Charge time difference between 60A and 50A?

[jeeden]

Contributing what I can because I did a lot of research when installing my charger myself and now doing more this week for a dryer extension cord for our Airbnb travels with the mobile charger. I don't like the video here because they go on and on about DC chargers, but the chart is good

https://insideevs.com/features/633791/rivian-r1t-charging-review/amp/

As mentioned above you need to charge at 80% of the circuit so the 48 amp charger is on a 60amp circuit. The 40 on a 50. The 32 is different because it is the portable charger so it would have to be on a 40 amp circuit or in the case of my dryer extension cord scenario I need to turn down the portable charger to 24amp.

These numbers change a little, here is our R1S on our Autel 48 amp charger just about to stop charging for the night after 1 hour of charging and it is at 22 miles an hour, but usually 25 miles an hour.

I think you should easily get 18 miles an hour so even if you plug it in at 9pm and unplug at 7am that is 180 miles on all purpose mode. That is still a lot in my opinion and should be good

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[jeeden]

So it just dawned on me I could just change the amps.on my charger through the app while my R1Ss is charging and tell you exactly what 40.amps hardwired does. Now I had to move the max charge to 85% so it might have been tapering a bit, but it got me 20 miles an hour on the dot. The chart looks funny because I played with the 24 amps I'm looking at for the dryer cord for travel (which was 11 miles an hour BTW, a little.less than I was hoping for, but enough)

Maybe when I'm bored someday I should log every charge rate at every 5 amps and post it for the forums haha

 

[larrydallas]

The charger should be set to max output of 40A, not 48A. Continuous loads like EVSEs shouldn't exceed 80% of the rated capacity of the circuit. .8*50A = 40A.

Thanks. Just ignorance on my part.

 

[larrydallas]

Have you ever had all 4 HVAC units running at the same time with the cooktop and all your lights on?

If this was my panel I'd go for the 60a since the difference in material is negligible and labor is the same. I ended up running 4ga THHN which was only a few bucks more than running 6ga. You can always throttle down the EVSE if in fact you need to. Additionally if you plan now for wire that can support 60a based on your run length, you have room in the future if your needs change. Maybe your panel can't handle it now, but let's say your A/C units goes out and you get a new one that is much more energy efficient? Maybe that would give you capacity for the 60a EVSE. You already got the wire run, just swap the breaker. If you sized the wire for a 50a then you'd have to run all new wire going to a 60a.

It's really about balancing energy usage and if you're charging at night when the sun is down and all 4 A/C units are blasting, you would probably be fine.

Although at the end of the day 22 vs 18 miles an hour probably isn't going to matter unless you drive a ton and get home late and leave early.

I like how you think. I live in Phoenix, and it’s possible we’d have all 4 units connected to that panel (we have a 5th on a separate 200A panel), the induction cooktop, and many of the lights on at once during the days where it’s blazing hot. It’s a small chance, but it’s there.

Is my interpretation correct that I can have my electrician run wire that can support 60A, but just install a 50A breaker and jumper to 40A on the charger, which would give me future upgrade options, but not cause any unwanted issues with my set-up now?

If it helps, I believe we have 400A total to the home with 3 panels, 1 200A main that’s clear on the other side of our house, 1 200A sub-panel in the garage, and 1 small 60W panel that just splits off the 200A main.

EDIT: For what it’s worth, the previous owners had a Tesla and already installed a 50A breaker for charging, which we’ll plan to reuse (assuming it’s good).

 

[LL75]

We charge at 48A on a dedicated 60A circuit, hardwired Rivian Wall Charger. Last I checked, that charge rate is adding about 22 miles of range per hour of charging. We charge almost exclusively during our "off peak" hours of 12 am to 6 am, for a max total of about 132 miles of range added during that window That's been fine because our daily driving is almost always less than 100 miles, so we wake up to a 70% charge every morning (we cap it at 70% for daily driving per Rivian's recommendation). If we wanted 80%+ every morning, we might have to do some additional charging outside of our off peak window if we're coming off a really long day of driving.

Interesting. We used the Emporia charger which maxed out at 40amp plugged in to our 50 amp nema 14-50 plug. We get 20 to 21 miles per hour

 

[Christopher]

I like how you think. I live in Phoenix, and it’s possible we’d have all 4 units connected to that panel (we have a 5th on a separate 200A panel), the induction cooktop, and many of the lights on at once during the days where it’s blazing hot. It’s a small chance, but it’s there.

Is my interpretation correct that I can have my electrician run wire that can support 60A, but just install a 50A breaker and jumper to 40A on the charger, which would give me future upgrade options, but not cause any unwanted issues with my set-up now?

If it helps, I believe we have 400A total to the home with 3 panels, 1 200A main that’s clear on the other side of our house, 1 200A sub-panel in the garage, and 1 small 60W panel that just splits off the 200A main.

Yes, with some caveats. You are allowed to run larger gauge wire for the smaller 50a breaker to give you room for a larger breaker in the future. BUT, the EVSE may not support the larger gauge wire, so you you have a couple options depending on local code and your electricians interpretation of the NEC.

1. Run the larger gauge wire to a junction box right before the EVSE and downgrade to a smaller gauge wire in the junction box to the EVSE. My local energy company did this and it passed inspection. For example, the Juicebox comes with a hardwire whip that is connected inside a junction box to the larger gauge wire that goes to your breaker.

2. Run larger gauge wire to a small sub-panel just before the EVSE and the breaker in the sub-panel would go to the EVSE with the smaller gauge wire that the EVSE supports.

When I had the Rivian charger, it only officially supported 6ga wire but I was able to fit 4ga THHN but it was a PITA. If I did it again I'd probably do option #1 due to the difficulty. I'd run these ideas by your electrician and see what they are comfortable with.

Also, depending on your length of the run, if the electrician is running 6ga THHN then it may be perfectly suitable for both a 50a or a larger 60a breaker.

 

[WSea]

I like how you think. I live in Phoenix, and it’s possible we’d have all 4 units connected to that panel (we have a 5th on a separate 200A panel), the induction cooktop, and many of the lights on at once during the days where it’s blazing hot. It’s a small chance, but it’s there.

Is my interpretation correct that I can have my electrician run wire that can support 60A, but just install a 50A breaker and jumper to 40A on the charger, which would give me future upgrade options, but not cause any unwanted issues with my set-up now?

If it helps, I believe we have 400A total to the home with 3 panels, 1 200A main that’s clear on the other side of our house, 1 200A sub-panel in the garage, and 1 small 60W panel that just splits off the 200A main.

EDIT: For what it’s worth, the previous owners had a Tesla and already installed a 50A breaker for charging, which we’ll plan to reuse (assuming it’s good).

That’s what I would do. Wire for a 48 amp charge but charge at 40 for now on 50 breaker

 

[larrydallas]

Yes, with some caveats. You are allowed to run larger gauge wire for the smaller 50a breaker to give you room for a larger breaker in the future. BUT, the EVSE may not support the larger gauge wire, so you you have a couple options depending on local code and your electricians interpretation of the NEC.

1. Run the larger gauge wire to a junction box right before the EVSE and downgrade to a smaller gauge wire in the junction box to the EVSE. My local energy company did this and it passed inspection. For example, the Juicebox comes with a hardwire whip that is connected inside a junction box to the larger gauge wire that goes to your breaker.

2. Run larger gauge wire to a small sub-panel just before the EVSE and the breaker in the sub-panel would go to the EVSE with the smaller gauge wire that the EVSE supports.

When I had the Rivian charger, it only officially supported 6ga wire but I was able to fit 4ga THHN but it was a PITA. If I did it again I'd probably do option #1 due to the difficulty. I'd run these ideas by your electrician and see what they are comfortable with.

Also, depending on your length of the run, if the electrician is running 6ga THHN then it may be perfectly suitable for both a 50a or a larger 60a breaker.

Yep. I bought the Rivian EVSE, so it sounds like I’ll ask my electrician about using 4ga and downgrading to 6ga using a junction box and see how he feels about it.

The run is only about 20ft from the sub-panel in the garage, but my understanding is that he has concerns about overloading the 200A panel if he puts in a 60A breaker. His recommendation was to go with 50A, but didn’t mention whether he could run 4ga to the EVSE.

 

[pc500]

For 20 feet I'd 6/3 romex that and be done.

As for max breaker size, he can do a load calculation. The NEC mandated formula will either say he can or can't.

 

[larrydallas]

For 20 feet I'd 6/3 romex that and be done.

As for max breaker size, he can do a load calculation. The NEC mandated formula will either say he can or can't.

I wish I understood what you just said… ?

 

[pc500]

I wish I understood what you just said… ?

You can get away with copper at 6 gauge for 48 amp charging 60 amp breaker at 21 ft. The cable is a bit more expensive but Romex will get the job done.

The second half is there's an actual formula for him to determine how much you can add to the panel. It's a binary yes no decision and not really an electrician value judgment. He needs to perform that load calculation.

 

[larrydallas]

You can get away with copper at 6 gauge for 48 amp charging 60 amp breaker at 21 ft. The cable is a bit more expensive but Romex will get the job done.

The second half is there's an actual formula for him to determine how much you can add to the panel. It's a binary yes no decision and not really an electrician value judgment. He needs to perform that load calculation.

Roger that. Thanks. Perhaps a separate question: Any idea on a ballpark cost I should expect? He’s cutting into drywall (not repairing after or repainting) for ~20ft away from the panel. He estimated $1500-$2000 for the project.

 

[pc500]

Roger that. Thanks. Perhaps a separate question: Any idea on a ballpark cost I should expect? He’s cutting into drywall (not repairing after or repainting) for ~20ft away from the panel. He estimated $1500-$2000 for the project.

The copper is only $400 of it. Most of it is labor.

If I pre ran all the wire and mounted the charger and all you had to do was do the connectors and the electrical panel, I'd offer $300. And I'd be in it $800 with materials.

I mounted mine right next to the panel with literally two feet of wire and no drywall to deal with for 250 installed by an electrician. But that's not your own install. And he was in and out in 30 minutes.

So his price is fair but it does feel like a West Coast price. It really depends on how much time he's crawling around running wire. I usually try to just time and material these things when able. And the cost and hassles of a permit

 

[beyond]

You can get away with copper at 6 gauge for 48 amp charging 60 amp breaker at 21 ft. The cable is a bit more expensive but Romex will get the job done.

The second half is there's an actual formula for him to determine how much you can add to the panel. It's a binary yes no decision and not really an electrician value judgment. He needs to perform that load calculation.

so everything I’ve read says Romex is only good for 55amp so a max of 40amp continuous. Unless the 6awg wire is thhn as mentioned in this thread which can handle 48amp continuously.

 

[larrydallas]

Final decision was to run 6awg copper wire the ~25ft to the 200W sub-panel in the garage. All 3 electricians said I was “borderline” to use a 60A breaker, so we went with a 50A breaker for now and will only charge at 40A. If, at some point, we shift a condenser or two off of the sub-panel or get better tech, we have the 6awg wire already buried in the wall to accommodate upsizing. Thanks for the recommendation, @Christopher @WSea @pc500!

Pics below after the electrician left. He was generous enough to mount the drywall pieces back into the holes with backer board. Nice work from my layman’s point of view. Just need to sand/tape/mud/paint and it should look nice and clean!

EDIT: For anyone interested, I had quotes Of $1100, $1200, and $1500 all-in. I went with the $1500, because it’s a guy we use a lot and he’s absolutely meticulous. Wanted it done right the first time.

EDIT 2: New rig should hit the local SC in Phoenix on Monday. We’re all set for it (I think)!

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