BareEVSE - an EVSE circuit for under $5

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BetterLeaf

Active member
Joined
Jan 30, 2013
Messages
25
OK, with fantastic solutions like OpenEVSE around, here is something with a different design goal:

A bare minimum circuit to successfully charge a Nissan Leaf with components that just sit idle in your parts box.
No programming required. Well, here it is:

6ekyvr.jpg


It's a good old NE555 that's putting out the 1 kHz PWM pilot signal. You can adjust the duty cycle and therefore control the maximum current that the Leaf onboard charger will draw.
It is small enough to fit into a J1772 plug. No more clunky in-cable box!

Pros: A great 2nd cable for top up charges while traveling. Easy to repair. No great loss if stolen. No in-cable box.
Cons: Must be present to start charging. No preheating or timer charges, no 80% charges. DTC warning code can be logged.

Hate the cons? Then continue reading to the end for the no-cons relay version.

The minimum components for the circuit are
a NE555,
any two diodes (1N4148, 1N4001...),
two 1k resistors (>=1/8 Watt, <=5%),
a 10nF capacitor
a 100k and
a 10k potentiometer (any type will do but precision pots are preferable).

a 12 Volt switching power supply that operates on 100-240 Volts. As the circuit draws less than 15 mA any type will do. Verify that it is well designed and isolated. Check the temperature.
So far you are looking at less than $5.

The bummer is the J1772 EV plug that sets you back a $130. With some good quality cable and a mains plug you are still under $170.
In this first version the mains plug is directly and permanently connected to J1772 plug!

The US electrical code for example, allows this only for devices up to 125V, 15A or 20A. For other countries please check you local electrical code if 240V 16A are acceptable.

So why does this technically work???

Well, there is the elaborate J1772 protocol but the Nissan Leaf does not enforce all requirements. Might be because it results in a better user experience if charging with all the non-compliant EVSEs around actually works.
The spec says the pilot should be a constant 12V in the idle state. The Leaf does not particularly care. It's happy even if the PWM is provided right away on the first plug in.
The spec says the pilot signal that the EVSE generates should alternate between -12V and 12V a thousand times per second. The Leaf does not care about the -12V. Alternating 0V and 12V is fine. The standard actually requires a diode so it can be assumed that most cars behave that way.
The spec says the power should be switched on only after the car drops the pilot voltage further and the Leaf onboard charger tests for this but there is a 10 second grace period. This is documented in the service manual.

So if you plug in the J1772 connector first, you have 10 seconds to turn on or plug in the mains. If you can fulfill that requirement, the Leaf will charge. It will slowly increase the power as usual. There will be no arcing when you plug in the mains. If you miss the 10 secs you can repeat the procedure by unplugging the Leaf. The Leaf will shut off normally after the batteries are full.

Now to unplug before the batteries are full, it is good practice with all EVSEs to unplug the J1772 first. If you press the proximity switch on the J1772 connector the Leaf will immediately stop drawing power. (Actually it drops to 70 Watts). If you disconnect the mains first, it will arc at the mains plug. Same thing happens on the standard EVSE, so generally it's a good idea to do it that way.

Now for the mains connection you must use a GFCI plug rated for your intended voltage and current. Preferably one that also contains a fuse or acts as circuit breaker. The nice thing here is that you can use it as an on-switch. That's faster than plugging in. There are units that automatically disconnect on power loss. That's even more convenient because you know the switch is always off when you plug in.

Is it safe???
Technically it is just as safe as the billons of other 220V-240V every-day household appliances worldwide (like electric stoves, (dish)washers, dryers, A/C units, electric lawn mowers). All of these require a good ground connection and follow code but none of these use a pilot signal and relay at the power source. It's up to you to figure it out! Technically the charge cable is just an over-priced extension cord.

Of course, the -12 V and the relays provide an extra safety margin.


The AC part is high voltage which can kill or burn down your house, so please only attempt to build this if you are qualified to do so. General rule: If you do not know what you are doing then please don't do it. Buy an EVSE and live.

It is your decision and you are doing so at your own risk!

Please do not violate your local electrical code!
The US electrical code only allows systems rated up to 125V 20A to be used without a relay located at the mains connection.

GFCI saves lives and is a must!
Some people think using no relay can kill your Leaf's on-board charger. Include a relay as shown below. Your choice, your risk.


Don't use this design with a car that is capable of drawing more current than the specs of your cable and plugs unless properly fused.

Note that the EVSE DTC code B29C1 can be logged if you miss the 10 sec grace period or sometimes if the battery is full. They just cause a display of the yellow warning symbol the next time the car is turned on. This will automatically go away when the car is turned off and on again. They cause no damage of loss of functionality.

The schematics:
kbzmvr.jpg


R2 is optional and not populated. R1 can also be dropped if you use and need a resistor to adjust the supply voltage closer to 12V like the PCB in the photo.
Pin 1 of JP2 connects to the pilot signal. R3 is important and must be 1K. No substitutions.

The 10k pot adjusts the frequency. The 100k pot adjusts the duty cycle. 25% at 12V is about 15A, 26.66% would be 16A. The Leaf should never go over 18A regardless of what the EVSE pilot advertises. (At 120V the maximum is 12A, so the same cable works for both voltages).
Please use a scope or multimeter that is capable of measuring frequency and duty cycle to adjust the pots.

And yes the signal is dynamic. The Leaf will adjust it's charging current and slowly follow the signal's duty cycle.

The Leaf charger does not care too much about the accuracy of the 1 kHz pilot, so the usual temperature drift of the NE555 RC based oscillator does not seem to affect it.

Here's what it could look like. The PCB is on the left, the 12V switching power supply on the right under the wires. Both warped in self-vulcanizing electrical tape rated at >200F and >400V.

Wiring up the proximity switch is a must! There are some pictures of how to assemble the cable on the web.

334og7d.jpg


But wait there is more...
... the relay version of course. Add a few more standard components and turn this into a more complete EVSE with none of the cons. Here's the right hand side of the schematics:

2u61lz4.jpg


The upper OP amp switches the 1 kHz signal on when the car says so. Puts out a constant 12V on idle as per spec.
The lower OP amp switches the power relay connected to JP3 on when the car requests it.

If you can find a proper >=16A relay that fits into the J1772 plug you can have your cake and eat it too. Make sure the transistor (and also the power supply) is rated properly for the required coil current.
For the Leaf to be happy it is sufficient to switch only one phase. No more DTCs. If you can find the space you can switch both.

Again, for 240V operation in the US both AC lines must be contain a relay and it must be near or in the mains plug.

Note that with this solution the relay will still be switched on if the pilot is shorted out.

Enjoy!
 
The relay is probably a good idea if you drop the 1772 plug into a puddle of water.. hopefully the GFI in the 240V plug will prevent a shock.
 
BetterLeaf said:
The Leaf will pull about an amp less of what the EVSE pilot advertises. It will never go over 16A regardless of the pilot. (At 110V the maximum is 12A, so the same cable works for both voltages).
The Leaf's OBC (On-Board charger) can pull up to around 18A. It most definitely goes over 16A when on lower voltages (such as 3-Phase wye here in the US, which is 208v). It most definitely does not draw 1 amp less than the pilot! I would surmise you have bad instrumentation.

Nissan will definitely void your warranty on your OBC and your Inlet if you use this device that is "always hot", which has been proven to destroy on-board chargers. It can also cause arcing and damage to your inlet. If you are concerned about multi-thousand dollar repair bills, I would avoid this!

There is a reason why the Leaf sets a DTC and lights up a warning! Connecting power to an asleep charger defeats the internal pre-charge system and if this happens, it can be catastrophic! Since there is nothing preventing this from happening except for a specific manual sequence, it's bound to happen at some point.

-Phil
 
DanBaldwin said:
Where can you get the J1772 plug and cord for $100.00? The cheapest I've seen is about $140.00.

I was refering to the plug alone. You are right, with a cord it is $134 at Leviton. I thought I saw the plug alone there some time ago for a little over $100. It's definately no longer offered now.

I paid a discounted rate at whole seller 8 months ago for a couple of plugs. Since this deal is also no longer available I corrected my estimation in my initial post just to avoid any confusion.

Thanks for bringing this to my attention.
 
I have read many of your posts during the past year and I certainly value your opinion.

So, thank you for responding.

I'd like to point out that both of the presented circuit versions were built around 8 months ago and have been tested almost daily with no adverse effects.
Ingineer said:
The Leaf's OBC (On-Board charger) can pull up to around 18A.
Yes, you are right of course. I have corrected that. Thanks for pointing that out.
Ingineer said:
It most definitely does not draw 1 amp less than the pilot! I would surmise you have bad instrumentation.
I've used a calibrated scope and also a multimeter on the pilot. Both showed identical values for the duty cycle. So that should be correct. I've used a cheap consumer device for measuring power and current consumption and that was .7A lower than what the pilot suggested. So maybe it was inaccurate. I've removed that statement. Thank you.
Ingineer said:
if you use this device that is "always hot",
As described in my initial post the J1772 connector is certainly not hot when plugged into the Leaf. The GPCI plug will ensure that if is always off. You need to manually reset before it will energize the J1772 plug.
Ingineer said:
It can also cause arcing and damage to your inlet.
That is unlikely to happen. I've never observed any significant arcing on any kind of connect. The charge current is raised very slowly by the Leaf.
On disconnect: When the proximity switch is pressed to release the charge handle the Leaf's power consumption will drop instantly to ~70 Watts. I am sure it has not escaped your attention that even with the original Nissan EVSE the Leaf's onboard charger will still not instruct the EVSE to open the relay. It will continue to draw a little power. On the pulling the plug the disconnection of the pilot pin will open the relay. If done quickly enough there is chance that the AC pins will still be hot even though they are longer connected.
Ingineer said:
If you are concerned about multi-thousand dollar repair bills, I would avoid this!
Absolutely and I would go as far as to generalize that:
If you are concerned about multi-thousand dollar repair bills I would certainly avoid driving any type of car.
Ingineer said:
There is a reason why the Leaf sets a DTC and lights up a warning!
Yes, of course: to detect and alert the driver about a stuck or broken EVSE relay.
I trust the Nissan engineers were smart enough to design a on-board charger that can cope with this likely event. The DTC seems to indicate that are at least aware of that condition.
Ingineer said:
Connecting power to an asleep charger defeats the internal pre-charge system and if this happens, it can be catastrophic!
The proximity detect is there, time to wake up!
During initial tests even hot plugging AC alone while asleep did not cause any damage, although I would never recommend doing that.
Ingineer said:
Since there is nothing preventing this from happening except for a specific manual sequence, it's bound to happen at some point.
Again, the same word of caution applies to driving a car. This involves a complicated manual sequence of pressing the correct pedals at just the right time.

No seriously, everything you have said should be taken into consideration and putting in a relay as shown in the add-on circuit is preferable.

Anyways, I have no commercial interest here, I just thought it would be good to share my ideas and my observations.

So thanks again and take care!
 
I'm not just being alarmist: Because I'm in this business, I get lots of reports of when something goes wrong, such as the GE Wattstation EVSE problems. While still relatively rare, your $5 EVSE is still likely to cause OBC failure, and if a handful of people build these and use them daily, I'm sure we'll see them sooner or later. I'd just hate to see someone get burned with an OBC replacement. If you happen to be reading this and your OBC has failed, please post so others will know what I'm attempting to warn about.

Driving a car is not the same as connecting the car in a special sequence. This may be fine if the car has only one user, but if there is a family situation with kids and spouses, it could easily be forgotten or skipped. With your always-hot circuit, All it takes is one power failure or dip, and BOOM!

-Phil
 
I think this micro EVSE circuit is fantastic! Not something I would use every day but if I had a 2013 Leaf with a 6kW charger I could see making a simple device like this for use at RV parks for longer trips. I wouldn't even bother with the relays... Of course with 3.3kW I personally don't consider those long trips viable. A moderate EVSE is a lot smaller than the 70lb Magnechargers we used to lug out of the trunks of our EV1s, but still a cable with no box on it at all would be awesome!
 
Besides that fact that a plug in 240V, 20A GFCI is almost impossible to find it is likely that someone will either skip using it or leave it behind even if it is available. I personally know of at least six instances of cords that have been cut for various reasons, two of which were very small dogs that ate the cord. This happens often with the LEAF EVSE believe it or not. I wonder how that is going to feel with a live cord energized? These type of "cheater" EVSE circuits have been around a long time but I would not use on on a modern EV or at all for the many reasons stated before. Besides, it defeats the main function of what the EVSE is supposed to do and opens one up for serious liability. Sure doing this in Europe is far less of a risk then in the states but I can also post all sorts of ways to cut corners and make electrical devices cheap and unsafe but that is not the point. I'm sure that if you were a US resident or had more concern for the safety of others and their property you would be less likely to make these irresponsible postings with cheap "hacks". Besides the lack of concern for safety, things like this almost always come back to reflect poorly on EVs in general once someone gets burned in every sense of the word.

This idea is nothing new and has been done before but just watch how "I told you so" comes up as well as a bunch of wining from those that ignored common sense and screw up their EV. Perhaps EV Charge America can start selling these...
 
EVDRIVER said:
Besides that fact that a plug in 240V, 20A GFCI is almost impossible to find it is likely that someone will either skip using it or leave it behind even if it is available.

That is unless you use Google, then it becomes a fact that it's easy to find and while someone implementing this could not buy and install the GFCI having it wired inline solves the issue of having to remember to plug it in/etc.

Then I would also guess that most use cases of this "BareEVSE" would be on 120volt so GFCI on that would be easily added, but it's only $70 for 120/240 volt GFCI inline: http://www.amazon.com/Power-First-5YL46-GFCI-Inline/dp/B001NPL8VQ" onclick="window.open(this.href);return false;

I would assume we are all comfortable with 120 volt and maybe even 240 volt being used outside when protected by GFCI? So I think that bit of safety can easily be ensured.

EVDRIVER said:
I'm sure that if you were a US resident or had more concern for the safety of others and their property you would be less likely to make these irresponsible postings with cheap "hacks". Besides the lack of concern for safety, things like this almost always come back to reflect poorly on EVs in general once someone gets burned in every sense of the word.
How is this any less safe than using an extension cord with the Nissan EVSE, Phil's upgraded EVSE at 240 volt, or OpenEVSE? Obviously safety should be considered when using an extension but I don't see scathing comments about how extension cords are cheap hacks and that suggesting the use of them is irresponsible....

Ingineer said:
Driving a car is not the same as connecting the car in a special sequence. This may be fine if the car has only one user, but if there is a family situation with kids and spouses, it could easily be forgotten or skipped. With your always-hot circuit, All it takes is one power failure or dip, and BOOM!
I think it's fair to say that even your EVSE Upgrade and the Nissan EVSE both need to be used in a special sequence which is similar to this. My question for you is does disconnecting the cord end of normal EVSE or power failure/dips have the same risk of causing OBC damage as it does in this always hot EVSE or are the additional relays and features in a normal EVSE adding additional protection?
Ingineer said:
Nissan will definitely void your warranty on your OBC and your Inlet if you use this device that is "always hot", which has been proven to destroy on-board chargers. It can also cause arcing and damage to your inlet. If you are concerned about multi-thousand dollar repair bills, I would avoid this!

There is a reason why the Leaf sets a DTC and lights up a warning! Connecting power to an asleep charger defeats the internal pre-charge system and if this happens, it can be catastrophic! Since there is nothing preventing this from happening except for a specific manual sequence, it's bound to happen at some point.
I don't understand the impact of what happens when the J1772 is hot when it's plugged in and what the internal pre-charge system does but I'll confidently trust that this part of getting the sequence wrong is as you said catastrophic.

Having said that, I'm certainly not going to be doing anything that Phil says not to, even if I don't fully understand why. I can't wait for my OpenEVSE parts to arrive. :)

BetterLeaf, thanks for taking the time to layout what you've done and for providing a conversation about this topic. I certainly wish the best for your LEAF and I hope you'll do some more research into the topics that Phil has addressed with regards to the OBC.
 
The OpenEVSE is fine if built using good practice. This thing is not. If there is a power failure on a normal EVSE, the relays open and STAY OPEN until the car is ready for power. On this "$5" hack (Really $130 after the handle), when the power fails, even for a fraction of a second, then resumes, the Leaf's OBC is hit with full power while it's "asleep". This is when it can self-destruct.

Again, if you are so cheap that you can't spend an additional $50 or so on an Open EVSE, then you deserve to have your $2000 OBC blown.

You spent over $20k for a car, it's not unreasonable to spend a few hundred on an EVSE. (1%) Now spending $2500 on a AV Install is a little excessive. (>10%)

We have thousands of upgraded EVSE's operating all over the world safely, and you can have it for $239 without any fuss. Why chance it?

-Phil
 
I just found a way to make an EVSE from a roll of aluminum foil and electrical tape. You use the parts listed above for the board but skip on the GFCI. $5 to start, take a roll of foil and electrical tape, twist the foil to make all the needed power and pilot wires and wrap them with tape, I know, overkill! Then stuff the foil wires into the car and solder the other end to the board. This design makes pull away issues a breeze. Cheap, easy, and safe! If you forget the wire at home you can use some burrito wrappers on the go. This is even more of a benefit in the US since we have more foil wrapped products. Remember it can be recycled so don't be concerned if you leave it behind. Der Grüne Punkt:) Don't spill fire sauce on the board, that is an actual problem. Live dangerously my friends!

***For a slower charging option (L1 --) use parchment paper in place of foil.
 
EVDRIVER said:
I just found a way to make an EVSE from a roll of aluminum foil and electrical tape. You use the parts listed above for the board but skip on the GFCI. $5 to start, take a roll of foil and electrical tape, twist the foil to make all the needed power and pilot wires and wrap them with tape, I know, overkill! Then stuff the foil wires into the car and solder the other end to the board. This design makes pull away issues a breeze. Cheap, easy, and safe! If you forget the wire at home you can use some burrito wrappers on the go. This is even more of a benefit in the US since we have more foil wrapped products. Remember it can be recycled so don't be concerned if you leave it behind. Der Grüne Punkt:) Don't spill fire sauce on the board, that is an actual problem. Live dangerously my friends!

ROTFLOL, maybe I could even use your "aluminum foil wiring" on my Tesla Model S, that foil can handle 75A, right? :)
 
Ingineer said:
Again, if you are so cheap that you can't spend an additional $50 or so on an Open EVSE, then you deserve to have your $2000 OBC blown.

You spent over $20k for a car, it's not unreasonable to spend a few hundred on an EVSE.

We have thousands of upgraded EVSE's operating all over the world safely, and you can have it for $239 without any fuss. Why chance it?

-Phil
Hopefully your message wasn't directed at me since I've got one of your upgraded EVSEs and it's great and am staying far far away from this design opting for the OpenEVSE.

Do note that AFAIK there isn't any EVSEs out there which can be had for a few hundred dollars. A 20 amp version of the 30 amp OpenEVSE kit would be slightly cheaper but the 30 amp version is $470. http://code.google.com/p/open-evse/wiki/OpenEVSE_Workshop?ts=1352676672&updated=OpenEVSE_Workshop" onclick="window.open(this.href);return false;
 
mitch672 said:
EVDRIVER said:
I just found a way to make an EVSE from a roll of aluminum foil and electrical tape. You use the parts listed above for the board but skip on the GFCI. $5 to start, take a roll of foil and electrical tape, twist the foil to make all the needed power and pilot wires and wrap them with tape, I know, overkill! Then stuff the foil wires into the car and solder the other end to the board. This design makes pull away issues a breeze. Cheap, easy, and safe! If you forget the wire at home you can use some burrito wrappers on the go. This is even more of a benefit in the US since we have more foil wrapped products. Remember it can be recycled so don't be concerned if you leave it behind. Der Grüne Punkt:) Don't spill fire sauce on the board, that is an actual problem. Live dangerously my friends!

ROTFLOL, maybe I could even use your "aluminum foil wiring" on my Tesla Model S, that foil can handle 75A, right? :)

Yes, Reynolds makes a heavy version of the foil, up to 80A. Expensive at an extra $2 a roll but hey, Model S!
 
QueenBee said:
Hopefully your message wasn't directed at me since I've got one of your upgraded EVSEs and it's great and am staying far far away from this design opting for the OpenEVSE.
You are "staying far away", yet you appear to condone it.

QueenBee said:
Do note that AFAIK there isn't any EVSEs out there which can be had for a few hundred dollars.
Every Leaf owner has an EVSE that comes with the car, and I can upgrade it for $239. That's about 1% the cost of the car you purchased, easily affordable and SAFE.

-Phil
 
Ingineer said:
QueenBee said:
Hopefully your message wasn't directed at me since I've got one of your upgraded EVSEs and it's great and am staying far far away from this design opting for the OpenEVSE.
You are "staying far away", yet you appear to condone it.

QueenBee said:
Do note that AFAIK there isn't any EVSEs out there which can be had for a few hundred dollars.
Every Leaf owner has an EVSE that comes with the car, and I can upgrade it for $239. That's about 1% the cost of the car you purchased, easily affordable and SAFE.

-Phil

EVSEUpgrade is not an EVSE for $239... It's an EVSE for $979 or an upgrade to an existing EVSE for $239. Some people may want more than one EVSE so it's not fair to say that you can "spend a few hundred on an EVSE" when you really mean to say you can spend a few hundred on upgrading the EVSE you already have

The only thing I'm trying to clarify is the safety to human life/dogs when used with GFCI protection near the receptacle AFAIK makes this as safe as using an extension cord with an EVSE.

As far the safety of ones OBC when using this I think you've very well established that this isn't a "Do it at your own risk" type of thing but a "you are rolling the dice" and eventually your luck will run out and you'll be buying yourself a new OBC or trying to convince Nissan that your non complaint "EVSE" isn't to blame.
 
While talking about safety please keep in mind that I have also presented a version with a relay. That turns it into the analog version of OpenEVSE.

Also note that I have only presented the 12V part of the circuit. So if your local electrical code allows for aluminum foil in burrito wrappers please feel free to use those. I certainly would never ever even consider skimping on the high current parts and wiring.

Regarding the dogs:
Oh yes, the dog sees the charging EV and starts chewing on the cable. It certainly knows that it must completely chew thru the entire copper wire to disconnect the pilot signal so that the relay will open.
Hmmm, I don't know... don't you think it is more likely that the dog will chew into the INSULATION. It will keep chewing until it gets to a hot wire, then it gets a brief jolt, tripping a ground fault. Then the dog runs off howling like it was hit by lightning.

I also don't know about the power distribution at any type of larger outdoor event. All those dangerous live cables these folks have there just lying in the grass. In Europe these are 3 phase 2xx volts at 63 amps so about 44 kW. Keep your dogs on the leash!

I'm not sure if you are all aware about this consumer EVSE:
http://charge-amps.com/um-evse" onclick="window.open(this.href);return false;

Power supply, pilot generation and relay is all contained in the J1772 plug.
The cable itself is energized all the time. All of this is following code and yes it is CE approved.
And look closely, no GPCI at the mains plug for Europe. OK, with US wiring you would definitely want one. And their planned US version will have one.

Given those facts, I'd prefer it if we could get back to the really interesting issue here, not just a commercially motivated extra safety discussion.

Correct me if I'm wrong but I thought all the on-board charger failures were caused by a shorted out or blown diode on the pilot. Surge on a badly designed 12V power supply maybe?

If there is anybody that has indisputably experienced a dead OBC because they were hot plugging AC or using a EVSE with a stuck relay, then yes please post it here!!!

I've seen that Phil's 6.6 kW charger upgrade seems to use the successor of this BRUSA EV charger:
http://www.brusa.biz/fileadmin/Diverses/Download/Manuals/NLG5xx_179_ab_Nr25.pdf" onclick="window.open(this.href);return false;

This one seems to be properly designed, it can be hot-plugged and the company even sells you a cable with a standard European 32A CEE mains plug. No relay, no extra GFCI.

In stand alone mode it even charges without a pilot signal up to 16A.

I cautiously assume that the Leaf's OBC just like all other electrical household appliances that can withstand a hot plug. Although currently I would still avoid it.

I have never seen the schematics of the Leaf's OBC only a block diagram with some waveforms, but it would certainly be an inferior design if it did die because of that.

Let's discuss pre-charge.
The Leaf uses a pre-charge relay but that is intended to reduce in-rush current when it connects the battery to the internal 400V consumers like the traction motor.

It is not obvious from the service manual if the OBC uses some form of pre-charge for the caps after the rectifiers. The really big cap seems to be after the inverter's transformer and rectifier and one can only assume that the inverter's power output increases slowly. It is not even clear from the manual if there is a significant cap after the first rectifier (before the inverter). It would also be a bad design if the OBC would turn on the internal normal charge relay until it is safe to do so. The rectifier should be able to handle the caps current.

I've never seen any significant in-rush current on the AC side during the few hot-plug tests.
Anyone else seen any?

I'm mostly interested in a technical discussion and I'm pretty sure anyone with a business interest in this will not noticeably suffer because of this.
 
BetterLeaf said:
While talking about safety please keep in mind that I have also presented a version with a relay. That turns it into the analog version of OpenEVSE.

This is exactly how OpenEVSE started so I am not going to go into the safety issues, seems those are all known at this point.

The circuit with the relay is nowhere near OpenEVSE. yet....

The current OpenEVSE hardware currently has:
GFCI
Ground Check
Stuck Relay detection
L1 - L2 autodetection with a configurable pilot for each
Diode Check
2 relay output for self check isolation (firmware coming soon)
GFCI self test (firmware coming soon)
J1772 plug Thermal cutoff (guide and firmware coming soon)

I would love to see an analog solution that complies with J1772 instead of just getting arround it. You are more than welcome to take parts of OpenEVSE and add to your circuit. GFCI using the OpenEVSE design would only add about $1 to the circuit and ~10 for the CT coil. Add 4 logic gates and you can inturupt the relay on fault, reset with button, manual test and light a GFCI fault LED. I will be happy to provide a schematic. Ground check and Diode check would not be too dificult either.
 
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