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Any reason not to leave roadster plugged into 120v outlet?

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I only drive the Roadster a handful of times each month and won't ever need it to recharge quickly, so is there any reason to not leave it plugged into a standard 120v wall outlet charging at 15amps? Are there any drawbacks to using this method rather than having an electrician install a 220v outlet for the sole purpose of having the car plugged in long-term for essentially the same level/rate of charge as the 120v outlet?
 
The car needs to be kept plugged in. 240v is best, but 120v is better than nothing. Just be sure to keep an eye on the charging, as 120v outlets have a habit of tripping breakers (GFI, especially). The car also won't be able to cool the battery on 120v, so be sure your ambient temps don't get too high.

A 240v outlet doesn't have to be super high current. A 30 amp "dryer" outlet (14-30) is plenty. Do you have one of them within reasonable reach? Such an outlet can be shared with a dryer with a "Dryer Buddy". Even a 20 amp 240v outlet (6-20) will do, charging at 16 amps.
 
The car is kept plugged-in, but on 120v. Will it be able to cool the battery adequately using the existing battery power? I leave it plugged in and set on standard charge. I use OVMS to monitor the car and every day or so it charges for 20 minutes at 15A.
 
When using a 110-125v outlet and charging at 15 amps, be sure it is a 20 amp outlet and not just 15. They are designed to run continuously at 80%, not 100%. If it is a 15 amp outlet, set the car to limit the charge at 12 amps using the display. Otherwise you could melt the outlet, or worse. You may find most of the outlets are only 15 amps and the ceiling outlet for the garage door opener is 20 amps.
 
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The car is kept plugged-in, but on 120v. Will it be able to cool the battery adequately using the existing battery power? I leave it plugged in and set on standard charge. I use OVMS to monitor the car and every day or so it charges for 20 minutes at 15A.
Generally, no. I believe the battery cooling will only kick in if the battery is *way* hot when plugged in on 120v. The regular cooling that occurs during a normal charge cycle does not kick in when charging from 120v. Usually that's ok because charging at such a low rate doesn't generate as much heat, but the down side is that if the battery does need cooling (either from a high ambient or from a prior drive), the power is insufficient.

If high ambient temps could be a problem, check with an electrician. There might be a way to create a 240v circuit without investing a huge amount. Or (warning: I've not tried this!) perhaps you could run things a bit more manually by cooling the battery with a mod... See Manual battery cooldown mod - a cure for the Roadsters insomnia
 
If I remember correctly, the Roadster will only initiate the battery cooldown on 110V if the temperature goes above 40 F similar to normal driving conditions. It's best to get a 240V line because that is the most efficient charging method and will prolong your battery life. With how tight parts are for these cars, any preventative steps are worth pounds more than the cure.
 
If you have an outlet that is the only thing on its circuit, it's easy to convert it to 240. You won't be able to increase the amperage, though. But converting a 5-15R or 5-20R to a 6-15R or 6-20R just requires a minor modification to the wiring in your breaker panel and a new two-pole breaker. Dryer outlets are good, too. That's what I used for years when I first got the Roadster.
 
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