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

Posted: Fri Sep 23, 2011 8:28 pm
by jwallace3
GeekEV wrote:Might all this angst be resolved with a simple title change of this thread? The current title seems to imply a viable product for $20 when that's not really what you're saying. May I suggest "experiments on the Panasonic trickle charger trying to enable cheap DIY L2"?
Yes, as of right now id like to change the title of the thread to my L1 ESVE findings. Until I come up with a proved solution or not a proved solution I'd like that. If I have positive results, which I think I will, I will post a new thread with instructions, findings, and a YouTube link of me completing the mod.

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

Posted: Fri Sep 23, 2011 8:48 pm
by jwallace3
There are 2 main ICs on the board. I can't tell what the micro is yet, but the other is an earth leak detector ic. Here is the link to the data sheet: http://html.alldatasheet.com/html-pdf/2 ... 134FP.html" onclick="window.open(this.href);return false;

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

Posted: Fri Sep 23, 2011 8:53 pm
by jwallace3
What appears to be the micro has markings 284k557 and a3k2b . Can't find anything on it as of yet. It appears to be a 20 pin surface mount micro.

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

Posted: Fri Sep 23, 2011 8:58 pm
by chris1howell
You can change the title of the thread by editing your first post.

As long as one is qualified to do the work safely I say go for it. There were a lot of people who questioned my EVSE built from scratch. I am not an EE but have enough knowledge and experience to do it safely. It has taken a while but I solved one problem at a time until I had a safe and working EVSE. I have learned a lot along the way and made many new friendships. Keep learning, sharing knowledge and don't hurt yourself...

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

Posted: Fri Sep 23, 2011 9:09 pm
by N952JL
Would changing the title, unsubscrib me from this discussion? I really am enjoying the information, and do not want to lose receiving the notice of additional posts.

I am currently in middle GA being forced to wait till December before I can receive my leaf. I'm not a EE but I know my 600 amp service has plenty of room for one or two more 40amp 240's in any one of the three main sub panels. I am still undecided as to buying an SPX or the GE Wattstation. I like the SPX because I can use have the correct plug installed and "plug" in vice having it hard wired.

That will allow me to move the SPX to another location if I need to. I could probably do the same, with the GE so I'm still in the air but with two more months before Dec I still have time.

In the end I also want to upgrade my EVSE even if I am only leasing. The modified EVSE is more useful. But what I and the Leaf really needs is a network of L3 chargers between Warner Robins GA and Atlanta GA. An interstate distance of about 120 miles.

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

Posted: Fri Sep 23, 2011 9:35 pm
by jwallace3
You should not be unsubscribed. Also I want it to be known that is anyone has anything constructive to add or questions to ask, please share or ask.
N952JL wrote:Would changing the title, unsubscrib me from this discussion? I really am enjoying the information, and do not want to lose receiving the notice of additional posts.

I am currently in middle GA being forced to wait till December before I can receive my leaf. I'm not a EE but I know my 600 amp service has plenty of room for one or two more 40amp 240's in any one of the three main sub panels. I am still undecided as to buying an SPX or the GE Wattstation. I like the SPX because I can use have the correct plug installed and "plug" in vice having it hard wired.

That will allow me to move the SPX to another location if I need to. I could probably do the same, with the GE so I'm still in the air but with two more months before Dec I still have time.

In the end I also want to upgrade my EVSE even if I am only leasing. The modified EVSE is more useful. But what I and the Leaf really needs is a network of L3 chargers between Warner Robins GA and Atlanta GA. An interstate distance of about 120 miles.

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

Posted: Mon Sep 26, 2011 6:31 pm
by jclemens
jwallace3 wrote:What appears to be the micro has markings 284k557 and a3k2b . Can't find anything on it as of yet. It appears to be a 20 pin surface mount micro.
not sure if this will help, or hinder, but Phil mentioned in a post a while ago something about programming assembly for a Fujitsu MB95280H. (http://www.mynissanleaf.com/viewtopic.p ... 1&start=60" onclick="window.open(this.href);return false;)

I couldn't find the top-marking for this part, but there is a specific version called: MB95F284K
However, i think this might still be a different part than what you are seeing. According to http://www.fujitsu.com/downloads/MICRO/ ... 00494e.pdf" onclick="window.open(this.href);return false; MB95F284K is a SOP 16 part.

Re: My L1 ESVE findings.....

Posted: Wed Sep 28, 2011 6:23 pm
by lincomatic
I did some testing of the ground integrity check w/o opening mine up. I connected the ground pin of the EVSE to an earth ground (a screwdriver driven into the dirt) instead of the house ground. It still passes the ground check and works normally, even though the impedance between neutral and gnd is very high, so this rules out the idea that it's checking the for neutral shorted to ground. My ammeter shows that there's a constant ~0.6A (sounds high to me.. but my two ammeters had the same reading) current running from hot to gnd. It checks the ground continously... if you disconnect it, the green ready light blinks, and when you reconnect the ground, it goes solid again.

So.. since it doesn't try to short neutral to gnd, and *if* there's nothing in the hot path through the relays that can't handle 240V, I think it should work on 240V with a power supply that steps it down to the 20V that the control board needs.

Some questions from the photo's I've seen of the insides:
1) Why is the small relay for GFI trip test 13A? Isn't that overkill?
2) Why is the fuse 25A when the main relays can handle only 20A, it's supposed to be used on a 15a circuit, and have 12A max current draw?
3) If it has a 25A fuse, why didn't the fuse blow when Ingeneer did the 26.5A smoke test?

Re: My L1 ESVE findings.....

Posted: Wed Sep 28, 2011 9:49 pm
by TomT
1) Why is the small relay for GFI trip test 13A? Isn't that overkill?
Perhaps, but that is likely a common component availability and that is what they used. Extra capacity won't hurt anything.

2) Why is the fuse 25A when the main relays can handle only 20A, it's supposed to be used on a 15a circuit, and have 12A max current draw?
Probably to protect against a serious short circuit if the circuit's own protection fails, but not blow under normal circumstances and cause a nuisance.

3) If it has a 25A fuse, why didn't the fuse blow when Ingeneer did the 26.5A smoke test?
A 25 amp fuse can handle a slight overdraw like that for a long time without blowing.

Re: My L1 ESVE findings.....

Posted: Thu Sep 29, 2011 2:07 pm
by jwallace3
120/0.6=200 ohm resistor. I will check for this. I'm still reverse engineering the DC path as of right now. As for the hot path, there are some tvss diodes that I'm not sure if they are good up to 240 or not. My guess is that they are not. One typically wouldn't design a circuit for 120VAC and use 240VAC TVSS diodes. They probably wouldn't do their job at 120 if they were spec'd for 240. And if overvoltage was applied to these diodes rated at 120 they would constantly be trying to short the excess energy to ground which would ultimately blow them up since they would be shorting all the time. Panasonic makes these TVSS diodes, here is the link to them:
http://industrial.panasonic.com/www-cgi ... 0002+4++WW" onclick="window.open(this.href);return false;

Notice there isn't one that convers the entire 120-240 range which is really more like 90-280 according to ANSI. So these must either be removed or an alternate path must be created for the second 120 leg of the 240 to maintain TVSS protection withing the ESVE. There is TVSS protection in the vehicle charger as well, but the J1772 recommends, if possible, to have TVSS protection on the ESVE end as well. The best way would be to add a third AC path with a third relay and another set of TVSS protection diodes from the second leg to the neutral as well. Then both are protected with respect to the neutral which should be at ground potential.


lincomatic wrote:I did some testing of the ground integrity check w/o opening mine up. I connected the ground pin of the EVSE to an earth ground (a screwdriver driven into the dirt) instead of the house ground. It still passes the ground check and works normally, even though the impedance between neutral and gnd is very high, so this rules out the idea that it's checking the for neutral shorted to ground. My ammeter shows that there's a constant ~0.6A (sounds high to me.. but my two ammeters had the same reading) current running from hot to gnd. It checks the ground continously... if you disconnect it, the green ready light blinks, and when you reconnect the ground, it goes solid again.

So.. since it doesn't try to short neutral to gnd, and *if* there's nothing in the hot path through the relays that can't handle 240V, I think it should work on 240V with a power supply that steps it down to the 20V that the control board needs.

Some questions from the photo's I've seen of the insides:
1) Why is the small relay for GFI trip test 13A? Isn't that overkill?
2) Why is the fuse 25A when the main relays can handle only 20A, it's supposed to be used on a 15a circuit, and have 12A max current draw?
3) If it has a 25A fuse, why didn't the fuse blow when Ingeneer did the 26.5A smoke test?