tps
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Re: $20 Panasonic trickle charge mod allows 240VAC @ 12 amps

Mon Sep 19, 2011 4:54 pm

chris1howell wrote:I believe the ground check uses the 3rd smaller relay (3rd picture far right) to pass a small current from L1 Hot to ground through a 5k or so resistor. If you listen carefully you can hear a clicking right after connection before the main relays engage. I do not think it is checking to see if Neutral and Ground are tied together only that there is a path to ground. Routing current through the 5k resistor would be enough to cause a ground fault so.... my theory is the EVSE powers the 3rd relay causing current to flow to Ground causing the GFCI to read a fault if so, ground and the GFCI CT coil is good. If ground is bad no current flows and the GFCI does not read a fault and the EVSE goes into Fault state.
I thought about that, but wouldn't that cause an upstream GFCI outlet which was supplying the EVSE to trip? My calcuation is that 5K would cause 24 mA to flow, which would definitely cause the GFCI to trip out. I'm guessing the current which is injected comes from the secondary of the 20 volt transformer. With this isolated source, they could put current into the ground, splitting the return current equally on the line and neutral, thus allowing a flow of current to test ground continuity while maintaining current balance on the L and N to prevent tripping upstream GFCI.

Edit: Now I think of it, that wouldn't work. Since return current it the same phase in L and N, it would add rather than cancel to zero in the CT core, so it would cause the external GFCI to trip...
Last edited by tps on Mon Sep 19, 2011 4:58 pm, edited 1 time in total.

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garygid
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Re: $20 Panasonic trickle charge mod allows 240VAC @ 12 amps

Mon Sep 19, 2011 4:56 pm

+10
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EVDRIVER
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Re: $20 Panasonic trickle charge mod allows 240VAC @ 12 amps

Mon Sep 19, 2011 5:17 pm

I find this thread title to be misleading, it should be called " How to make a dangerous simple hack" Professional engineers NEVER recommend or encourage such modifications, this is not only extremely dangerous it is irresponsible and shows a lack of judgement and disregard for the safety of others and their property. To encourage general users to do such things is not only irresponsible but a liability. Professional product engineers with years of experience not only understand the time involved to do things properly but take the time to insure all details are addressed and go to lengths to insure their designs are well thought out, fully tested and in the customers best interest. This type of suggestion jeopardizes people, property and the health of the EV movement in general and encourages individuals to do things that they may not be qualified to do by over simplifying the process.

In regards to manufacturing new EVSE units, anyone that wants to build and sell a safe, reliable and UL (or not) listed EVSE to sell on the open market without a budget of about $300K or more, I say good luck! Lets not forget the customer support, economies of scale, distribution, etc, etc.

Stoaty
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Re: $20 Panasonic trickle charge mod allows 240VAC @ 12 amps

Mon Sep 19, 2011 5:29 pm

Ingineer wrote:I fully support DIY efforts like this, but I'd like to issue a warning that this modification as presently implemented defeats the GFCI function of the EVSE and could result in electric shock or death by electrocution in the event of a mishap.
This really tells me all I need to know about this modification... and since I DON'T know what I am doing I would only entrust my EVSE to someone who has made a modification that doesn't compromise any of the safety features. In other words, evseupgrade.com is the only source I would use if I wanted 240 volt charging from the Panasonic L1 charging dock. Saving a bit of money in this case is penny wise and pound foolish.
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davewill
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Re: $20 Panasonic trickle charge mod allows 240VAC @ 12 amps

Mon Sep 19, 2011 5:36 pm

Whoa! Folks need to take a stress pill and sit down. JWallace hasn't given instructions or suggested that anyone else do anything yet. He's just described (in general) what he's done so far and stated an intention to come up with a DIY project that parts out cheaply. At least wait until he tells someone to do something dangerous before jumping on him.
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Re: $20 Panasonic trickle charge mod allows 240VAC @ 12 amps

Mon Sep 19, 2011 5:44 pm

+10 Yes, everyone, take a chill pill. As davewill pointed out, he's not advising anyone to do what he's done. Please don't run him off the board before he has a chance to finish his mod.

Stoaty
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Re: $20 Panasonic trickle charge mod allows 240VAC @ 12 amps

Mon Sep 19, 2011 5:45 pm

davewill wrote:He's just described (in general) what he's done so far and stated an intention to come up with a DIY project that parts out cheaply.
Yes, but he has apparently done something that defeats one of the key safety features of the EVSE. Telling other people you have done that isn't a way to build confidence. Perhaps rather than describing that he should wait until he has a modification that is safe.
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Re: $20 Panasonic trickle charge mod allows 240VAC @ 12 amps

Mon Sep 19, 2011 5:45 pm

davewill wrote:Whoa! Folks need to take a stress pill and sit down. JWallace hasn't given instructions or suggested that anyone else do anything yet. He's just described (in general) what he's done so far and stated an intention to come up with a DIY project that parts out cheaply. At least wait until he tells someone to do something dangerous before jumping on him.
I agree. I am pretty sure Jack would find a way to add the safety features back if he ever were to provide instructions on how to do the mod.
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garygid
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Re: $20 Panasonic trickle charge mod allows 240VAC @ 12 amps

Mon Sep 19, 2011 5:51 pm

The parts are not the expensive part.

Having a GOOD design, getting the RIGHT parts, and the LABOR of doing the work properly and competently are a lot of what you are paying Ingineer for.

However, if you are competent to evaluate the design of the modification, obtain reliable parts, do the work, check for errors, and test your work, then ... go for it.

I prefer to have a skilled surgeon do my operation, not use my steak knife and a flashlight.
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Re: $20 Panasonic trickle charge mod allows 240VAC @ 12 amps

Mon Sep 19, 2011 5:58 pm

Regarding figuring out how the EVSE does its ground check. We have two theories 1) it checks if ground and neutral are tied together 2) it simply checks to see if current will flow to ground.

One way to rule out (1) is to test by connecting the ground pin to an earth ground rather than the ground wire in the socket, and seeing if it throws a fault. If it doesn't, then it's not checking to see if ground and neutral are shorted together, and powering the controller board via a H-G-H setup should work OK w/o throwing a fault.

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