Home power loss when charging

[E90M3Jerez]

Hi all. I have owned my MYP since Sept 2022. Have gen 3 HPWC on a 60A breaker. Lost power twice while charging at home twice last night. No dryer or dishwasher on. Temps outside 30F. Lost power a few times in the summer when window AC units were cranking. My electrician did suggest I may need more power coming into the home eventually when he installed the home charger.

It now seems like I need to upsize to at least a 100A breaker. My question is, Would 100A be enough or should I go 200A or would that be overkill? Thanks all!

 

[VT_EE]

Hi all. I have owned my MYP since Sept 2022. Have gen 3 HPWC on a 60A breaker. Lost power twice while charging at home twice last night. No dryer or dishwasher on. Temps outside 30F. Lost power a few times in the summer when window AC units were cranking. My electrician did suggest I may need more power coming into the home eventually when he installed the home charger.

It now seems like I need to upsize to at least a 100A breaker. My question is, Would 100A be enough or should I go 200A or would that be overkill? Thanks all!

Um, you have a 60A charging circuit on a household service that is less than 100amps? If so, that is grossly insufficient. Definitely go with a 200amp service. 100amp is also insufficient for what you appear to be using.

 

[Soul Surfer]

Um, you have a 60A charging circuit on a household service that is less than 100amps? If so, that is grossly insufficient. Definitely go with a 200amp service. 100amp is also insufficient for what you appear to be using.

Ditto. What they said....

 

[RTPEV]

Agree with the 200A recommendation, as if you're going to upgrade, you might as well go to 200A which is the standard these days.

However, in the meantime (if you wish to defer this decision), simply turn down the charge speed on your car if possible. If you are charging overnight, do you really need to be pulling the full 48A (assuming that's what you're doing)? I charge at 30A every 4-5 days and even then my car only takes 6 hours or so to complete a charge (25% - 75%). Unless you are driving an enormous number of miles each day, you should just try setting your charge rate to something reasonable/workable in the car and not pull so much power.

 

[E90M3Jerez]

Thanks all for the replies. Yes I am pulling 48A when home charging and don’t drive often. Wife and I share the Y. I walk to work.

Have been living in the house for 20 years without any electrical upgrades. It’s time. Thanks again, everyone!

 

[ATPMSD]

Yes I am pulling 48A when home charging and don’t drive often.

As you look to update also check the wire running to the wall connector as there is a good chance is it not sufficient to support a 60-amp circuit. The 80% rule requires if you are going to pull 48A as a continuous load the wire must be rated at 60A. Really good chance #6 romex was used, which is rated at 55A, and is not acceptable for a 60A circuit. Strongly suggest changing the wall connector configuration to 50A (or less) until you have verified the wire capacity, and upgraded the panel.

 

[Rocky_H]

I think there must be some drastic miscommunication here, because there shouldn't be any way you actually have going on what we think we hear you saying.

Have gen 3 HPWC on a 60A breaker.

So this circuit by itself is a 60A circuit?

It now seems like I need to upsize to at least a 100A breaker.

This is what doesn't make sense. The main feed to your entire house is currently LESS than a 100A circuit?!! What size is it? Is the whole feed 70 or 80?

My electrician did suggest

What kind of bat-$#*& crazy electrician would allow adding an ADDITIONAL 60A circuit into a whole house supply that's just barely more than that?

So is there something different than that? Sure, you could increase your main supply, or you could reduce that charging circuit down to something sane, like 20 or 30 amps.

 

[STS-134]

It now seems like I need to upsize to at least a 100A breaker. My question is, Would 100A be enough or should I go 200A or would that be overkill? Thanks all!

At least 200A! If the service line is underground, just go all the way to 400A because trenching is expensive.

BTW, J1772 allows charging at up to 80A. Two 80A OBCs going simultaneously maxes out a 200A panel with 160A of continuous load (80% rule). 100A is so 1970s and before and is insufficient for any new install.

 

[E90M3Jerez]

There is a main breaker (100A I think) with two sub panels (60A each in a two family house). The 60A sub panel that is with my unit keeps tripping. I hope this makes more sense. I’m in healthcare and have no idea about anything that has to do with electrical. I’m sure I’m leaving some important details out, but it seems as though I need to upgrade power to that 60A that keeps tripping?

 

[STS-134]

There is a main breaker (100A I think) with two sub panels (60A each in a two family house). The 60A sub panel that is with my unit keeps tripping. I hope this makes more sense. I’m in healthcare and have no idea about anything that has to do with electrical. I’m sure I’m leaving some important details out, but it seems as though I need to upgrade power to that 60A that keeps tripping?

Sounds like you need to upgrade the subpanel and 60A breaker. Drawing 48A through the HPWC leaves you only 12A for everything else on the subpanel. Turning on one vacuum cleaner or toaster oven can max out the breaker and anything else will put it over the limit. After you upgrade the subpanel though, I think you'll also need a main panel and service line upgrade because you're likely to start tripping the main breaker if you don't.

 

[brkaus]

They really should not have put a 48a (60a breaker) in a 60a sub panel with other significant loads.

But it sounds like you’re in a multi-family building? Who owns the building?

You can set the current down in the car or provision the WC to have a lower maximum.

 

[STS-134]

They really should not have put a 48a (60a breaker) in a 60a sub panel with other significant loads.

But it sounds like you’re in a multi-family building? Who owns the building?

I'm assuming that either the OP does or got permission from the landlord to upgrade the panel and service line if the OP is asking about a service upgrade.

You can set the current down in the car

That's a fire hazard. Don't do it. Tesla's software sometimes dumps configuration settings when upgrading the firmware.

or provision the WC to have a lower maximum.

That would work but OP would likely need to set it extremely low with only a 60A breaker. 60A subpanel for a living area that includes HVAC, garage, and everything else a family would use seems like it's out of the 1940s or 1950s (when HVAC was less common and EVs and microwave ovens didn't exist). It's overdue for an upgrade.

 

[Big Earl]

If the subpanel for your side of the duplex is fed with 60 amps, your car charger by itself is maxing it out. That means you have zero capacity remaining for other things like cooking, washing clothes, or even lighting.

Until you get this resolved, I recommend reducing your car's charging current to 24 amps, which should give you a decent buffer for other electrical consumption, without tripping the circuit. Charging at 24 amps should still be enough to completely charge your vehicle from empty in about twelve hours.

 

[E90M3Jerez]

I do own the building so I can upgrade per all of these recommendations! Thanks again to everyone. I appreciate all of the feedback.

 

[STS-134]

If the subpanel for your side of the duplex is fed with 60 amps, your car charger by itself is maxing it out. That means you have zero capacity remaining for other things like cooking, washing clothes, or even lighting.

Not zero. It leaves 12A for everything else which is grotesquely inadequate but nonzero. Stoves, washing machines, etc., are not continuous loads so they're allowed to use that last 20% of capacity. Of course, a clothes dryer typically uses about 20-25A (on a 30A circuit) which would put the breaker over capacity but it might not necessarily trip because clothes dryers cycle their heating element on and off to maintain the proper temperature. They do not draw continuously.

 

[jjrandorin]

There is a main breaker (100A I think) with two sub panels (60A each in a two family house). The 60A sub panel that is with my unit keeps tripping. I hope this makes more sense. I’m in healthcare and have no idea about anything that has to do with electrical. I’m sure I’m leaving some important details out, but it seems as though I need to upgrade power to that 60A that keeps tripping?

Its not your fault for not being an electrical pro, you hired someone to do that for you. If what you are saying here is correct, and If you actually hired an "electrician" and not "a handyman", then I would suggest throwing away any contact information you have for that person and never speaking to them again.

In the short term, If I were you, I would look into the information on configuring the Gen 3 Wall connector and configure it for a much smaller circuit size, if it in fact is configured for a 60amp circuit like it sounds like it is. If it were me, since I dont know how to do load calculations etc, I would probably configure it for a 20amp circuit (so that it wouldnt pull more than 20amps) and see if that amount of charging was fine.

I mean, you can look at increasing your electrical capacity, but no electrician should have installed a 60amp device on a 100amp main service that was being split by 2 units, which is what it sounds like you have.

 

[Rocky_H]

There is a main breaker (100A I think) with two sub panels (60A each in a two family house). The 60A sub panel that is with my unit keeps tripping. I hope this makes more sense.

Oh my goodness. Well yes, that certainly does make more sense, but it's even worse that it sounded at first. You have set up the car charging circuit to be the entirety of your whole supply that you get. That is crazy.

If the subpanel for your side of the duplex is fed with 60 amps, your car charger by itself is maxing it out. That means you have zero capacity remaining for other things like cooking, washing clothes, or even lighting.

Yes--this. 100% correct. If it were the only thing in the panel, it would just be a pass-through, but it does fully consume the capacity of it, and there can't be any other loads there.

Not zero. It leaves 12A for everything else which is grotesquely inadequate but nonzero.

Incorrect.

 

[brkaus]

If you have 2 units I'd definitely look at 200a minimum at the main panel. I'd check, but might be a big step up in cost to 320/400. It sounds like there would only be a single meter before the main panel? or are they individually metered? Would there be a chance of a 2nd car charger in the future (for you or the other unit)?

 

[RTPEV]

That's a fire hazard. Don't do it. Tesla's software sometimes dumps configuration settings when upgrading the firmware.

While I agree that Tesla's software upgrades tend to forget certain settings, in my experience, max current doesn't appear to be one that is easily forgotten. My car has forgotten plenty of settings, but in the 4 years I've traveled to my in-laws in my car, it has always remembered my max current setting at their house (I set it to 8A because I don't quite trust their house wiring).

Certainly a better option would be to upgrade service & breakers. And if programming the wall connector itself to a lower setting is doable, then yes, that's better as well. But as an easy, interim solution, reducing the max current setting in the car seems quite reasonable to me. Is it zero risk? No, for the reason you stated, but even if the car's settings were to get cleared, you also still have the breaker as well. Characterizing it as a fire hazard, while technically true if there is a double failure, is a bit of a exaggeration of the level of risk.

 

[Rocky_H]

While I agree that Tesla's software upgrades tend to forget certain settings, in my experience, max current doesn't appear to be one that is easily forgotten. My car has forgotten plenty of settings, but in the 4 years I've traveled to my in-laws in my car, it has always remembered my max current setting at their house (I set it to 8A because I don't quite trust their house wiring).

It's really not very close to reliable, because it also depends on detection the car's position accurately enough. Over the last few months, I've had more than a few times where I was getting home, and it didn't open my garage door, which confused me, and then I found that it didn't honor my reduced amp setting. That was because it was pretty thick, overcast, rainy skies, and the car wasn't getting a good GPS signal and was showing my car about a block away in the subdivision, so it didn't go to that memorized location for my Homelink or custom amp setting.

So programming the limit in a wall connector or using a specific plug type on the mobile connector to really force an appropriate amp limit is much more solid.