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diy solar

EV charger not working when fed from inverter AC output

Azydo

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Nov 1, 2023
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I have a 10KW Sungoldpower hybrid inverter (SPH10K48SP) along with 2 X 48V 100AH Server Rack Lifepro battery SG48100P solar system. Inverter AC input is fed from the main panel. Inverter AC output is feeding a subpanel. The ground and neutral are bonded at the main panel but not at the subpanel. I have the inverter setting 01 at SBU, which indicate AC out source priority to Solar then battery then utility. Setting 06 is at SNU for battery charging mode. Setting 63 is set to DIS to prevent neutral and ground bonding at the inverter.
My EV charger will not work and give a red light, which indicates an improper grounding, when fed from the subpanel through a nema 14-50 outlet. It works normally if connected to a regular outlet power from the main panel. All other loads fed from subpanel are working normally. The ground wire for feeding AC input from the main panel is connected to inverter AC ground input while the ground wire for feeding AC output to the subpanel is connected to the inverter AC output. I really want to use the subpanel in charging my EV to take advantage of solar power. Not sure if I'm missing anything that is causing the ev charger to see a grounding problem. Thanks for any help.
 
I have two SRNE inverters (so does @42OhmsPA) in parallel, the OEM for your SGP 10k. I think I have a clear picture of your wiring from your description, but want to toss a couple things out there. You could try 63 ENA, I'd be curious if that works. That might be easier and supply the NG bond needed.

In wiring mine, I carried the neutral and ground from my main panel over to the sub panel (unbonded, they're on distinct bus bars). On your inverter, if you take a multimeter and test the ground outputs from AC-in & AC-out, you'll find continuity (at least on the SRNE units), so only one ground needs to be carried to your sub panel, and then sub panel to main panel. As long as the wiring path does not create a ground loop, you're tied back to your main NG bond.

I found out I had a missing link in my neutral in a roundabout way -- not with an EV charger -- but with the UPS that protects my servers. It started giving me a warning about improper wiring. That was fixed as soon as my neutral was carried over to the sub panel.

Let us know how it goes.
 
I’m unable to change the 63 setting. It remains at DIS regardless of how many times I press the up and down arrows. I had no issues changing other settings but not this one.
Alternatively, I bonded the screw at the sub panel for the neutral and the ground. Amazingly, this solved the problem and the ev charger is working again. Now, I’m concerned if this will cause the grounding loop since the bonding screw is on for both the main panel as well as the sub panel. What if this hybrid inverter switches to utility mode instead of batteries? Is there anyway to verify if the grounding of the entire setup is proper? Thanks.
 
Electricians generally verify it by doing it right, TBH. Yeah I know it’s tautological

You can somewhat easily check if it’s wrong, if you clamp the correct ground and see current when 120V loads are active. But this presumes you already knew which grounds were in the loop. Usually if you can reason that out, you would not introduce the loop in the first place. IOW this is highly prone to false negative, where you erroneously think it is OK.

As for someone verifying for you. Spam a ton of photos and drawn schematics. Based on what you wrote I can imagine both correct and incorrect.
 
I’m unable to change the 63 setting. It remains at DIS regardless of how many times I press the up and down arrows. I had no issues changing other settings but not this one.
Did you try powering off the rocker switch on the bottom right side? You'll still be able to access the settings for a few seconds until the display shuts off, once you're in the settings it will stay on until you back out.
 
I’m unable to change the 63 setting. It remains at DIS regardless of how many times I press the up and down arrows. I had no issues changing other settings but not this one.
Alternatively, I bonded the screw at the sub panel for the neutral and the ground. Amazingly, this solved the problem and the ev charger is working again. Now, I’m concerned if this will cause the grounding loop since the bonding screw is on for both the main panel as well as the sub panel. What if this hybrid inverter switches to utility mode instead of batteries? Is there anyway to verify if the grounding of the entire setup is proper? Thanks.
afaik the neutral is switched in the transfer switch. When the inverter is supplying power it need its own N-G bond because the neutral is disconnected from the main and hence the main panel bond is disconnected. All seem normal and ordinary without concern. Clear to charge the vehicle.
 
afaik the neutral is switched in the transfer switch. When the inverter is supplying power it need its own N-G bond because the neutral is disconnected from the main and hence the main panel bond is disconnected. All seem normal and ordinary without concern. Clear to charge the vehicle.
Doesn’t that mean if the inverter is transferred to grid there will be a ground loopv
 
Did you try powering off the rocker switch on the bottom right side? You'll still be able to access the settings for a few seconds until the display shuts off, once you're in the settings it will stay on until you back out.
That did allow me to change the setting with ID 63 into enabled. Consequently, I removed the bonding from the sub panel. The ev charger is working normally and so is the rest of the loads. Thank you for the help.
 
Can you please check in the sub panel L1 to ground voltage, L2 to ground voltage and neutral to ground? Plus do this at the NEMA 14-50 socket. Make certain L1 and L2 were not somehow switched along the wiring way to screw up the split phase. Carefully trace the wire from inverter to outlet. I have made that mistake in the past.
 

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