Volt Owners: Here’s Why Your Delayed Charging Failed

2011 Chevrolet Volt plugged into Coulomb Technologies 240V wall charging unit

2011 Chevrolet Volt plugged into Coulomb Technologies 240V wall charging unit

Enlarge Photo

We have greatly enjoyed our 2011 Chevrolet Volt range-extended electric car since its delivery early in January 2011, and it has seen much more use than the Nissan Leaf battery electric car that arrived about a month later. 

However, 15 to 20 percent of the time we've connected our Volt to the Coulomb 240-Volt wall charging station to charge itself late at night using the delayed-charge setting, we would find that it had failed to charge when we came out in the next morning.

At first, I thought the problem was some kind of mistake on my part concerning how I inserted the charging handle. But we also used the Coulomb charging station with our Nissan Leaf, and we never experienced a charging failure with that car.

After more than a year of frustration, I concluded that the problem was between the Volt and the wall unit.

About two weeks ago, I had the Volt fully checked out by my local servicing dealer (Hanlee’s Chevrolet in Davis, California), which found no faults recorded in the Volt’s black box.

So now it seemed that the problem was located in the wall charger, so I sent in a problem report to the Coulomb website.

This is the response I received:

Working cooperatively with GM, Coulomb's engineering team has identified the root cause based upon extensive testing in our lab with a Volt charging system and successful testing in the field with Volt customers using Coulomb charging stations.

Coulomb Technologies CT-500 electric vehicle charging station

Coulomb Technologies CT-500 electric vehicle charging station

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.

We made an engineering enhancement in our charging station to address this issue when charging with the Volt, and although not covered specifically under warranty, Coulomb is offering for a limited time to replace those Volt customer units affected by this problem.

Clearly, any Volt owner with the Coulomb 240V home wall-charging system who has experienced ANY failures to charge--particularly with delayed-charging time settings--should contact Coulomb quickly and report the problem in full detail.

Using delayed charging, for both cost and environmental reasons, is one of the primary advantages of electric cars. No owner should have to avoid this option due to of a design shortcoming in a wall-charging station. 

If you have experienced more than a single such failure to charge, it's possible that you too may have a technical problem in your Coulomb wall charger.


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Comments (15)
  1. Good catch George. Yep, if you wanna' be a pioneer, you're gonna have to take a few arrows for the team. Go Ags!!!

  2. George, great job tracking this one down and sharing the result with other Volt owners.

  3. This is interesting information. I just purchaed my 2012 Chevy Volt last month and I am having a CT500 station installed next week. I will definitely be paying attention when it comes to delayed charging. However, if you read into the wording of the response received, it seems like this might actually be a short-coming associated with the Volt and Coulomb is working to solve their problem.

  4. Sort of, but my read is that Coulomb did not properly design the early home wall units to function with the car's delayed timing process...and there might be similar problems (but much less frequently) with the Nissan Leaf.

  5. I have had this problem with my 2011 Volt and Coulomb CT400 EVSE. The Volt now has over 19,000 miles. I almost always noticed it before it caused a problem. We also have a LEAF with a ClipperCreek charger. I have used the ClipperCreek charger on the Volt many times, and never had a failure.

    Coulomb replaced my charger once, a couple of months ago, and the problem changed and became worse. With the first charger, I got hard groundfault errors occasionally. With the second charger, I get soft groundfault errors, but very frequently. A soft groundfault error tries again and attempts to restart after fifteen minutes. After three tries, it gives up. I have seen this happen repeatedly. I get text messages every time it happens.

  6. Continued... ... so I have quite a log. There was one other failure that Coulomb told me indicated an internal error in the Coulomb EVSE.

    My third Coulomb CT500 arrived the other day, and will be installed soon. In the meantime, I'm charging the Volt with the ClipperCreek EVSE, no problems.

  7. Correction first post said Coulomb model CT400 ... should be CT500.

  8. i never used delayed charging (benefits of no TOU in WA i guess) but a 15% failure rate would have been something i would have investigated a long time ago. now not sure what "high-frequency ground currents" actually means as in "occurs often" or high sine wave activity? but guessing its the later and it seems amazing to me that this is the problem. but either way, glad you found the fix. i claim no in depth knowledge of how these things are required to be so complicated to work...

  9. I am surprised that no one found a problem with this statement (and attitude) from Coulomb:

    "We made an engineering enhancement in our charging station to address this issue when charging with the Volt, and although not covered specifically under warranty, Coulomb is offering for a limited time to replace those Volt customer units affected by this problem."

    Seriously? They know it's broken by design but don't consider it a warranty issue? Don't get me wrong-we should be pleased that they are fixing the issue. But it's an expectation, not a gift.

  10. I found it highly questionable that they did not send out any kind of "consumer notice" to all their customers.

  11. It remains to be seen if Coulomb makes good on this promise at all. I sent my request in a week ago and although it appears in their system, nobody has contacted me so far. I've had this problem since day 1, going all the way back to January 2011.

  12. Keep us updated on any contacts from Coulomb. It was about a week for them to actually contact me, but they have been responsive, and I have seen other Volt owners on the Volt Forum report similar positive experiences. HOWEVER it should not have required us, as users, to recognize this problem when THEY KNEW about it for some time.

  13. Thanks for the tip. My Volt is at the dealer now for this problem. I just contacted Coulomb, they say my charger has not thrown the errors they expect for the 'Volt Issue' (or any errors for that matter), they are looking further into it. I had to call Coulomb, an email support ticket got no response form them. My Chevy dealer tells me that they have never seen this issue, the car has not produced any codes.

  14. Chevy wants me to do Delayed charging with the factory charger for a week. After the car charges for a week without trouble, that will point to the charger.

    Coulomb tells me that once the car is cleared of trouble, they can turn on some diagnostics in the charger and try to figure it out. My charger has not produced any faults, like the GFCI fault. Even though the symptoms are the same Coulomb does not think I'm having the same issue.

  15. my Phoenix holden volt trips RCDs.
    another volt from Melville Holden, Perth trips

    tripped RCD at my home when using mitsubishi EVSE
    http://www.charge-amps.com/um-evse trips
    http://evseupgrade.com/ - 2012 model trips

    15 amp circontrol
    don't trip

    elektrobay bollards

    holden's own 10amp evse OK

    according to http://teslatestandtag.com/
    there is earth leakage with the volt

    mitsubishi imiev has no problem with all the above chargers.

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