One feature missing from a Tesla sedan is Vehicle-to-Load! V2L means that you can draw Alternating Current (AC) Power from the car to use while camping, in a blackout, or however else you would like to use it. Vehicles like the Ford F150 Lightning and the Hyundai EV6 have this feature.
So, what would it take to ADD this feature to a car which does NOT have it, such as my 2013 Tesla Model S? I’ve been pondering this for a while. In fact, I even had some successful tests of doing the same with my Mitsubishi iMiEV. (See those videos HERE.) Unfortunately, that needed a large external solar inverter and a specially-made CHAdeMO connection.
For the Tesla, I’d love something that could look like it actually came from the manufacturer. When I was troubleshooting the Supercharging feature on the car, I discovered that there was some extra space under the back seat, and it would be fairly easy to connect to the battery pack at the High Voltage Junction Box, (also under the back seat.)
What I would need is an inverter which could take in EV Battery Pack voltage, and output 120VAC, all WITHOUT being a large/heavy/bulky solar inverter. After kicking around a few ideas and trying to find the right thing, I found a particular inverter board on AliExpress. These board are essentially sold as PART of an inverter. A full inverter would need a case, fusing, cooling fans, etc. But the important thing is that I found one that will take in high voltage DC in a range of about 300V-450V, and output 120VAC.
I just got the board in the mail today.
First thing I would need is a source of high-voltage DC. So, I used the same solution as when I was testing a Nissan Leaf Motor – running 240V power to a bridge rectifier. The rectifier converts the 240VAC to about 338VDC. I then connected that to the DC INPUTS on the inverter board.
Making sure not to touch anything (as none of this was inside a protective enclosure,) I tested the output with my multimeter, and saw that the board was producing 220VAC! But I had ordered the 120V version!
Hmm. The next thing to look for was any sort of jumper or potentiometer on the board. I powered it down, waited for the LEDs to go out and test that there was no longer any high-voltage DC present. Then I inspected the board and found a tiny brass adjustment screw. I gave it a few twists counterclockwise, then powered up the board and tested the output again. This time it showed 172VAC. Still not what I was looking for, but I was glad to see the output was adjustable and I was going in the right direction.
After repeating this procedure a few times, I got the output to test at exactly 120VAC.
Next, I connected a low-current 120VAC LED light bulb. Sure enough, it lit up just fine.
So, these tests seem to show that I’m on the right path for an inexpensive piece of equipment which would be appropriate for a DIY V2L setup.
I also took a look at the car for where I might want to connect an exterior outlet. I’d love to be able to re-use the charging port, similar to how the EV6 does, but based on how things are connected internally in the Model S, that might not be an option.
I noticed that on the opposite side of the car, there is a reflector which takes up the matching space as the charge port door. Of course, it’s fixed and just part of the taillight assembly. I removed the taillight and was then able to remove the reflector. With it gone, it looked like there was enough space to install a weather-proof electric outlet. With a little modification, I think I could even 3d print a spring-loaded bracket to hold the reflector to make it open and close. Essentially, I would duplicate the charge port, but on the other side of the car, and this would be for the V2L power outlet.
Well, that’s my idea for now. I also have a 120V-capable Variable Frequency Drive on order. That should make it easy to output 120 OR 240, and have it be easily selectable between the two. That would mean I could even use my car to charge OTHER electric cars!
But you’ll find out more about that when I get it.
Until then, stay charged up!
-Ben Nelson
