FilterGuy
Solar Engineering Consultant - EG4 and Consumers
From what we can figure out it is an Isolating transformer that is used as an autotransformer when it is in passthrough mode and used as an isolating transformer when in inverter mode.
EG4 6000EX - Double Ground/Neutral
- Thread starter HLD
- Start date
from the drawing, can some one confirm zero/low-resistance (L1-IN vs L1-OUT) and (L2-IN vs L2-OUT) with every off and disconnected ? please, thanks
I do not have the AC input connected as my garage does not have a 240V outlet. I've tried connecting to the main house panel ground only, or the dedicated off-grid ground only, or both the main house/dedicated grounds together. Without the neutral ground bond in my critical loads panel (EV charger only), none of the ground combinations allowed the EV chargers to work.
However, by adding the neutral ground bond in the critical loads panel, the Tesla charger worked in the 8A current limited mode only, but it also faulted a short time later (< 1hr?) with an "overload" error. Wondering if the output NG bond is causing this? But without the NG bond, the charger won't work! I tried using only the main house cold water pipe ground per your suggestion but still got the 8A current limited fault on the Tesla charger (Juicebox doesn't work at all for any ground combination). So at this point, I am still unable to charge my car at >8A and the inverter may shut down again with the overload fault even at the 8A charging current level. Very frustrating...
I found the thread https://diysolarforum.com/threads/signature-solars-new-eg4-6000-120-240v-inverter.46208/page-8 where @thanhrodke is using his 6000Ex to charge his Tesla. Hopefully he will reply to my post.
Is anyone else using the 6000EX to charge a Tesla? I've seen the videos where Will Prowse is using the split phase 6500EX to charge his Tesla but I opted to go with the 6000EX because I have six window air conditioners that I plan to connect in the future and figured the 6000EX would be a better choice given the air conditioner compressor startup currents. Also watched his video where he suggested using the MPP version of the 6000EX (low frequency inverter), but he didn't show it actually charging his Tesla.
Still waiting for a response from Signature Solar tier 3 tech support after all of my issues were escalated...
did you try charging the Tesla with the PV disconnected, both (+/-) ?
Hi Summit,
Thanks for the suggestion. Haven't tried disconnecting the PV+/- yet. For some strange reason, the Tesla charger can now go up to 15A without faulting. The 6000EX isn't faulting either. No idea why both are working now with the same ground configuration as the other day when both were faulting. I'm wondering if the 6000EX takes a while to stabilize? I noticed it cleared the earlier overload fault when I left it running over night. If either faults again, I'll try disconnecting both the PV+/-. BTW, my current disconnect only disconnects the PV+. Is it common practice to disconnect both the + and -?
Thanks for the suggestion. Haven't tried disconnecting the PV+/- yet. For some strange reason, the Tesla charger can now go up to 15A without faulting. The 6000EX isn't faulting either. No idea why both are working now with the same ground configuration as the other day when both were faulting. I'm wondering if the 6000EX takes a while to stabilize? I noticed it cleared the earlier overload fault when I left it running over night. If either faults again, I'll try disconnecting both the PV+/-. BTW, my current disconnect only disconnects the PV+. Is it common practice to disconnect both the + and -?
Not common, in fact we want PV connected, it was just a test to eliminate the potential current leakage through the PV(-). I had a similar occurence charging my Bolt, it took a while to decipher my PV(-) was partially coupled, ~280K-ohm, to ground. I had left the PV(-) connected to a non-operating grid-tie inverter, which had some sort of ground coupling. I've since disconnected the PV(-) from the old grid-tie, but still have to verify. Things were not working as expected until the PV(+/-) were disconnected.
Take a look at post #47 here, not sure it's applicable to the 6000EX:
Why do we use a PV disconnect that breaks both the positive and negative side of a PV circuit?
It's only a situation with AIO's, as far as I know. Yes, that would be a dead short. Then I guess over current protection is required on the pv side regardless of the number of pv strings. I wonder if pv.negative and bat.negative are common?
diysolarforum.com
Hi Summit,Not common, in fact we want PV connected, it was just a test to eliminate the potential current leakage through the PV(-). I had a similar occurence charging my Bolt, it took a while to decipher my PV(-) was partially coupled, ~280K-ohm, to ground. I had left the PV(-) connected to a non-operating grid-tie inverter, which had some sort of ground coupling. I've since disconnected the PV(-) from the old grid-tie, but still have to verify. Things were not working as expected until the PV(+/-) were disconnected.
Take a look at post #47 here, not sure it's applicable to the 6000EX:
Why do we use a PV disconnect that breaks both the positive and negative side of a PV circuit?
It's only a situation with AIO's, as far as I know. Yes, that would be a dead short. Then I guess over current protection is required on the pv side regardless of the number of pv strings. I wonder if pv.negative and bat.negative are common?
Thanks for the feedback and reference posts. Here's my wiring diagram below. My Tesla charger started faulting again, so I tried disconnecting the PV+/- per your suggestion, and the Tesla charger faults went away (most of the time)! I cranked up the Tesla charger to 25A and it ran for a few minutes and then faulted and current limited to 8A again. Weird thing is that it seems to have recovered and is charging at 15A now.
While I'm happy that this allows me to charge at >8A, I guess this means I can only charge from battery while the PV+/- is disconnected. That disconnect switch is going to get a lot of wear and tear!
Questions:
1. Even stranger, the charger cycles between 15A and 22A on its own! Did you see that behavior with your charger?
2. After removing your non-operating grid tie inverter, did the 280 kohm resistance between PV(-) and ground change?
3. Are you using AC in and did you have to bond your EV charger subpanel to neutral/ground to get the charger to work? Since my charger only works when using my main service panel ground, I'm still concerned that some of my inverter neutral current could be backfeeding the grid neutral via the main service panel NG bond. Any thoughts on that? Note that I'm fully off-grid (no AC in), so although it appears that I have a double NG bond (critical loads panel and main service panel each have a NG bond), I think that's OK since I'm not using AC in.
4. Did you tie your battery ground to your inverter ground to establish a system ground? In that case the system ground is then tied to earth ground.
Sorry for all the questions. Would appreciate anyone else chiming in as well.
that PV disconnect was just a test, not to be operational
haven't try yet but will. I tested yesterday at just 8A on 120vac level-1
yes, it's now in Mohm and the U5648gk is behaving as expected. I was happy that it can now also power my HP water heater
no AC-IN to the inverter, yet. My current test is "off-grid" running from the critical load subpanel. Yes, N-G is bonded, has to be for the EVSE to work. It's part of the boot-up test.
your EVSE doesn't work from the critical-load-panel ? is it a Tesla's EVSE ? do you have a different one ? or can borrow one to try ? since it can charge 15A/22A, it must be 240vac; in which case it only needs L1/L2/Grd - no Neutral
what happens when charging from critical-load-panel ?
did not ground Batt-neg
what's the resistance reading PV-pos & PV-neg with respect to the EG6000 chassis ? I question the wisdom/need to ground the Batt-neg. Maybe someone more knowledgable can chime in. Does EG4/SSolar recommend it ?
Zwy
Emperor Of Solar
You have 2 N-G bonds, remove the N-G bond in the critical loads panel.
SunFarmer
New Member
Folks,
The EG4 6000EX-48 does have an internal NG bonding screw for the AC output. Confirmed by SS tech support and my own testing. I did not attempt to remove the screw for fear of voiding the warranty.
The EG4 6000EX-48 does have an internal NG bonding screw for the AC output. Confirmed by SS tech support and my own testing. I did not attempt to remove the screw for fear of voiding the warranty.
Yes, I understand it was just a test, but the Tesla charger self limits the current to 8A or completely faults and stops charging if the PV+ and PV- aren't disconnected, so I will need to disconnect every time I charge the car. With PV+ and PV- connected, I got a warning on my Tesla screen every 10s or so saying "Wall plug adapter error - Charge rate reduced." The Tesla universal mobile charger (UMC) has a removable plug adapter dongle with different plug types. I tried removing and re-seating the adapter several times. Also swapped the 240V adapter to the 120V adapter for L1 charging but it still gave the same error.
I still got the error a few times yesterday even with both PV+ and PV- disconnected, although it didn't fault every few seconds like it did when PV+ and PV- were not disconnected. So as of now, I can only charge my car with the solar disconnected, meaning I can only charge off my battery - pretty crazy!
Yes, bonding the critical loads panel NG is the only way I can get my Tesla universal mobile charger (UMC) to work because of the NG bootup test. But I'm concerned about the double NG bonding in the house main service panel and my critical loads panel, although in my case I'm only using the main service panel ground (No L1, L2, neutral connections) tied to my critical loads panel ground (EVSE didn't work with my auxiliary off-grid ground as the system ground). Since I'm not using the main service L1/L2 for the AC in bypass, I believe that's OK (Filter Guy thinks it's OK, but just saw ZWY's comment that I should remove the NG bond. But if I remove it, the charger won't work at all!
Do you have a dedicated ground rod for your off-grid system? Or are you tied into your main panel ground?
The Tesla UMC is plugged in to a 240V NEMA 14-50 plug which does have a neutral. The plug is powered by the critical loads panel. It's a factory 14-50 plug dongle so I assume the neutral is required to power the internal controller at 120V. I have a Juicebox EV charger but it won't work, even with the NG bond in the critical loads panel. The Juicebox is the EVSE that I prefer to use since it bolts to the wall whereas the Tesla UMC dangles from the outlet. Unfortunately, the Juicebox is a wall ornament at this point.
All of the symptoms described above occurs with the Tesla UMC plugged into the critical loads panel via the NEMA 14-50 plug.
I'll measure the PV+ and PV- to the inverter chassis later when I get a chance. I assume you are using the output ground terminal next to the L1/L2 terminals for your system ground since there is no chassis ground.
Thanks again for your feedback and comments.
Hi Zwy,
Yes, I'm aware that I have 2 NG bonds, however, my EV charger will not work without the critical loads NG bond. Since I'm not using the AC input (no AC bypass), the grid isn't being used as a source, so I don't believe there's a neutral return current or objectionable current on the EGC returning to the grid L1/L2. If I were using the AC bypass, then I would definitely remove the critical load panel NG bond to avoid any objectionable currents in the EGC (parallel neutral path).
Having said that, I am concerned that my inverter could be providing neutral current back to the grid since the neutrals are tied together via the critical panel NG bond. Or is the neutral current shunted to ground via the earth ground?
Hi SunFarmer,
I asked Signature Solar if there is an internal bonding screw, and they told me that some units are shipped with the screw and some are shipped without the screw. I was also told that the warranty would be voided if I opened the unit and that I would need an email or written statement from my electrician that the screw needs to be removed. Apparently, my PhD in electrical engineering isn't sufficient (I asked)!
PreppenWolf
Solar Addict
- Joined
- Oct 10, 2022
- Messages
- 932
Welcome to government created monopolies where people with no idea how electricity works get to decide who's allowed to make decisions.
Zwy
Emperor Of Solar
Looked at your diagram again. I'd remove the EGC from the main service panel to the critical loads panel. Then install a ground electrode for just that system, leave the N-G bond in the critical loads panel. As you do not have AC input, treat it like an off grid system separate from the main service panel. I would not run an EGC from PV unless you have to for inspection but you could run it and leave it disconnected from the critical loads EGC busbar.
Concerning the screw in the inverter, either test for N-G continuity with the N-G bond removed in the critical loads panel or try to use the charger with the N-G bond removed in the critical loads panel. The Tesla charger is smart enough to determine if some type of fault exists in the N-G bond, whether it is a parallel path or doesn't have N-G bond.
Most likely the bonding screw is there and you have a parallel path between critical loads panel and the inverter.
Hi Zwy,
Thanks for your suggestions. For reasons I don't understand, the Tesla universal mobile charger (UMC) only works when I connect the EGC to the main service panel ground and bond the N-G in the critical loads panel. I previously had a separate ground rod for the off-grid subsystem only (see rev 2 diagram below - I've since revised the wiring to what's shown in rev 3, which is the version you were commenting on). I'm now only using the auxiliary ground rod to ground the panels and it is not connected to the critical loads EGC busbar.
With the rev 2 wiring, the Tesla UMC kept faulting and current limiting to 8A. At one point, I had to use both the separate auxiliary ground rod and the main service panel cold water pipe ground to get the charger to work but it still current limited to 8A.
After disconnecting the PV+ and PV- per Summit's suggestion as shown in the rev 3 diagram, I was then able to charge at up to 25A. However, the Tesla UMC still faulted occasionally and throttled back to 8A before jumping back up to 22A on its own for unknown reasons. I also have a Juicebox EVSE charger but it won't work with any of the ground, NG combinations. It used to work when tied to the grid.
BTW, in the rev 3 diagram, the dashed green lines are not connected (forgot to annotate that).
I forgot to mention that I'm also powering a 120VAC 15,000 BTU air conditioner that draws 11 A. It runs fine so far, in spite of my Tesla charger travails. Since the Tesla EVSE is 240VAC, there's no neutral return current. However, my air conditioner does have a neutral return current, hence my questions/concerns about leakage currents to the grid. I'm guessing any current in the EGC is shunted to ground and doesn't back feed the grid neutral.
FilterGuy
Solar Engineering Consultant - EG4 and Consumers
When you say 22A, is that 22A on the AC?
Is it running when the tesla charger faults or current limits?
On a 6000w split phase system, you can pull a total of 6000/240 = 25A. If you are already running 11 amps on one phase, when you add 22A of 220V, the combined current of 33A is exceeding the capability of the inverter.
22A is the Tesla charger current at 240 V. I normally charge at 15A. I monitored the charger current with my Tesla app and noticed that the charge current spontaneously throttled up to 22A several times so I manually reset it to 15A. Weird.
The charger faults seem to be ground related but can't pinpoint it.
The air conditioner is off when charging the car.
It is sounding like your system has 3x NG bonds: inside the EG4, CRpanel, Main-panel. Confirm also that AC volt L1-N and L2-N, are the same. Since the EVSE is connected to the CRpanel, I would do some baby step tests:
1. remove CRpanel NG bond, 2. Check EG4 NG bonding (volt then ohm), 3. Check PV+/- G-bond also
My system has only 1 NG bond in the Main-panel when it's tie to the house wiring. In off-grid mode, the CRpanel has NG bond with G still sharing Main-panel G-rod, but no N connection
1. remove CRpanel NG bond, 2. Check EG4 NG bonding (volt then ohm), 3. Check PV+/- G-bond also
My system has only 1 NG bond in the Main-panel when it's tie to the house wiring. In off-grid mode, the CRpanel has NG bond with G still sharing Main-panel G-rod, but no N connection
