Can I use an 220v extension cord to use the 220v dryer plug for charging my RAV4 PHEV?
Charging my PHEV
kram2
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The adapter I was linking to was the one that has a single 14-50 (240v) plug. And, yes, any person that uses such an adapter should take careful measures so that it is not used for any devices other than the car charging cable.
I do know that many many prius phev users have successfully used such adapters in the usa. And pretty much all prius phev and rav4 phevs in europe are by default using their toyota cables with voltages in excess of 200v.
I have no argument with your posts, Templeton. Nor do I judge those who charge in this manner. I just thought there should be some awareness to the risks raised once the link was provided since this link had none to date. You never know who might see this one thread, take the suggestion, and not research any further.
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Sure, I think that if one reads anything on the interwebs, it is always important to verify every single thing that one reads. And, yes, one should not use any electrical adapters in any application unless one knows exactly what one is doing. And, as always, every action is always taken at one's own risk.
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Ha, so the answer is yes and no.
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The 2022 on R4P has an internal 6.6KW charger. I see 7.2-3KW on my 240V cord. I believe that is too much load for a 120v based cord. the prius and old Rav4P did not exceed 3.3 kw charging internally, so a 20 amp 120v dedicated circuit was ok.
if the poster can afford a R4P he should play it safe and Do what is recommended. I am also told that the dryer outlet is not rated for the duration and load of EV charging.
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Just so you understand, the amps don't change when charging on 240v, just the voltage.
Let me try to clarify this whole issue. First, let's talk about Level 1, 120 volt charging. A Level 1 EVSE is what your Prius Prime, BZ4X, and Rav4 Prime come with at no extra charge. You can plug this into any 120 volt, 15 or 20 amp outlet. These EVSE's have internal current limiters that will not allow the vehicle to draw more than about 12 amps, which is 80% of the maximum rating of a 15 amp circuit breaker, which is what most homes have for the regular wall outlets. I have owned 2 of these Toyota-supplied Level 1 EVSE's, and I've never seen either 1 supply more than 10 amps. When you subtract the 8% resistive heat loss inherent in the charger (meaning the AC to DC charger under the rear seat of these cars), the actual DC power flowing to the battery from a Toyota-supplied Level 1 EVSE will be about 1,100 watts, if the outlet is actually supplying the full 120 volts. I've charged both my Prius Prime and Rav4 Prime many times on the OEM L1 chargers that the cars came with, monitoring the charge rate with an OBD-II scan tool, and 1,150 watts maximum seems to be consistant. NOTE: In some parts of the US, your power company may be supplying 220/110 volts instead of 240/120. If you live in a community where the residential transformers are of this lower voltage, your maximum Rav4 Prime charge rate on the OEM level 1 charger will also be less; about 1,000 watts instead of 1,100.
The reason that Level 1 charging is so slow, is that the building codes only require 14 gauge Romex for wiring 15 amp, 120 volt wall outlets, and 14 gauge is not very "heavy". If your house is wired with 12 gauge Romex, and a 20 amp circuit breaker, you can safely run a Leval 1 EVSE at 16 amps instead of 10 or 11, but usually you will only see 20 amp circuits in laundry rooms, kitchens, and garages, and only in homes built after 1980. You can tell a 20 amp wall outlet from a 15 amp by the configuration of the slots: if one of the slots is "T" shaped, that's a 20 amp outlet, and can accomodate either 15 amp or 20 amp plugs.
Now on to Level 2. Things get a little more complicated here. Level 2 EVSE's generally come in a bewildering assortment of power ratings and plug types. For one thing, there are three different current ratings for 240 volt wall outlets that you might see in a house (specifically in the garage or laundry room), depending on when it was built. Homes built before 1996 typically have a 3-prong NEMA 10-30 dryer outlet. This outlet is rated for 30 amps, for up to "a very short time" (1~2 minutes), and 24 amps (80% of the maximum) continuous. The circuit breaker is 30 amps, and the circuit will be wired with 10 gauge Romex. After 1996, the 3-pin NEMA 10-30 was banned because it didn't have a dedicated Neutral wire. 30 amp dryer outlets then switched to the NEMA 14-30 outlet, which has 4 prongs, but still carries only 24 amp continuous loads. You MUST NOT run a Level 2 EVSE off of a NEMA 10-30 or 14-30 dryer outlet at any current level exceeding 24 amps; the outlet might be able to handle it, at least for a few minutes, but the 10 gauge wiring in the wall will be overstressed, and so will be the circuit breaker. Personally, when I was charging off the NEMA 10-30 dryer outlet in my garage, I never exceeded 16 amps, even though the EVSE I had could go to 24 amps. This was before I installed a dedicated EV charging station with a 50 amp breaker and 6 gauge wiring.
Next you have 40 amp service. I've never actually seen this in a house myself, but there is a standard for it in the NEMA code, so somewhere there must be some houses that use it, maybe for big air conditioning compressors or electric cooking ranges. The outlet is typically a NEMA 14-50, but the wiring to the outlet will be 8 gauge, and the breaker will be 40 amps for 1 minute, 32 amps continuous. You can safely run a 32 amp Level 2 EVSE on one of these outlets, but not a 40 amp model, at least not at full power. I've seen 40 amp JuiceBox EVSE's installed in homes where the owner has an EV with a big traction battery, like a BZ4X, Nissan Leaf, Rivian, or Tesla, but thse are overkill for a Rav4 Prime.
Lastly, there is 50-amp service. If you don't have a 30-amp electric dryer outlet in your garage, and you are sick of waiting 12 hours to charge your Rav4 Prime on a Level 1 charger, this is what you want to install. 50-amp service also uses a NEMA 14-50 outlet, but the wiring between the breaker and the outlet is 6-gauge, and the breaker can handle up to a 40-amp EVSE continuously, and the usual 32 amp EVSE that Rav4 Prime owners use will be no strain at all. This is what I have. You need to be aware of a couple of things when considering installation of a 50 amp outlet for EV charging:
1. 6 gauge Romex is crazy expensive, $7.50 to $8.00/foot. If your breaker panel is within 5 or 6 feet of where you want to install the outlet, the cost is not too bad; the wire will cost you $60~70, and another $60 for a Bryant industrial grade NEMA 14-50 outlet and a metal junction box. But if your garage is like 100 feet or more from your breaker panel, you are looking at well over $1500 to install a 50 amp EVSE outlet.
2. DO NOT allow your installer to use a cheap $10 Leviton outlet for EV charging! These are meant for electric dryers and cooking ranges that do not carry high current loads continuously, and that only get appliances unplugged and re-plugged into them a few times in 20 years or more. For an EVSE, you need an "industrial grade" 14-50 outlet. These are much more rugged than household outlets, they grip the prongs on the plug much more tightly, they are made of materials that can dissipate heat better, and handle high current loads continuosly, and they are made to have power tools and air compressors unplugged and re-plugged many times a week without losing grip strength on the plub prongs. Get a Hubbell ($80) or a Bryant ($50). These are actually the same outlet, made by the same company. You know how you might say that a Lexus is just a Toyota Camry with fancier upholstery and some wood trim, but under hood they're the came car, right? A Bryant industrial grade NEMA 14-50R outlet is basically the same as a Hubbell 14-50R, for about 20 bucks less.
As for using an extension cord with an EVSE: It can be done, if you are certain of your equipment and know what you are doing. I have used a 10 gauge, 25 foot extension cord with my Level 1 EVSE. This is acceptable as long as you don't exceed 1,200 watts. 10 gauge copper wire can carry the 12 amp / 1440 watt load of a Level 1 EVSE safely, as long as the plug and socket connectors are clean and not corroded.
If you have a Level 2 EVSE with a NEMA 14-50 plug, you can buy 6 gauge extension cords from Amazon, or most RV supply stores, in 15, 25, and 50 foot lengths. I have a 15 foot one that I use with my portable Level 2 EVSE at campgrounds that have RV electric hookup pedestals; sometimes the pedestal is on the side of the parking pad opposite of where the charge port on the Rav4 Prime is located, and I need that extra 15 feet to reach it. When I use this rig, I limit the charge rate to 20 amps, well below the safe limit of the cord, and it still gives me a full charge in about 5 hours, which is plenty fast enough when I'm camping. Here's what the 50 foot cord sold on Amazon looks like:
![Image]()
I've used both of these extension cords to charge my car several times, and have never found any signs of heat build-up in either the cords or any of the connections.
Just be forewarned that the 50 amp RV cords are really bulky, very heavy, and pretty expensive, especially the 50 foot one; it costs $179. My 15 foot one was $59, as I recall.
The reason that Level 1 charging is so slow, is that the building codes only require 14 gauge Romex for wiring 15 amp, 120 volt wall outlets, and 14 gauge is not very "heavy". If your house is wired with 12 gauge Romex, and a 20 amp circuit breaker, you can safely run a Leval 1 EVSE at 16 amps instead of 10 or 11, but usually you will only see 20 amp circuits in laundry rooms, kitchens, and garages, and only in homes built after 1980. You can tell a 20 amp wall outlet from a 15 amp by the configuration of the slots: if one of the slots is "T" shaped, that's a 20 amp outlet, and can accomodate either 15 amp or 20 amp plugs.
Now on to Level 2. Things get a little more complicated here. Level 2 EVSE's generally come in a bewildering assortment of power ratings and plug types. For one thing, there are three different current ratings for 240 volt wall outlets that you might see in a house (specifically in the garage or laundry room), depending on when it was built. Homes built before 1996 typically have a 3-prong NEMA 10-30 dryer outlet. This outlet is rated for 30 amps, for up to "a very short time" (1~2 minutes), and 24 amps (80% of the maximum) continuous. The circuit breaker is 30 amps, and the circuit will be wired with 10 gauge Romex. After 1996, the 3-pin NEMA 10-30 was banned because it didn't have a dedicated Neutral wire. 30 amp dryer outlets then switched to the NEMA 14-30 outlet, which has 4 prongs, but still carries only 24 amp continuous loads. You MUST NOT run a Level 2 EVSE off of a NEMA 10-30 or 14-30 dryer outlet at any current level exceeding 24 amps; the outlet might be able to handle it, at least for a few minutes, but the 10 gauge wiring in the wall will be overstressed, and so will be the circuit breaker. Personally, when I was charging off the NEMA 10-30 dryer outlet in my garage, I never exceeded 16 amps, even though the EVSE I had could go to 24 amps. This was before I installed a dedicated EV charging station with a 50 amp breaker and 6 gauge wiring.
Next you have 40 amp service. I've never actually seen this in a house myself, but there is a standard for it in the NEMA code, so somewhere there must be some houses that use it, maybe for big air conditioning compressors or electric cooking ranges. The outlet is typically a NEMA 14-50, but the wiring to the outlet will be 8 gauge, and the breaker will be 40 amps for 1 minute, 32 amps continuous. You can safely run a 32 amp Level 2 EVSE on one of these outlets, but not a 40 amp model, at least not at full power. I've seen 40 amp JuiceBox EVSE's installed in homes where the owner has an EV with a big traction battery, like a BZ4X, Nissan Leaf, Rivian, or Tesla, but thse are overkill for a Rav4 Prime.
Lastly, there is 50-amp service. If you don't have a 30-amp electric dryer outlet in your garage, and you are sick of waiting 12 hours to charge your Rav4 Prime on a Level 1 charger, this is what you want to install. 50-amp service also uses a NEMA 14-50 outlet, but the wiring between the breaker and the outlet is 6-gauge, and the breaker can handle up to a 40-amp EVSE continuously, and the usual 32 amp EVSE that Rav4 Prime owners use will be no strain at all. This is what I have. You need to be aware of a couple of things when considering installation of a 50 amp outlet for EV charging:
1. 6 gauge Romex is crazy expensive, $7.50 to $8.00/foot. If your breaker panel is within 5 or 6 feet of where you want to install the outlet, the cost is not too bad; the wire will cost you $60~70, and another $60 for a Bryant industrial grade NEMA 14-50 outlet and a metal junction box. But if your garage is like 100 feet or more from your breaker panel, you are looking at well over $1500 to install a 50 amp EVSE outlet.
2. DO NOT allow your installer to use a cheap $10 Leviton outlet for EV charging! These are meant for electric dryers and cooking ranges that do not carry high current loads continuously, and that only get appliances unplugged and re-plugged into them a few times in 20 years or more. For an EVSE, you need an "industrial grade" 14-50 outlet. These are much more rugged than household outlets, they grip the prongs on the plug much more tightly, they are made of materials that can dissipate heat better, and handle high current loads continuosly, and they are made to have power tools and air compressors unplugged and re-plugged many times a week without losing grip strength on the plub prongs. Get a Hubbell ($80) or a Bryant ($50). These are actually the same outlet, made by the same company. You know how you might say that a Lexus is just a Toyota Camry with fancier upholstery and some wood trim, but under hood they're the came car, right? A Bryant industrial grade NEMA 14-50R outlet is basically the same as a Hubbell 14-50R, for about 20 bucks less.
As for using an extension cord with an EVSE: It can be done, if you are certain of your equipment and know what you are doing. I have used a 10 gauge, 25 foot extension cord with my Level 1 EVSE. This is acceptable as long as you don't exceed 1,200 watts. 10 gauge copper wire can carry the 12 amp / 1440 watt load of a Level 1 EVSE safely, as long as the plug and socket connectors are clean and not corroded.
If you have a Level 2 EVSE with a NEMA 14-50 plug, you can buy 6 gauge extension cords from Amazon, or most RV supply stores, in 15, 25, and 50 foot lengths. I have a 15 foot one that I use with my portable Level 2 EVSE at campgrounds that have RV electric hookup pedestals; sometimes the pedestal is on the side of the parking pad opposite of where the charge port on the Rav4 Prime is located, and I need that extra 15 feet to reach it. When I use this rig, I limit the charge rate to 20 amps, well below the safe limit of the cord, and it still gives me a full charge in about 5 hours, which is plenty fast enough when I'm camping. Here's what the 50 foot cord sold on Amazon looks like:
I've used both of these extension cords to charge my car several times, and have never found any signs of heat build-up in either the cords or any of the connections.
Just be forewarned that the 50 amp RV cords are really bulky, very heavy, and pretty expensive, especially the 50 foot one; it costs $179. My 15 foot one was $59, as I recall.
I made my own 50a cables, just bought the heavy duty wire, and screwed the connectors on.... I prefer plugs and sockets I can open and visually inspect (and tighten every so often, like the maintenance you should do on your electric panel).
By the way, my home was built in December 1997, and is in Southern California, and has the 3 blade 220v connector, so perhaps your statement about being banned in 1996 is off by a couple of years, perhaps plans APPROVED after 1996 is what happened...
I had a second "dryer" circuit put in my garage near the garage door, was for a 220v compressor, but now plug the level 2 charger into it... am changing to 4 pin connector, since I bought a second level 2 charger that came with that plug. My first charger was a kit, and I added the power cable and plug myself.
If your wires get warm, you should consider a larger gauge, but the voltage drop really comes in the plug and socket. After 10 years of plugging and unplugging (switching between compressor and charger) these need replacing... that's good enough for me.
(by the way "charlot", you MUST be an engineer, right?)
Greg (also engineer)
By the way, my home was built in December 1997, and is in Southern California, and has the 3 blade 220v connector, so perhaps your statement about being banned in 1996 is off by a couple of years, perhaps plans APPROVED after 1996 is what happened...
I had a second "dryer" circuit put in my garage near the garage door, was for a 220v compressor, but now plug the level 2 charger into it... am changing to 4 pin connector, since I bought a second level 2 charger that came with that plug. My first charger was a kit, and I added the power cable and plug myself.
If your wires get warm, you should consider a larger gauge, but the voltage drop really comes in the plug and socket. After 10 years of plugging and unplugging (switching between compressor and charger) these need replacing... that's good enough for me.
(by the way "charlot", you MUST be an engineer, right?)
Greg (also engineer)
Greg- I've been a draftsman, an engineering technician, and a land survey tech (LSIT). 14 years in the nuclear power industry (1974-1988), the rest with CalTrans (1988-2013). I'm not a licensed engineer, but I've absorbed a lot of knowledge on the job, you might say. I could probably have passed the EIT if I had decided to go that route and studied for it. I did pass the LSIT, on the first attempt, an achievement I take quite a bit of pride in. And the 4 other people in our little study group all passed on their first attempt, as well, so the time we spent studying and doing practice exams was well spent. Most of my experience as an engineering tech and draftsman for those first 14 years was in mechanical (piping system static and seismic analysis), with some electrical. After I got in with CalTrans, it was all civil engineering work: highway bridges, retaining walls, and drainage structures, and the last 7 years on a land survey crew with CalTrans District 10 out of Stockton. As a survey tech, I added construction survey staking, digital terrain mapping, and some property boundary and right-of-way work. I almost got my professional land surveyor license: passed the National Principles of Surveying exam, but couldn't quite pass the State Specific in two attempts. If it had been a 6 hour exam instead of only 4 hours, I could have easily passed. I had the knowledge, but what killed me was the construction and photogrammetry problems: these are math-intensive, take at least 10 minutes each to solve, and I just ran out of time, and failed to accumulate enough "points" on those two sections of the exam to pass it. When I took the PLS exam the second time, in April 2015, I was already retired, and realized that the chances of me ever really wanting to go back to work as a land surveyor were pretty much zero, so I gave it up. BPELSG was charging $600 a pop to apply for the PLS and PE exams at that time, and I realized that was too much money to just get a piece of paper to frame and hang on the wall.
But one other thing: I've been a gluttonous consumer of SciFi, and a gadget freak, my whole life, and was probably destined from birth to be in some profession related to the physical sciences, like engineering, architecture, electronics, or computer science. Land surveying is where I ended up, in the last few years of my career. My paternal grandfather, who was born in 1894 I think, was a civil engineer and land surveyor, so you might say I followed in his footsteps. This Rav4 Prime is the most advanced piece of technology I've ever owned, and it never ceases to amaze me that Toyota has managed to take the Rav4 from it's first version in 1996, that got only 18 city/22 highway mpg, to this PHEV version that's capable of 44 mpg at 55 mph, and about 80 mpg-E if you take full advantage of it's plug-in capability. It's so smooth, powerful, and quiet, too. 304 total hp out of a powertrain built around an Atkinson cycle 2.5 liter 4-banger and a couple of electric motors is pretty amazing. You used to have to buy a gas-guzzling V-8 to get that kind of power.
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The catch with using an existing 220 volt outlet is that that it may not be able to supply enough current. My girlfriend and I have two houses. We had the electrician install a 50 amp 220 volt line in the house where we just have a one car garage. But we had him put in 100 amp line to support two level 2 chargers in our house where we have a three-car garage.
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An actual level 2 charger plugged into 220 volts with adequate current will charge my RAV4 Prime completely in 2 and 1/2 hours.
I have A 2021 SE so my full charge time on a 220V L2 EVSE is 4-1/2 hours (actually finishes in about 4h10m).
I was surprised to learn that using the stock EVSE with 220V supply only cut my charge time from 12h to about 6h until I learned the stock EVSE is current limited.
I was surprised to learn that using the stock EVSE with 220V supply only cut my charge time from 12h to about 6h until I learned the stock EVSE is current limited.
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Interesting. When I have tested my 2023 SE with the stock cable at 240v, it charges in about 4.5 hours.
The estimate on the dash says 6 hours initially, but then it continuously updates during charging and eventually charges in 4 hours (on actual clock time).
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6.6 kw
My house only has 125 amp service. The larger 2 story houses in our subdivision have 200 amp, but the single-story models like mine only have 125. I've been told that there's no way to increase this unless the power company installs a larger transformer on our block, which they're not going to do for just 1 homeowner. The electrician I was talking to about this told me that families with 2 EV's often face a problem: their electrical service may only have enough reserve capacity to support "one" Level 2 EVSE at 32 amps, so if you have two EV's, and need to charge them both at the same time (typically overnight), each one can only charge at 16 amps. Then there's the issue of cost. To increase my home service to 200 amps, assuming the transformer would support it, I'd have to run a new, heavier gauge cable, about 350 feet from the transformer to my house, and since utilities in our neighborhood are all underground, doing this would likely require digging a trench to lay the cable. And I'd need a new breaker panel and a new meter. The cost for all of this would probably run north of $35,000, according to the electrician, and more than likely, it simply couldn't be done. This is a disadvantage of having underground electric service compared to hanging the power lines from poles: there's no easy way to upgrade the equipment and wiring.
These are all valid considerations, but my [rhetoric] question was about EVs having an onboard EVSE . From the point of view of overloading or not overloaded the circuit it doesn't make any difference if the EVSE is portable, or mounted on the wall, or integrated into the car. In the case of the RAV4 Prime it's going to draw up to 30 amps @ 220VAC ... a little less if the voltage is higher.
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When a car charges at 6.6 kw vs 1.3 or 3.3 there is obviously more flow. more flow makes me think more heat. more heat destroys the washer outlet and wires (As it is not designed for heavy loads and long duty cycles). when wire casing fails due to heat it cracks off or catches fire. FIRE BAD!
When I charge on 120v with a 15amp fuse i get 11-12 amps, when i charge on a 20 amp fused circuit i get 16 amps. when i charge on a 240v (14/50)outlet i get 32 amps. More AMPS, More Heat, Larger wire size.
Bottom line. If you can afford a Rav4 Prime. Get the correct stuff and do not be cheap. If my renter did something stupid like merging outlets, or hooking up a car charger to the laundry dryer... they would not be renting from me or anyone who asked for a reference.
The OP i believe got a new Rav4P, and maybe 21 on had an optional 6.6 KW onboard charger, and 22 on came with a 6.6KW. That is twice the capasity of the previous ones.
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