Worth the breaker upgrade? 40A->50A

[awdpilot]

I picked up my 3P on 11/30 and currently I have the home charger hard-wired on a 40A circuit, so I'm charging at 32A every night.

The wire from the panel is a 6 gauge, which is capable of 50A, would it be worth it to have the breaker upgraded so that I could charge the car at 40A instead of 32?

Not sure which would be more "efficient" from a power consumption point of view.

 

[DayTrippin]

When I use the S, I am typically putting about 150-250 miles on it. If I am just staying in the city, the S is not my first choice.

I vastly prefer the 3 over the S in the city as the 3 is a lot more efficient and most importantly, it has stalks. I have a lot of blind intersections to deal with. The stalkless S has resulted in too many near misses (difficult to find reverse quickly) to the point I'll take the 3 whenever I am mostly in the city.

I normally start at about 45-50% and top up before I go to get the buffer I need to get back home without being to close to empty.

 

[TydalForce]

Note: I'm in CA and since you are im MA, I am curious what kind of heating you are using for your home,
and in particular water heating, as I am considering installing a water heat pump.
I think this would be more efficient and cheaper that the water gas heater that I am using.

I have electric water heater, and my old one started leaking a couple weeks ago and had to be replaced. I asked the plumber about the heat pump models, and he said they weren't worth it - they might save some money but there's added expense setting them up, and still not great on reliability. (He had less nice things to say about the instant heaters!) His opinion was, the tank style is the best option right now.

 

[Sophias_dad]

they might save some money but there's added expense setting them up,

Your plumber is a liar. They do save money and there is the same expense setting them up. Its the same power input and cold/hot pipes to connect. I'm also not sure of the current utility benefits, but a few years back I believe they could be installed for considerably LESS than a conventional electric after rebates.

On the flipside, they are probably considerably less reliable, take longer to heat the water, and cool off the room they are in. It is for THOSE reasons I probably wouldn't want to install one(in MA, anyway)

 

[dmurphy]

Note that if the wire is #6 romex you CANNOT upgrade to a 60A circuit and then charge at 48A, period. A continuous load cannot exceed 80% of the wire rating. #6 romex is rated at 55A and 80% equals 44A, which is lower than the 48A than the wall connector uses when set to a 60A circuit.

I realize this is an older post but …. It should be noted that 6AWG may be OK, depending on the wire used.

My wall connector uses #6 THHN (90* C) in a 1” conduit, which means it’s 75A rated. Downrate to 80% and we’re at 60A. Perfectly OK for a 48A wall connector.

So depending on how the install was done (romex, conduit etc) - it’s possible a 60A breaker could be used here, allowing the car to charge at its maximum 48A rate.

 

[TydalForce]

Your plumber is a liar. They do save money and there is the same expense setting them up. Its the same power input and cold/hot pipes to connect. I'm also not sure of the current utility benefits, but a few years back I believe they could be installed for considerably LESS than a conventional electric after rebates.

On the flipside, they are probably considerably less reliable, take longer to heat the water, and cool off the room they are in. It is for THOSE reasons I probably wouldn't want to install one(in MA, anyway)

There's definitely an added expense setting them up, as you at least need a drain system for the condensation created by the heat pump, which would for many folks require a condensate pump. For someone like watts_up moving from gas, there may be an additional expense running 240V electric.

 

[SageBrush]

Your plumber is a liar.

Probably.

Its the same power input and cold/hot pipes to connect.

Unless a 240V circuit has to be installed.

I believe they could be installed for considerably LESS than a conventional electric after rebates.

Ymmv, with a range from less to more

It is hard to generalize. Location and climate make huge differences. I would not want one in the home because of the noise, but in a mild - moderate winter climate a DHW HP in the garage is probably pretty awesome. One very important consideration is that a HP should have a tank size a good 30%, if not 50% larger than needed for pure electric because you want it to heat during the optimal hours of the day, not when the shower is typically running. I'm looking forward to swapping out my NG for a DHW HP to run off our home PV during the day.

 

[Sophias_dad]

Unless a 240V circuit has to be installed.

Sure, but @TydalForce says he had an electric water heater installed, and I'm pretty sure that every HW heater in the whole house-scale is already running on 240V. The whole claim-to-fame for heat pump water heaters is that they use less power.

 

[SageBrush]

Sure, but @TydalForce says he had an electric water heater installed, and I'm pretty sure that every HW heater in the whole house-scale is already running on 240V. The whole claim-to-fame for heat pump water heaters is that they use less power.

Good point

 

[Sophias_dad]

There's definitely an added expense setting them up, as you at least need a drain system for the condensation created by the heat pump, which would for many folks require a condensate pump. For someone like watts_up moving from gas, there may be an additional expense running 240V electric.

I had forgotten about the condensate drain and probably pump! I could see where that would drive up the price a bit.

 

[Watts_Up]

I have electric water heater, and my old one started leaking a couple weeks ago and had to be replaced. I asked the plumber about the heat pump models, and he said they weren't worth it - they might save some money but there's added expense setting them up, and still not great on reliability. (He had less nice things to say about the instant heaters!) His opinion was, the tank style is the best option right now.

You can replace 'heat pump' by 'electric vehicle'
and 'electric or gas water heater' by 'ICE or hybrid vehicle'
and you will get the same type of conversation !!! LoL

 

[TydalForce]

I don't pretend to be an expert, I'm just relaying the advice given to me by someone with more experience than I have. As with any advice, it will vary from person to person. And since my need was pretty urgent and just 2 days before a major holiday, I didn't exactly have the opportunity to shop around heh.

Good discussion, perhaps it's time we stop hijacking the thread (sorry, I started it! lol)

 

[father_of_6]

I wanted to charge at 48A just to have "the fastest I can get setup with", but ended up with 40A because of my electrician's choices. I didn't find out until after the job was done. At that time, I was slightly disappointed - but in 1.5 years of using it the difference would have been negligible.

I've got the car set to 60 or 65%, and typical days the battery doesn't make it below 40 or 50%. At most, the car charges for a few hours at night.

If I could bump up to 48A by tossing in a $20 breaker, I would do it "just because"... but it would make absolutely no difference in my life. Maybe the $20 would be better spent on toilet paper or tacos. Or rotisserie chicken. Or jogging pants.

 

[ATPMSD]

It should be noted that 6AWG may be OK, depending on the wire used.

That is why I said ROMEX, #6 THHN is fine.

 

[TesslaBull]

"If it ain't broke, don't fix it"...

Unless you don't have enough time to charge during your 'off peak' rate,
or need to fully charge two cars the same night, I don't see the advantage of this minor update.

I doubt you could measure any efficiency change. I charge using a 30 A (24 A nominal)
and comparing the value displayed by the power meter I installed next to my charger
and the value displayed inside the car, the charging efficiency is around 85%.

Note: I'm in CA and since you are im MA, I am curious what kind of heating you are using for your home,
and in particular water heating, as I am considering installing a water heat pump.
I think this would be more efficient and cheaper that the water gas heater that I am using.

Heat pump water heater is awesome. We bought one in 2022. Total net cost including installation was $500 after sale, rebates and tax credits. 2023 credits are even better. You should only have to pay for installation basically. Just make sure you have a good place/way to run the condensate line. Ours is next to our furnace so we simply tied into the existing condensate line/pump. We get "free" dehumidification of our basement as a side effect.

Yearly energy use is predicted to be $105. It will cool the room or space it is in. This might be a minor benefit or minor drawback, but not a major one in either case IMO. They do make some noise, but mine is in the basement and we don't notice it *at all* upstairs. If it was in a closet next to me in the living room it would be audible....maybe like a window unit A/C on low.

Water heater is the biggest energy draw in a home other than heat and A/C. Definitely worth reducing that energy draw by 75% forever IMO. Also pairs well with solar for those that consider going that route. That's my plan....solar, and electric everything in the house, cars included. With net metering, I'm hoping to have 0 net energy cost forever after the one time upfront cost of solar installation for both home and autos.

 

[TesslaBull]

TBH, you could just turn up the charger as if it has a 50 amp breaker. If the 40 amp breaker is in your 60F basement and not flanked by other high-load breakers, it may well not trip. If it does trip, then a breaker replacement would stop the tripping. If you weren't doing the work yourself, I'd suggest just not making the breaker upgrade unless you really need that extra 8 amps. If the wire is conductors-in-conduit, you could even go to a 60 amp breaker and 48 amp charging.

Side note: I'm running 48 amps out of my 50 amp breaker for hours on end not far from you, and its never tripped.

This sounds like a terrible idea and I would strongly advise anyone against bypassing established electrical safety standards. If your family dies in a fire caused by overloading your EV wiring in order to charge 10 minutes faster for no reason, I doubt that's a tradeoff many would feel good about.

 

[Watts_Up]

I don't pretend to be an expert, I'm just relaying the advice given to me by someone with more experience than I have. As with any advice, it will vary from person to person. And since my need was pretty urgent and just 2 days before a major holiday, I didn't exactly have the opportunity to shop around heh.

Good discussion, perhaps it's time we stop hijacking the thread (sorry, I started it! lol)

I build an off-grid Solar system for my home and to power my car.
I have now some surpus of Solar energy so I am now considering installing a heat pump.

 

[STS-134]

I picked up my 3P on 11/30 and currently I have the home charger hard-wired on a 40A circuit, so I'm charging at 32A every night.

The wire from the panel is a 6 gauge, which is capable of 50A, would it be worth it to have the breaker upgraded so that I could charge the car at 40A instead of 32?

Not sure which would be more "efficient" from a power consumption point of view.

Charging faster and allowing the car to sleep (computer consumes hundreds of watts whenever it is on, and it is on whenever the car is charging) is the most efficient.

There's definitely an added expense setting them up, as you at least need a drain system for the condensation created by the heat pump, which would for many folks require a condensate pump. For someone like watts_up moving from gas, there may be an additional expense running 240V electric.

The evaporator coil and compressor should be outdoors. Creates less noise, allows you to have a more powerful heat pump (indoor evaporator units are always weak because manufacturers worry about freezing the room they're in) and thus allows a recovery rate that's fast enough that it doesn't need an electric resistance heater as a backup, which is inefficient. And of course, no condensate drain required, because the water simply drips off the outdoor unit, just like with an air source heat pump in heating mode.