What Max Amperage to Consider for Home Charging? (40, 48, 80)

[R1TFTW]

I use a ChargePoint home flex that allows 50A. Requires a 60A breaker. That delivers the max 11.5kwh the Rivian can take. At 40A I got 9.5kwh (with a 50A breaker)

I don’t like how chargepoint advertises 50amp max. They say on there the wiring max is 6ga to attach to the charger. There is no way within code you could make that work. They might as well as said 48amp max. Even if charger can do it, it wasn’t even made to handle 4ga wire. I also had some beef with them about a few other things. Now I have a rivian and a Tesla charger. Both do great.

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[CommodoreAmiga]

I don’t like how chargepoint advertises 50amp max. They say on there the wiring max is 6ga to attach to the charger. There is no way within code you could make that work. They might as well as said 48amp max. Even if charger can do it, it wasn’t even made to handle 4ga wire. I also had some beef with them about a few other things. Now I have a rivian and a Tesla charger. Both do great.

To be fair, they do specify that you need a 70A breaker to configure the EVSE for 50A operation:

And 6AWG THHN, THWN, or THWN-2 are all rated with sufficient ampacity to support 50A charging:

What I don't like about this is that the real-world benefit of 50A vs 48A is almost nil. Few vehicles can take more than 48A L2 charging. And the ones that can will often support much higher rates -- beyond 50A -- so those people wanting to go beyond 48A but limiting themselves to 50A seems unlikely. The extra 2A is negligible in terms of miles-per-hour of range gain.

The number of people who have a vehicle capable of 50A+ L2 charging and where 50A gives them a meaningful benefit over 48A charging is such a small subset of EV owners, imo.

 

[JeremyMKE]

I think 48 amps is good for most home charging. I am getting consistently 10kw an hour added to my R1S at 44 amps. That is a good solid 20-22 miles an hour. Unless you need more than 160 miles daily which is 8 hours of charging.

On the occasion I need faster I’ll just go to a DCFC around the corner.

To your point I am on a 60 amp breaker charging at 48 amps and I charge at 11kwh adding approx the same amount of range you are getting.

 

[brancky3]

If you are giving the vehicle 20-25 miles per hour of range, you have more than enough speed to charge 250+ miles overnight at home. Anything else is overkill IMO.

The only exception is for those people who are on time-of-use plans, they would want to charge as fast as possible because they can't just leave it charging for 12 hours. I have a flat rate so our 40a charger is enough, but I could see why some people want more amperage.

 

[R1TFTW]

Wow. I guess it has been a while since I really looked into it. I thought 6ga THHN at 90c was 60amp not 75amp. But too I don’t know many cars that would do that nowadays. And also think that 2amps is like .48 kw per hour extra. So not that much no matter how you look at it.

 

[Dark-Fx]

Above 60A requires a locally accessible disconnect according to code. It actually makes it easier to plan for an upgrade. I ran wiring to a fused disconnect to support the 100A (80A continuous load), with a 100A breaker in the panel and 60A fuses to my hardwired 48A charger.

Wiring from the disconnect is short and a smaller gauge wire that will most likely just get recycled if/when we upgrade the EVSE to an 80A one to support a future vehicle.

 

[DTown3011]

The only exception is for those people who are on time-of-use plans, they would want to charge as fast as possible because they can't just leave it charging for 12 hours. I have a flat rate so our 40a charger is enough, but I could see why some people want more amperage.

We can only charge from 9pm to 6am in the morning to qualify for our rate and incentives. 9 hours is plenty of time 98% of the time.

 

[paco180]

The bottom line is that, Rivian can’t charge any faster than 11.5 kW. ( Max vehicle onboard charger) @ home doesn't matter if you use a 48amp charger or 80amp charger. so why put a 70amp or 100amp breaker, when all you need is a 60amp breaker.
if a home charger says you need a 70amp breaker to output 48amp. That seems like inefficient charger. So look for a 48amp charger- that outputs 11.5kw

Rivian and Tesla wall charger both do this.

 

[jollyroger]

Above 60A requires a locally accessible disconnect according to code. It actually makes it easier to plan for an upgrade. I ran wiring to a fused disconnect to support the 100A (80A continuous load), with a 100A breaker in the panel and 60A fuses to my hardwired 48A charger.

Wiring from the disconnect is short and a smaller gauge wire that will most likely just get recycled if/when we upgrade the EVSE to an 80A one to support a future vehicle.

That's weird, none of the quotes I got had anything about a disconnect being installed. Is it common for electricians to not follow code, or is that something that might be based on your locality?

 

[shrink]

The bottom line is that, Rivian can’t charge any faster than 11.5 kW. ( Max vehicle onboard charger) @ home doesn't matter if you use a 48amp charger or 80amp charger. so why put a 70amp or 100amp breaker, when all you need is a 60amp breaker.

I think the OP was just seeking feedback and discussion on future proofing. Since the J1772 spec supports up to 80amps/24kW, the question was should a line that supports the max capabilities of the spec be installed - especially if batteries become larger in future EV's.

I actually hadn't realized Lucid supports 80amps/24kW.

 

[paco180]

The connector J1772 spec supports up to 80amps/24kW, Not the vehicle

 

[Dark-Fx]

That's weird, none of the quotes I got had anything about a disconnect being installed. Is it common for electricians to not follow code, or is that something that might be based on your locality?

It's in the NEC. Whether or not your locality will care about that specifically, no idea. For a 48A EVSE, there's no need for it. Circuit has to be breakered higher than 60A for it to apply. I suspect that's part of the reason its rare for a vehicle to have more than 48A charge rate on level 2.

 

[CommodoreAmiga]

That's weird, none of the quotes I got had anything about a disconnect being installed. Is it common for electricians to not follow code, or is that something that might be based on your locality?

Both, lol.

 

[BigSkies]

I think most new EV owners overthink this. I know I did before I had an EV. I don’t have my Rivian yet, but I’ve had a Tesla for a decent while.

I use the Tesla mobile charger which caps out at 32amps. And this is way more capacity than is really needed.

It’s easy to forget that you’re only charging for the miles you drive in a single day when you plug it in at night. I use less than 10% of the battery on most days. Yours could be more if you have a longer commute. But honestly ask yourself how frequently you drive more than 100 miles a day?

And the times you do road-trip, you might be topping off the battery from 50% instead of 0%. It really isn’t that big of a deal unless you’re driving hundreds of miles a day on back-to-back days.

I’d say get a NEMA 14-50 outlet, and some charger that will plug into that. It gives you flexibility for different chargers, cars, and standards in the future.

 

[shrink]

The connector J1772 spec supports up to 80amps/24kW, Not the vehicle

I’m pretty sure everyone in this discussion realizes that.

For at least the 4th time, the OP was just seeking a discussion, thoughts, and feedback about future proofing

From the first post:

“I can't seem to find good information if the industry "thinking" that 48,50 amps is going to continue to be enough for charging EV's going into the future.”

What if a Lucid becomes his next EV or replaces his Rivian or there’s a movement back to up to 80 amp charging? It’s a reasonable question. My first EV was a 2011 LEAF and back then I thought 30 amps at home would be all I ever needed. Things change quickly.

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