. If I actually wanted to charge to 100% it might take just about all of the down time, but there is no need to charge to more than 83% or so for a 50 mile commute at mixed speeds, and that includes both not using the last 20% and leaving a 10% reserve for unexpected side trips. I only charge to 100% by accident, and have no range anxiety at all. I use an outlet strip (not a surge protector) for the EVSE, and leave it on when not in use. If I ever did need to turn it off, I'd use the strip. Nothing gets more than "warm" in the charging setup, and this is during one of our Hottest Summers ever. During my off days I charge to 80%.

 

[cgaydos]

All explanations sound plausible, but none of them or even all of them combine do *not* IMHO rise to the level of the car maker writing black-on-white that they "do not recommend" using trickle-charging as the predominant mode. Unless some other evidence comes to light, this is not a truthful description of reality on the part of Nissan.

I am not usually one for conspiracy theories, but I have long suspected that Nissan is required to say this by their contract with AeroVironment.

Sounds plausible to me. Also plausible is that the AeroVironment contract prevents Nissan from offering a dual-voltage EVSE like the EVSEupgrade.

Another possiblility (and these are not mutually exclusive) is marketing-related. By calling L2 a "Normal" charge and by discouraging L1 they are saying that the "Normal" charge time is 6-7 hours from low battery (2011/2012, 2013 S) or 3.5-4 hours (2013 SV/SL). This encourages people in the press to write articles using the shorter durations instead of the longer ones.

That may seem a bit over-the-top until you consider how the EPA saw that 80% charge was recommended and degraded the 2013 range estimate from 84 to 75 as a result.

 

[dgpcolorado]

The problem with many of the above assertions is that they aren't true. I use 120 volt charging only, and have no trouble with my 45-50 mile commute three days a week. Some of you are instantly assuming that I start with a 100% "buffer" the first day and have less left every day, but nope, I get to my desired 90-95% charge on all three of those days, with about 5-6 hours left over. If I actually wanted to charge to 100% it might take just about all of the down time, but there is no need to charge to more than 83% or so for a 50 mile commute at mixed speeds, and that includes both not using the last 20% and leaving a 10% reserve for unexpected side trips. I only charge to 100% by accident, and have no range anxiety at all. I use an outlet strip (not a surge protector) for the EVSE, and leave it on when not in use. If I ever did need to turn it off, I'd use the strip. Nothing gets more than "warm" in the charging setup, and this is during one of our Hottest Summers ever. During my off days I charge to 80%.

Yes, it can be done if you are willing to work at it. But how about five days a week at 50 miles? And what are you going to do in winter? You are in for a big surprise if you try to do back to back 50 mile days in winter on nothing but trickle charge. I'll check back with you in February and see how it is going.

 

[davewill]

The facts are that for most people with a standard commute (not able to charge at work), 120v charging means that they can't use the car to its maximum range multiple days in a row. That, all by itself, says to me that Nissan wouldn't/shouldn't "recommend" it. There's no real need to look for too many other reasons.

 

[LeftieBiker]

Yes, it can be done if you are willing to work at it. But how about five days a week at 50 miles? And what are you going to do in winter? You are in for a big surprise if you try to do back to back 50 mile days in winter on nothing but trickle charge. I'll check back with you in February and see how it is going.

Some people really hate good news, apparently. If I can do three days a week with no decline in charge each day, I could do five...or seven. Did you not read that I can easily charge to 95%, or were you in such a hurry to naysay that you skimmed right over it? A 50 mile commute in Winter in most climates shouldn't require 95%, much less 100%. And if it does, it's an unsafe distance to begin with. If you mean "50 miles at 70MPH with the heat blasting" then I suggest you slow down in Winter, and use the seat heaters more and the heater less. I'd suggest slowing down even if you drove an ICE. Finally, while my present regime requires going out in the evening to reset the charge limit (Now there's something that needs to be added to CarWings!), I can also use the charge timers to start the charge at about 10:00AM, and it will be at 95% when I leave for work. If I didn't care about charging to 100% and letting it sit a few hours, I'd have no extra effort at all.

 

[Reddy]

Lots of previous threads on L1 trickle charging:
http://www.mynissanleaf.com/viewtopic.php?f=34&t=10776&p=247635#p247635
As others have said, yes you can do it. Less than 50 mi RT daily is pretty easy (although winter is more of challenge depending upon temps, hills, etc.). More than 50 mi RT daily is more difficult and will likely require a hypermiler, slower driving, and 16 hr charging. YMMV and your comfort point will also vary so don't take the 50 mi recommendation as absolute. You will need a "nearly" dedicated 15 amp circuit (20 amp is better). No, you can't have a fridge/freezer on the same circuit because it they will start and stop randomly throughout the day. Lights, partial use computers, electric tools, etc. are probably ok as long as you remember to not use them at the same time as charging the Leaf. Since I charge at night for only a couple of hours, I'm sleeping and not running the electric lawn mower, weed eater, skil saw, drill press etc. during my Leaf charging. It hasn't been a problem for me in nearly two years. I plan on using this method for another 20-30 yr.

 

[Assaf]

Hi all,

Thanks for chiming in to my question (re: Nissan's recommendation in the driver booklet against L1 charging). Sorry if it has caused tones to slightly escalate; we are all friends here, right?...

I stand corrected regarding efficiency; it makes sense that pure electric efficiency (% of the KWh consumed that actually goes into the battery) is better with L2. It was more a linguistic error on my part: I thought about *effectiveness*. When my 'hours to 100%/80%' show say 10 hours, it usually ends up being 8 or so. So it is a rare occasion for us (light Leaf users, ~15 miles/day average) to fall far behind via the trickle. Clearly your daily pattern will dictate your needs.

My only beef with Nissan is that when you read recommendations in the driver's booklet, you assume these are either safety or car-longevity related. If Nissan wants to make lifestyle or consumption-economy recommendations, they should clearly describe them as such. Part of proper customer orientation IMHO. The net end result of the way they framed their recommendations (as well as the general public impression), is to my guess, a certain chunk of EV drivers who installed an L2 but don't really need it.

 

[Nubo]

Thanks to both of you for your responses.

All explanations sound plausible, but none of them or even all of them combine do *not* IMHO rise to the level of the car maker writing black-on-white that they "do not recommend" using trickle-charging as the predominant mode. Unless some other evidence comes to light, this is not a truthful description of reality on the part of Nissan.

It's not a description of reality, it's merely a recommendation.

Imho, this thread exemplifies the reasons to recommend against L1 charging. There are too many instances of sub-par wiring or overloaded circuits, and too many people who aren't familiar enough with electricity to recognize the problems. L1 charging for up to 20 continuous hours is at the extreme end of duty a homeowner puts on a 120V outlet.

What I'm curious about is the insistence on not having a fuse box. There are fairly modern fuse boxes out there that were still being installed after circuit breakers made their way into the home wiring scene. There are also circuit breakers that will screw in as replacements for fuses...

Again, it's a recommendation not an evaluation of your particular situation. Presence of a fuse box just means it's much more likely that the wiring is old and may have problems such as ungrounded outlets, or presence of knob-and-tube wiring. Nissan is wise to give such a recommendation. If you know your wiring is up to the task then no problem. This is exactly why they also recommend the services of an electrician -- someone who can accurately assess a specific home's situation and make sure they have a safe charging setup.

None of this means L1 is inherently dangerous, but from the manufacturer's standpoint use of L2 makes it much more likely that the homeowner will be using a dedicated circuit that was properly installed. Also, as mentioned, L1 makes more extensive use of coolant pumps in the car and that may also be a wear consideration.

 

[Assaf]

@Nubo: Oh, needless to say using L1 or any EV charging on antiquated circuitry is unsafe. And the booklet is *very* clear on that part.

As to overloading a 120V circuit: I beg to differ regarding the risk and the uniqueness of doing that. People nowadays have plenty of appliances that use a few amps each for hours at a time (large-screen TVs and other electronics come to mind). The L1 with its actual current of 11-13A, typically drawn for 10 hours or less (rather than 20 as you write) and mostly during off-peak hours, is really not the end of the world - even for a 15A breaker and certainly for a 20A one. Especially if you use modern circuitry as you should.

From all I've read here, I haven't heard a real justification for Nissan to *recommend* L2 over L1 to you inside the driver's booklet. L2 being faster is a no-brainer. It is not substantially better for your car or for your home electrical system. A purely consumer decision, IMHO, dictated by your driving needs.