See This Range-Extending Toyota-Tesla Trailer In Action


And learn a bit about Toyota’s 2nd-gen Rav4 EV

A while back we shared a project by Rich Benoit, he of the Rich Rebuilds YouTube channel, that took a Tesla battery pack and turned its shell into a trailer. While it looks great and is an awesome repurposing project, a lot of his viewers thought it was something of a wasted opportunity. That is, they thought that it should carry some amount of batteries, perhaps to, say, act as a range extender. Well, it seems Mr. Benoit has found someone who has done that very thing.

In the video above, Benoit takes a trip to visit James Klafehn who has built his own “Tesla trailer.” While it doesn’t use the aluminum shell of a Tesla Model S pack — it appears to be an off-the-shelf utility trailer — it does have a battery pack attached to its top which is full of Tesla cells. The twist here is that the pack is actually from a Toyota Rav4 EV, which the Japanese automaker stopped producing in 2014.

Now, not to be judgmental, but Klafehn’s trailer is not attractive. At all. However, it is useful. Holding about 41 kWh worth of energy it approximately doubles the 130 miles of range that he gets with his all-electric Toyota. Through an arrangement of connectors and electrical contactors, the battery in tow is in parallel with the one in the vehicle. This means he can pull power from them both at the same time. He can also recharge them at the same time and in the video here, you can see him doing just that using the Chademo DC fast charger connector in the nose of the Rav4 EV.

Overall it’s a pretty interesting project and the video does a great job of going over all the details of what was involved in making it work. We can only hope it inspires Benoit (or anybody, really) to meld the two different approaches together — use the Tesla battery pack shell with some amount of modules inside, and make it look aesthetically pleasing as well as functional.

If you’re curious about what the Toyota/Tesla battery pack looks like with its cover off, you’re in luck. We’ve embedded a video below showing just that. Enjoy!

Source: YouTube

Categories: Tesla, Toyota, Videos

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22 Comments on "See This Range-Extending Toyota-Tesla Trailer In Action"

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Why Not Place a Solar Cell Array Over the Top Of The Battery Trailer..


Why not just place the panels on the roof of the house where they belong?

Jim Klafehn

Exactly! A couple 300 watt solar panels will do nothing when you have a 41+kwh battery pack.


Solar panels over the pack could charge it in a few weeks,
then you have an extra 200 miles for that weekend trip.


Good work. I have a Nissan Leaf: MY-2013. If anyone can teach how to mount a very powerful generator than can power the vehicle beyond its 84 mile range, let me know and I will try it.

Texas Leaf

Go buy a plug in hybrid

Jim Klafehn

There is a guy on Youtube that is going to be offering larger batteries for the Leaf very soon. He is overseas somewhere though


There was a company that sold range extender/chargers that went in the trunk well at the back. They don’t sell them anymore, but it seemed like a possible winner.

Andrei Gloaba

very very cool. Respect

Jim Klafehn

Thank you so much!


Toyota needs to put out a Tacoma EV and a 4Runner EV…
If they put in a 100kWh battery, that would be good for about 250 miles of range, at 55mph. Add in support for 150kW DCFC, and you get an 80% charge in 40 minutes. Put a strong motor and regen in there as well, they would be excellent vehicles that would sell very well…

They might only get 125 miles when towing 5,500lb’s but that’s okay, if the Electrify America network hurries up and gets installed, combined with the EVgo, and ChargePoint networks, there will be stations every 50 miles anyways…

Jim Klafehn

Toyota is anti EV. They have too much money tied up into hybrid tech and hydrogen. They dont currently offer any EV’s. The only plug in is the Prius which has the lowest range of any PHEV. They didnt want to make this car so they hired Tesla to make it.

Texas Leaf

I thought about doing this kind of thing a lot when I had my 2013 Focus Electric. I don’t see much much need to do this on my 2018 Leaf other than having dual batteries would probably keep the batteries much cooler on long trips with multiple fast charges. I’m glad someone has actually made a battery trailer and shown me rest of us how to do it.

Texas Leaf

Since the Leaf battery does not have a water cool TMS, it should be much less complicated to make the Leaf battery into a trailer battery. I’m not really interested in adding a trailer battery to my 2018 Leaf right now but maybe when it gets older.

Jim Klafehn

Thank you! Glad you like my project!

Texas Leaf

I have heard a lot about un-balanced batteries burning up when they are charged. It makes me wonder why one of these battery packs doesn’t burn up. Is it because the packs are in parallel?

Mike I.

The Tesla BMS is still active in the trailer pack, still balancing itself. He connected to the CANbus and is monitoring it all. The two packs are in parallel, so they are forced to be the same voltage. That’s the main reason that the charging works the same as the car alone. It also helps that the two packs are the same, even though they are aged differently due to a different number of miles on each pack.

Jim Klafehn

Holy cow you ran a story about my trailer! Awesome!

My name is Jim and I built this trailer. I call it the T-Rex, Tesla Range Extender.

I built it over the course of a few months. Since, I have taken many road trips with it. Its working great! If anyone has any questions they can email me and/or watch my youtube videos at


Bill Howland

I can verify Jim’s story – I saw his TWO RAV4EVs at the Drive Electric in Ithaca, NY.

That said, you have to really be INTO ev’s (and have it as a HOBBY besides), to do all the work required to tow a trailer along with you. Now, if you could integrate the battery into a usable camper or something, now that would be really practical.

It must have been an effort to get the ‘California Only’ cars to NY State.

I wonder if any MIRAI owners are in NY State, that also happen to work for AIR PRODUCTS so that they can refuel?

Jim Klafehn

Hi Bill!


Could 3 Tesla Powerwalls achieve the same results?

Jim Klafehn

I dont know much about them. They dont have cooling or heating systems so I suspect you would have a lot of work ahead of you. But those are also extremely expensive. You are much better off buying an EV battery