I'm looking forward to a company that tries just having every piece of equipment with a direct HV connection, and its own voltage step down circuit if it can't be run off HV. Having a secondary battery system that has to be independently managed is just weird and has caused a lot of issues. Issues that aren't avoided by changing the voltage of secondary energy storage.
And that would be inovative…
Certainly the 12v loads in the last 50 years have exponentially increased. For that reason, we can either stop cramming more low voltage stuff in or increase the V as you say.Not sure about dying on a hill, but as an EE I have harped for a while that we need to bump the LV side voltage with the currents we are asking from modern vehicle systems. You know, p=va... there comes a point that if you don't boost the "v" variable the "a's" start becoming unwieldy.
A lithium 48v LV battery can withstand exponetially more abuse, draw-wise, than the 12 lead-acid MC batteries Rivian is using. The "keeping it charged" portion of the problem also get's easier. The system can count wh in & out, rather than monitoring voltage. Draw 50% from your 12v pb battery, and you are done; not going anywhere. Draw 50% from your 48v lithium LV battery, & it fires your vehicle up as it would at 100%... while making a note to add wome wh's to it.
Seems a good plan to me...
So your argument is really that lithium is a better battery chemistry than lead-acid for this application, as opposed to 48V is better than 12V. That's neither here nor there, because the problem with Rivian's 12V system has nothing to do with the chemistry or the voltage, so switching either doesn't fix the fact that the BMS has had bugs which allow the 12V batteries to fully drain, regardless of their chemistry.
The issue here is if there is an issue that the vehicle needs to blow the HV fuse, the fire department needs to kill the HV, the shipping mode disconnects the HV, it kills the entire system.
Could you elaborate on why either of those situations would be an issue? Rivian's transport mode doesn't fully disable the HV battery anyway.
Say you have an accident that damages the HV battery. Would it be safer for the HV to control the contactor that disengages the HV or a separate voltage system that can fully function if the HV battery is compromised? It's a safety feature.
And problem solving like that is what makes it innovative. If they come up with a circuit with capacitors holding a charge in the event of a HV failure that could control the shutdown.
You don't need the remainder of the electronics to be active for an extended period of time in that situation. The vehicle is undrivable when disconnecting the HV system as a significant portion of the electronics is disabled.
My R1T died in my driveway. Part of the reason why it may have taken 2.5 weeks to get a mobile appointment is I live 2.5 hours from the closest service centers (although my mobile tech lived about 1 hour 15 minutes from me). Rivian did not suggest or mention trying to jump it myself. I thought about trying, but decided not to. I do also have a 2019 Wrangler, so I wasn't without a vehicle. In my mind, if I did jump it or revive it on my own, how long would it last? Would it die again in my driveway, or at a store, or at work? I did not get a 12v system warning either, at least within the weeks before it happened. I remember getting one months ago, but it cleared before I backed out of my driveway.
While I have never had an undrivable vehicle, based on my experience, they don't seem to differentiate between vehicles that are in service where they are paying for a rental, and one where the owner opted not to do a rental. Both situations were unacceptably long.
