Aerovironment EVSE install information

[EVDRIVER]

Both sides of the Charger/Extension cord debate are right, but it is not a meaningless semantic debate (like whether you say "data is" or "data are").

The prices for all of the EVSEs are exorbitant. I am sure that the subsidy, scale issues, and opportunity play a factor, but $2,300 or more is craziness.

When you call it a charger, the price seems more fair, because you imagine all sorts of complicated components like inverters and controllers.

When you recognize it as a gussied-up extension cord with a relay, then it makes it harder for the companies to sell the price.

We are all on the same side here, and we should keep the pressure on AV, Leviton, and the others to produce EVSEs that are cheap enough to be ubiquitous. At the current prices, they just feed the media/social dialogue that the electric car charging infrastructure is too expensive.

Sorry,

data and data are pronunciation differences and are the same, extension cord, charger cord are all fine but it is in NO WAY a charger in any sense and to use that term is confusing and ignorant once one knows better. Call it a charger cord, a power cord, charging cord dock or EVSe but please don't call it a charger as it only confusing people further and spreading ignorant terminology. You certainly don't call a PFC-30 an EVSE, or charge cord or call the Leaf's actual charger the same.

 

[palmermd]

This is probably a bad analogy, but I'm going to try anyway. When you fill up your car, you don't say you are going to the oil refinery to fill up, you say your going to the gas station. These are two very different things, and they have different names. Both are required in order for you to gas up your car, but you do go to the gas station and not the oil refinery to do it. How do you know the difference? People have used the correct term for each of these for a while and it became common knowledge. EVSE and Charger are both required to charge up your car, but they are very different things, and should be call by the correct names as well. If we use the correct term people will learn to call them what they are. By mixing names, it will only continue to be confusing.

I'm not saying that one is like the refinery and one like the station. I'm only using two related things for gas cars and two related things for ev's.

 

[DeaneG]

Funny thing: I selected the high power charging port when I requested a quote for my Leaf.

Now I realize that I'm going to have to explain to my wife that the L1 or L2 thing on the wall in my garage is NOT a charger, but the big DC ("L3") box we will plug into in when visiting San Francisco IS a charger. Or I can just call them BOTH chargers, and somehow live with with the burden of perpetuating a falsehood

 

[EVDRIVER]

Funny thing: I selected the high power charging port when I requested a quote for my Leaf.

Now I realize that I'm going to have to explain to my wife that the L1 or L2 thing on the wall in my garage is NOT a charger, but the big DC ("L3") box we will plug into in when visiting San Francisco IS a charger. Or I can just call them BOTH chargers, and somehow live with with the burden of perpetuating a falsehood

It's simple, there are on board chargers and ones that are not. The cord that supplies the power is just that, a cord and nothing more. It may supply AC or DC but it is not a charger. Just tell you wife it's a charge cord and in both cases that is correct. Anyone that want's to understand the difference will the 30 seconds to understand the concept and continue to refer to the devices correctly.

 

[DeaneG]

"Charging cord" is perfect. Life is too short for acronyms anyway.

 

[evnow]

Funny thing: I selected the high power charging port when I requested a quote for my Leaf.

Now I realize that I'm going to have to explain to my wife that the L1 or L2 thing on the wall in my garage is NOT a charger, but the big DC ("L3") box we will plug into in when visiting San Francisco IS a charger. Or I can just call them BOTH chargers, and somehow live with with the burden of perpetuating a falsehood

In a couple of years when you need to change that port .... never mind.

 

[EVDRIVER]

Funny thing: I selected the high power charging port when I requested a quote for my Leaf.

Now I realize that I'm going to have to explain to my wife that the L1 or L2 thing on the wall in my garage is NOT a charger, but the big DC ("L3") box we will plug into in when visiting San Francisco IS a charger. Or I can just call them BOTH chargers, and somehow live with with the burden of perpetuating a falsehood

In a couple of years when you need to change that port .... never mind.

Or just get an adaptor. At least the wiring will be there.

 

[johnr]

"Charging cord" is perfect. Life is too short for acronyms anyway.

Ok, I can go along with that - but those "charging cord" manufacturers won't be too happy to hear it called that - it would be hard to justify their exorbitant prices :lol:

This is kind of like how you charge a cell phone. The power adapter you plug in to a wall outlet to recharge your cell phone is not a charger, although people call it that all the time. The actual charger is built in to the phone. The power adapter only converts the voltage to something more suitable, but the charger inside the phone is what regulates the amount of power going to the battery and shuts it off when the battery is fully charged.

The EVSE for an electric car is similar to that cell phone power adapter, except an EVSE doesn't even change the voltage, but it does provide safety functions and communicates with the charger that's inside the car to tell it just how much current to draw.

 

[EVDRIVER]

"Charging cord" is perfect. Life is too short for acronyms anyway.

Ok, I can go along with that - but those "charging cord" manufacturers won't be too happy to hear it called that - it would be hard to justify their exorbitant prices :lol:

This is kind of like how you charge a cell phone. The power adapter you plug in to a wall outlet to recharge your cell phone is not a charger, although people call it that all the time. The actual charger is built in to the phone. The power adapter only converts the voltage to something more suitable, but the charger inside the phone is what regulates the amount of power going to the battery and shuts it off when the battery is fully charged.

The EVSE for an electric car is similar to that cell phone power adapter, except an EVSE doesn't even change the voltage, but it does provide safety functions and communicates with the charger that's inside the car to tell it just how much current to draw.

The power adapter is the charger, it converts AC to DC and the phone has in effect the BMS. An EVSE does no voltage conversion. In a sense the phone adapter is like a L3 charger but it has no control circuit.

 

[planet4ever]

Hmm, maybe we should abolish the term "charger" altogether. I guess the most accurate statement would be that there is an EVSE, a rectifier, and a BMS. L3 differs from L1 and L2 in that the rectifier is outboard. I'm not an EE, but it is my impression that almost all of the weight, size, and energy loss is in the rectifier. The "power brick" between the wall plug and your laptop computer is a rectifier. It is (relatively) big and heavy, and generates heat. And that is for a comparatively tiny amount of electricity used by the computer.

It is the rectifier that I have been calling a charger.

 

[tps]

Hmm, maybe we should abolish the term "charger" altogether. I guess the most accurate statement would be that there is an EVSE, a rectifier, and a BMS. L3 differs from L1 and L2 in that the rectifier is outboard. I'm not an EE, but it is my impression that almost all of the weight, size, and energy loss is in the rectifier. The "power brick" between the wall plug and your laptop computer is a rectifier. It is (relatively) big and heavy, and generates heat. And that is for a comparatively tiny amount of electricity used by the computer.

It is the rectifier that I have been calling a charger.

While it is true that the switch-mode power supplies which are used in the on-board charger and laptop "power bricks" contain rectifiers, and the rectifiers exhibit a small forward-voltage drop which produces a small amount of heat, most of the weight, size and energy loss is not in the rectifiers, as they are only a part of the supply. A switch-mode supply usually contains an input rectifier to turn the AC to DC, then the DC is turned back to essentially pulse-width-modulated AC at a much higher frequency which goes through the isolating transformer, then it goes through another rectifier to convert it back to DC. Using a high switching frequency allows a smaller isolating transformer, while using PWM allows efficient regulation of the output voltage and current from a very wide range of input voltages.

 

[garygid]

Four major parts (I am an EE):

1. Power Connection: This is the connection from the AC Grid, sometimes with Safety (or other minor) features. It often includes wires, breakers, usage meters, timers, GFI, switches, and a "power cord". The L1 and L2 EVSEs are essentially specially designed, very Safety-Oriented, "Power Cords", which also include some minor intelligence and information communication to the EV "appliance".

2. Power Supply: Transforms the Grid AC to "controlled" DC appropriate to use for charging the battery. The Charge Controller might tell the Power Supply what DC voltage or current (or both) to produce. Most of the heat is produced here. The Power Supply is internal to the LEAF for L1 & L2, but external for L3. It is often in the Power Pod for most Cell-Phones.

3. Charge Controller: This is the HEART of the "charger" (of the charging process). The Battery Pack often has some associated Battery-Cell Monitoring System, which usually monitors the State of Charge (SOC) and temperature of the battery cells in some way. Using this information, the "charger" (charge controller) derermines how fast to charge, when to slow down, and when to stop. Sophisticated systems monitor each cell to protect and even "equalise" (or "balance") the cells to help keep the Battery Pack healthy and at maximum capacity. This is inside the LEAF for L1, L3, and L3 (QC) charging.

4. The Battery: The Battery Pack is often just called "the Battery", but it might consist of just one cell, several cells, hundreds of cells (the LEAF), or thousands of cells (the Tesla). This is the "e-tank" that the EV uses to hold the "e-fuel". Its care and health are critical to the EV's performance.

 

[EVDRIVER]

A typical EV has what is commonly called as a charger. This device converts AC to Sc and supplies the DC to the pack. The charger is more than a power supply in that it has control capabilities that allow the BMS (Battery Management System) that monitors the cells and other aspects of the charge process and talks to the charger letting it know what to do in terms of output, etc. Some aftermarket chargers have multiple sensor inputs for a few temp sensors, CAN control, and some basic functions as well as keeping track of kw in/out and running charge profiles. Most OEM EV chargers get this info from a BMS over CAN communication.

A charger is basically a smart power supply but it could be as basic as some diodes on a board. People mistakenly call an EVSE a charger because of the box at the wall end, that is simply a switch. If you remove the switch and do what people have done for years and use a cord then people would call it a power cord or charge cord because that is exactly what it is and it has no charge functions, it is supply equipment.

A charger has a specific role and it can be split into components but it must at least convert voltage or have voltage control capabilities like an L3 charger which supplies DC straight to the pack. It is possible to have a charger with no control as in the case of a "bad boy" charger but this relies on the user to monitor the pack for damage or is voltage matched for the pack to hit it's voltage knee at about 80%. If one tried to connect an EVSE straight to the pack it would not charger the car, so it is not a charger.

 

[DeaneG]

I'm going with "charging adapter" to my wife and friends.

 

[gasmiser1]

Gary-

In item #3, do you think the Leaf battery management system will monitor charge and equalize the cells for battery life longevity?

 

[mitch672]

I am not gary, but usually on the last %20 of charging (the "finish" charge), the cells are balanced by most BMS's.

 

[EVDRIVER]

I am not gary, but usually on the last %20 of charging (the "finish" charge), the cells are balanced by most BMS's.

Yes, and if the pack is not fully charged as it does not need to be it will not need BMS to equalize but to monitor for temp and failed cells only. The charger will not have bms features.

 

[smkettner]

I am not gary, but usually on the last %20 of charging (the "finish" charge), the cells are balanced by most BMS's.

Yes, and if the pack is not fully charged as it does not need to be it will not need BMS to equalize but to monitor for temp and failed cells only. The charger will not have bms features.

I don't think the pack is ever fully charged. Leaf just uses the middle 80% approximately. I might be wrong with these cells but I will say that a fairly deep discharge and "full" recharge is about the best shot for equilizing.

 

[mitch672]

Yes, it is believed Nissan is using from the low of %10 SOC to the high of %90 SOC (%80 capacity), so then the finishing %20 would be from %70-%90, get it?

 

[garygid]

I am not aware of any production EV or Hybrid that does full, individual cell balancing. However, that is primarily do the fact that I do not have access to that level of information. If you know of such information, I would like to read it.

The "Head in the Sand" approach (do nothing and hope) generally does NOT work well, but some battery systems still try it. Some have a special "equalize" operation that is just needed (they hope) occasionaly or rarely, but ... buyer beware, I think. Setting usage limits far from the "real" limits may delay the "unbalanced" problem (sometimes past the warranty), but generally does NOT eliminate it.

For good Battery Pack health, when using a battery chemistry that will NOT tolerate over-charging, and do not routinely get discharged "fully", there seems to be only a few main choices for this important task:

1. reduce the charging current into the "high" cells,
2. increase charging to the low cells,
3. bleed some charge out of "higher" cells (at any time),
4. "shuttle" some charge from high cells to low cells (can be done even when the battery is not being charged).

In any case, cells with:
1. a smaller capacity or higher SOC will tend to get "full" first, and tend to reduce or stop the charging.
2. a larger capacity or lower SOC will tend to lag behind and not get "fully" charged.

During use (discharge), those with smaller capacity or lower SOC tend to limit the "useful" capacity of the whole pack.

If a cell is just different in SOC, a "balancing" (equilizing) process can help considerably. A cell mismatched (smaller) in capacity will tend to limit the entire pack's usable capacity, and may need to be replaced, if identified.

So, since battery-cell health and uniformity of charging is so important to Battery Pack's performance, I just assume (fervently hope) that the LEAF will have a good Battery Management System.

But, so far, I (we?) have no infirmation about this highly-confidential (probably) system of the Nissan LEAF.

Again, I would welcome some factual information.
T