Hi all; I am getting error code 954 (line voltage lost sync) on the VDS, and flashing red lights (no blink code) on my UMC, even charging at 24 amps (on my 40 amp circuit) after charging for over an hour, sooner at 32 amps. It does not respond to the reset button, but after sitting a while unplugged the UMC will show green again without pushing the reset button. This is my second UMC in the month since I got my (CPO) Roadster by the way... I still have my G.E. Wattstation left over from my Leaf, and am wondering if maybe using it with a J1772 adapter would result in smooth sailing. But - I don't know what exactly if anything was wrong with my current, or what to have an electrician look for. I certainly wouldn't want to risk damaging my Roadster because the Wattstation would let too much variation in current pass through! The Leaf (now gone - no room for both) never had a problem charging through the Wattstation (same circuit), by the way. (I am considering this notion because I already have the G.E., as opposed to getting a Tesla wall unit for another two grand, and don't want to do that only to find out it's a problem with my house circuitry!) Anyone have any experience or suggestions? Thanks!
Doug_G
Lead Moderator
The EVSE has only three functions: ground fault detection (leakage to ground), signalling the car how much current the circuit can handle, and flipping a mechanical switch to turn the power on (the switches are known as "contactors").
In short, the EVSE is just a switch. Nothing more. It doesn't control the charging at all - the car does.
The Wattstation can't damage the car any more than the UMC can.
In short, the EVSE is just a switch. Nothing more. It doesn't control the charging at all - the car does.
The Wattstation can't damage the car any more than the UMC can.
+1 to what Doug said. I've charged from a GE Wattstation using my CAN J1772 adapter without any problems.
That usually happens when one leg of the 240v circuit becomes disconnected. For example, if a 240v breaker trips, both sides don't usually disconnect at exactly the same time. If one of the SSRs (electronic versions of contactors) in the UMC disconnects, or the relay, but not at the same time as the other, you will usually get that message.
Did you get your UMC from Tesla with a warranty? Did they replace the last one? Charging with the Wattstation will help isolate whether it's the UMC or something strange about the power supply in your neighborhood. Have you tried charging anywhere else with the UMC or on another Roadster?
Good luck and let us know what you find out.
That usually happens when one leg of the 240v circuit becomes disconnected. For example, if a 240v breaker trips, both sides don't usually disconnect at exactly the same time. If one of the SSRs (electronic versions of contactors) in the UMC disconnects, or the relay, but not at the same time as the other, you will usually get that message.
Did you get your UMC from Tesla with a warranty? Did they replace the last one? Charging with the Wattstation will help isolate whether it's the UMC or something strange about the power supply in your neighborhood. Have you tried charging anywhere else with the UMC or on another Roadster?
Good luck and let us know what you find out.
Happily, the UMC is covered under the 37 month bumper to bumper warranty that all the CPO Roadsters come with. The first one, by the way, failed in the same way at the Rockville Tesla as well. I haven't gone to Rockville this time (yet). My neighborhood (and my house) date from the early 60's, so it may indeed be a problem in the power supply. The circuit itself is new, put in when I first got my Wattstation for the Leaf. (The company that did that had done many charging station installations.) So; what do I have an electrician check for? I'd rather do that bit first before getting an adapter or a Tesla wall unit (if that would even be a solution). Another question: has anyone else found they can't reset their UMC right off? I find it strange that it resets itself after a while. (I don't know the time period on that, but it does get pretty warm, maybe a component is cooling off?) I appreciate your thoughts.
dhrivnak
Active Member
By chance do you have a neighbor that has a NEMA 14-50 or a campground nearby to test out your UMC? If the UMC works there then it is likely your house/circuit.
It could be a simple as a lose wire.
It could be a simple as a lose wire.
It sounds very much like something is causing the UMC to overheat. There's a thermal sensor in the control body and there may be another in the plug for the adapter. The fact that it stops charging sooner when drawing more amps is a clue as well as the fact that it resets automatically after it cools down enough. The sensor could be bad but it's more likely that something is causing it to heat up, which is bad news. It could be a bad connection/loose wire or a bad crimp somewhere. Find out what gets hot first. Is it the NEMA 14 outlet or the UMC control box or one end of the plug/adapter?
I got a UMC with my roadster that I bought in November. The UMC worked fine for a couple of months and then it started acting up. Initially it would charge at any amperage but it just kept getting worse and worse until it would only charge at 15 amps. I then tried to "fix" it and it never worked again.:tongue:
EVsport
Member
I have the GE wattstation purchased at Home depot married up to HCSHARP's adapter "THE CAN". 220v with 60amp availiable. Havn't had any issues.
sethr, I'm up in Winchester, VA, PM me if you know of any Roadster gathering's this summer.
sethr, I'm up in Winchester, VA, PM me if you know of any Roadster gathering's this summer.
Only the UMC control box gets hot. In fact, it starts out rather warm: with the garage at 73, I measured the box at 91, even though it was just sitting plugged in but hadn't been charging for 8 hours. Does that seem excessive? By the way, I have a NEMA 6-50 outlet, since that's what the G.E. Wattstation required. I haven't yet measured it's temperature while charging, and won't be able to for a week (I'm flying out of town today, unfortunately. First thing to do when I return.) Thoughts? Thanks.
Yes. When not charging it only has a very low wattage power supply that might heat up, but not that much. You should only expect that box to heat up when you are charging. Even then it should only get warm, not hot.
Maybe not hopeful, but I am using the GE Wattstation with the MS and its adapter. No issues whatsoever.
NigelM
Recovering Member
WRT the OP "line voltage lost sync" message, I get that every time I try to start charging the car after it has been in storage mode. I had forgotten about it but just came back from a couple weeks away and the same thing showed up again. The correction for me is to unplug everything, close the charge port door, turn the car on and reset the charge mode to default, turn car off and then plug the UMC back into the wall and then the car. Works every time.
