Prepping for EVSE Installation for New House Under Construction

I do not think anyone knows the charging specs of the 20121 Rav4 Prime, sorry. So I am going to make a SWAG and tell you what I do know.

The Prius Prime charging cable is designed for 12 amps and North America uses 120 volt mains. Since most common outlets are rated at a peak of 15 Amps (12 Amps sustained) that is likely true for the Rav4 Prime as well.

The Cable Toyota includes with the Prius Prime is electronically similar to the cable Toyota Provides in Europe, which is 230 Volts, only the plug differs.

So the Prius Prime charges in 5.5 hours on a 120 volt, 15 Amp circuit. (if the Rav4 Prime uses the same cable, expect 10 hours to charge in 120 volts)

If you install a 240 volt outlet in your garage, the Prius Prime is then limited to 16 Amps and so can charge in 2.25 hours. So you want to have AT LEAST a 20 Amp breaker, 12/3 romex, and a 20 Amp receptacle.

The Rav4 Prime is promoted at 39 miles EV instead of 25 miles so we can hope that it charges twice as fast to keep the same 2.25 charge time. If it allows 32 Amp charging then we need AT LEAST a 40 Amp Breaker, 8/3 Romex, and a 40 Amp receptacle. In practice , the NEMA 14-50 receptacle is very common.

Just about the largest home outlets provide 50 Amps sustained and so need a 60 Amp breaker, 4 gauge wire, and a 60 Amp Receptacle.

To go larger, you would need to hard wire the EVSE, not plug it in. You can get 100 Amp hard wired EVSE (chargers) for the home.

So 20 Amp is all a Prius Prime ever needs, the Rav4 Prime ought to support 40 Amp circuits. Once you are envisioning true Electric Cars, bigger is better and it is a matter of what you can afford. If you want a BEV someday I would wire for 100 Amps.

In North America, the vast majority of 120 volt outlets are NEMA 5-15R, but 240 Outlets are not nearly as standardized. The NEMA 14-50 is used a lot in RV parks, so is valuable for long distance travel. The NEMA 6-20 is the minimum you should be considering.

Circuit Breakers are unique to the Service panel you own. You have to buy matching breakers.

 

1) This would be a code requirement that your Electrician would know, it would be based on your 120v / 240v choice with an Amp rating between 20 to 50 amps for your wanted/needed outlet.

2) Same as above.

3) Are you planning to save Big $$$ by using your Toyota OE EVSE unit with an adapter for fast 240v charging ?


Rob43

 

i put in a 10 gauge wire and 40 amp circuit

 

Not trying to be funny.... but is your homeowners insurance up to date ?



Rob43

 

i hope so, i'll check in the morning

 

Technically speaking, 10 AWG = 30 Amp circuit and 8 AWG = 40 Amp circuit...

EDIT: You never want a situation where the wire gauge is to small and then acts as a circuit breaker by getting too hot and frying. So effectively the wire "trips", not the breaker. (Extreme Danger)



Rob43

 

ah, i'll check my breaker too, thanks!

 

Yes. You will need an adapter to go from your NEMA 14-50R to your Toyota EVSE plug.

If you get one from me, I'll build you a great one using the best materials including 10 AWG Pure Copper wire.



Rob43

 

Are we getting a bit ahead of the curve here by assuming the 2021 Rav4 Prime will ship with the same EVSE 240/120V compatibility as the current Prius Prime? Is this already known?

Rather than assuming that a potentially higher power unit with carry the same feature, I'd think it best to leave that as a TBD for now. I.e. don't put it past them to discover some cost savings in a 120V-only unit for a higher expected North American volume.

 

I hear you,....and I gave this a bit of thought before I posted the above.

I'm going to go "All In" right now by saying that Toyota USA will ship the RAV4 Prime with the Exact Same EVSE that we enjoy on our Primes.

This reasoning is simple:

1) Toyota are ready has a Great working EVSE unit, why spend millions of dollars reinventing the wheel.

2) Most every home, new & old have 120v 15 Amp accessibility. Increasing this would mean many potential customers would Not be able to charge.

3) Toyota would not want to lose sales by making new buyers upgrade their existing electrical systems ($$$) just to accommodate this new model.


Rob43

 

I start by saying no one knows much about the 20121 Rav4 Prime and contrast what i (think I) know about the Prius Prime and how that might change.

North America uses so much 120 volt, 15 Amp NEMA 5-15 connectors, I just can't see that changing. I do hope the Level 2 charging changes from the Prius Prime. And I gave guesses how that might be.

 

For 120 V charging, you need the NEMA 5-15 plug. For 240 V charging, you need the NEMA 14-50 plug for the best present and future compatibility for EV charging. If you want to use the OEM cable for the 240 V charging, you need to get a NEMA 14-50/5-15 plug adapter or such one accordingly for your particular 240 V plug. User Rob43 sells them. Otherwise, buy an aftermarket EVSE.

NEMA 5-15 has three wires: hot, neutral, ground (usually bare wire).
NEMA 14-50 has four wires: hot 1, hot 2 (180° opposite phase), neutral, ground (usually bare wire).

The thicker the wire gauge is the better because you get less voltage drop on the wire, which results in faster charging. The downside is the increasing cost with the thicker gauge. There are online calculators that calculate the voltage drop for a given copper wire as a function of the given gauge, length, and current. For the length, make sure that the calculator takes into account the return wire (neutral or hot 2); otherwise, you need to double the length.

The circuit breaker should be rated according to the plug amperage (15 A, 50 A, etc.)

Last but not least, all outlets in a garage must be GFCI according to electric codes, as well as Toyota.

Don't forget to install a hook for the EVSE.

 

Due to an out dated and stupid US law, you cannot use the locking receptacles (starts with an L) on a circuit with a car at the end.

They worry about you driving off, even though you can't drive off with a J1772 protocol cable.

So don't use one with an L, but know it is silly. (I am often the one erring on the side of safety, but this is just wrong)

 

^ To add to this, I'm personally not really a fan of the locking receptacles because their 3 or 4 weaker male blades.

The Non-Locking NEMA: 6-50, 10-30, 10-50, 14-30, 14-50, & 14-60 all have VERY strong and robust blades when compared to their locking counterparts.


Rob43

 

Strictly speaking, one does not need a plug with a Neutral for car charging, but you are supposed to have a Ground. Others have mentioned that the trend is toward the NEMA 14-50, which has both. My Chargepoint Home charging station uses NEMA 6-50, so that is what I had put in. I don't know if the electrician ran 4-wire from the breaker to the outlet and then just ignored the Neutral, but the total run was only around 3 feet (the breaker box is on the outside garage wall, and the outlet is directly opposite it inside), so I just left it up to him to do "the right thing".

 

You will need the neutral for 120 V and any appliance that needs both 120 V and 240 V; so, it's much better to have it.