[MinhSATx]

Hi, I haven't seen this discussed. I put a deposit for an i4 M50, and I want to look at setting up a charging point at home. On June 1st, 2021, BMW posted a spec BMW USA News - The New 2022 BMW i4 eDrive40 and i4 M50 that shows the AC single phase charging to be 11kW and 8.25 hours 0-100%, but the latest i4 manual says 11kW tri-phased (no home in the US has that!) and 7.7kW single phase. The installation guide of the BMW wallbox says it maxes at 32A, which, on 240V, also gives 7.7kW. So is it worth getting a direct-connect ChargePoint Home Flex CPH50 (and a non-standard 60A circuit) to get the 11kW, or is the car truly limited to 7.7kW on home AC?

 

[teamzans]

Although I don’t know the answer, that’s a great question and share the interest in knowing.

 

[wdtoddnix]

My wife currently has an e-tron and I have an i4 on order. Below notes are what we are currently doing with the e-tron - but expect to carry over to the i4.

We had a 50amp circuit with a 14-50 plug installed. I'd recommend sticking with the 14-50 for flexibility vs a hardwired charger.

We use the charger that came with the e-tron - I expect it will be similar to what BMW delivers with the i4.

I mounted it to the wall using a couple of hooks from Home Depot and just leave it there.

The car has a timer so that it charges overnight and is ready by 6am - time and target charge settings are all programmable within the car or through the app.

I get a consistent 8.6kw which is totally fine since I'm always charging overnight - I don't think you would notice a big difference in experience with 7.7kw.

I'm considering switching to a Juicebox in the future to move the scheduling to the charger instead of the car, but for now this works great.

 

[MinhSATx]

@wdtoddnix , I agree 7.7kW and 8.6kW are not that different if the battery is not depleted, as the case would be on most day. However, I do road trips about once a month that will bring the battery down to 10%, so bring it back up the next day to 80%, which would be my normal non-road-trip desired SOC, would require 57kW, and take 7.4 hours on a 7.7kW charger, 6.6 hours on a 8.6kW charger and 5.2 hours on an 11kW charger. Not a huge difference indeed, but depending on the circumstances and how early I have to leave the next morning (we are working from home now but we'll get back to the office early in 2022), the lower charge rate may be somewhat less than ideal, though I probably can do my commute, run my normal errands, and still get home with enough charge and then bring the morning SOC up over the following few days. I guess, since I have never lived with an EV yet, I might be over-obsessing the whole "recharge to 80% every morning" thing. But you do have to admit having the confidence your car will be recharged in 5-6 hours even if you bring it down to 10% is a nice reassurance...

My wife currently has an e-tron and I have an i4 on order. Below notes are what we are currently doing with the e-tron - but expect to carry over to the i4.

We had a 50amp circuit with a 14-50 plug installed. I'd recommend sticking with the 14-50 for flexibility vs a hardwired charger.

We use the charger that came with the e-tron - I expect it will be similar to what BMW delivers with the i4.

I mounted it to the wall using a couple of hooks from Home Depot and just leave it there.

The car has a timer so that it charges overnight and is ready by 6am - time and target charge settings are all programmable within the car or through the app.

I get a consistent 8.6kw which is totally fine since I'm always charging overnight - I don't think you would notice a big difference in experience with 7.7kw.

I'm considering switching to a Juicebox in the future to move the scheduling to the charger instead of the car, but for now this works great.

 

[Dmeinen]

The i4 can home charge up to 11kw. In the USA to deliver 11kw you will need a home charger rated at 240 volts 48 amps on a single phase. It will need to be direct wired on a dedicated 60 amp circuit. I have a "Wallbox Plusar Plus" installed in my garage at 240 volt 48 amps single phase. I am ready once I can order and take delivery next year of my i4 M50.

 

[MinhSATx]

Perfect, this is great. This helps a great deal. I'll also look into your wallbox. The amperage and direct wiring is also what is recommended by Chargepoint for their Home Flex wallbox. Thanks much!

The i4 can home charge up to 11kw. In the USA to deliver 11kw you will need a home charger rated at 240 volts 48 amps on a single phase. It will need to be direct wired on a dedicated 60 amp circuit. I have a "Wallbox Plusar Plus" installed in my garage at 240 volt 48 amps single phase. I am ready once I can order and take delivery next year of my i4 M50.

 

[teamzans]

Perfect, this is great. This helps a great deal. I'll also look into your wallbox. The amperage and direct wiring is also what is recommended by Chargepoint for their Home Flex wallbox. Thanks much!

Ditto. Thank you…

 

[MinhSATx]

Ok, thank you again @Dmeinen , the Chargepoint Home Flex is on order and the electrician is scheduled. The car delivery is next summer but the 30% federal credit currently runs until 12/31/2021 so I'm playing safe.

 

[teamzans]

Ok, thank you again @Dmeinen , the Chargepoint Home Flex is on order and the electrician is scheduled. The car delivery is next summer but the 30% federal credit currently runs until 12/31/2021 so I'm playing safe.

@MinhSATx - curious - why did you order the Chargepoint Home Flex over the Wallbox Pulsar Plus that @Dmeinen has? Looking at the two, the Wallbox seems to have the best of both the Chargepoint and Juicebox (able to connect 2 on the same circuit for 2 cars and also able to automatically govern the amps down to match any loading issues)? Other factors critical to you? Thank you and appreciated.

 

[MinhSATx]

@teamzans , I did look at the wallbox and it's mostly esthetics and availability of info, the Home flex has the cord hanger and a connector port incorporated, and an installation guide readily available on their website with specifics about hard wiring for full 11kW/48A charging. I do know that hard wiring is required above 32A/7.7kW, and the wallbox documention did not inspire as much confidence.

 

[teamzans]

@teamzans , I did look at the wallbox and it's mostly esthetics and availability of info, the Home flex has the cord hanger and a connector port incorporated, and an installation guide readily available on their website with specifics about hard wiring for full 11kW/48A charging. I do know that hard wiring is required above 32A/7.7kW, and the wallbox documention did not inspire as much confidence.

Gotcha. Thank you, @MinhSATx. I would hope a qualified electrician would be able to work around any documentation gaps. Maybe that’s misplaced!

 

[MinhSATx]

Woohoo! I won't have an electrical car for another 6 months but my garage is ready for it! I did have a master electrician install it, he did a great job. 11kW on a 240V/70A circuit. After it powered on, I activated it in the Chargepoint App and it connected on my home Wi-Fi. Ready to go. The wire is 25 ft (7.6m), it can reach the charging port pretty much wherever it is in the car.

 

[teamzans]

Awesome! Looks great, and we’re now waiting for the best part to arrive in our garages.

 

[Phil1001]

@MinhSATx What type of plug is that? I thought 70A will have to be hardwired.

 

[MinhSATx]

@MinhSATx What type of plug is that? I thought 70A will have to be hardwired.

It's a NEMA 14-50P. I did ask my master electrician twice, but he pointed out that the note in the installation guide says specifically that IN CANADA, you have to hard wire the ChargePoint charger, but apparently in the US it's fine to go through this plug, and it is OK to draw 50A continuous from it, though the breaker does have to be up sized to avoid unwanted tripping, and he refused to hardwire it. So who am I to argue with a Master Electrician?

 

[JToddK]

It's a NEMA 14-50P. I did ask my master electrician twice, but he pointed out that the note in the installation guide says specifically that IN CANADA, you have to hard wire the ChargePoint charger, but apparently in the US it's fine to go through this plug, and it is OK to draw 50A continuous from it, though the breaker does have to be up sized to avoid unwanted tripping, and he refused to hardwire it. So who am I to argue with a Master Electrician?

Hmm... By definition (it's in the name) a NEMA 14-50P is rated for 50 Amps. AFAIK 80% is usual for continuous duty. In some cases, you are permitted to go to the next upsize breaker - say 6-3 wire rated for 55Amps can use a 60Amp breaker, 'cause that's the next closest rating. A 70 amp breaker on a 50 amp device pulling 50 amp continuously wouldn't be my choice, but I'm conservative. This is probably not the place to discuss NEC related issues and I'm not really qualified. Hope it works out.

 

[MinhSATx]

I had the same concern, but he should know his stuff. And frankly, I doubt very much I'll have an issue with it.

 

[JToddK]

I had the same concern, but he should know his stuff. And frankly, I doubt very much I'll have an issue with it.

I certainly hope not. Just up-sizing a breaker to prevent tripping reminds me of putting a penny in a fuse box (yeah, I'm that old). When In doubt, I used to let the Inspector make the call. Most home stuff today, except for new construction, doesn't usually get an independent inspection.

 

[MinhSATx]

I certainly hope not. Just up-sizing a breaker to prevent tripping reminds me of putting a penny in a fuse box (yeah, I'm that old). When In doubt, I used to let the Inspector make the call. Most home stuff today, except for new construction, doesn't usually get an independent inspection.

I thing you are exaggerating a bit. The NEC does suggest to upsize the breaker by 20% from the constant current draw not to trip the breaker, and the NEMA 14-50 is rated for 50A constant current. Yes, it would be more conservative to find a 70A plug, but there are no such thing, and my master electrician elected to go with the NEMA 14-50 instead of branching directly to the charger because he was concerned that there would be no other way to shut off the current to the charger than going all the way outside to shut off the breaker. Upsizing the breaker by 20% is not the same thing as putting a quarter instead of a fuse, a quarter would not melt at 24A. And I never heard of a house going on fire because somebody put a 30A fuse in place of a 20A or a 20A instead of a 15A fuse.

The only way to keep the whole circuit "rated" at 70A would be put yet another disjunctor box in proximity to the charger and direct wire it, but honestly, the ChargePoint input wire are limited to #6AWG, which again is rated for 50A continuous but not 20% over-rated to match the recommended breaker size. So I do support my master electrician's decision. He IS certified Master Electrician in Texas, so you are certainly entitled to disagree, but I'm happy with my installation.

Minh

 

[JToddK]

I thing you are exaggerating a bit. The NEC does suggest to upsize the breaker by 20% from the constant current draw not to trip the breaker, and the NEMA 14-50 is rated for 50A constant current. Yes, it would be more conservative to find a 70A plug, but there are no such thing, and my master electrician elected to go with the NEMA 14-50 instead of branching directly to the charger because he was concerned that there would be no other way to shut off the current to the charger than going all the way outside to shut off the breaker. Upsizing the breaker by 20% is not the same thing as putting a quarter instead of a fuse, a quarter would not melt at 24A. And I never heard of a house going on fire because somebody put a 30A fuse in place of a 20A or a 20A instead of a 15A fuse.

The only way to keep the whole circuit "rated" at 70A would be put yet another disjunctor box in proximity to the charger and direct wire it, but honestly, the ChargePoint input wire are limited to #6AWG, which again is rated for 50A continuous but not 20% over-rated to match the recommended breaker size. So I do support my master electrician's decision. He IS certified Master Electrician in Texas, so you are certainly entitled to disagree, but I'm happy with my installation.

Minh

Yes, the old penny trick was a bit of an exaggeration.

I thing you are exaggerating a bit. The NEC does suggest to upsize the breaker by 20% from the constant current draw not to trip the breaker, and the NEMA 14-50 is rated for 50A constant current. Yes, it would be more conservative to find a 70A plug, but there are no such thing, and my master electrician elected to go with the NEMA 14-50 instead of branching directly to the charger because he was concerned that there would be no other way to shut off the current to the charger than going all the way outside to shut off the breaker. Upsizing the breaker by 20% is not the same thing as putting a quarter instead of a fuse, a quarter would not melt at 24A. And I never heard of a house going on fire because somebody put a 30A fuse in place of a 20A or a 20A instead of a 15A fuse.

The only way to keep the whole circuit "rated" at 70A would be put yet another disjunctor box in proximity to the charger and direct wire it, but honestly, the ChargePoint input wire are limited to #6AWG, which again is rated for 50A continuous but not 20% over-rated to match the recommended breaker size. So I do support my master electrician's decision. He IS certified Master Electrician in Texas, so you are certainly entitled to disagree, but I'm happy with my installation.

Minh

Yes, the old penny trick was an exaggeration. One of the great things here is to see how other people are doing things. My approach will be hard wire on a 60A circuit, with a 48A limit on charging - something different than what you''re doing. With hard wire there is no requirement (since the 2020 code updates) for a GFCI at the panel. I'm trying to avoid two GFCI's in the same circuit (one built into the box and another in the panel)- the box manufacturers recommend against it. If you're happy with upsizing a breaker by 40% and (maybe) eliminating the GFCI for the garage mounted receptacle, cool. Just noting that there are other alternatives. Peace.