Charge time difference between 60A and 50A?

[larrydallas]

Had an electrician over to assess our second 200A panel in the garage. Unfortunately, we have 4 condensers, 4 air handlers, a cooktop, and more on it already. His advice is to go with a hardwired 50A hookup to be safe.

Wondering if anyone has an estimate or experience enough to tell me what the downside is here from a charging perspective? Is it a significant drop? Would like to be able to charge to 80% overnight easily. Electrician says it’ll be no problem, but just looking for an intelligent second opinion…

Thanks in advance!

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[mikehmb]

I run a 50a circuit to a Juicebox for effective 40a / 9.6kW, and have never had an issue pulling enough to charge the truck overnight. Haven’t gone 0-100%, but if you assume 135kWh at 9.6kW continuous, that’s about 14 hours of charge time.

Truck handles it fine. And I would concur with your electrician’s recommendation on hardwiring. Vast majority of 14-50 setups out there today cannot handle continuous 40a load. They’ll melt. I’ll dig up a photo and post as an opportunity to learn from my mistakes. Munro did an explainer on it as well.

 

[Mike Hunt]

60A gives me 22 miles per hour charge time
50A gives me 18 miles per hour charge time

 

[Dark-Fx]

40A is about 14 hours for a full 0-100% charge. 48A is about 11.5 hours

 

[WSea]

I run a 50a circuit to a Juicebox for effective 40a / 9.6kW, and have never had an issue pulling enough to charge the truck overnight. Haven’t gone 0-100%, but if you assume 135kWh at 9.6kW continuous, that’s about 14 hours of charge time.

Truck handles it fine. And I would concur with your electrician’s recommendation on hardwiring. Vast majority of 14-50 setups out there today cannot handle continuous 40a load. They’ll melt. I’ll dig up a photo and post as an opportunity to learn from my mistakes. Munro did an explainer on it as well.

I made that mistake wiring my house 3 years ago. Went with 6 GA romex so now on a 50amp breaker with charger toggled to 40.
Never had an issue getting enough charge in time. The biggest issue is wishing for a charging schedule to finished charging just prior to a scheduled time

 

[evguy]

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.

 

[mikehmb]

Behold - melter of conductors. Fryer of garages. This f****ng thing:

 

[evguy]

I run a 50a circuit to a Juicebox for effective 40a / 9.6kW, and have never had an issue pulling enough to charge the truck overnight. Haven’t gone 0-100%, but if you assume 135kWh at 9.6kW continuous, that’s about 14 hours of charge time.

Truck handles it fine. And I would concur with your electrician’s recommendation on hardwiring. Vast majority of 14-50 setups out there today cannot handle continuous 40a load. They’ll melt. I’ll dig up a photo and post as an opportunity to learn from my mistakes. Munro did an explainer on it as well.

Agree that plug in is not worth the risk. Our 14-50 plug melted overnight while charging our Tesla (32A charge rate on a 50A circuit) at our old house, lucky we didn't burn the place down! Hardwiring forever now.

 

[Dark-Fx]

Behold - melter of conductors. Fryer of garages. This f****ng thing:

Wiring error when only one hot is melted.

 

[mikehmb]

Wiring error when only one hot is melted.

Something went kablooey in the connector itself. I suspect it heated and loosened, ultimately cracking the housing, then deteriorating further until we got to the melty bits you see above.

It is entirely likely that the installing electrician didn’t crank down each conductor, but that would be a seriously rookie mistake.

 

[larrydallas]

Agree that plug in is not worth the risk. Our 14-50 plug melted overnight while charging our Tesla (32A charge rate on a 50A circuit) at our old house, lucky we didn't burn the place down! Hardwiring forever now.

Definitely hardwiring. Sounds like a 50A breaker shouldn’t be an issue with the jumper at 48A. Our daily driving is minimal and we can pre-prep for longer drives.

Going to gut into the drywall for wiring to ensure a clean, hidden look to the unit about 25ft from the panel. Cost was higher than I expected ($1500-$2000), but I know this guy does fantastic work.

Appreciate all the feedback! We got the Rivian charger and I’m a little remorseful I didn’t do more research, but should handle fine and even maybe be beneficial if they can improve their currently barebones-looking app.

 

[Autolycus]

Definitely hardwiring. Sounds like a 50A breaker shouldn’t be an issue with the jumper at 48A. Our daily driving is minimal and we can pre-prep for longer drives.

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.

 

[WSea]

Need 60amp breaker for 48amp charging

 

[opnwide]

…and no #6 Romex or NM-B for 48A on 60A breaker, it must be #6 THHN strands run in conduit or flex to be up to code! (Unless your EVSE wiring terminal accepts #4 Romex, mine maxes at gauge 6).

 

[Christopher]

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.

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