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Discussion Starter #1
Volt had been charging in the garage for a couple hours when it started chirping.
It turned out the Coulomb CT500 level-2 EVSE was displaying this error message:
FAULT: RELAY STUCK CLOSED​

It seems Coulomb will replace the unit though SPX, but it will take some days.
Evidently this is a known problem with a subset of CT500 EVSEs.
 

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Sorry to hear that. Out CT500 has been giving GFCI faults more often lately, a couple of times a day for a few days last week. I hope that it's not about to break. The 120v Voltec EVSE that came with the car as been flawless.
 

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I have experienced many faults with the CT500. Because the fault error usually occurs at the start of charging, it's a frustration to wake up to an uncharged Volt if the charge starts early in the morning. The workaround is to manually charge the vehicle rather than let it start automatically with the Volt's scheduler. Having a TOU meter, I manually start the charge after 9 PM for optimal savings.

If a fault occurs, removing the charging handle from the Volt and reinserting it is all it takes to clear the fault. The bright red light on the charge station makes it easy to realize that charging failed.
 

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Volt had been charging in the garage for a couple hours when it started chirping.
It turned out the Coulomb CT500 level-2 EVSE was displaying this error message:
FAULT: RELAY STUCK CLOSED​

It seems Coulomb will replace the unit though SPX, but it will take some days.
Evidently this is a known problem with a subset of CT500 EVSEs.
Any idea what subset of CT500 by serial numbers? I have one coming and hope they are not shipping known bad units.
 

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Discussion Starter #5
If a fault occurs, removing the charging handle from the Volt and reinserting it is all it takes to clear the fault. The bright red light on the charge station makes it easy to realize that charging failed.
I didn't make this clear, but this RELAY STUCK CLOSED thing is a permanent fault. The red light never goes out. Reinserting it does nothing. I have had a few GFI faults and they are as you describe, but this is different.
 

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I never experienced a relay problem. Sorry it totally trashes the CT500. This is one reason I have spare Voltec 240 volt model sitting in a box, ready to charge the Volt if the CT500 totally fails.

I only shared the lesser fault problem to help add data that the CT500 needs some serious design improvements to make it 100% reliable. The ongoing easy to fix fault problem has changed the way I charge the Volt. Sounds like the relay problem would require total charge station replacement.
 

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Discussion Starter #7
Mark Z, I'm sorry your unhappy with your CT500? Do you think the 240V Voltec would be any better for you?
That is, do you think your problems at the start of charging with are do to a flaw in the CT500, as opposed
to the Volt or your household wiring?
 

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My CT500 got installed this morning (after a 30 day wait) and this evening, just as it finished its first 100% charge, it gave me this error. Technical Support says it is dead and they will ship me a replacement unit. Not giving me a lot of long-term confidence in these units.
 

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I have two of the CT500's and one of the Voltec 220's. all 3 have been working fine.

was there a recal of the CT500's? luckily, mine are both working fine, one after a year of use and placed outdoors on the side of house, the other after about 6 months of use, but placed inside the garage.
 

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I have one of these units in the garage since Nov and have had no issues. I hope this post does not change my luck.:)
 

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Discussion Starter #11
I'm waking a zombie thread because I just discovered some information (from 2012) about Coulomb (Chargepoint) CT500 ground fault failures, similar to those described in this thread. The link is https://www.greencarreports.com/news/1076764_volt-owners-heres-why-your-delayed-charging-failed and here's google's cache.
Excerpt: We were able to characterize this problem as resulting from high-frequency ground currents induced by the Volt on-board charger and causing GFCI trips on the EVSE when its contact relay closes at the start of a session or upon closing the relay when instructed by the Volt battery management system. This problem does not manifest itself on all Volt EVs, and occurs more frequently when the Volt is set in delayed charge mode. In delayed charge mode, the Volt "wakes up" multiple times per hour and instructs the charging station to close the contact relay, thereby increasing the probability of a GFCI fault.

Presumably this was issue cleared up in the units they manufactured after mid-2012. Since my unit with the "relay stuck closed" problem was replaced (with a refurb unit) under warranty in 2011, it's possible it has this ground fault problem but I don't think I've ever experienced it. Then again, I don't use delayed charging.

BTW, it seems that these Coulomb CT500 units have two common failure modes:
  1. power supply failure [info link]
  2. continuity failure where the external J1172 cable connects to the internal wiring [info link]
"Relay stuck closed" doesn't count as a common failure, as I haven't seen anyone else experience it. However my replacement CT-500 did eventually experience the continuity failure issue, which I fixed by replacing some of the internal connectors and cabling.
 
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