Backup power - replacing a gas generator for now, V2H in future?

[ajdelange]

I’m really hoping for V2H at launch.

It's pretty certain that isn't going to happen.

That would be a great benefit for any homeowner.

Not, apparently, to the 12.5% of respondents to the poll who said they would never use it.

At least I could run critical systems with the confirmed (3) 120v circuits. Septic pump, furnace fan (gas heat), and a bedroom for lights and phone power. Running the fridge would be 4th on our list. Considering not all 4 circuits would need to run simultaneously, I could engineer a way to flip power around every 6-12 hours, but I’d rather not do the gymnastics. Our worst outage in 4 years has been 12 hours, but the neighbors told me about a 2 week outage within the last 10 years…

There are many solutions to the emergency power problem and which you adopt depends on how often you have power outages, how long they tend to last, how long is the longest you want to be able to sail through comfortably and how big a load "comfortably" implies. The "best" solution is a solar system backed by batteries as with such a system of sufficient size you can run everything indefinitely as long as the sun is shining. Enduring long periods of no sun is handled by installing more battery but that's very expensive so many choose to have generator backup to the battery backup. This adds cost and complexity but with such an arrangement you can go forever as long as the propane truck can get to you which it can't always do - you'll never get to five 9's.

For very modest loads (light, small fridge, cell phone charging) you can put together a relatively modest emergency supply with a battery pack (Yeti, Jackery...) and a couple of solar panels. You may need to convert 110 to 220 in order to run a furnace fan, well pump etc and you will have to ration power depending on sunshine.

I would only use a BEV as a last resort as I want as many miles in the tank ad I can reasonably have. Remember that a BEV battery loses about 1% of its charge each day.

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[DucRider]

Remember that a BEV Tesla battery loses about 1% of its charge each day.

Your "Tesla only" experience is leading you astray again. Not all EVs suffer this malady - only time will tell how the Rivian performs

 

[crashmtb]

Try to understand these comments beyond literal interpretation. As an example I have sump pumps that could easily be covered with lead acid batteries. But I also have heat pumps which keep the house warm in winter. The max Rivian battery would run the main heat pump for 3 days but not if it isn't at the house.

In case you are stuck with literal interpretation I will repeat the post slightly reworded:

So what happens if the storm rolls in while you are at your hunting cabin and the power goes out? You'd better have a backup for your heat pump that doesn't depend on your truck and I do. Given that, of what value is house backup from my truck?

Oh. I get it now! Leave one rivian at home at all times. Then you have a hot spare, and power backup for the house!
?

 

[E.S.]

Can't speak for anyone else but myself - I already make extensive use of solar to power my home and my EV (and already take advantage of lv 2 charging at my house). I really have no need for a petrol fueled back up generator.

 

[ajdelange]

Your "Tesla only" experience is leading you astray again. Not all EVs suffer this malady - only time will tell how the Rivian performs

It seems there is a need for some education on phantom drain. All lithium batteries are subject to it - even when nothing is connected to the terminals. So all EVs that have a battery "suffer" it. Someone who tells you otherwise does not know what he is talking about.

But the self discharge is not the major source of phantom drain in a modern BEV. A modern BEV is never "Off". The closest to that state it ever reaches is "sleep". Even in sleep it is not off, that is, there are internal functions going on which use power and, thus, drain the battery. The general health of the car is continuously being monitored and if something is amiss you will be notified of this. If you are parked outside the cell phone modem will be on so that the car can send messages to you but it is always on so it can receive, for example, instructions to flash the lights or blow the horn (to help you find it in a parking lot) to send you a message that you forgot to lock it, to receive your command to lock it, to recieve destinations for the trip planner, to download OTA software updates and to monitor and report battery status. If you are parked indoors the WiFi radio will be on to enable this sort of communication. The Tesla has a receiver that listens for your fob and wakes the vehicle if you approach even opening the door automatically for you if that's set. It has another receiver to detect that the charge port door is being signalled to open. If it senses that the battery is hot, it will cool it. Any energy taken from the battery that is not taken when the car is in D or R is counted as phantom drain.

Some of the biggest consumers of phantom power are third party logging programs. These periodically poll the car asking it about temperatures, charge state, odometer, status speed, location etc. When on the road the energy required to respond to these polls is logged against trip consumption but when the car is is neutral or parked it is logged as phantom.

One can reduce phantom drain by not using such programs but i think a lot of people will want to use them assuming, of course, that someone makes such programs available for Rivian.

Experience and the Tesla manuals indicate that you can expect 1% phantom drain. Is this a reasonable number to expect for Rivian? Of course it is and that's why I offered it. We don't think Rivian has a new battery that is immune to self discharge. We don't think Rivian will be missing most of the features that Tesla provides though we don't expect the feature suite to be identical. There will doubtless be an app that relays messages to you from the car and that lets you remotely control the car to some extent. You will doubtless be able to receive OTA updates and plan trips while the car is parked.

There are a couple of things that could make the Rivian reported phantom drain different. The open circuit self drain scales with the battery size but the electrical load of the background processes that draw it down do not. It should take as many watts to run an idling midrange R1T as the max range. But 1 kWh out of a 130 kWh battery is 0.8% but from a 180 kWh battery it is 0.6%

 

[ajdelange]

Oh. I get it now! Leave one rivian at home at all times. Then you have a hot spare, and power backup for the house!

That does solve the problem.

 

[ajdelange]

Can't speak for anyone else but myself - I already make extensive use of solar to power my home and my EV (and already take advantage of lv 2 charging at my house). I really have no need for a petrol fueled back up generator.

Curious about your system. Do you have batteries?

 

[Forager]

Not, apparently, to the 12.5% of respondents to the poll who said they would never use it.

There are many solutions to the emergency power problem and which you adopt depends on how often you have power outages, how long they tend to last, how long is the longest you want to be able to sail through comfortably and how big a load "comfortably" implies. The "best" solution is a solar system backed by batteries as with such a system of sufficient size you can run everything indefinitely as long as the sun is shining. Enduring long periods of no sun is handled by installing more battery but that's very expensive so many choose to have generator backup to the battery backup. This adds cost and complexity but with such an arrangement you can go forever as long as the propane truck can get to you which it can't always do - you'll never get to five 9's.

For very modest loads (light, small fridge, cell phone charging) you can put together a relatively modest emergency supply with a battery pack (Yeti, Jackery...) and a couple of solar panels. You may need to convert 110 to 220 in order to run a furnace fan, well pump etc and you will have to ration power depending on sunshine.

I would only use a BEV as a last resort as I want as many miles in the tank ad I can reasonably have. Remember that a BEV battery loses about 1% of its charge each day.

I’d love to have solar at my home but we live in a forest. The tree canopy makes it prohibitive. If we do any backup that isn’t a BEV wired for V2H, it’s going to be a fuel generator.

It seems like the majority of respondents would appreciate V2H. I’m surprised it’s a polarizing issue.

 

[ajdelange]

I wouldn't say it is polarizing beyond the normal "This is how I do it and therefore that's how you should do it" stuff. The most contention I see is over whether it is wise to use your means of escape to cool your epoisse and I guess the second most regards the constant cycling of your battery pack and its potential effect on longevity.

 

[lefkonj]

Our problem isn't the short outage but the extended one. Sure V2H is great for an hour or two but the last 2 hurricanes to hit our area we were out for over 2 weeks. No way the battery lasts that long, so NG generator it is.

 

[ajdelange]

Yes that's the problem sure enough. Those first couple of 9's come pretty cheap. It's the latter ones that can really drain the bank accound and, if you are lucky, never get called upon.

 

[E.S.]

Curious about your system. Do you have batteries?

Yep. Currently using a LG-Chem RESU10H 9.8 kwh (with room for a 2nd one if the need ever arises to it).

 

[Forager]

In the recent Q&A video posted V2H compatibility is posed and RJ confirms current R1 design is capable of V2H and the only hardware required is a modified EVSE (external hardware) and will be available sometime after launch.

 

[Zoidz]

In the recent Q&A video posted V2H compatibility is posed and RJ confirms current R1 design is capable of V2H and the only hardware required is a modified EVSE (external hardware) and will be available sometime after launch.

I question the statement "the only hardware required..." To do V2H, the NEC (National Electric Code) requires a Transfer Switch on the incoming mains to the house. The purpose is simple - to prevent backfeeding power from your home generator into the power line. Without a transfer switch, the power from your home generator could kill an unsuspecting lineman working down the street.

 

[ajdelange]

I question the statement "the only hardware required..." To do V2H, the NEC (National Electric Code) requires a Transfer Switch on the incoming mains to the house.

No reason to question it. The implication, and there is no doubt about it, is that this EVSE must incorporate the disconnecting means. The much more challenging problem (IMO) is how load shedding is going to be handled.

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