Questions for Rivian

[ajdelange]

The Tesla S and X run all the accessories the same way ICE vehicles do, from a 12V battery. As this battery never has to handle a cranking load it is small. If it dies you can't control the car. But if it dies you can jump it in the same way that you jump an ICE vehicle and, presumably, then control the car enough to get it out of park. Now IIRC the 3 does not have the low voltage battery running all the control systems from as DC/DC converter. I have no idea whatsoever how Rivian will supply the low voltage loads in their vehicles. However they do it they will, we hope, design such that we can get out of a dead battery pickle without requiring drastic techniques.

{EDIT} IDNRC (I did not recall correctly). The 3 does have a 12 V battery.

 

[ajdelange]

Portable gas generator in the bed would take care of any range issues.

So let's think about how this works. You take your Home Depot 5 kW generator and some jerry cans along and when your battery gets low you pull over, fire up the generator, charge for a few minutes, and get back on the road. Sounds like a plan but let's just check on what a "few minutes" might amount to. The R1T will go about 400 miles on 180 kWH. That's 400/180 = 2.2 miles per kWh. Relative to generator power it's actually going to be more like 2 because of charging inefficiencies and 2 makes the math easier so your 5 kW generator will give you about 10 miles of range per hour of charging. Yes, that may get you out of a dead battery disaster if you are close to some place where you can plug in and charge but note that unless that place has a DC super charger you are only going to be able to charge at about 20 miles per hour as the AC charger in the truck is only rated 11 kW.

From another POV: could you drive 300 mi out into the boonies, camp for a week and run the generator 15 hrs to recharge the batteries for the return trip? Why not?

Ran my entire home off one many times after a storm. I used the 220 outlet and back fed the whole house thru the clothes drier plug as it's wired to both 110 buses.

Unless you opened the service disconnect you put lives at risk. This practice is absolutely forbidden for that reason. Lest you think me holier than thou I confess that I have done this but there were two disconnects between the panel I energized and the utility and they were always both opened. I did not allow anyone in my family to set this up except me. I have degrees in electrical engineering. Nonetheless i could forget and degrees or no this is still illegal.

If you want to power your house from a portable (or other) generator you must install a proper transfer switch configured such that the generator and utility cannot ever be connected to each other. They are relatively inexpensive and available from Amazon, Home Depot etc.

 

[RLXXI]

Unless you opened the service disconnect you put lives at risk. This practice is absolutely forbidden for that reason. Lest you think me holier than thou I confess that I have done this but there were two disconnects between the panel I energized and the utility and they were always both opened. I did not allow anyone in my family to set this up except me. I have degrees in electrical engineering. Nonetheless i could forget and degrees or no this is still illegal.

If you want to power your house from a portable (or other) generator you must install a proper transfer switch configured such that the generator and utility cannot ever be connected to each other. They are relatively inexpensive and available from Amazon, Home Depot etc.

You're not the only one with experience on this subject, I also have extensive electrical/electronics background . Of course I turned off the main when I used the portable generator in this fashion.

I no longer have a portable for power outages but I would use one again in a heartbeat in the same fashion if needed. I now have a Generac whole home back up with auto switch installed.



Don't assume anything ever and thank you for your concern but you're preaching to the choir.

 

[ajdelange]

Don't assume anything ever

Bad advice. The wise man is a Bayesian. He considers what he knows a-priori and merges it with what he observes to make assumptions on which to base his decisions. Besides which much of the advancement of science is based on analysis which begins with assumptions.

Do you think I'm completely stupid?

Bayesian reasoning says that's the wise thing to do in this case because if one does he is likely to fire off a caveat against back feeding and that is what I did.

Now lets look at how well you follow your own advice about not making assumptions:

Do you think I'm completely stupid?

You have assumed that the caveat against back feeding is aimed at you personally. In fact it was put out to warn others against this practice.

I also have extensive electrical/electronics background .

You are assuming I have an extensive electrical/electronics background.

Of course I turned off the main when I used the portable generator in this fashion.

You are assuming that this is safe practice. Were it so the NEC would simply require that one shut off the main disconnect. But it doesn't. It requires a transfer switch. There is a real danger in doing what you (and I) did, other readers should be strongly warned against it and if we did it in the past we were indeed stupid!

I now have a whole home back up with auto switch installed by a licensed electrician.

Did you see his license? If not you assumed he was licensed.

...thank you for your concern ....

You're welcome, I guess but the concern wasn't really for you but for the linemen whose lives you endangered.

 

[RLXXI]

Oh great god of knowledge, please feed me more of your unending wisdom.

Everything permanently installed where I live must be inspected by the local Firechief as well as the county electrical engineer, and building inspector.

Take your b/s and peddle it else where.

 

[ajdelange]

Be happy to help you if I can but I don't see how the fact that inspections are required in your jurisdiction (as they are in nearly all) has relevance to the discussion at hand.