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Re: We need a portable 240v EVSE

Posted: Wed Jun 23, 2010 1:08 pm
by pgrovetom
I have been told by Nissan that ONLY the Aerovironment EVSE may be used and received an email saying "I must provide proof of compatibility of any other EVSE".

That seems to force everyone to either use the Level 1 120V slow charging or pay for the AeroVironment at whatever price they demand. Aerovironment told me I could only receive the federal tax credit if I used them. Seemed very odd. They claimed safety but everyone would use the SAE J1772 connector and only the communication is left. The SAE 2487 communication is not as yet defined since the Smart Grid is not yet deployed. AV provides a card that allows some future upgrade depending on how the Smart Grid communication protocol goes. Other than that, they light some LEDs. So that only leaves the GFI circuits which have been used for years.

Remember the Level 2 is just 220V which is just two 120V legs to earth so from an earth to conductor point of view, there is no safety difference. Its almost impossible to put your body across that SAE J1772 connector to get 220V so from a safety point of view, Level 2 EVSE's are only marginally more dangerous than Level 1 and every 120V chord and outlet in your home represents a greater hazard. So what's the safety issue? What's the compatibility issue since the Comm channel is TBD?

So any EVSE can provide physical layer compatibility with the 220V through connection and GFIs.

At the upper layers, the common channel is up for grabs even though a PLC or Power Line Modem at level 1 makes most sense to get back to the meter. If they want to get to the homes internet connection, they better think that one through carefully. I see just about every communication protocol is being considered - just like everywhere else from Zigbee, to Bluetooth to PLC to WiFi.

Something is wrong!


http://www.franklin-gov.com/Modules/Sho ... entid=3119

Re: We need a portable 240v EVSE

Posted: Wed Jun 23, 2010 6:40 pm
by EVDRIVER
Bicster wrote:Everyone who thinks they can future-proof their EVSE is in for a rude surprise.

In spite of standards, things will evolve quickly. My old man always says, "The great thing about standards is that there are so many to choose from."

Just worry about getting the power connections future-proofed. You'll be replacing your EVSE when you get your next EV.

Not if you buy one that supports 12kw. They are available now.

Re: We need a portable 240v EVSE

Posted: Wed Jun 23, 2010 6:43 pm
by EVDRIVER
evnow wrote:30A (continuous) is close to 32A allowed for a 40Amp connection. So I don't see a problem here.

Yes, may be in 2020 we will all get quick charge stations at home that draw down 200A ... until then I'm fine with 30 amps.

I've been charging at home with 50A so 30A is a downgrade for me. I'm not going to pay $2k to get lower charging capacity.

Re: We need a portable 240v EVSE

Posted: Wed Jun 23, 2010 6:50 pm
by evnow
EVDRIVER wrote: I've been charging at home with 50A so 30A is a downgrade for me. I'm not going to pay $2k to get lower charging capacity.
Makes sense - but as you can probably appreciate, you are in a tiny minority.

Re: We need a portable 240v EVSE

Posted: Wed Jun 23, 2010 10:26 pm
by EVDRIVER
evnow wrote:
EVDRIVER wrote: I've been charging at home with 50A so 30A is a downgrade for me. I'm not going to pay $2k to get lower charging capacity.
Makes sense - but as you can probably appreciate, you are in a tiny minority.

So are EV drivers, now. I bet there are more people charging at 240 30A then there are factory EVs on the road. And the Tesla home charger supports 16kw. I don't expect to be in the minority for more than a year and I don't plan on paying for two charging stations.

Re: We need a portable 240v EVSE

Posted: Thu Jun 24, 2010 12:44 am
by garygid
Thinking about DYI EVSEs, for 240v:

I Googled
double pole hot tub contactor
and found 30 (to 50) amp versions for about $25 (to $35).

On the Power inlet side:
probably a twist-lock socket on the DIY-EVSE for short 240v 50 amp (continuous rating) socket-adapter pigtails.

Perhaps a rotary switch to select 12, 16, 24, 32, 40, and 50 amps "max-current" settings. This is a 12v 1000 Hz square wave, with duty cycle from about 10% to 90%.

Then, a "break-away" connector to for the e-hose, perhaps to match the one on AV's EVSE. Then, the AV J1227 hoses could be used, at least for 30-amps and under.

A small 12v power supply, a few LEDs and labels, a little logic and a couple of level detectors, and probably a small relay to energize the big relay, and a $10 current-sensor for the GFI function, mounting hardware, wire and connectors, a printed circuit board for about $10, and a suitable box ... that is about it, roughly.

The J1772 plug and its "handle" remain the big problem. $900 is WAY too much. AV is unlikely to pay more than $100 each ... that is my guess.

Re: We need a portable 240v EVSE

Posted: Thu Jun 24, 2010 8:17 am
by EVDRIVER
garygid wrote:Thinking about DYI EVSEs, for 240v:

I Googled
double pole hot tub contactor
and found 30 (to 50) amp versions for about $25 (to $35).

On the Power inlet side:
probably a twist-lock socket on the DIY-EVSE for short 240v 50 amp (continuous rating) socket-adapter pigtails.

Perhaps a rotary switch to select 12, 16, 24, 32, 40, and 50 amps "max-current" settings. This is a 12v 1000 Hz square wave, with duty cycle from about 10% to 90%.

Then, a "break-away" connector to for the e-hose, perhaps to match the one on AV's EVSE. Then, the AV J1227 hoses could be used, at least for 30-amps and under.



What is the point of current settings, if your max capacity of the wire and outlet is greater than the charger it is pointless. I think that anyone with basic electrical know how can make a cord and adaptors and make it work for portable use and I bet someone makes an inexpensive portable EVSE soon enough.


A small 12v power supply, a few LEDs and labels, a little logic and a couple of level detectors, and probably a small relay to energize the big relay, and a $10 current-sensor for the GFI function, mounting hardware, wire and connectors, a printed circuit board for about $10, and a suitable box ... that is about it, roughly.

The J1772 plug and its "handle" remain the big problem. $900 is WAY too much. AV is unlikely to pay more than $100 each ... that is my guess.

Re: We need a portable 240v EVSE

Posted: Thu Jun 24, 2010 12:33 pm
by pgrovetom
I have 25 years in Telecom system design and did circuit and software design early in my career. We designed Telecom systems that the old Bellcore, now Telcordia, Bell System specs which were second to military specs. I did detailed and rough cost estimates on many a system and PCB. I got a block diagram off an SAE based presentation and did a rough conservative cost estimate of the Level 2 EVSE.

Here is the Aerovironment Spec: http://evsolutions.avinc.com/uploads/pr ... 061110.pdf

This thing is NEMA 4 enclosure which is outdoor capable even though the majority will be mounted inside garages. To run conduit outdoors and use the pedestal will add a lot of cost but a typical garage is a 25 foot run of EMT conduit plus 3 #8 conductors and a #10 ground plus a new 40A breaker in your garage panel. I have a 100A panel in my garage and bought the EMT conduit and wire plus breaker for less than $100. It took me a few hours to run the conduit and wire and install the new breaker. I'm planning on having everything wired right to a box where my EVSE will be mounted. That way the install is trivial.

Here is my rough estimate based on the blocks in the diagram and my knowledge of roughly what they must do functionally.

These numbers are high except maybe that crazy J1772 coupler which is designed like a high end F16 Military connector. Right now it could be more as the volumes are low. But since all my other numbers are high, the estimate is probably +/- 20% and vendors will give good prices given Nissan has contracted for it and the DOE is funding everything.

The Round Enclosure $25
The SAE J1772 Coupler $50
5 conductor cable 25' (maximum offered) $25
A PCB and power supply $20
GFCI Circuit 30A $20
Pilot Monitor and Controller $15
LEDs and buttons $15
CPU, memory and upstream Comm Controller $25
Power Line Modem $25
Misc Hardware $10

These add up to the $200-$250 and is conservative

This range which is doubled for retail so if the market was competitive this thing should be less than $500

So it's interesting they want $2200 on average

$200-$300 in Electrician labor tops
$100 conduit and wire and breaker
$500 retail value (could be $250 if sold by Costco)

So that's $800-$900 tops...

Is it fair to charge the federal tax credit twice the real value... That's the tax payers and the guys who gave Nissan a $1.6B loan and another $100M to the EV Project launching them.

Doesn't sound right to me!

Re: We need a portable 240v EVSE

Posted: Mon Jun 28, 2010 10:26 am
by muus
drees wrote:No sense in making/selling 70A capable EVSEs when all the cars in the near future will only take up to 30A. The electronics required to handle double 70A instead of 30A will greatly increase costs.
The ONLY currently available electric vehicle you can go out and purchase TODAY is a Tesla and their EVSE is capable of 70A (although not yet J1772). So let's say you spend over $2000 for your 30A EVSE and then a couple years later you decide to upgrade to the new Infinity EV (or Tesla Model S) wich is able to take full advantage fo the the J1772 capabilities (80A). You will be stuck charging at 30A or pay another $2000 to upgrade your EVSE installation. Doesn't make much sense to me. They should at least give you the option of paying a little more to future-proof your investment.

Re: We need a portable 240v EVSE

Posted: Mon Jun 28, 2010 10:39 am
by evnow
muus wrote:So let's say you spend over $2000 for your 30A EVSE and then a couple years later you decide to upgrade to the new Infinity EV (or Tesla Model S) wich is able to take full advantage fo the the J1772 capabilities (80A).
C'mmon. $2K is small change for anyone who can afford Model S or Infinity EV :D

You will always pay more and upgrade sooner when you are an early adopter. Fact of life.