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Tesla + Honda Generator on a trailer = 1,000 mile range?

The base Tesla model S has a 20kw battery, with a range of 160 miles. If I were to tow a Honda 240v generator, and keep running while driving on the highway, couldn’t I theoretically drive forever? Admittedly this would diminish the overall look of the Tesla, but hey on a road trip who cares?


The generator would have to be at least a 7 kilowatt unit – probably a larger unit to allow for inefficiencies of wiring, converters, and other losses. You are probably looking at a 15 horse power plant. Then there is the fuel tank capacity, consumption, and refilling. The 15 horse engine running at full load will probably consume 1.5-2.0 gallons an hour. Then you have to figure the lowered fuel economy due to the Tesla having to drag around the generator, converter, trailer, and fuel – not to mention the aerodynamic drag of the trailer and equipment.

It would probably be better to make the generator a DC unit that yielded voltage and current that matched Tesla’s battery and the converters for the motors. This would mean a specially designed generator by Honda which would not have the price of an off the shelf AC emergency house power generator.

If Tesla thought through the concept of a true hyrid, they would not have had so much difficulty finding/engineering a high capacity battery and packing it into the car in the first place.

The battery is 20 kilowatt-hours of capacity, which is different than kilowatts, which is a rating of power.
You’d probably need a steady 10-20 horsepower to keep the Tesla battery charged on the highway, which works out to a 7.5-15kw generator.
Is the Tesla’s charger capable of accepting that rate of charge?
Are the Tesla’s circuits capable of charging and discharging the battery simultaneously?
Probably not, since that would add cost and complexity.

Yeah, better check your owners manual before you try that one…You want unlimited range? Buy a Volt. Forget the trailer and generator…

A while back a caller said they wanted AC in the summer and better heating in the winter on their 1960’s VW Beetle, and Tom and Ray jokingly suggested this approach, duct-tape an combo home AC/Heating unit in the window, then power it with a trailor mounted generator. I think if you look in the dictionary under Rube Goldberg Contraption, you’d see a photo of what this Tesla would look like! … lol

I’d think that a big airplane manufacturer and a lithium battery manufacturer are going to surplus a bunch of nearly new, very low cycled batteries. Just watch for them on Ebay or Amazon. Load up on them, use a HarborFreight $120 tagalong, and #4 gauge jumpers.

Boeing … Boeing … you posted a good one @longprime … lol!

The potential smell of burning electrics in a modified Tesla may lead to some 5 digit financial bad news at the dealer after the tow truck unloads it…

Go to a friendly chevy dealer and Purchase a Volt. It does exactly what you are trying to accomplish.

I would venture to guess that it would be harmless to drive the car with a working charger attached. Isn’t it possible that someone might want to move the car a couple of feet for whatever reason within a garage while the charger is attached? Check your owner’s manual and ask Tesla. You might not be able to drive continuously but the 160 mile range could be extended.

As Wha Who noted, assuming it’s OK to drive the vehicle with a working charger attached, you could “extend your range” if you:

  • Look at the specs for the current draw for when the vehicle is plugged into the wall.
  • Then make sure your generator is capable of providing some increment capacity over that.
    How far your range is extended will likely depend on the ratio of input charging power to the power used when the vehicle is driven.

If this were a hobby car and you wanted to get creative, there might be a way to connect your trailer-generator to a large battery charger that connects directly to the Telsa’s 20kw batteries. Tread carefully as there are lots of sensitive vehicle electronics that could get confused or blow if you choose this route.

The teslar would no longer have that 160 mile range while towing. There are no free lunches. To get the performance of a 100 hp electric, plus charge the battery for that kind of range, you WILL need close to that or more in a generator extender motor depending on the available charge in the battery. The motor will suck up all the energy from the gas generator of that size, just to tow the trailer. Once depleted, it will be a negative. This assumes you aren’t always driving down hills. Going up hills and accelerating (and towing) are real battery killers.

1000 miles ? You would be lucky to go 160 as the generator would probably just “pay” for itself. The only way to recharge the battery with that size generator, it to park it and wait, a long time. Motors and their corresponding generators are matched pretty well for safety purposes. It takes time to charge a battery…it’s not like pouring gasoline into a tank and it you are driving while trying to charge you will need a much bigger generator…and the added weight will draw even more current from the motor. A loose, loose. Just buy a Chevy Volt…they have already done the “Gazintas”. A 100 hp gas motor will turn a 75 KW generator…what does that tell you about your needs and your little 7K generator.

BTW, it’s not very efficient to use a gas engine that way. Parallel hybrids where the gas motor helps drive the wheels is better. The cat is out of the bag and even the Volt is more like a plug in Prius then just having a gas extender motor…they work together through a gear set at higher speeds. More GM fakery at work !

My former company made equipment for tesla to assemble their battery packs. Interesting design. I still have a box of 100 of their battery cells used to make the modules. I think the Boeing 787 uses similar batteries and yes, the tesla had concerns about overheating and burning out individual batteries and tailored the design to accommodate the issue.

The potential for the extra hassle, problems, and cost seem to outweigh the potential benefits by a large margin. If you can afford a Tesla, you should be able to afford a Volt. Use the Tesla as a daily driver… A nice one at that… And use the Volt for longer trips.

The cost of repairs on a car like the Tesla caused by improper modifications might very well pay for a Volt.

I have actually seen some cars (usually old beaters) where they have a window AC unit somehow mounted in the car and a generator to power it bolted to the trunk, or some other part of the car. I guess this might be cheaper than fixing the regular AC if you can find a generator and window unit at a yard sale but it seems like more trouble than it is worth.

Expected much more abuse - I’m rather disappointed. I know that my options are: 1) gas or gas hybrid or 2) electric only and careful trip planning. The Volt is not as sexy as the Tesla though, but much more practical.

Thanks all!

It’s quite possible that even if you could tow a big enough generator behind you, that the Tesla’s software would not allow charging while the vehicle is in motion.

You are defeating the purpose for owning a Tesla. To generate enough power to recharge the battery, I bet you would use as much if not more gasoline than to run a car of similar size and weight with a gasoline engine.
Interestingly, I have seen more hook-ups for electric cars. The hotel where we stay near Nashville, TN when we visit my son has a recharging station for electric cars. I attended a minor league baseball game in Indianapolis and the parking garage had a recharging station for electric cars. On the university campus where I taught, a recharging station has been installed in the gymnasium parking lot. One is required to purchase a permit to park in the space and use the charger. I think you will see more recharging stations in the future and you won’t need to tow a generator behind your Tesla.

@cwatkin “I have actually seen some cars (usually old beaters) where they have a window AC unit somehow mounted in the car and a generator to power it bolted to the trunk, or some other part of the car.”

Around 1975, I was picked up at a NYC airport by a sales rep in, believe it or not, a Ferrari with a window A/C unit installed in the back. As I recall, it was powered by an inverter, and the owner was happy to have the cooling. I wonder how it worked out in the long run. I’ll bet it killed the resale value :slight_smile: .

Even if the generator worked it being a low tech carburetor engine devoid of any emission equipment would mean your Tesla could be belching out 10x the emissions of a regular car. Kind of defeats the purpose of buying a electric car in the first place.

Here’s a compromise: drive 150 miles, stop for a meal, and charge the car on 240V with your generator. Then go another 150 miles, stop for another meal, and charge again. You can do it a third time, and then stop for the night. Maybe the hotel will have an outlet that you can use to charge overnight.: