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Can the Model S battery be used to power appliances ?

Can the Model S battery be used to power appliances ?

Would there be a way to plug a fridge/freeze to the tesla battery ?

That would be pretty damn cool to have as an option where the electricity goes out to power vital appliances

jat | April 28, 2013

This has been much discussed for EVs in general (look for v2g [vehicle to grid] and v2b [vehicle to building]). Personally, I think it is pretty non-sensical -- you have to do much of the electrical work in your house that you would have to do for generator or solar system, and then you still have to modify the car to be able to get the DC power out of the battery and convert to AC split-phase power for your house. You might be able to reuse part of the drive inverter for the motor, but it is intended for higher voltages and 3-phase power, so it isn't clear it would work.

But the biggest problem is that if I am without power for several days, the last thing I want to do is drain my car's battery and be stuck at home. In fact, with two EVs (my wife drives a LEAF), I am more likely to get a generator for the house just so I can charge them if needed.

Joel N. Weber II | April 28, 2013

There's a good chance that the Supercharger hardware in the car already makes it possible to get DC out of the car to an external inverter. And that external inverter looks a lot like the one that a solar panel system would have, although solar is usually designed to stop powering the house when the grid has an outage, and you might want an inverter capable of handling higher peak loads than what the solar system can produce.

An RV with a Tesla powertrain would be a great idea, if the battery could be used to power appliances at night away from the grid, with solar panels to both cover the daytime loads and charge the batteries to cover the overnight use. You'd also want Supercharger compatibility for long highway trips. Given that an RV can probably have a larger battery pack than a Model S, 120 kw might be slower than is ideal, so maybe it would use a larger connector, but if not, having some of the Model S Supercharger installations have parking lot geometry that could cope with an RV using the Superchargers would be a good idea.

A single phase, 120V, 15A or 20A inverter as an option for powering appliances inside the Model S would probably also be a good idea.

jat | April 28, 2013

@Joel - RVs are dying anyway, so I can't imagine that Tesla would want to get into an even more niche business than the Model S -- they need to move up the volume ladder to GenIII, not down it.

Solar inverters run at a much lower voltage than the Model S battery, so you aren't going to take something off the shelf. I would much rather just buy a generator or battery backup system for my house rather than try and use my car.

DouglasR | April 28, 2013

The warranty does not cover any damage caused by using the vehicle as a stationary power source.

Robert22 | April 28, 2013

I guess I won't be wrapping my car in Christmas lights this year,

David Trushin | April 29, 2013

See the thread on the espresso machine.

Flaninacupboard | April 29, 2013

Prius owners do this, either with a 12V inverter (generally good for up to ~1kw) or there's now a HV DC unit which i believe has 3kw output. Not sure what it's voltage range input is, or how the S would react to a drain put on the main battery terminals it wasn't expecting (the prius is not too bothered so long as you don't draw over the current discharging limit)

Can you leave the car "on" without someone in the seat though?

jat | April 29, 2013

@Flaninacupboard - if you are hacking up your car, it doesn't matter about leaving the car on -- just hook in before the main contactor (of course you run the risk of killing the battery by completely draining it, but you are running a lot of risks already if you decide to modify systems capable of producing 320kW).

hiroshiy | May 1, 2013

Nissan has Leaf V2H unit called Leaf to Home:
http://ev.nissan.co.jp/LEAFTOHOME/

This system seems to focud on achieving lower electricity cost, rather than preparing for emergency power outages.
In Japan electricity costs 1/3 at night.

fluxemag | May 1, 2013

It voids the warranty to use the car as a stationary power source, or to plug it in to anything besides utility supplied power.

jbunn | May 1, 2013

Jack the back end of the car up, put it on a generator, and put the car in gear. An example of how this works can be found near the end of Ferris Bueler's Day Off.

http://www.youtube.com/watch?v=G-Nunm3Sbzo

bt77057 | May 1, 2013

@jbunn...

The absolute funniest thing I've read on this forum. My entire office was in stitches also...

shs | May 1, 2013

@fluxemag

Are you saying that it will void the if our backup generator comes on during a power failure and the car is plugged in? Charging during a power failure is a critical need and we can go a week without utility power in the case of a major snow storm like we had a few years ago.

DouglasR | May 1, 2013

@fluxemag - I don't see any restriction in the warranty regarding plugging in to non-utility supplied power. Could you please cite your source? Most of these type limitations do not automatically void the warranty. The warranty may, however, exclude coverage for any damages caused by improperly charging the vehicle. So if your generator doesn't cause the damage, the warranty is still good.

derek | May 1, 2013

I'd love to see a V2G offering from Tesla, similar to what Nissan has for the leaf. I would not hack to make it myself, but if it came with official software and hardware, I'd gladly partake.

Most power outages are very brief, a large number are on the order of 1-4 hours, and very few are natural disaster-types of a week. The 85Kwh battery could easily bridge the 1-4 hour outages, and would be cleaner and quieter than a generator, plus avoiding the purchase and maintenance of the genny.

I would assume that a home grid/car switch would have to be installed as a one-time cost, as with any generator to avoid sending power down the utility line during outages.

The 40Amp mobile connector could easily provide enough current for my home in an outage situation (turn off AC, spa, etc.) My house uses about 2.5Kw at normal use when people are home. That's about 20 amps. I could dial that down by half when on Model S power.

Anyway. I can dream. I know Tesla has bigger fish to fry for now.

shs | May 1, 2013

Solar City offers a battery backup system " through our partnership with Tesla Motors", that likely uses similar technology to that used in the car.

http://www.solarcity.com/residential/energy-storage.aspx

In the blurb they mention being able to time shift your grid electric usage, i.e. charge the battery at night at low rates and use from the battery on summer afternoons when the rate is high. Not sure what the payback time would be, but I like the concept very much. And of course it would cover the shorter time scale power outages. For the record, in the last 5 years since we started building our house, we have had two winters with power out for a week or more, and no battery backup system I might want to buy will cover that.

jat | May 1, 2013

@derek - the Mobile Connector just sends AC to the car and provides some smarts about GFI protection and communicating the available current (based on the adapter used). To run your house, you need a big inverter that converts the DC to AC, and then you need to run that into a transfer switch (automatic or manual) that feeds your main breaker (if your inverter is big enough to run the whole house, otherwise a subpanel with critical loads). Backfeeding through a breaker is allowed in some cases, but you have to be sure that the utility connection is broken before that is allowed, plus you will not be able to run much in your house.

elephant in a bottle | September 30, 2014

Also, this feature sounds a lot lucrative if we consider charging the MS during off-peak hours , then using the stored energy for home use on or mid peak hours. The table shows 60% savings between On-peak and Off-peak rates.
Is this the future?

PGE rates below

Time period Price per kWh*
On-peak 12.142¢/kWh*
Mid-peak 6.967¢/kWh
Off-peak 4.048¢/kWh*

sule | September 30, 2014

@jat: not that I think this is a good idea (I don't) but some people may (cottage?) and you don't have to do much in the house really. You could actually plug in your generator into a dryer or stove outlet to feed your system backwards. No renovation necessary.