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Roadster UMC / thermal failure - Refurbishment possible?

bonnie

I play a nice person on twitter.
Feb 6, 2011
16,429
9,928
Columbia River Gorge
I've replaced my UMC after 2.5 years of use. I had the dreaded '4 red blinks' indicating a thermal failure and couldn't even charge dialed down to 12amps. I now have a new UMC and all is good.

But it sounds like the old one should be repairable. Or maybe recycled with use of the cable and Roadster head. What are the possibilities?
 

bonnie

I play a nice person on twitter.
Feb 6, 2011
16,429
9,928
Columbia River Gorge
Thanks, guys! Seems wrong to just throw it away. I'll look into repair, and if not repairable, if I can reuse the cable and Roadster head on a switchable J1772. Or something. Never hurts to have a backup UMC.
 

TonyWilliams

Active Member
Jun 11, 2012
1,438
759
San Diego - Tesla powered Rav4 EV
This Roadster UMC was flashing a green light for charge status, but as the picture shows, something got "smoked" inside:


null_zps93ec21e3.jpg




null_zpsc840ce29.jpg
 

apacheguy

S Sig #255
Oct 21, 2012
5,092
1,294
So Cal
I've replaced my UMC after 2.5 years of use. I had the dreaded '4 red blinks' indicating a thermal failure and couldn't even charge dialed down to 12amps. I now have a new UMC and all is good.

I guess I'm a little late to the game on this one, but wouldn't your failed UMC be replaced under the 4 year/50,000 mile warranty? Or does the Roadster warranty differ from that of the Model S?
 

bonnie

I play a nice person on twitter.
Feb 6, 2011
16,429
9,928
Columbia River Gorge
I guess I'm a little late to the game on this one, but wouldn't your failed UMC be replaced under the 4 year/50,000 mile warranty? Or does the Roadster warranty differ from that of the Model S?

The UMC warranty for the Roadster was only for 2 years. My Roadster warranty is for 3 years. Model S is different.
 

wiztecy

Active Member
Apr 29, 2012
2,905
566
Santa Cruz, California, United States
I'd definitely connect up with Tesla and share your findings on the failure, they may want to know about it. How old's the UMC? Was it ever in contact with the outside elements? I could see water possibly making its way under the laminate / led section if not tacked properly and causing a short/failure.
 

bonnie

I play a nice person on twitter.
Feb 6, 2011
16,429
9,928
Columbia River Gorge
2.5 years old, garage use only. There were several UMCs around the age of mine that failed in the same way. I should have asked to have it replaced before the 2 year warranty was up. I think (not sure) that it exhibited some early signs at higher amperage. But since I usually charge at lower amperage, I didn't really pay attention. So that's on me.
 

TonyWilliams

Active Member
Jun 11, 2012
1,438
759
San Diego - Tesla powered Rav4 EV
I called the folks at North Shore Safety (who actually build the UMC for Tesla) today to ask about possibly fixing the UMC. Unfortunately, the have "potted" the electronics in the UMC, so it will have to be a destructive intrusion.

It looks like I'll have to disassemble it similar to my Model S UMC disassembly!


IMG_2129.jpg


- - - Updated - - -

2.5 years old, garage use only. There were several UMCs around the age of mine that failed in the same way. I should have asked to have it replaced before the 2 year warranty was up. I think (not sure) that it exhibited some early signs at higher amperage. But since I usually charge at lower amperage, I didn't really pay attention. So that's on me.

If you still have it, I'd like to do a (destructive) failure analysis on it.

If you want to get rid of it, I can recycle it into an "OpenEVSE" controlled unit for future years of use.
 
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shrink

Supporting Member
Supporting Member
May 21, 2013
918
437
Phoenix, AZ
That's my UMC Tony is playing with! :smile: I bought the thing on eBay and it was obviously a bum unit. Grr....$500 paperweight.

Thanks for looking at it, Tony! I appreciate the effort, enthusiasm, and fearless tinkering. It'd be great if it were fixable, but at the very least I hope you can learn something from it.
 

hcsharp

Active Member
Jun 7, 2011
3,417
1,465
Vermont
...
If you want to get rid of it, I can recycle it into an "OpenEVSE" controlled unit for future years of use.

If FlasherZ were listening he would have something to say. While I appreciate your good intentions in offering to help Bonnie, your suggestion is illegal and potentially unsafe. What she could do that would be safe and legal would be to buy a Model S UMC and replace the MS connector with her old Roadster connector.

I have nothing against OpenEVSE, it's fine for building your own non-mobile charging station. But it doesn't do the same thing as the UMC. The UMC senses what adapter you are using and automatically regulates the amperage via the pilot signal. That prevents you from pulling more amps than a circuit is rated for. OpenEVSE doesn't do that with the hardware that Bonnie has for adapters. (Is there a version yet that even does this at all?) You might say "well she can limit amps from the VDS" but that only works if she remembers to do it every time she uses it. All she has to do is forget once to burn somebody's house down. Even if she always remembers, what if somebody else borrows her UMC and doesn't know? How about a PlugShare Roadster member who shows up at her house and uses it, and burns HER house down!

Another way to solve this issue would be to permanently attach a NEMA 14-50 plug to the end of it with neutral prong in place, so it cannot be used with adapters and cannot be plugged into a NEMA 14-30 or anything else. Then you can set the OpenEVSE to 40A.

Another solution would be to write some code for OpenEVSE so that it does the same as the UMC. There's plenty of documentation here on TMC that you can search for that tells how the UMC senses which adapter you have. The code would be easy to write. I've done it, but not for OpenEVSE. I did it for my own custom UMC that I made before OpenEVSE ever existed. If you want to support OpenEVSE, this would be a good way to do it because lots of UMCs have failed and lots of Roadster owners could use it.

Am I overreacting? 2 years ago I would have said "yes." But I've seen some crazy stuff happen in 2 years of road tripping and selling Roadster charging accessories. Recently as an experiment I tested a brand new 40A breaker to see when it would trip. I slowly kept increasing the amperage draw until I stopped at 64 amps and everything got too hot to continue. The breaker never tripped!

Tony please don't interpret this as me attacking you. I like what you're doing to help EV owners especially eRav4. I just wasn't sure if you were aware of the risks. As soon as somebody starts a fire charging their EV it will be headline news that EVs are dangerous and Fox will show pictures of babies in burning homes and the oil industry will love it.
 

TonyWilliams

Active Member
Jun 11, 2012
1,438
759
San Diego - Tesla powered Rav4 EV
I have nothing against OpenEVSE... Tony please don't interpret this as me attacking you. I like what you're doing to help EV owners especially eRav4. I just wasn't sure if you were aware of the risks.

You make a LOT of assumptions that I'm not quite sure why. First, the most troubling is the "illegal" part. Please provide the statue that I'm breaking.

Secondly, I'm well aware of the "extra" control pin from the wall plug end to control max amps. Obviously, this can be incorporated into OPENevse (it's already in the works).

I'm well aware of the risks, also, which is why I must respond to issues like your post. When that house burns down (and it will somewhere), the lawyers will use snippets from posts like yours to "prove" I'm negligent and a law breaker. I need to nip that in the bud today.

As to whether a Model S UMC/MC is better or worse than a Roadster one, let's just be clear. They both fail... a lot. The Roadster wiring is FAR more industrial grade and robust than that of the Model S unit, and therefore much heavier.

Since the Model S unit has already been cut open, I'll cut this one that I have open to hopefully compare hardware.
 
Last edited:

hcsharp

Active Member
Jun 7, 2011
3,417
1,465
Vermont
You make a LOT of assumptions that I'm not quite sure why. First, the most troubling is the "illegal" part. Please provide the statue that I'm breaking.

You're right I made some assumptions. In your post you said "I can recycle it into an "OpenEVSE" controlled unit for future years of use." My assumption was that you would actually do that. Using an OpenEVSE unit the way it is currently implemented is illegal to control a UMC. The statute is the one that says you have to comply with the National Electric Code. If you make an electric device, let's say a toaster, with a very common household NEMA 5-20 plug on the end, then you are required to design your toaster so that it can't possibly exceed the capacity of the circuit required to feed a NEMA 5-20 receptacle. That means it can't exceed the circuit capacity no matter what the end user does. For example, you can't make your toaster with a high and low setting, and label it with instructions that say, "Never use the high setting unless you are plugged into a NEMA 5-30 receptacle."

The same is true with an EVSE. The Roadster UMC comes with multiple adapters so that you can plug it into various types of outlets. The UMC automatically determines what type of receptacle you are plugged into by testing the adapter which has some simple passive components configured so the UMC can easily identify it. Then it scales the pilot signal down to match 80% of the capacity of the circuit required to feed that type of outlet. Due to this automatic scaling of the pilot signal, the Roadster, like the first toaster example above, can never pull more than 80% of the rated circuit capacity regardless of what the person charging the car does. They can forget to lower the amps on the VDS, or not even know they need to. The UMC will automatically do this.

That's why I still don't think you really understand the risks. OpenE is not currently designed, as you admit yourself, to automatically scale the pilot signal down to a safe level based on what outlet the UMC is plugged into. "In the works" as you say is not the same thing as it being done, and done exactly the same way as the Roadster UMC. If you read my post carefully again you will notice that I said this could be implemented in OpenE with some new code, and I even suggested that you should do it to help out the OpenE community.

Many people have suggested "why not have user-selectable amps on the control itself? Wouldn't that make it safe?" No. And it wouldn't make it legal. You have to understand that most EV users are not as smart as you and wouldn't set the user-selectable amps correctly. It might only take doing it wrong 1 time to burn a house down. Most people can't look at a dryer outlet and tell you "That's a 30 amp outlet, and I need to adjust my current down to 24A." I hope you're starting to see why it's unsafe.


Secondly, I'm well aware of the "extra" control pin from the wall plug end to control max amps. Obviously, this can be incorporated into OPENevse (it's already in the works).

That's why I said in my post that you should do this. You made no mention of your intentions in that regard, or that you were aware of the necessity. Perhaps you should have said "a future version of OpenE that is in the works."

I'm well aware of the risks, also, which is why I must respond to issues like your post. When that house burns down (and it will somewhere), the lawyers will use snippets from posts like yours to "prove" I'm negligent and a law breaker. I need to nip that in the bud today.

A bit far fetched?

As to whether a Model S UMC/MC is better or worse than a Roadster one, let's just be clear. They both fail... a lot. The Roadster wiring is FAR more industrial grade and robust than that of the Model S unit, and therefore much heavier.

I'm sure we agree on most things, and this is certainly one of them. It's always been a bit of a mystery to me why Tesla can make such fantastic cars, and such [email protected] chargers. Only the stuff made by ClipperCreek is any good.

From what I can tell, the weak link in the UMC (both of them) is the relay. Did they seriously think a relay wouldn't get hot after years of continuous use at it's max rating? In theory it would never break contact unless there's a ground fault but let's face it, max rating for a device like a relay is not sustainable long-term. It's also surprising to see a design that pulls 40A through traces on a circuit board, no matter how wide they are. After a few years of thermal cycles, they develop cracks and get hot.

I'm sorry if I ruffled your feathers. Didn't mean to.
 
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TonyWilliams

Active Member
Jun 11, 2012
1,438
759
San Diego - Tesla powered Rav4 EV
You're right I made some assumptions....
I'm sorry if I ruffled your feathers. Didn't mean to.

Certainly, telling folks they are criminals isn't probably the best way to approach such a subject, and then wonder why that might not be well received. Just to be clear, all your assumptions are exactly that, assumptions. Your issues with my alleged criminal activity are merely fictions from your imagination based on your assumptions.

As to the issues related to the actual thread, the OpenEVSE will work perfectly fine in both the Model S and Roadster UMCs with the upcoming additions that I previously mentioned. The end user experience would be exactly the same. The alluded to legal issues are fabrications that do not apply.

Here's a question for the Roadster folks... is there any restrictions in the owner's manual about using this in rain outdoors? I ask because after disassembling the Roadster UMC that I have, I found a hole in the top of the relay housing. This hole is actually the tiny little hole right below the charge status light:



null_zps93ec21e3.jpg
 

Doug_G

Lead Moderator
Apr 2, 2010
17,882
3,391
Ottawa, Canada
IIRC the UMC is not intended to be used in wet environments. When I've used it outdoors and there was any chance of rain I've always protected it.
 

hcsharp

Active Member
Jun 7, 2011
3,417
1,465
Vermont
Certainly, telling folks they are criminals isn't probably the best way to approach such a subject, and then wonder why that might not be well received. Just to be clear, all your assumptions are exactly that, assumptions. Your issues with my alleged criminal activity are merely fictions from your imagination based on your assumptions.

If you ever hear me proposing to do something that is illegal and potentially dangerous, please let me know. It might prevent me from making a mistake that could seriously injure somebody or damage property. You would be doing me a favor and I wouldn't be offended. I never called you a criminal. The reason I provided the legal tip was to help you avoid becoming one. Mostly I wanted to help you avoid doing something dangerous.
 

TonyWilliams

Active Member
Jun 11, 2012
1,438
759
San Diego - Tesla powered Rav4 EV
If you ever hear me proposing to do something that is illegal and potentially dangerous, please let me know. It might prevent me from making a mistake that could seriously injure somebody or damage property. You would be doing me a favor and I wouldn't be offended. I never called you a criminal. The reason I provided the legal tip was to help you avoid becoming one. Mostly I wanted to help you avoid doing something dangerous.

Alright, thanks for the positive intentions. Let's move on....
 

Nvbob

Roadster 1256
May 6, 2009
388
190
Just east of Lake Tahoe, Ca.
I charge our Roadster using a Roadster UMC at 32 amps on a 50 amp circuit and it is scheduled to start at 10pm nightly. When I purchased our car six years ago, I purchased two UMCs and typically switch them monthly to extend their lifetime. So far they have worked without issue.

Two nights ago, the car charged normally but in the morning I noticed the UMC fault led was on. The led was blinking four times reflecting a thermal failure. I cycled the 50 amp breaker in the house panel which reset the fault led (it returned to green “ready”). This morning, I noticed the fault led was on again with the same number of fault led blinks.

Well, I switched the UMCs and noticed the 14-50 connector seemed to be stuck. I finally was able to disconnect it and what I found really surprised (and startled) me. It appears that one of the hots had burnt badly. The house breaker had not tripped nor had the GFI on the cable. Nor were there any errors on the VDS.

Luckily, I had noticed this because of a potential fire hazard. According to other posts, this is a thermal failure. I will see how the second UMC does. If it starts displaying the same issues, I will have the circuit tested by an electrician and have the car checked by the SC.

Since the rest of the UMC appears to be fine (GFI is intact) I wonder if it can be resurrected?

14-50 UMC 1.jpg

14-50 UMC 2.jpg
 

gregd

Active Member
Dec 31, 2014
2,586
1,802
CM98
Isn't that the connector that attaches between the 14-50 pigtail and the UMC itself? I think the connector has some means of sensing what kind of pigtail is attached to it. You might be able to chop off the burned connector and replace it with a regular 14-50, but will need to hotwire that sensing thing (resistor?) or the max current could be set wrong.

That said, if that UMC turns out to be toast, contact me first before recycling it. I need a charging cable (sans UMC box) to finish an OpenEVSE charger.
 

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