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Hello everyone first post on this forum,
I am hoping that an informed individual may answer this question of mine.

I found a previous thread in regards to this question but it was months ago, so I decided to start a new thread if that is not against the forum rules.

So in regards to the (EVSE) electric vehicle service equipment "level 2", I am seeing them starting at $300+. Due to my naivety I think this is ludicrous for a box with some circuitry, when the chevy volt is capable of taking in direct AC. What specifically is this box supposed to be doing? The only thing I keep finding online is that it provides "safety features". This is too vague for my liking. A fuse is a great safety feature that prevents damaging shorts. That is to say why can't I just get a 50A line with two plugs [1 to the volt and the other to the 220/240V single phase outlet and an appropriate fuse (I think the volt is up to 15A?). I looked at the pin out of the J1772 plug and the only interesting aspect are the control pilot pin and the proximity sensing pin. Does any one understand if these pins have active modulated signal or are just DC levels? Or where might this information be posted?? If it is just DC levels it seems that it might be able to be bypassed. Or if it is actively modulated then I suppose one can use an arduino or labview interface although this would be more time consuming. My search results online have been less then fruitful and the owners manual I have does not go into this detail.

I am sorry for the lengthy post and many questions, however I can not purchase an EVSE for that much without being able to justify it. :confused::confused::confused::confused::(

Thanks to whomever reads this post
-sincerely confused recent volt owner
 

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You're on the right track. The pilot signal is a simple analog 12v square wave that has been successfully generated with Arduino and other programmable microcontrollers. Do a quick google for OpenEVSE and you'll get all the technical details along with step by step guides written by people who have done it. Mine is in there somewhere. There is nothing voodoo about how the EVSE operates, but due to relative newness and lack of competition, the companies making them can command a premium and people who don't know squat about electronics are willing to pay it. I built my stationary EVSE from scratch for under $250 in about a week. I converted my L1 EVSE to be auto switching L1/L2 using another OpenEVSE brain board for under $100.

To answer the question of "what good is it", there is no high voltage present at the plug until the control pilot has successfully negotiated with the car and the car requests power. Even if you happened to be SO lucky as to find a mud puddle to dunk your cord into with just the right amount of conductivity/resistance to fake the EVSE into thinking it is connected to a vehicle, it still wouldn't turn on the juice because there is also a diode test where it looks for the car to block negative voltage and have a specific amount of resistance on positive voltage. All these details are very well documented on the OpenEVSE site. Part of the square wave analog signal is a variable duty cycle that encodes a maximum allowable amperage that the car can pull. All J1772 compliant cars must respect that limit and not pull more amps than advertised by the EVSE. So, the bottom line is that the EVSE really is just an expensive extension cord with a fancy safety mechanism to prevent electric shocks or circuit overloads. Oh, it also includes a built in GFCI protection and fuses.
 

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Due to my naivety I think this is ludicrous for a box with some circuitry, when the chevy volt is capable of taking in direct AC
First of all, the Volt won't take any power without seeing proper J1772 signals.

The EVSE basically does 3 things: First of all it provides ground fault protection to prevent shocks. Second, it signals the vehicle with the amount of power available (the EVSE doesn't limit current - fusing isn't mandatory; it just tells the vehicle how much current is allowed and it's up to the vehicle to abide by that limit) Third, it provides switching - the most important of which is de-energising the circuit right before the plug is removed to prevent arcing.

There's way more going on than just a fat dumb extension cord. $300-500 is really not that much in the grand scheme of things, considering only a couple of years ago $1000 for home units was the norm. The J1772 protocol is 15 years old and has gone through several major overhauls, even Tesla uses it for their home charger (albeit with a non-standard connector)
 

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Don't worry about the nitty gritty. The bottom line is getting a Level 2 EVSE is liberating. Charge times drop from 10-12 hours down to 4.5 hours. You can take multiple trips to places during the weekends or late at night without dipping into fuel. The convenience of not having to remember to switch from 8 to 12 amps alone makes the cost of the EVSE worth it. If you really want to build your own, try an OpenEVSE, but the cost and time spent probably can't touch the least expensive ClipperCreek.

I also recommend getting an electrician to install this, so if your house burns down or your car fries, it's on them.
 

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My GE cost $999 minus $300 fed tax credit. Early adopters get to pay for the privilege. We are still in the early/hobby phase of EV ownership.

L2 is well worth the cost to me.
 

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For 30 bucks you can make your GM provided EVSE run on 240V, see the link in my signature to the GM-Volt thread that has the instructions
 

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I am sorry for the lengthy post and many questions, however I can not purchase an EVSE for that much without being able to justify it. :confused::confused::confused::confused::(

Thanks to whomever reads this post
-sincerely confused recent volt owner
As llninja says, the justification is taking your charging time from 10+ and on newer volts having to tell it every time you want 12 amp charging to 3.5 hour charge time. This is really nice for topping it off over lunch or after work before running out to supper or some other errand. It really depends on your driving style though.

EVSEs are a necessary evil when dealing with electric cars, yes, you could have just a plain old plug that pulled out from the car (like a Vacuum cleaner?) and plugged in, but then you would probably have to do something like flip a switch in the car to enable it, and what would happen if someone came up and disconnected the plug, in some instances carrying up to 240 V at 80 amps (Tesla dual 10kw charger)? It probably wouldn't be pretty, that is 20,000 watts of power. I see arcing when I unplug an electric skillet at 1440 watts. I wouldn't be unplugging an electric skillet in the rain.

The cost is that these units use expensive relays to switch high current power to keep you, your car, and your cars wiring safe in all weather and environmental and wear conditions. I went with a clipper creek as it is a lot better quality than the included EVSE, although the one included with mine has worked fine.

It might be that the included EVSE is perfectly acceptable, I got by with mine for 6 months just fine, but prefer the 240 V unit I have now. I use the portable one at work on cold days to keep my battery warm and preserve some range.
 

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Think of it this way. In the first few months of ownership you will probably easily save $400 in fuel costs (maybe longer since the price of gas is low). If you had an gas powered car you wouldn't think twice about paying for gas when the tank was empty. So if you think of an L2 EVSE as required just get one. Don't do the math comparing how much potential EV miles you might gain with L2 vs L1. l2 is well with it in convenience. It will free you from feeling stranded on a weekend waiting for the battery to fill up before venturing out.
 

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The EVSE has a housing, a circuit board filled with electronic components, many surface mount, some larger, such as the low voltage transformer and the power relay, a cable for the 240 V supply, and the cord to the car with the plug including a non-trivial amount of copper. For a company like ClipperCreek to make one, there was design cost, validation and acceptance testing including product ratings, parts acquisition, manufacture time and cost, customer support, etc. Their employees are likely not volunteers, and they need salaries, health care, etc. Also, I imagine they need to make a profit to be self-sustaining.

Clearly there are a subset of EV owners who enjoy DIY ranging from building kits to modding existing EVSE. No company can compete with hobbyists who typically want to pay no more than what the parts cost, or in many cases little to nothing.

Some DIY kits projects are very safe and wonderful projects, as could be some mods. Some mods, for example leaving out line fuses, may be problematic, especially where the line circuit breaker is relatively large. Once you leave the realm of certification agencies and commercial practice, safety has a wide range from stupid, to likely will not cause a problem, to as good as the certified units.

DIY, hobby projects, mods, all have their place and are great fun. With increasing quantities, commercial EVSE will continue to drop in price. However, below some price point, there can only cheaply be built imports, and the quite likely an end of U.S. manufacturing of EVSE.
 
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