Survey: High Voltage Battery Junction Box issues?

[SpaceEVDriver]

Thanks for starting this poll! It’ll be interesting to see if there are any trends.

Thanks for responding! Feel free to share it in the various threads about this so more people respond. The embedded spreadsheet is updated a few minutes after a response is entered, so everyone should have access to the raw data.

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[SpaceEVDriver]

I am going to do fieldwork in a couple of days so won't be monitoring the thread or spreadsheet, but when I get back, I'll do some reduction and analysis.

 

[Mach-Lee]

Build date (if known) and current mileage should have also been included in the survey IMO.

 

[SpaceEVDriver]

Build date (if known) and current mileage should have also been included in the survey IMO.

I updated the survey.
I asked for mileage at failure, as well as current mileage.

Of course given that we have a few answers already, some of the possible correlations won't be entirely valid for all data, but that's not a big deal.

 

[AllenXS]

Thanks for doing this. It may be that is not a large issue but it’s still a pain. Heading into three weeks now, no loaner. Good to monitor as I’d hate to have to do this more than once (replace the HVBJB, not do the survey)

 

[Socalsp3]

Seems RWD is the least represented with hvbjb problem. Even so I have a rwd shipped that I'm hesitant on keeping. I have another order for later in the year that I may keep instead and hope they figure out this issue by then.

 

[SpaceEVDriver]

Seems RWD is the least represented with hvbjb problem. Even so I have a rwd shipped that I'm hesitant on keeping. I have another order for later in the year that I may keep instead and hope they figure out this issue by then.

Yeah, so far, about 29% of the responses are RWD owners, but only about 11% of the vehicles with failures are RWD, so yeah, if these early numbers hold up, RWD may be under-represented in the failures.

The ~24% "failure" response rate (9 total vehicles) you see here is way over-represented for a number of reasons, including my asking people who experienced the failure to respond, and people on the forum click on the threads that are of interest to them. If someone's not interested in the engineering and haven't seen the failure in their car, they may choose not to even click on the thread, much less respond to it. There's no possibility that the at-large failure rate is anywhere near 24%. My guess is that it's closer to about 0.1% to 0.2% of all vehicles delivered have experienced a failure of the HVBJB.

However, there are very few conclusions I would be willing to make so far. There's just not enough data.

 

[jimitoast]

Thanks to OP for doing this. This is a great idea. I am one of many soon-to-be owners that is very concerned about a failure like this after waiting 10-12 months for my car.

One potential opportunity for improvement: people may fixate on the "Stop Safely Now" message and you could receive responses from people that had a software problem or something other than a HVBJB that needed to be replaced. If the survey includes many failure modes and root-causes, it may be difficult to derive actionable insights from it. The survey might benefit from some clarity on the type of problem (software, hardware) and the action taken (software update, replaced HVBJB, replaced XYZ, etc). Then there is the question about whether or not the "solution" actually worked but that is starting to sound complicated. Thanks again!

 

[Rabidsquirrel22]

I got the “Stop Safely Now” message, but it ended up getting a new BECM, not a HVBJB. I don’t think we can blame all of these issues on one part.

 

[mkhuffman]

Happened to me twice in less than two months apart. Build date 07/21.

Your HVBJB was replaced twice? If so, you are the first to have that happen I believe. I have not seen any other reports of a second failure.

 

[generaltso]

There is some incorrect information in the question about daily charge level.

The owner's manual for 2021 Job 1 recommends 90% for everyday charging. That was changed in the 2021 Job 2 manual to "less than 100%". Then it was changed back to 90% in the 2022 manual. No version of the manual recommends 80%.

 

[SpaceEVDriver]

There is some incorrect information in the question about daily charge level.

The owner's manual for 2021 Job 1 recommends 90% for everyday charging. That was changed in the 2021 Job 2 manual to "less than 100%". Then it was changed back to 90% in the 2022 manual. No version of the manual recommends 80%.

Will remove reference to the manuals. I had skimmed the 2021 manual online.

 

[dtbaker61]

First draft of the Google Form survey is here.

https://forms.gle/w5VpcyMLv8LecH3G7


If you can think of missing questions, please post here.

great survey.... going to get some good data there I think.

In the meantime, I have a new theory on root cause of contactor (HVBJB) failure.... I'm thinking is could start with low 12v system voltage causing contactor relays to 'flutter' and not close solidly, arc, and weld shut.

I'm thinking that if the 12v battery happens to be run down, lets say close to 12.0 v, you hop in the car, start, turn on 12v loads like heat/air conditioning, then drive off right away... flipping on the 12v loads pulls the 12v system voltage down before the dc-dc has time time to 'charge the 12v', and the contactor relay can't hold good contact while you are accellerating getting rolling, and weld themselves together; which the car notices probably at your next stop when the contactors fail to open. This might also happen at a DCFC station I suppose if the 12v system is low, you plug in the DCFC and have big current flowing and the 12v system voltage sags a bit and can't hold the contactors....

This may explain why the vehicles don't have, or solve 12v charging issues, avoid the HVBJB problem.

 

[AllenXS]

I got the “Stop Safely Now” message, but it ended up getting a new BECM, not a HVBJB. I don’t think we can blame all of these issues on one part.

For mine I sent a note on the HVBJB issue then they advised they were doing the Becm. This weekend they started on the HVBJB. Hopefully that’s the end of the hardware.
God to see it’s not all HVBJB.

 

[Caliroute1]

Your HVBJB was replaced twice? If so, you are the first to have that happen I believe. I have not seen any other reports of a second failure.

Yes Sir Twice.
Towed in 01/04/22
Drove it it 02/14/22

I have several posts on this

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