First thing that you have to understand is that the None of the level 1 or 2 devices are chargers. They are electrical interfaces from the building electrical to the cars electrical. The job of charging or best said controlling the charging is under the hood in the car. So that the efficiency is derived in the cars charging unit. It is somewhere around 86%. That means 86% of the power goes to the battery the rest is in converter losses in the power systems of the charger. That is why it take about 12.5 KWh to charge from the wall and about 10.5 goes into the battery. The various level 1 and 2 interface devices only use 3 to 5 watts in themselves to run the line control and safety circuits.

I use a level 2 device, because it is more efficient from a use point of view in that I can get a fairly fast partial charge if I need it.

Hope I was helpful...
Pat

 

I bought the SPX charger and am REALLY happy with it. I spoke with a GM engineer about this and it is my understanding that the Level 2 Charger (or Electrical Interface if you prefer) is up to 25% more efficient, especially in extreme temperatures. This is because a portion of the electrical energy will be used to keep the battery at a 'healthy' temperature.

Let's say that at a REALLY cold temperature, the Volt uses 500 watts to keep the battery at a 'healthy' temperature. With a 110V line, you have 1500 watts - 500 watts = 1000 watts available to charge. With a 220V line, you have 3000 watts - 500 watts = 2500 watts available to charge. 2500 watts is more than double 1000 watts, even though the amount being metered out of your house is exactly double (3000 watts vs. 1500 watts).

This can be seen in charge times: A 220V "level 2" charger has double the power output as a typical wall socket, and yet it can take up to 2.5 times as long to charge on a 110V line vs. a 220V line (10 hours vs. 4 hours). I observed this in the winter when it was in the mid-20's at night, and my Volt took over 9 hours to charge from a nearly depleted state on a 110V line.

I have had a level 2 SPX Voltec charger installed on the side of my house and consider it well worth the money. I often come home for a lunch break in the middle of the day, and am now able to get 5-6 miles of extra charge, which allows me to drive gas-free every day. On the 110 line, it was more like 2 miles at the most on my lunch break, and the gas engine would sometimes kick-on on the way home. If you're in south Jersey, I can send my electrician your way to install one. It only cost me about $500 (but I didn't need any long line or fancy work).

 

With a 110V line, you have 1500 watts - 500 watts = 1000 watts available to charge. With a 220V line, you have 3000 watts - 500 watts = 2500 watts available to charge. 2500 watts is more than double 1000 watts, even though the amount being metered out of your house is exactly double (3000 watts vs. 1500 watts).

To be picky, Level 1 charging is 1440 watts @ 120V (L1 limited to 12 amps by J1772 standard). Level 2 charging is 3300 watts @ 240V (L2 being limited by the 3.3 kW charging capacity of the on board charger). So the differences are actually greater than the above example.

If addition to thermal management load, there's the drain to run the charger. I believe it's the same wattage at 120V vs 240V, so just like with thermal load it's a higher percentage of the 120V charging ability.

The way I think about the two charge levels is at Level 1 you charge at 4 MPH, and Level 2 you charge at 10 MPH. That is to say, you get 4 miles or 10 miles of additional range per hour of charging (roughly).

 

I hadn't heard about the cold temperature power diversion but I do know that GM has said that 240V charging is more efficient because the power electronics are used less. IOW there isn't any greater draw with 120V charging -- in fact the draws are the same -- but the draw is longer for the 120V because the charging takes longer. I don't think they've released an official number but I doubt it would be more than a percent or so.

 

Thanks for the info. I truly appreciate the knowledge!

 

From the figures I've seen reported, at most the 240V charger saves you something like 0.5-0.8 kw-hrs per full charge. Not enough to offset purchase + installation costs, just from the efficiency factor, even over 10+ years. The scenario where it's worth considering getting the fast charger is if your driving habits are such that you both can top off sometime during the day for some non-insignificant range increase and need that top-off to stay in the all-electric range and would do this enough to make it worthwhile, or you are just extremely concerned about staying all-EV (and then in this scenario why didn't you get the Leaf?)

I personally would benefit from being able to top off maybe once a month at most, so I am just going to stick with the 120V. I think that's going to be true for a lot of people. For people with longer commutes, what you really want is for your employer to provide charging at work; 240V at home isn't going to add significant value or convenience. Even for Room_A113's scenario of coming home for lunch, to me it's not really worth it if you can only charge for half an hour. You get an extra 4 miles of range, for saving something like 0.05-0.10 gallons of gas each time you do this? You might be able to squeeze out that extra range just driving slower on the freeway.

Now if it were some scenario where you could charge for say 1.5 hrs, then it could be worth it if you do it on a regular basis and drive 50-60 miles per day.

 

From the figures I've seen reported, at most the 240V charger saves you something like 0.5-0.8 kw-hrs per full charge. Not enough to offset purchase + installation costs, just from the efficiency factor, even over 10+ years. The scenario where it's worth considering getting the fast charger is if your driving habits are such that you both can top off sometime during the day for some non-insignificant range increase and need that top-off to stay in the all-electric range and would do this enough to make it worthwhile, or you are just extremely concerned about staying all-EV (and then in this scenario why didn't you get the

For people with longer commutes, what you really want is for your employer to provide charging at work; 240V at home isn't going to add significant value or convenience. ...

Now if it were some scenario where you could charge for say 1.5 hrs, then it could be worth it if you do it on a regular basis and drive 50-60 miles per day.

If you have a time of use meter and rate, the shorter time of the 240v let's you stay in the lowest rates during the summer. With just 120, I will be 40% of my charge at a higher rate. That pays for the EVSE over time.

 

Both charge cords generate heat loss (the copper gets pretty darn warm). Since 240V charging takes less time, it loses less heat and (for this reason too) it charges more efficiently.

 

Generally higher voltage translates to better energy transport in terms of efficiency. At 240V, the voltage doubles while current only increases from 15A to 20A (less than 40% increase), so the voltage increase should well compensate the current increase.

 

I'll defer to the others on the electrical efficiency, but don't overlook the value of the time efficiency as well.

I use the Voltec at home and the 110V at work everyday. It is much faster and simpler to unplug the voltec, store the cord and go than it is to unplug the 110v from the car and the wall and wind it up and put it back in the storage compartment.

I also get good use of convenience charging if the wife and I go out for dinner, most restaurants are much closer than my work, but if I didn't have an hour or so to charge when I got home before we head out I would end up using some gas, where with the Voltec I don't.

 

Someone made a comment about the EVSE getting warm, apparently the Volt's EVSE uses smaller gauge wire and is lighter duty then the Leaf's EVSE.. and the cost is similar, something you may want to keep in mind if you want to get a spare unit. Volt uses #16 wire and the Leaf's uses #12.. IMO, #16 wire is awfully thin for such an expensive device.

You can buy a modified Leaf EVSE that can plug into 240V or 120V here:

http://evseupgrade.com/

 

You can buy a modified Leaf EVSE that can plug into 240V or 120V here:

http://evseupgrade.com/

Has anyone successfully tried using a Leaf (original or upgraded) portable charger with a Volt? I think I read a posting by someone at the main Leaf forum site that claimed it didn't work with the Volt because of some timeout problem during the initial charging "handshake".

 

Isn't there also a constraint on pre-conditioning the cabin using 120V? I seem to remember reading that pre-conditioning could actually outrun the 120V supply and cause some battery drain while still plugged in, but that the same wouldn't happen on 240V.

I had a ClipperCreek charger installed yesterday- the new LCS model rated for 240V, 20 amp charge rate (25 amp circuit). But I don't actually have a Volt to plug it into yet!

 

You are correct, if it is very warm or cold, the battery temperature maintenance will take more than the 1400W that the L1 system can deliver. You will actually see the battery level drop by 2-4% and then it will take 15-30 minutes to recharge the battery. With L2 the battery seems to be fully charged just a couple of minutes after the battery maintenance finishes, so it must be "keeping up".

 

240 is best, but the beauty of the Volt is whatever works for you is what is best - you have a choice. I only used 110 for the first month or so and finally put 240 in my home garage so it could be charged in a shorter time. I just got the building where my office is to agree to install a charger in my reserved space in the garage. They will pay for the installation and the electricity and I furnish the Voltec Level 2 Charger. Sounds like a deal to me.
#2499

 

As far as I know, all rechargeable batteries charge most efficently at their high charge rate limits (all conditions concidered) from a minimum charge level, until near a full charge.

 

Most li-ion chemistries charge most efficiently at about 1C. Which would be 16kw for the Volt battery. However, most efficient charge rate is definitely not the best charge rate for longevity of the battery.

 

Another reason in favor of L2 charging is that "off-peak" electric rates - at least in California - go from midnight to 7am. A full charge using L2 takes ~4 hours (or even LESS). However, a full L1 charge can take up ~10 hours (or MORE, even as much as 12 hours. To stay comfortably within the "off-peak" rates, L2 charging is a slam dunk guarantee!

 

That's the reason I decided to get level 2. My utility has a peak time for 4pm to 8pm. With the level 1 charge taking up to 10 hours, I was too often not getting a full charge by the time I had to leave in the morning.

 

To further complicate things, my OEM charger charges my car in 13 hrs at 12 amps. I just ran a new circuit outside for 240 volt for under 90.00 and 2-3 hrs of work. I plug in my car and it charges last night in 5 hours using the charger that came with it. I’m happy!!’ Then I noticed the wire with the charger was only 16 gauge which is not enough for the 16 amps L2 is supposed to draw. Here’s where it gets funky.

I put an amp meter on the circuit and it’s only drawing 11.5 amps at 240 volts. What happened to 16 amps for level 2? Yes I’m using the stock charger but why does it charge in less than half the time at the same amps? What will happen if I buy a real L2 charger that charges at 16 amps? Will the car charge in 3-5 hours?

 

I think you got your question answered in the other thread you started but bottom line is that I believe you have a Gen 2. The EVSE that came with you vehicle can run at 120V or 240V (with a pigtail) which you are apparently using. The EVSE is not a charger. The EVSE is limited to 12A in either configuration.

The charge is inside by bumper of the car. It is limited to a Max 240V 16A. Therefore if you want to get the full charge rate out of the onboard charger then you will need to purchase an EVSE rated at 240V and 16A or greater.

 

kuykenr71: are you saying you are pushing 240VAC into the stock Level 1 charger that is really only designed for 120VAC?

 

On reading over this thread it seems to me the original poster's question has not really been answered properly. There is a lot of opinion and very little fact. The question was is Level 2 more efficient than Level 1?

The answer is yes, but by a relatively small margin - nominally 2-3%, but the efficiency gets better if you charge in small increments of power (in other words only use a few km and plug it in each time).

Here is a proper engineering study that provides you with the facts:

https://www.veic.org/docs/Transportation/20130320-EVT-NRA-Final-Report.pdf

From a winter driving perspective it has also been shown (I will post the link later) that if you enjoy pre-conditioning your vehicle then a Level 2 charger is MUCH more efficient at doing that.