Vacation Ruined - catastrophic failure

[Dark-Fx]

Is there any 'proof' to premise that Rivian redesigned the 12V system to use a single battery? Is the speculation that it's lithium? Would like to see a Munro kind of tear-down of the whole 12V system - ideally a before and after - if there really is a redesign.

Mobile service has typically been quoted as the ones mentioning it when handling a 12V battery issue. It's possible every person talking to them misunderstands what they are saying.

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[RexRemus]

Text from service:

“Hi Soupdc, we have completed service on your R1T and found that 1 of the 12V batteries needed replacement.”

If this is the result of a single 12v battery dying... like... can they not wire up some redundancy? Even if it only lasted a short time, wouldn't you want to "limp" the vehicle as far as possible to avoid this kind of horror story? It seems nuts to me that what amounts to the CMOS battery in this "computer on wheels" seems really poorly thought out and prone to frequent, and catastrophic (as far as results) failure...

Like 12v systems are the most "legacy" part of this entire vehicle outside like... "the wheel" - we have like 100 years of experience with low voltage DC in vehicles...this shouldn't be causing issue this severe when there's a giant battery in the vehicle that can supplement this subsystem of the vehicle - I understand why there's a dedicated 12v system, but why not design for "protect the driver at all costs" if there's another method to delver that voltage/current - use it, throw all the alerts you want, say "the moment you shut this off, it will no longer work, but keep the vehicle running and let the driver have the BEST chance to get it off the road to somewhere safe.

 

[SoCal Rob]

I seem to recall seeing batteries with a different form factor on some really old cars from the 1930s or 1940s. They almost looked like they were half the width and twice the length of what a typical battery of today looks like. I could see Rivian using a single battery like that in place of the dual battery setup which seems to be so trouble-prone.

If it would be too difficult to have such an unusual battery made, what about going to two 6v batteries wired in series? If each was the same size as the existing 12v batteries Rivian is using, and if each was half the voltage with up to twice the amp-hours then the total power available should be roughly the same right? While it doesn’t address the issue of 2 batteries which can fail instead of one, it does address the issue of power draw per side. By that I mean that right now if something on one side of the vehicle is drawing more power than it should then one of the two relatively weak (in amp-hours) batteries could be rendered dead twice as fast as a single 12v source (1 large 12v or 2 large 6v in series) with twice the amp-hours.

I guess the real question is: why are some of these 12v batteries being discharged until dead? Is there an issue with defective batteries (in which case leaving the vehicle alone and getting better batteries will help) or is there an issue with the vehicle’s electrical architecture (in which case tying the 2 sides of the vehicle together to a single power supply with more amp-hours will help fix the problem or make it lesS likely)?

I’m not an engineer so I won’t be at all offended if anyone thinks my simplistic view is completely wrong.

 

[Dark-Fx]

I seem to recall seeing batteries with a different form factor on some really old cars from the 1930s or 1940s. They almost looked like they were half the width and twice the length of what a typical battery of today looks like.

Likely just 6V lead acid batterys. Lead Acid battery cells are 2V each. Cars these days use 6 cell batteries.

 

[SoCal Rob]

Likely just 6V lead acid batterys. Lead Acid battery cells are 2V each. Cars these days use 6 cell batteries.

But the concept is the same: change the form factor of the battery to effectively be the shape of the 2 Rivian short thin batteries* into a single long thin battery which fits the existing space and is still 12v but now has ~twice the capacity in amp-hours.

*Compared to a more common short thick form factor we see in most other 12v vehicle batteries

 

[ZipZamZoom]

Has any resourceful owner figured out a field repair for this (more specifically a get out of the field repair) or does this require a system reconfiguration of some sort?

I worry less about failures than I do about terminal failures where there is no workaround.

 

[NY_Rob]

Love the idea that now the 12v system has effectively double the chance of failure, since it's basically inoperable with half the system down.

Why in the world would they build it this way I wonder, every other car just has the single 12V bus, why would there be two nonredundant systems?

This one boggles me too....what is the upside of this design?

Even more of a head scratcher is Rivian's choice to use fuses that are not available at any auto parts store in the USA?
Please... no one reply "packaging" because as that is likely the case of using 2 smaller batteries in place of one larger 12V battery... the crazy fuses Rivian has decided to use are no smaller than conventional automobile fuses that you can find in virtually any location on the continent.

 

[240vPlug]

I may pull my cover off today and see if my March built 23 has a single 12v

 

[Donald Stanfield]

Even more of a head scratcher is Rivian's choice to use fuses that are not available at any auto parts store in the USA?
Please... no one reply "packaging" because as that is likely the case of using 2 smaller batteries in place of one larger 12V battery... the crazy fuses Rivian has decided to use are no smaller than conventional automobile fuses that you can find in virtually any location on the continent.

I think that’s an attempt at avoiding end user fuse replacement.

 

[NY_Rob]

I think that’s an attempt at avoiding end user fuse replacement.

Not disagreeing with your statement.... but how does that benefit Rivian or the vehicle owner?

If replacing a simple 12 volt automotive fuse is considered too complicated or somehow now considered too dangerous... we're screwed as consumers.

 

[Donald Stanfield]

Not disagreeing with your statement.... but how does that benefit Rivian or the vehicle owner?

If replacing a simple 12 volt automotive fuse is considered too complicated or somehow now considered too dangerous... we're screwed as consumers.

Yeah I would tend to agree with you, but I have also seen some really stupid things attempted by end users so I suppose I can see some sort of justification for the choice.

 

[NY_Rob]

Yeah I would tend to agree with you, but I have also seen some really stupid things attempted by end users so I suppose I can see some sort of justification for the choice.

I think at this point... with where Rivian decided to place the two fuse boxes- many customers would have their local garage replace a blown fuse just because they made them difficult to get at. But, that would depend on the garage having access to replacement fuses.... which no one has other than Rivian.
I guess my whole issue is self serviceability.... I for one do not want to waste a full day driving to and from the "closest" Rivian Service Center just to replace a simple blown fuse because the license plate bulb on my boat trailer shorted out and popped a fuse.

 

[Zorg]

At least in my Tesla, car gave me a warning that 12V was about to die. Ranger service came to my house and replaced it within days.

It's kind of ironic that the 12V battery is the weak point in EVs.

 

[ironpig]

The 12V system is badly designed and the whole "1 battery for each side of the truck" should have been killed in development.

BUT - We are stuck with it.

So Rivian needs to be able to update software to show the health of each battery so the owner can decide when to proactively replace one or both of those batteries rather than waiting for one of them to die leaving them stranded.

EDIT (also really sorry that your trip was ruined. That sucks and I feel for you especially after having that many miles on the vehicle and making the logical assumption that it would perform as needed on your trip)

 

[Donald Stanfield]

I think at this point... with where Rivian decided to place the two fuse boxes- many customers would have their local garage replace a blown fuse just because they made them difficult to get at. But, that would depend on the garage having access to replacement fuses.... which no one has other than Rivian.
I guess my whole issue is self serviceability.... I for one do not want to waste a full day driving to and from the "closest" Rivian Service Center just to replace a simple blown fuse because the license plate bulb on my boat trailer shorted out and popped a fuse.

Yeah I’m not at all disagreeing with you there. I think not using standard fuses was a mistake.

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