Charging Rivian with Home Generator

[Riviot]

We've had some record winds whip through Western Washington last night, enough to down a healthy evergreen that luckily threaded between my neighbor's house and propane tank, and we've been without power for a while with restoration not likely for a day or two. I got a 13kW Generac wired in for cheap, $7500 all in, in 2020 after getting a lowest bid of $30k for 8kW solar system. 22 year payback period in our area is too long on a not-forever home.

Since we're running the generator anyway for the normal uses and filling the pump house tanks every few hours, I figure why not plug in the truck and try a load? (that's what she said) I either need to charge here or at a DCFC on the way to work tomorrow, so let's math it.

13kW 1/2 load consumption: 1.47 gal/hr
Max load: 59 amp
Charge off laundry plug: 24 amp, 5.5kW
Mathed consumption: 1.2gal/hr
Propane: $2.71/gal
Cost: $.49/kWh

$.49/kWh isn't terrible, cheaper than Shell and EA around here, but the Tesla near work is charging $.35/kWh. That's pretty cheap compared to across the water, so I wonder if they intentionally lowered during this major outage period? Granted it's way more than my standard $.08/kWh off-peak rate.

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[mkhuffman]

We've had some record winds whip through Western Washington last night, enough to down a healthy evergreen that luckily threaded between my neighbor's house and propane tank, and we've been without power for a while with restoration not likely for a day or two. I got a 13kW Generac wired in for cheap, $7500 all in, in 2020 after getting a lowest bid of $30k for 8kW solar system. 22 year payback period in our area is too long on a not-forever home.

Since we're running the generator anyway for the normal uses and filling the pump house tanks every few hours, I figure why not plug in the truck and try a load? (that's what she said) I either need to charge here or at a DCFC on the way to work tomorrow, so let's math it.

13kW 1/2 load consumption: 1.47 gal/hr
Max load: 59 amp
Charge off laundry plug: 24 amp, 5.5kW
Mathed consumption: 1.2gal/hr
Propane: $2.71/gal
Cost: $.49/kWh

$.49/kWh isn't terrible, cheaper than Shell and EA around here, but the Tesla near work is charging $.35/kWh. That's pretty cheap compared to across the water, so I wonder if they intentionally lowered during this major outage period? Granted it's way more than my standard $.08/kWh off-peak rate.

Have you tried it yet?

Is there a reason you are using the dryer plug instead of a EVSE?

 

[Riviot]

Have you tried it yet?

Is there a reason you are using the dryer plug instead of a EVSE?

Yep, it's been running for a couple hours now, no problems!

EVSE is on my main panel, not the generator's subpanel. If I put it on there, I'd be pulling almost max load just to charge, not worth running the generator so hard or stressing other items with load fluctuations.

 

[Electrified Outdoors]

Comes down to convenience if you ask me. Tesla is $0.14 cheaper per kWh but you have to find something else to do while it’s charging.

 

[COdogman]

Think about the quality time you can spend with Mrs. Riviot and Douglas Fresh if you charge at home. It’s worth it. Plus, if you go to a Supercharger station there is a chance you might see a Cybertruck and who needs that?

 

[Riviot]

Comes down to convenience if you ask me. Tesla is $0.14 cheaper per kWh but you have to find something else to do while it’s charging.

What I couldn't find from Generac is the minimum load/consumption of the generator. What's the overhead cost? I'm sure a fair amount of it running for the basics is excess production, so I'm putting that towards the truck. When I started charging, I didn't hear it kick into a higher gear, so I think it's either 1/2 load or full load.

 

[mkhuffman]

Yep, it's been running for a couple hours now, no problems!

EVSE is on my main panel, not the generator's subpanel. If I put it on there, I'd be pulling almost max load just to charge, not worth running the generator so hard or stressing other items with load fluctuations.

I know this next question is irrelevant to your situation because you don't have the EVSE on the generator circuit, but if you did, could you set the charge current in your R1 to a lower amount to avoid stressing the generator?

BTW - I have an Emporia EVSE and it the current output can be controlled via the Emporia app. Pretty cool. I have never needed to drop it from 48 Amps, but if charging off a generator, I would do what you did.

 

[Riviot]

I know this next question is irrelevant to your situation because you don't have the EVSE on the generator circuit, but if you did, could you set the charge current in your R1 to a lower amount to avoid stressing the generator?

BTW - I have an Emporia EVSE and it the current output can be controlled via the Emporia app. Pretty cool. I have never needed to drop it from 48 Amps, but if charging off a generator, I would do what you did.

Yes, Chargepoint make it easy, plus the Rivian can be lowered as well

 

[Riviot]

Think about the quality time you can spend with Mrs. Riviot and Douglas Fresh if you charge at home. It’s worth it. Plus, if you go to a Supercharger station there is a chance you might see a Cybertruck and who needs that?

And that's why I charged at home. If it was at Costco, that's no brainer. But Target and the local bank? I've got nothing to do there.

 

[godfodder0901]

And that's why I charged at home. If it was at Costco, that's no brainer. But Target and the local bank? I've got nothing to do there.

Where's your spirit of adventure? Costco is only a few mile walk...

 

[DD4ST]

Great it is working. I’d be careful though as home charging is still AC. I’m not an electrician, but I do have a home generator and have researched a lot about its output. The generator puts out AC sine waves that approximate what comes in on house current. From what I’ve read this can put stress on electronics in appliances. I don’t know what effect this would have on the Rivian. Maybe someone here can confirm or correct me on this.

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