QueenBee
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Re: BareEVSE - an EVSE circuit for under $5

Wed Feb 06, 2013 7:45 pm

EVDRIVER wrote: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 ... B001NPL8VQ

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 wrote: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 wrote: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 wrote: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.

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Ingineer
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Re: BareEVSE - an EVSE circuit for under $5

Wed Feb 06, 2013 8:33 pm

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
Easily Learn Electricity HERE! - - - - Website: http://evseupgrade.com/ - - - - Like us on Facebook: EVSE Upgrade

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EVDRIVER
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Re: BareEVSE - an EVSE circuit for under $5

Wed Feb 06, 2013 9:05 pm

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.

mitch672
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Re: BareEVSE - an EVSE circuit for under $5

Wed Feb 06, 2013 9:08 pm

EVDRIVER wrote: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? :)
2012 Advanced Plug in Prius (sold)
I Support OpenEVSE: http://code.google.com/p/open-evse/
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QueenBee
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Re: BareEVSE - an EVSE circuit for under $5

Wed Feb 06, 2013 9:09 pm

Ingineer wrote: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 ... E_Workshop

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EVDRIVER
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Re: BareEVSE - an EVSE circuit for under $5

Wed Feb 06, 2013 9:13 pm

mitch672 wrote:
EVDRIVER wrote: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!

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Ingineer
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Re: BareEVSE - an EVSE circuit for under $5

Wed Feb 06, 2013 9:18 pm

QueenBee wrote: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 wrote: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
Easily Learn Electricity HERE! - - - - Website: http://evseupgrade.com/ - - - - Like us on Facebook: EVSE Upgrade

QueenBee
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Re: BareEVSE - an EVSE circuit for under $5

Wed Feb 06, 2013 9:36 pm

Ingineer wrote:
QueenBee wrote: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 wrote: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.

BetterLeaf
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Re: BareEVSE - an EVSE circuit for under $5

Thu Feb 07, 2013 4:18 am

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

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 ... b_Nr25.pdf

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.

chris1howell
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Re: BareEVSE - an EVSE circuit for under $5

Thu Feb 07, 2013 10:46 am

BetterLeaf wrote: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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