48A vs. 40A for home charging??

[Jobiwan]

I own 2 different properties, 1 hardwired 60 amp with a Rivian charger, the other via a Nema plug also on a 60 amp circuit

i get 22-23 mph on the hardwire
16 on the plug in

always regret not hardwiring my other charger; every now and again I’m in a hurry.

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[Mathme]

I have a 40a charger at each of my homes. on 40a the truck charges at 8-10kWh or about 18-19 miles per hour. It took about 9ish hours to charge from 26-85% overnight the other night.

 

[NineElectrics]

At one property, I have a charger on a 50A breaker. At another, 60A. 60A helps in rare instances when one forgets to charge and the battery is fairly depleted. Worth it, in my opinion, for the extra piece of mind.

 

[Tomgriff]

I have a Tesla Model S and Chevy Bolt that I use a Wallbox EVSE and NEMA 14-50 on a 50 amp breaker. For an extra safety factor I have limited to 32 amp (Wallbox is adjustable up to 40 amp). I have never run into an issue. When I get the R1S (next month, in the 8 steps now!), I'm going to see how charging at 32 amps goes, which based on my use case I'm pretty sure will be fine. I suspect for most people, particularly if there are no time of use differences in your electricity rates, more than 40 amps won't be needed. If you are charging in the evening/overnight an extra hour or two makes no difference. If you are routinely driving several hundred miles a day, then a higher amperage will probably be necessary.

All that being said, I'm planning to rewire the garage in the next year or two and when I do, I will add a second 220 circuit that will be at least 60 amps, probably 80 amps, for future proofing. If you are starting from scratch I would go the hardwire route at 60-80 amps.

 

[TXR1S]

If you can, it's better (safer) to hardwire a charger. If that's not possible in your case, then make sure you're using a good quality 240V outlet that's rated to handle the load of an EV charger. Many regular dryer outlets aren't designed to handle that kind of load. Just my $0.02.

https://insideevs.com/features/625675/how-to-install-ev-charging/

THIS. Hardwired is empirically safer.

 

[lefkonj]

50A with a NEMA-14-50 connected to a juicebox. Works perfectly fine for our R1S and I4M50, never had any challenges and it delivers plenty of power.

 

[Sevn86]

I vote hardwiring the unit with 60amp breaker. That’s what I have and love that it delivers approx 22-24 miles range per hour of charge.

 

[Rivdog]

I’ve had 3 EVs and been on forums for each. I’ve routinely seen issues with plugs melting for one reason or another. I’ve seen a hardwired one fail too, but it’s much more rare.

If you hardwire, you can reduce the amperage either with the EVSE app (on some, at least) or within the Rivian itself.

 

[Zeus]

@Baymax you might also want to consider your electrical panel to confirm you have enough space or if you'll need an upgrade to accommodate a 60 amp circuit.

 

[JoulesVerne]

Another strike against a plug - if it's outdoors it is possible to steal the EVSE by unplugging it. I read an article about thieves in California targeting homes with outdoor chargers.

With a hardwired connection the thief must disconnect live wires which is much less likely to happen.

 

[eemri]

Although this wasn't a scenario asked about, I charge at 32A (~7kW) at home. One of the convenient side effects of this throughput is that I add ~5% SoC every 1 hour. This makes for a very easy, poor man's departure timer: I figure out when I want to leave, count back the number of hours I need to charge to get to that SoC (based on 5%/1hr increments usually) and then set my charging schedule accordingly.

(Assumes large pack)

 

[CrazyOne]

I used Rivian EVSE and the highest guage wire that can be used with EVSE. I don't recall the guage but I think it is one higher than the one manual calls for. Breaker is the recommended size though.

You can always reduce the charging speed, but I think anything upto 48 amps should be very gentle on the battery. This is designed to DC fast charge at 150 - 200 KW. 11 KW should be nothing. You can reduce the amps to be gentler on the wiring, car , etc from EVSE/car.

I went with Rivian EVSE as I wanted to reduce any finger pointing in case of issues. In the 9 months I have had it, car refused to charge twice, but started back up after plugging and unplugging a few times. One time, it refused to disengage the lock and turning off breaker released it. Those were the 2 issues I had so far.

If you use a NEMA plug, I recommend going with 50% of rated capacity to be safe. Those plugs can overheat and start fires, when under constant load for several hours.

 

[Throwdown]

I'm debating on 2 different wiring scenarios for installing our Rivian (or possibly aftermarket) wall charger. We are going to be charging an R1S with the 135 kWh Large battery pack. I'd specifically like to hear from anyone currently using 40A to charge their R1 at home. Do you wish you had gone 48A instead? Have you ever run into any hairy situations where you haven't had enough amperage when charging overnight for 75/80% SOC for daily use or 100% SOC for a road trip?

I only charge at 20a set to charge between 9pm and 5am. I charge to 50% daily with a 70mile daily round trip commute. 40 to 48a is wholly unnecessary for 90% of people's daily commutes. If I need to charge to 100% like for a trip I just turn the timer off and let it slowly creep up to 100% over a couple days, or if it's short notice I'll charge at a fast charger for 10 minutes

 

[jjswan33]

Personally I have a Chargepoint Home Flex on a Nema 14-50. It has been adequate in 98% of situations. I also had extra some extra ROMEX 6/3 after installing my hot tub so it was an easier decision for me.

I like the flexibility that if something went wrong with my charger I could just plug a different one in otherwise I agree with others if you are starting from nothing might as well go with a full 60A hardwired installation

 

[bhopkins]

50A circuit charging at 40A. Never been an issue charging even from nearly empty.

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