Also, based on some other posts, if it's real cold out, you might run into issues if it can't heat things up enough to start charging if you only have 110 @ 9 amps.
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Converting 110 outlets for home charging ?
- Thread starter bigevil
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Also, based on some other posts, if it's real cold out, you might run into issues if it can't heat things up enough to start charging if you only have 110 @ 9 amps.
Hi folks - I am actually running into a somewhat similar issue and need help to arm me to deal with electricians - I need a $2k or less solution or I think the dream is dead for now!
I live in a rowhouse; I have the top unit (floors 3 and 4). My breaker box is on floor 2, inside my unit in an entrance stairwell. Plenty of amperage but the cable run would be up a floor, through my unit, out the back wall, down the back wall, and to the parking spot - and the conduit install + cable run would probably be an expensive nightmare.
Instead, I have a 110v GFCI outlet on my back balcony, and the wiring to that already comes up out of a RMC conduit. Could I get an electrician to splice and extend this existing conduit, run it down my back wall, and to the spot? Would be a 25 foot run or so. Yes, it's only 110V, but it doesn't involve heavy construction or add 5%+ to the price of the car (I own, but probably only 3-5 years from selling).
I am not an electrician and know only enough to stay away from electricity. Your advice will be invaluable!
I live in a rowhouse; I have the top unit (floors 3 and 4). My breaker box is on floor 2, inside my unit in an entrance stairwell. Plenty of amperage but the cable run would be up a floor, through my unit, out the back wall, down the back wall, and to the parking spot - and the conduit install + cable run would probably be an expensive nightmare.
Instead, I have a 110v GFCI outlet on my back balcony, and the wiring to that already comes up out of a RMC conduit. Could I get an electrician to splice and extend this existing conduit, run it down my back wall, and to the spot? Would be a 25 foot run or so. Yes, it's only 110V, but it doesn't involve heavy construction or add 5%+ to the price of the car (I own, but probably only 3-5 years from selling).
I am not an electrician and know only enough to stay away from electricity. Your advice will be invaluable!
@Bleedblue82 In Boston, yeah, you're going to have a problem charging outside on only a 120V circuit. In some of those Winter weeks, it may be running the battery heater all night and get no actual charging.
First thing to check is to find out whether that outside outlet is on a known breaker you can find and confirm if it is by itself, or if there are other outlets on it. If it is truly by itself, then yes, you would be in luck, that you can easily switch over the breaker and make that a 240V circuit on the same wiring run, since wire thickness is determined by the amps, not the volts. So if that is already a 20A circuit, you could easily make it a 240V 20A circuit, and that should do...OK through the Winter. It may still spend an hour or two warming up before it gets to any real charging overnight, but it should eventually work. And if you really can replace that wiring run with something a little thicker that could do a 30A circuit, then you would be golden.
First thing to check is to find out whether that outside outlet is on a known breaker you can find and confirm if it is by itself, or if there are other outlets on it. If it is truly by itself, then yes, you would be in luck, that you can easily switch over the breaker and make that a 240V circuit on the same wiring run, since wire thickness is determined by the amps, not the volts. So if that is already a 20A circuit, you could easily make it a 240V 20A circuit, and that should do...OK through the Winter. It may still spend an hour or two warming up before it gets to any real charging overnight, but it should eventually work. And if you really can replace that wiring run with something a little thicker that could do a 30A circuit, then you would be golden.
davewill
Active Member
It depends on what else is on that circuit. The car is going to use the full capacity of the circuit, so you can't have anything that draws any significant current on the circuit at the same time.
Now, if you can end up with NO other plugs on the circuit you can use the same wires to create a 240 volt circuit instead of a 120v. That would come close to tripling your effective charging rate. You would have a 6-15 (or 6-20 if the wires are big enough) outlet at your parking spot, which Tesla sells an adapter for.
Even if not solo it might be doable. Everything on the circuit must be all 240 or all 120 (you can't run a mix).
eprosenx
Active Member
Totally agree. This is my philosophy as well. Compared to the cost of the car, I just don’t want to have to think about planning for my cars state of charge. For me it was cheap to install the wall connector on a 60a circuit to max the charge possibilities. Several times this summer I came home at the end of the day from work and then topped it off before heading out for a long weekend while packing the car.
I should note though that charging the last 10% from 90 to 100 is not the perfect use case for the high speed charging since above about 93% it has to start tapering the charge rate to avoid damaging the battery. The full 48 amps of charge ability is best for charging below about 93%.
The only 120v charging I have done has been at vacation homes as it is horribly slow, but with that being said, typically where I stay is within the 310 miles of range of the car and then I stay for a three day weekend, so even though 120v is stupid slow, it gives me enough range over a weekend to make it home or at least back to a supercharger.
I have slowly been adding 14-50 charging receptacles to all my common vacation home destinations and family houses. So far I have them in three locations and I am working on a couple more. ;-)
eprosenx
Active Member
Can you post pictures of everything and the areas you want to run conduit? RMC for a porch outlet sounds overkill bit maybe! Depending on how it is setup we might be able to add a *new* circuit in the existing conduit separate from the 120v. Maybe you could get 20 (16) amps at 240v or something.
Please post pictures of the electrical panel and stickers and schedule on the door of the panel.
Basically one question is what the wire path is from outside to your panel. If all in conduit then we can run conduit fill calculations to see if it could support another circuit. That might be a viable option for you. Conduit rocks since you can change things around later...
Here’s the situation. Posted the breaker box (relevant switch is the 15A single pole top right with knockouts above), the conduit, the external GFCI outlet, and some context for the cable run (Tesla would live where white car is now).
Breaker controls external outlet and two internal outlets (probably can rewire those to another outlet). So converting it to 240V seems possible and safe.
IANAE but it doesn’t seem crazy to pop outlet off, continue conduit, run down building and terminate in outlet - for less than $2000. 10 mph charge (and charging in winter) is fine for me. 15-20 would be better, but...
Breaker controls external outlet and two internal outlets (probably can rewire those to another outlet). So converting it to 240V seems possible and safe.
IANAE but it doesn’t seem crazy to pop outlet off, continue conduit, run down building and terminate in outlet - for less than $2000. 10 mph charge (and charging in winter) is fine for me. 15-20 would be better, but...
ai4px
Wes
If I were going to have to charge from a 120v outlet all the time, I’d audit all the outlets on that circuit and make sure the wires were attached by screw terminals and not simply pushed in the stabs in the back of the outlet. There is a such animal as a dryer buddy that allows you to automatically switch between a clothes dryer and your UMC. You could buy a DPDT open frame relay for about $20 and hook it to a $26 current sensor from amazon. The current sensor is adjustable and clamps around the wire leading toward your dryer. When the dryer draws current, the open frame relay could pull in and disconnect the UMC. This might work even better if you have a hot water heater in an outside area.
eprosenx
Active Member
Do you have any other photos that shows the wiring type? Specifically I would like to verify that there is 1/2 in RMC all the way back to the panel?
Do you feel you foot safely take the panel cover off and post some more pictures?
The great news is that is a beautifully modern electrical panel with plenty of open positions and only two 240v loads. AC and the dryer.
So presuming you actually have a full 200a service, then you have oodles of available capacity. You could easily support a 60a circuit for a Wall Connector (or maybe even higher) if you wanted. You must have gas heat I presume and a gas range/cooktop?
I don’t like stealing a circuit that feeds other things in the house for EV charging since generally that circuit was already installed for a reason (generally code required). Stealing it for EV use may cause a lack of capacity elsewhere. If you do have conduit all the way back to the panel you may have interesting options. At a bare minimum you could likely upsize the wire to 12 gauge to make it a 120v circuit. Or by adding a single additional wire you could give it a dedicated circuit (sharing a neutral which is perfectly safe if done right).
Best case you pull two new 12 gauge wires in the existing conduit and you get a new dedicated 6-20 circuit in addition to the existing 5-15.
Thanks for your help! Unfortunately I do not feel at all qualified to pull the cover off... but now I know to suggest these things to an electrician which is a win for me! I doubt there is RMC all the way back sadly - while this is an 1880s brick rowhouse the gut renovation about 5 years back (reason for the new panel!) probably rerouted all the wiring. The RMC is likely only in the exterior wall, probably not all the way back.
There are a couple of circuits in the adjoining room that are very low load, so maybe we can rewire the two outlets this breaker supports to those.
Thanks again - this is fantastic - after describing my situation to a couple electricians this AM I thought I was out of luck, but seems like this may be doable.
There are a couple of circuits in the adjoining room that are very low load, so maybe we can rewire the two outlets this breaker supports to those.
Thanks again - this is fantastic - after describing my situation to a couple electricians this AM I thought I was out of luck, but seems like this may be doable.
eprosenx
Active Member
No problem!
FWIW, I also might be concerned about charging ability even with a 240v 20a circuit. As you say, it gets cold there. We really don’t have a lot of cold weather experience yet with the Model 3 to say for sure what happens in very cold places. I don’t even know how many amps of heating the M3 battery heating system (uses the motor) can draw.
Good luck and please report back!!!
P.S. Where is your electrical meter to the building? I wonder if it could be tapped more directly, or you even might be able to install a second dedicated electrical service just for car charging... Sometimes you have to think outside the box!
NathanielHrnblwr
Member
Perhaps an electrician can grab power from where your meter is instead of the panel in your house.
So is there a cheaper alternative to getting a NEMA 14-50 installed? It requires about 55 feet of wire so the lowest price I got is $900. I don’t need to charge 30 miles an hour but with Midwest winters, I imagine I’ll need more than the 4-5 mph I get currently. I believe in my garage, it’s just two outlets: one where I plug in my UMC and the other on the ceiling to power the garage door opener. At work, my commute is 40 miles round trip and I am usually there for 10 hours and so I usually cover my commute at work.
Instead of going all the way up and down the building, consider adding a tap directly off the meter box. Surely the distance from the meter to the parking space would be less and you would end up with a more capable connection. You might have to reduce the breaker in your breaker panel from 200A to 150A so that you could install a 50A breaker for the car charging, but I think this is a much better solution.
Well sure. You don't need to do the 14-50. That's just the adapter type that already comes with the car, but for a smaller sized circuit, you could go for a 14-30 or 6-20. Tesla sells adapters for those types of 30 amp and 20 amp circuits that are still 240V. The wire size will be a little smaller, so it would save a bit of money on the materials cost, but in practical terms, most of the cost is in the labor of the electrician's time and just physically doing a 55 foot wire run. The 14-30 is a pretty good option, though, since it would be a bit cheaper, and is still a very healthy level of charging. Extra adapters can be bought on Tesla's website for $35 here:
https://shop.tesla.com/us/en/product/vehicle-accessories/model-s_x_3-gen-2-nema-adapters.html
Of course, but you also supposedly aren't supposed to let it sit at 100% so i charge to 90 overnight then bump it shortly before departure. Every little bit helps
I got lucky with my install; the solar installers forgot to charge me for the HPWC install, got a free HPWC from a Tesla referral, and got $500 back from PG&E. So I'm in the black on that one.
On the car, maybe in 20 years
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