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Is it recommended to charge two EVs at the same time from the same outlet? My wife and I own a Bolt and a Model 3. There's only one 30 watt NEMA 220V outlet in the garage. Can we buy a NEMA splitter and charge both cars at the same time? Will this be safe or slow down the charging?
 

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Well, you need to work through limiting the chargers so that they only draw in totality up to the limit of the circuit. There is no code violation to splitting a single circuit, in fact the Tesla charger has a section on it and JuiceBox supports it officially and both of these chargers have the ability to share a circuit and 'talk' to chargers from the same family of chargers so that they can maximize charging. The Tesla charger requires a CAT 5 cable plugged between each charger and Juice does it via the cloud so internet access is required.

To be clear; you can take one 30 amp circuit and have two or more 30 amp outlets on that same/single circuit. If you try to draw more amps than the circuit is rated, you will pop the breaker.
 

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You can setup two JuiceBox charging stations to share a circuit. I think they talk to each other to limit current. I am sure they draw more than 30 watts.... ( you mean 30 Amps)

"Manage Load Configure two or more JuiceBox charging stations to share a circuit."

 

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Your Bolt OEM EVSE will draw 12A
Your Tesla portable EVSE will draw 32A (though you can turn it down)
So, by default, 42A > 30A * 80%, so that would be a no.

However, if you turn down your Tesla to charge at 12A, then you will be drawing a total of 24A.
So 24A = 30A * 80% and you should be fine.
 

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Will this be safe or slow down the charging?
As has been pointed out above, it can be safe if you slow down the charging to 12 A per car. That would require about 24 hours to fully charge a Bolt or standard range Tesla from 0%. If that is good enough, you have a simple solution with the Bolt OEM EVSE and setting the Tesla to 12 A. If that is more than enough for one car but not enough for the other, you'll need a pair of the smart power sharing EVSEs to divert the full 24 A to the car that needs it when the other car is full. If both cars regularly return home below 50% and need to be ready to go again the next day, you will need some electrical upgrades for more power.
 

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The other approach is to start one car charging immediately and the other set to start charging in sufficient time to get charged up (100%, 90% or whatever) by a certain departure time. Be careful to not depend on the breaker to save your house. If you both need "small" charges over a long period of time (12-15 hours?) this should work.
 

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Your Tesla portable EVSE will draw 32A (though you can turn it down)
Yes, but it depends on which adapter (Gen 2 NEMA Adapters) he's using. If OP only has a 30 amp outlet, it'd better not be drawing 32 amps on it or even 30 amps continuously. If it really is a "30 amp" outlet, I'm guessing it's NEMA 10-30 or 14-30.
 

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You are really stressing that circuit if you try to charge both at once ?. It can be done with extreme caution, but i wouldn't recommend it ? (ie, no more than 24A continuously load at the same time on a 30A circuit as mentioned above with their:geek: ideas of how it can be done ).
 

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J1772 Hydra - charge two vehicles with one charger is a possibility.

Too bad you don't have a 40 amp circuit, which is what would be required for HCS-D40 Dual Charging Station| Level 2 | ClipperCreek.
This one doesn't throttle when charging two or allow prioritization / charging rules. I'd suggest that you get two Juices or two Tesla units because they can charge better .... dynamically. I am a big fan of Chargepoint so I suspect better things are coming from them soon.
 

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Breakers work a lot more reliably than I think you are insinuating with your post. There are testing reports available online from the famous and well known rating and certification laboratories to dispel anyone fears. Circuit breakers are an everyday item in all of our lives.
Yes, breakers do generally do their jobs, although the trip curves are interesting. If you run a circuit just 10% over its rated current, it may be some considerable time before it trips.

Several months ago, my JuiceBox Pro 40 had some kind of conniption. It died, and in doing so tripped the breaker. The breaker did its job, helping to make sure the out-of-control JuiceBox got cut off from power. When I reconnected the power, the JuiceBox was dead to the world (and I got it replaced under warranty).

But breakers are like seatbelts or airbags. They're a safety device. It's always better if you don't get to the point that they are what saves your bacon.

Fires due to wiring overloads do happen.
 

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Yes, breakers do generally do their jobs, although the trip curves are interesting. If you run a circuit just 10% over its rated current, it may be some considerable time before it trips.

Several months ago, my JuiceBox Pro 40 had some kind of conniption. It died, and in doing so tripped the breaker. The breaker did its job, helping to make sure the out-of-control JuiceBox got cut off from power. When I reconnected the power, the JuiceBox was dead to the world (and I got it replaced under warranty).

But breakers are like seatbelts or airbags. They're a safety device. It's always better if you don't get to the point that they are what saves your bacon.

Fires due to wiring overloads do happen.
Agree 100%, safety devices are there to save you if you unknowingly do something stupid, or a device fails causing a dangerous situation. You should never intentionally push the limits on a system and rely on safety devices to bail you out. Just like your UL listed Juicebox (tested and approved) failed, a tested and approved circuit breaker can fail and lead to a fire when something like the Juicebox fails. The more you rely on safety devices instead of relying on best use practices the more likely you are to have a dangerous failure.

That being said, shoddy workmanship (using 14 gauge wire on a 20 amp circuit breaker because it is what the cheap electrician had handy) or ignorant home owner repair work "this 15 amp breaker keeps tripping, I will replace it with a 20 amp breaker" are the most common causes of electrical problems and / or fires.

In my childhood fuse boxes were pretty common in houses, and if you had a fuse that kept blowing people would replace it with a higher current rated fuse, or put a quarter under the fuse in the fuse socket! This is one of the reasons fuse boxes are less common today, and type S fuses (different sizes for different amperage so you can't mix and match) are used instead of Edison style fuses.

Keith
 

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Breakers work a lot more reliably than I think you are insinuating with your post. There are testing reports available online from the famous and well known rating and certification laboratories to dispel anyone fears. Circuit breakers are an everyday item in all of our lives.
I was commenting less on the reliability of breakers and more on the advisability of relying on them for safety. For example, it's probably a poor idea to deliberately crash a car just because you know you have airbags, even if you do believe them to be reliable.
 

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But breakers are like seatbelts or airbags. They're a safety device. It's always better if you don't get to the point that they are what saves your bacon.
Fires due to wiring overloads do happen.
Of course. The purpose of my post was to address the notion that was insinuated that they aren't reliable. This discussion is quite open ended at best. The point is, and there's plenty of data on it that if things are wired properly, the breakers are likely to function as designed. The wiring in the house, let's talk that 10% curve are rated well beyond a 10% margin for safety. In fact, the breakers are set for the 75 degree celsius limits whereas many people look at the rating on the wire and see 90 degrees on much if not all of it. I encountered that confusion when I did my project. Amperage cable limits list more than one temperature standard.
 

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That being said, shoddy workmanship (using 14 gauge wire on a 20 amp circuit breaker because it is what the cheap electrician had handy) or ignorant home owner repair work "this 15 amp breaker keeps tripping, I will replace it with a 20 amp breaker" are the most common causes of electrical problems and / or fires.
Agree 100%, safety devices are there to save you if you unknowingly do something stupid .....

It's the shoddy workmanship .... specifically loose connections, especially a neutral which caused a load center fire in my house that is the cause of fires. You'll find a lot of homes in America where the electrician and the homeowner swapped out a 15 amp breaker for a 20 on 14ga wire. It's not to code, it's done a fair amount. An interesting part is the use of 14-3 wiring to supply two 110v circuits. In my lifetime that was actually allowed and within code, but it isn't anymore. The fear is the return voltage from both hot, yet independent legs returning on the single/common neutral. Learned about this when I took a class at the tech college when I self-installed my whole house Generac 22kW generator.

I don't think I saw any post where someone was suggesting that anyone knowingly do anything stupid. There's plenty of that going on anyway.
 
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