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

jollyroger

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I have a Chargepoint home Flex and am currently getting quotes to move from the 14-50 NEMA plug to hardwire (going to keep the plug for backup). But the J1772 standard seems to allow up to a maximum 80 amps charging. However, with maybe the exception of Lucid and whatever Ford is doing, most EV's are not going much higher than the 50 amps my Chargepoint "can" support. I'm having a hard time getting the Rivian charged overnight with the current setup.

Chargepoint has a limitation in that the largest wire it can support is 6AWS THHN 90 degree rating. But going up to 80 would require a larger wire, so I can't really future proof by just sticking a 100 amp breaker in there with the supporting wire. I can only go up to 70 amps.

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. I don't want to continue paying for upgrading the electrical system as new EVSE's and EV's come out. but right now even the EVSE's are limiting me to 6AWG it seems like.

Thoughts?
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DTown3011

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50A is the max your Chargepoint home flex can handle (which would require a 70/80A breaker), which is plenty fast for Level 2 charging a home. Most of your charging is done overnight, or over an 8-10 hour period. 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.

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greatdane1588

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I have a Chargepoint home Flex and am currently getting quotes to move from the 14-50 NEMA plug to hardwire (going to keep the plug for backup). But the J1772 standard seems to allow up to a maximum 80 amps charging. However, with maybe the exception of Lucid and whatever Ford is doing, most EV's are not going much higher than the 50 amps my Chargepoint "can" support. I'm having a hard time getting the Rivian charged overnight with the current setup.

Chargepoint has a limitation in that the largest wire it can support is 6AWS THHN 90 degree rating. But going up to 80 would require a larger wire, so I can't really future proof by just sticking a 100 amp breaker in there with the supporting wire. I can only go up to 70 amps.

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. I don't want to continue paying for upgrading the electrical system as new EVSE's and EV's come out. but right now even the EVSE's are limiting me to 6AWG it seems like.

Thoughts?
Whats the charge rate you're currently avg at home with your Rivian (miles per hour charged I mean)?

And yeah I had similar thoughts this past year when I got a Model 3 and then switched to a Mach-E, and how I should future proof if possible, but I gave up trying and just went for a 48 amp Wallbox for now so I wouldn't have to mess around with existing wiring.
 

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I have a Chargepoint home Flex and am currently getting quotes to move from the 14-50 NEMA plug to hardwire (going to keep the plug for backup). But the J1772 standard seems to allow up to a maximum 80 amps charging. However, with maybe the exception of Lucid and whatever Ford is doing, most EV's are not going much higher than the 50 amps my Chargepoint "can" support. I'm having a hard time getting the Rivian charged overnight with the current setup.

Chargepoint has a limitation in that the largest wire it can support is 6AWS THHN 90 degree rating. But going up to 80 would require a larger wire, so I can't really future proof by just sticking a 100 amp breaker in there with the supporting wire. I can only go up to 70 amps.

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. I don't want to continue paying for upgrading the electrical system as new EVSE's and EV's come out. but right now even the EVSE's are limiting me to 6AWG it seems like.

Thoughts?
I have the same setup at home with a Chargepoint… it’s more than enough for Model Y charging overnight as you probably know. I don’t have my R1T yet but starting to think more juice is needed as you just confirmed. Maybe the easy workaround is to immediately plugin regardless of time of day.
 

JohnB R1T

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I don't think that any of the "50 Amp" chargers are actually 50 amps. If you dig into it, I think you'll find that they are 48 amps. These, all other things being equal, will require 6 gauge copper (not in a UF-B cable). 48 amps is the max that the Rivian can/will accept, and it needs a 60 amp breaker and hardwiring. If you want to futureproof against the day that you might put in a bigger charger, run the larger wire from your panel to a "junction box" (next to the charger) with the proper screw-down connectors and drop down to the 6 gauge that your charger will handle from there. That way, if you ever do move up to a larger charger, all you have to do is drop in a bigger breaker without upgrading the majority of your wire run.
 

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If batteries were to keep getting bigger, there's reason to question whether charging overnight at 48A would be adequate 5-10 years from now. But I don't think that's where the industry is going; EVs already have too much mass and battery materials are too scarce. I think the focus will be on improving battery chemistries and reducing the mass of motors and other components (which could increase range AND shorten charging times), rather than stuffing ever-bigger batteries into these cars. Just my 2 cents, I'm no expert.
 

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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.

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The earliest Teslas supported higher amperage charging with the Roadster at 70 amps and early Model S's with up to 80 amps with the dual charger option. Seems like the industry is now settling in at 48 amps.

My best guess is that things will stay around 48 amps for a while for a few reasons:

1) Higher amperage charging will require a massive panel. Most older homes have 100 amp panels and newer homes have 200 amp panels. Setting aside nearly half of a 200 amp panel for an EV might not very practical and upgrading to a 400 amp panel is very costly. Utilities also might not like too many homes pulling that much juice. It could wreak havoc on load management and existing lines.

2) In multiple EV homes, the load sharing charging stations seem far more practical.

3) Public charging infrastructure is supposed keep improving and if one needs the extra range, I think the expectation would be to use a public Level 3 charging station as needed to supplement daily home charging capabilities.

Just my best guess, of course. Who knows what will really happen.

If you have the panel space, maybe just go for an 80 amp capable line? While Rivians are currently capped at 48 amps, it's reasonable future proofing for a future EV or load sharing with a second EV.
 

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Been using the Rivian charger toggled to 32 and charging time has been fine around 16mi/hr. Hardwired with 6ga except for a short whip at 8. Still planning to replace the whip wire but hasn't been a priority since the amount of time for charging has never been an issue. As far as future proofing I can't imagine needing more amps unless you're on TOU
 

paco180

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At home, max 60A Breaker. Rivian can’t charge any faster than 48amp via AC.
On the road, they are DC fast chargers. So that would be at~250amp or less.
 

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At home, max 60A Breaker. Rivian can’t charge any faster than 48amp via AC.
On the road, they are DC fast chargers. So that would be at~250amp or less.
DCFC on a Rivian can get up to 500A.
 

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Even if a car could take it, I cant really imagine any situation where 48amps at home wouldn’t be enough. You’d have to be coming home from a very long trip where you took the battery to near 0, then did another ~300 mile trip in less than 8 hours. Even then you’d have public infrastructure. I’m even considering bumping down to 40amps so I can use an extension. Even 40 is plenty For home
 

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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)
 
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jollyroger

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My best guess is that things will stay around 48 amps for a while for a few reasons:

1) Higher amperage charging will require a massive panel. Most older homes have 100 amp panels and newer homes have 200 amp panels. Setting aside nearly half of a 200 amp panel for an EV might not very practical and upgrading to a 400 amp panel is very costly. Utilities also might not like too many homes pulling that much juice. It could wreak havoc on load management and existing lines.

2) In multiple EV homes, the load sharing charging stations seem far more practical.

If you have the panel space, maybe just go for an 80 amp capable line? While Rivians are currently capped at 48 amps, it's reasonable future proofing for a future EV or load sharing with a second EV.
It "seems" like the industry is more or less settling on 48 amps at the moment. If that's where things stay I rather not have huge breakers in my panel. I'm inclined to agree with you, but then Lucid and went and supported the max amperage J1772 can muster. Noted they are a bit special. And the fact that Tesla abandoned the 72 amp option.

Even if a car could take it, I cant really imagine any situation where 48amps at home wouldn’t be enough. You’d have to be coming home from a very long trip where you took the battery to near 0, then did another ~300 mile trip in less than 8 hours. Even then you’d have public infrastructure. I’m even considering bumping down to 40amps so I can use an extension. Even 40 is plenty For home
It's a little tricker than that, we had a combo charge needed. Tesla M3 and the Rivian, both low charge. (I was running a bunch of errands that day, and my wife just came home from a womans trip). Both vehicles were in the 15 % range and we needed to charge.

I guess I could have taken one to a DCFC but I don't like the battery pressure that causes if we are not on a road trip.

Anyway I think most are in agreement that 48 is probably going to be okay for a few years. And I'm still keeping my 14-50 socket so I can use the mobile chargers if needed to charge two overnight if needed.
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