How Many Amps Does Your Home Charging Station Really Need?

MAR 11 2019 BY STAFF 60

Level 2 is the way to go. That’s for sure.

There’s a lot of factors to consider when shopping for a home charging station for your electric vehicle. You certainly want to make sure you’re buying a unit from a reputable company, that is has a good warranty, and that it’s built to last many years.

However, one of the other important considerations is how powerful of a charging station do you need? Most electric and plug-in hybrid vehicles available today can only accept a maximum of 16 to 32-amps, while charging on a level 2, 240-volt charging station. However, there are charging stations available today that can deliver more power, even though very few electric vehicles can actually accept it.

That can be confusing to some consumers shopping for a charging station, so let’s take a closer look at what the difference between a 30-amp unit and one that can deliver 40-amps.

The average daily distance North Americans drive is between 26-31 miles. For electric vehicles, this requires about 10 kWh of electricity (Most EVs average between 3 & 4 miles per kWh. Charging an EV at 40 A (9.6 kW) means it will take a little more than one hour to charge to the minimum required daily amount, compared to 1 hour and 20 minutes at 30 A (7.2 kW).

Since most EV drivers charge overnight, this is not a significant difference, especially when the car stays plugged in for 8 to 10 hours. Another factor to consider is the initial cost to power a 40A EVSE vs a 30A EVSE can be very substantial. That’s because the entire circuit needs to use a thicker wire, and the circuit breaker needed is more expensive. Plus, many residential electrical systems do not have the spare electrical capacity to add a 40A charger, since it requires a 50-amp dedicated circuit.

As the auto industry increasingly shifts to EVs, combined with the fact that the average family owns two vehicles, it is probable that two EVSEs per household will soon be the norm. Even if the present capacity allows starting with a 40A EVSE, it will certainly be a challenge for any household to add a second one in the future. Two 30A power sharing-enabled units (drawing a combined maximum of 32A) to charge two family EVs is more cost-efficient than to have to swap the charging connector from one vehicle to another every evening.

When shopping for a home charging station, make sure you get all the features and quality you need. However, make sure you’re not paying for an option that your EV can’t use, will cost you more to install, and may not even be compatible with your home’s electrical supply. FLO Home charging stations deliver up to 30A, which is more than enough power to fully charge your EV overnight, and have you ready to go the next morning.

The FLO Home line of charging stations is packed with features and details, not available on most charging stations. They are made of the highest quality components and built to last many years. That’s why they come with an industry-best, 5-year limited warranty. Check out why FLO Home is the charging station that should be in your garage.

  • 5-year limited warranty (industry average: 3 years)
  • Rugged, 100% aluminum casing, NEMA 4X certified
  • Sleek, practical design
  • FLO Home X5 smart features can be managed in the FLO mobile app

MSRP: $1,095 (X5 with Tungsten casing) / $995 (X5 with Carbon casing) / $795 (G5 model). Purchase online at flo.com or on amazon.com. Free express shipping anywhere in the US

**FLO is an advertiser on InsideEVs, but we received no direct compensation for this article.

Categories: Buying Advice, Charging

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60 Comments on "How Many Amps Does Your Home Charging Station Really Need?"

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Answer: As many as you can do safely & economically. Even if your current car can’t handle a big draw now, your next car probably will.

Yes, but that doesn’t mean you need it. I find 32 A charge rate perfectly adequate, even if I get a Model 3 LR my needs for charging rate won’t change. L2 at 16 A or slower is fine for overnight for lower range EVs, but 32 is great for PHEVs where you need to recharge between trips. Our Clarity PHEV has on average more than a full charge every day, so slower charging means less EV miles.

A Model 3 LR is never going to need charging during the day unless driving long distance when it would be charged at a Supercharger. I really only need overnight charging and Superchargers. So 32 A is fine for me.

I just want to encourage people to think ahead. If you pay a couple dollars for bigger conduit now & lower wire gauge, you’ll be very happy if/when you eventually upgrade. If not, it only cost a few bucks more and was safer.

For those times when you need to drive 500 miles but only have an hour to plan ahead AND you don’t want to drive a few blocks to a fast charger instead?

Sounds like the EV equivalent of prepping. The point Viking is making is that the scenario where you absolutely need to charge twice as fast on a level 2 is unlikely to ever arise because better options are already available for that use-case.

When vehicles like the Rivian truck are out, there’s a good chance people are going to want more than 32A, especially the 180 kwhr one. If you use 75% of the pack in a day, it’s going to take 18 hours to recharge. That’s way too long if you need to use it again in 12 hours.

Depends on your daily mileage.
The more miles you average a day, the higher the charge rate you need.

Technically true, although only an issue for those that empty it and need the full range next day for a trip. In such a case I personally would just hit the 350 kW charger for a few minutes. You are right, that the less efficient vehicles need more powerful default chargers.

I would suspect 10 kW would be ideal for that truck, but again, I would just keep my 7 kw as I don’t have the use case where I drive 300 miles one day and then turn around 8 hours later and drive 300 miles, where I am not driving across country and just using DCFC. I might regularly drive say 50-100 miles and turn around and drive it long distance the next day, but my 7 kW charger could handle that case fine.

You’re overlooking that it is a truck rated to pull a significant amount of weight. If you are pulling a trailer, how many DCFC stations are arranged to be able to park at them without having a trailer hanging halfway across a parking lot? Lots of work trucks drive 150 miles with a trailer in a day and do it all over the next.

Agree, I suspect the Rivian is not marketing to those people. At the little Electrify America station I went to, in order to see what they offered, a trailer would be no go (disconnect it first).

If you were to get the Rivian to do that (not use CCS, but need to do max range trips every day), you would definitely want faster than a 7 kW charger. What I am saying is that I don’t need a charger faster than 7 kW, and I suspect most people wont. I am not saying: no one needs a charger faster than that. I like that they offer it, but I am not willing to pay for it. Make it a upcharge option or something.

Actually you can probably get an extension cord. I think I’ve seen those sold. Probably need to be careful of the length/current being drawn, of course.

Same thing here. 32 Amp line, but set to push 25 Amps.
Have never needed more or faster charging: BMW i3.

I find 16 amps to be painfully slow. The problem with 16 amps (or worse L1) is if you forget to plug in or end up needing to drive more than normal you can be in big trouble.

I agree that 32 amps is fine, but that isn’t too say 40 amps wouldn’t be better. More amps means faster charge time to make up for a mistake or an unexpectedly long trip. Faster charging has a lot of convenience potential.

True and you can always install Tesla 48A wall charger and dial the amperage back a bit. Say to 16A or 20A for overnight charging, if you want.
I currently have a 20A Leviton charger on a 30A circuit (I share it with my fiancée’s Leaf), but thinking of upgrading to 48A Tesla HPWC (on a 60A circuit) and dialing it back a bit. That way I still have the full 48A capability for emergencies.

For a PHEV, 120V 20A is plenty, cheap to wire in a dedicated circuit and no home charger to buy.

As I mention before, PHEVs (and smaller battery BEVs) often need 7.2 kW chargers (or faster) as you can get more EV miles. Our Clarity PHEV has 47 mile electric range yet averages over 60 EV miles per day. The only way this is possible for our use case for the car is if it is able to recharge rapidly between runs. Yeah, if you drive to work and sit at work 8 hours 120 is probably fine, but if it only has 30 min to 1 hour opportunity charges between errands or at lunch then 7 kW or more really helps get more EV miles.

The problem there is that a lot of PHEVs (at least older ones) have slower chargers (3.3kW) in them. For mine, that still charges in ~2 hours on L2 16A.

Agreed, our Mitsubishi Outlander goes more electric miles thanks to our 16Amp charger (3.3 kW) than would be possible on a regular outlet (12A, 1.4 kW) charger. I do kinda wish I had future proofed by installing an EVSE capable of 6.6 or 7.2 kW, but when I got my 2012 Leaf it maxed out at 3.6 kW, so 3.3 kW seemed plenty. Now I have a 2019 Leaf which can take a 6.6 kW charge rate. Could be useful when I forget to plug in… or superfluous thanks to the larger battery. Story time: Monday I walked out to the car and realized that I failed to plug the car in the night before. First thought: “Oh crud, I better take the PHEV!” Second thought: “Wait, no, I can just plug in at work. Expensive, but doable.” Third thought: “I have 35% battery remaining, 59 miles according to the gauge. That’s more than my 2012 had on a full battery. I used to do this drive every day. Suck it up, get over your range anxiety, and go to work!”. Made it to work and back (36 miles) without even hearing the car’s pleasant voice announcing “Low Battery Warning”.… Read more »

Even easier and better to make that a 240v, 20a. Gm provides dual voltage evse’s and it was easy to convert the dedicated 120-20a line in my garage to 240v. Simply change the plug and the breaker, instant 240v circuit.

The 120v circuit could not keep up with our Volt, but the 240 does it easily and can almost keep up with my Bolt. It probably can keep up in summer, but not when it’s cold out.

in my experience with my volt I’ve found this to be mostly true. There are a few rare times when a 240 charge throughout the day would keep me from using gas. Most times, however, it’s the limitation of range of the battery rather than charging speed.

Brian, I have a Gen I Volt and while I wish it could charge faster than 3.3Kw when I am trying to top off the pack during my lunch break on one of my busy day, most of the time at night I don’t even need to turn the amperage up from the standard 8 amps to 12 amps because 10 or 11 hours is plenty to top it off.
But even given that, if 7.2 Kw charging had been an option, I would probably have paid to get it. Nothing more irritating than having the genset kick on when I am just 3 or 4 miles from home at the end of the day. The faster charging option wouldn’t have paid for itself, but it would have been nice to have.

OpenEVSE is cheaper, very fully featured and entirely hackable if you’re into that…

https://www.openevse.com/stations.html

Cheaper isn’t usually better. In fact….

I have an Open EVSE and it’s great. I haven’t had any problems with it. And it’s modular so you can add more features like wireless reporting if you want.

I’m fine with DIY but our regulators and insurance companies in this country are not so keen on non-certified equipment.

Since this looks like a free ad for Flo, I’ll through in a bit of balance by noting that the Amazon Prime Choice is:
EVoCharge EVoInnovate, Level 2 EV Charger, 240 Volt 32 Amp
Which has an almost perfect 5 star review rating and retails on Amazon for only $479 (significantly less than Flo ;))

But Amazon doesn’t support InsideEVs as an advertiser. That said, the Tesla charger is only a touch more expensive than the EVo Charge at $500 even:
https://shop.tesla.com/us/en/product/vehicle-accessories/gloss-black-wall-connector.html

Do Not Read Between The Lines

If 32A charging is sufficient for a Tesla you can pay $300 for a spare mobile connector and leave it plugged in

What people fail to realize is that this Flo EVSE is really at its heart their commercial unit that they use in their own public charging network, so able to withstand all kinds of temperature and abuse, put in a nice and sturdy enclosure. Not cheap just good enough junk made in China by the lowest bidder.

Do Not Read Between The Lines

Clipper Creek HCS-40P, $589. Not a smart EVSE, but Clipper Creek EVSEs are rock solid and made in the USA.

(⌐■_■) Trollnonymous

If I were having something installed it would be 240 volts and 50 amps.

That’s what I did. I had a 50amp circuit from the mains run to a sub-panel in the garage. I then had the lights, outlets and the 40-amp EVSE (GE WattStation) run from the sub-panel. Very flexible. Since I have only owned PHEVs, the GE is just puttering along in low gear for almost 6 years now.

When I got the CT6 PHEV, I got an EVSE extension cord since it has the port in the rear not the front like the other two. Cord is rated at 32amps, but, the Caddy only uses 16amps.

Answer: 8-10 Amps…

Hah! I see what you did there. Yes, the question was NEED, and 8-10 amps is the bare minimum for a 120v outlet in the USA.

30A or 40A doesn’t make much difference compared to single phase versus three phase. Most homes in Europe now have three phase which an increasing number of European version EVs now support. For example the best selling EV in Europe for four years running is Renault Zoe which charges at 3 x 32A = 22kW. Audi E-Tron Wuattro charges at 3 x 16A = 11kW or 3 x 32A = 22kW. BMW i3 senond and third generation both charge at 3 x 16A = 11kW and Tesla charge st 3 x 24A = 16.5kW.

The problem is that if you plug in a Tesla to a 32A or 40A single phase you will still only get 24A = 5.5kW and with a recent BMW i3 you will only get 16A = 3.6kW. So the important thing is to get a three phase home charger if you have a three phase electricity supply.

US centric story since they reference a US product.

Tesla Model 3 can charge at 11 kW (3 x 230 V x 16 A).

Do Not Read Between The Lines

Bjorn Nyland tested and found it was only charging at 10A on 3-phase.

I posit that 16A is more than sufficient for most use cases. The only situation that 16A doesn’t support is back-to-back road trips. 45kWh from 8PM to 8AM is more than sufficient for other cases.

Plus, 16A allows for easier integration into a home panel, and/or allows for 2 separate chargers later (which is way easier than 1 30A charger for a 2-EV household).

A 16 amp level 2 will actually suffice for the vast majority of people even if their car can do more.

Most people really don’t need much. When we got our Volvo XC60 T8, it came with a 3kw charging cable so I Installed a 220v/16amp plug for that (about $30 in parts). It takes 3 hours to fully charge the 10kwh battery.

We then got a Bolt. I decided to wait to upgrade and see if we needed more. Nope. The single 3kw charger has been more than ample to keep both of our vehicles topped off.

I suspect we could easily even get away with a simple 120v charger, but especially for the Volvo with only about 20 miles of electric range, it’s nice to be able to recharge it between outings during the day. Given that we can keep the Bolt plugged in 16 hours a day, there is no problem keeping it topped off whatever the charging rate.

If Tesla sold their wall connector with a J1772 plug, they’d sell a ton of them at $500/ea. You can get load-sharing, 80A capable charging stations for less than half the cost of the FLO unit. Or get two for less than the cost of one.

I’ve used a UMC V1 with my car for about six months. I switched between 32 and 40 amps and to be honest, it’s not that huge of a difference. Most of the time the car is sitting for and hour or two. Now, L1 at 120V is glacial at any amperage. Just jumping to 240V is a big improvement.

Two years ago, we went with a 50A, NEMA 14-50, which gives a 40A maximum charge rate. But our BMW i3-REx only charges up to 7.2 kW (240VAC, 30A.) Soon I’ll replace our Prius Prime with a Standard Range Model 3.

So we can use the J1772 at 40A with either car or plug the Tesla directly into the NEMA 14-50 and get a little more. There are reports a Tesla can safely pull close to 48A from a NEMA 14-50 … we’ll see.

Do Not Read Between The Lines

The SR only has 240V x 32A AC charging, so you won’t be stressing the socket.

If you need a new wire installed, as most probably will, I recommend getting a 50 amp installed. That leaves your options open for the future. You can always run less than 40 amps across the line if you need to.

A 40 amp Open EVSE doesn’t cost you that much right now. On top of that, I don’t see why there won’t eventually be shared 40 amp units. More potential current is always going to be more future proof. If you’re going to the expense anyway I say it’s worth spending a little bit more.

If you have ToU rates with a smaller window for cheaper charging, it is worth it to have bigger amperage. Similarly, the bigger the battery pack and the more cases where you might arrive home with a low charge and want it mostly full by morning, one needs more amperage. For reasonable future proofing, 48 amps is about right. Can fill a 70-85 kWh pack in just over 8 hours. At volume, shouldn’t cost much more than the lower amperage versions. Tesla sells their 80 amp HPWC for $500 which is J1772 protocol compatible, so others should be able to do that or near that too.

For many, the biggest bang for the buck answer is Tesla HPWC plus adapter. Dial down to the right amperage for your breaker box.

Rule-of-Thumb is that a 40-amp line will deliver 200 miles in 8 hours. That basic formula covers the needs for most multi-car households. It’s fast enough without becoming too expensive. Taking into account how much the typical service-panel has available for capacity, that idea of a continuous 32-amp draw (7.2 kW rate) of electricity from 2 plug-in vehicles at the same time may actually be pushing it. So, carefully consider plans for the future. In my household, we installed two 40-amp lines connected each to 100-amp meters for Time-Of-Use discounts. The dedicated hardware makes tracking usage as simple as looking at the monthly bill. They break down the tiered pricing for each meter and show the usage in each category. Also, we choose to use larger-than-needed conduit. So in the future, we could pull higher gauge wire if there was the desire to beef up a charger. Lastly, keep in mind that some people have their service-panel in or near the garage. That’s quite convenient. Some have it clear on the other side of their house. That quite expensive. So, the ideal may not work out. But even just sharing a 240-volt line works fine, since some chargers will allow… Read more »

I think there is another thing that should be addressed. We have both a 16 amp and a 32 amp EVSE installed at our house. (We do have 5 EVs to charge, after all). Sometimes we really need to get a certain EV charged quickly, so we’ll use the 32 amp. But in most situations, probably 95% of the time the 16-amp unit suffices. However, one often overlooked benefit to getting a 16 amp unit besides lower cost, is that the wire will be thinner, lighter, and easier to handle. Our 32-amp system has a really thick wire. And when it gets cold outside especially, the wire can become very stiff and annoying. And if you get getting a really long wire on your EVSE, that will make a lot of difference.

We charge our Model X with a 120V outlet. Works great. Maybe once a month we have to charge at an L2 somewhere. Maybe twice a month we take a trip and supercharge. No need for expensive electrical upgrades.

I’m offended that you publish what is 100% an advertisement as if it were an article — it qualifies as one by any imaginable criterion, since it promotes and “recommends” a certain company’s products without even mentioning any other option, of which of course there are many, let alone comparing them, and has direct “buy” links.

The facts that you acknowledge said company is an advertiser, and that you don’t receive any direct compensation are immaterial (you certainly get goodwill from the advertiser, which isn’t negligible).
Really? You think this is acceptable practice in any kind of journalism?
Let’s see if you’re willing to leave this comment.which is certainly polite & to the point, undeleted, and are willing how many of the site’s readers agree & disagree with me.

I was just thinking about home charging when looking at onboard chargers. Many homes may already be equipped with various 30-50amp outlets. Previously used for AC, Stoves, dishwashers, dryers and welders.
As more cars come out with 14kw onboard chargers. Its going to cost a lot to install.

Something to consider is many get off peak discounts. So charging quicky as posible is ideal.
Or in my case i can make random trips. So needing the car just a hour in might be a need.

Question:

Using solar panels to charge a stationary battery pack during the day.

Use the energy from the stationary battery pack to charge the battery pack of an EV during the night.

Can that be done from DC to DC (during the whole process)?
So, no need to convert DC to AC at any point?

Can it be done without using electricity from the grid?

I thought EV’s DC charge was performed at high voltages. Not 12 or 24V. So conversion is still needed.

I know a couple of people that have a 40-50kWh battery pack at home (acid-lead) and they charge their cars at night with them, so I suppose it’s a valid approach. I can’t tell if it’s an economic solution though.

@ Chris Hansen

“I thought EV’s DC charge was performed at high voltages. Not 12 or 24V. So conversion is still needed.”

Interesting comment.

When charging a battery pack of an EV directly from solar panels during the day, that isn’t performed at high voltages, right?

In Spain going from the standard 20A@220V to 40A can result in more than 70 euros more per month in your bill regardless of your consumption. So increasing intake power is a big NO-NO.

There is one more aspect of slow charging. If you on a power plan with time of use., longer you charge, more chances you have to hit the high peak rate.

Do Not Read Between The Lines

When you see an article written by “staff”, you know that there’s something up with it, because nobody wants their name on it.

In this case it’s an advertisement disguised as an article.

The bigger battery, the less is needed from your home charger.

10 amps is easily enough. Three phase, of course. Kinda stupid when some manufacturers still release cars unable to charge on anything faster than 2,2 kW, when every other household in Europe has access to 11 kW through three phase charging.