Towing with a Hybrid?

[Mick F]

I know that we can't tow a trailer with a Yaris Hybrid.  It's not homologated for it.  You can with a "normal" Yaris, so why not a Hybrid?

Why is towing with a Yaris Hybrid not allowed?

Mick

[PeteB]

Until relatively recently, all Toyota and Lexus Hybrids were stated by the manufacturer to be unsuitable for towing because of concerns about overheating the Hybrid components, especially the HV Battery and Inverter.  In the early days they were probably worried about breaking the Power Split Device, but that has proved bullet proof of 22 years since the first Prius came out.

The Battery has an air cooling system (the vent under the rear seat on most cars) which also sucks in cabin heat when it's cold to help warm up the Battery.  The Inverter has a separate water cooling system.  Heat management (along with limiting the maximum power flowing into, out of and through them plus limiting SoC of the battery) of these two components have been key to their longevity, which confounded the early naysayers.

Some people have towed small trailers without problems, but it probably wouldn't help if you needed warranty repairs on the Hybrid system if they found a tow bar had been fitted.

Some more recent Hybrids, like the Gen 4 Prius and the RAV4 are certified to tow, in the case of the latter, a much higher weight on 4WD models than the Front Wheel Drive versions.

I believe the Lexus RX can tow too, but that has a much beefier main Motor/Generator (MG) which is mated to a 3½ Litre V6 petrol engine and also has an extra MG on the rear axle to give 4WD (as does the 4WD RAV4).

The limo sized Lexus LS saloon may be able to tow too, with it's leviathan 4WD Hybrid System which until the latest model included a 5 Litre V8.  It could propel the 2½ ton beast to 60 mph in about 5½ seconds, but I somehow think few people would see that as an ideal tow car.  I was lent one (worth nearly £100k!) for a couple of days a few years ago and it was very entertaining, but driven sensibly was amazingly docile and managed around 30 mpg (computed) with such treatment.  A brief exploring of the performance saw that figure plummet though.  It had some amazing toys too.

Edited May 14, 2019 by PeteB
added red text

[Mick F]

Thanks for that.

I was thinking that if a Yaris Hybrid can carry five adults, have a boot full of luggage, fit a roof-rack for more luggage, and hurl up the motorway for hours, why can't you tow a trailer?

Cars that are allowed to tow have a "train weight" on the VIN plate, so they are limited to the weight of the trailer or caravan.  There's no reason at all that a Yaris Hybrid couldn't tow a trailer.  The fact that's it isn't homologated to do it is a thorn in its side.  If you do fit one ...................... providing you DIY because a reputable professional towbar fitter wouldn't do it ................... your insurance would be invalid.

Note our VIN plate.  Note that the gross train weight is the same as the gross vehicle weight.

Mick.

[Mick F]

PS:

This is the VIN plate from our Fiat500 that we sold a couple of years ago.

Note the differences in the weights.  Little car like that can tow!

Mick.

[PeteB]

1 hour ago, Mick F said:

I was thinking that if a Yaris Hybrid can carry five adults, have a boot full of luggage, fit a roof-rack for more luggage, and hurl up the motorway for hours, why can't you tow a trailer?

Toyota's engineers were probably thinking about someone doing all that and towing a caravan as well!

1 hour ago, Mick F said:

This is the VIN plate from our Fiat500 that we sold a couple of years ago...

In the 1970s I had a Fiat 126 which had a 600cc 24hp 2 cyl air cooled engine in the boot.  It took 60 secs to reach 60 mph, unless there was a head wind in which case it couldn't even reach 60!

The manual included specification and instructions for fitting a tow bar!

BTW it averaged 42 mpg over 12,000 miles, and could do up to mid 50s on a gentle cross country run under favourable conditions.

Considering my Prius averages 63½ and over 80 on a good cross country - shows have things have progressed.

[Mick F]

16 minutes ago, PeteB said:

Toyota's engineers were probably thinking about someone doing all that and towing a caravan as well!

Yes, but the rules are that you can't legally exceed the gross train weight.  Overloaded vehicles are dangerous and if you are caught by the rozzers, you'll be pulled over and not allowed to proceed ........... let alone being fined or worse.

Mick.

[FROSTYBALLS]

A couple of extracts from Toyota blog UK:

"Some European-specification Auris Hybrid models have been specially configured to tow light loads but these models are not available in the UK. Their cooling systems are different and the components cannot be retro-fitted to UK-spec cars."

 So perhaps with the Yaris hybrid, it is the cooling system that is the limiting factor as regards towing.

"Not all vehicles have been homologated to tow, but those that have will display either three or four sets of figures on the VIN plate. Reading from top to bottom, these will be the gross vehicle weight (the maximum mass of the vehicle including occupants, fuel and load), the gross vehicle train weight (the combined maximum mass of the vehicle and trailer) and the maximum loads across the front and rear axles respectively.

In order to create a recommended maximum towing capacity, vehicle manufacturers usually deduct the gross vehicle weight from the gross vehicle train weight."

So in the case of your Yaris and using your figures, to obtain the recommended maximum towing capacity, deduct the gross vehicle weight from the train weight:  1565 - 1565 = 0.

[Mike J.]

There is a Toyota designed and supplied tow bar for the Yaris Hybrid, but it is called a "Stand alone bicycle holder" 😉

Check out Toyota installation PDF

[FROSTYBALLS]

3 minutes ago, Mike J. said:

There is a Toyota designed and supplied tow bar for the Yaris Hybrid, but it is called a "Stand alone bicycle holder" 😉

Similar for the Prius and Prius+

[Mick F]

3 hours ago, Mike J. said:

There is a Toyota designed and supplied tow bar for the Yaris Hybrid, but it is called a "Stand alone bicycle holder" 😉

Check out Toyota installation PDF

Is this unit fitting on a tow ball perhaps?

Mick.

[FROSTYBALLS]

Probably be similar to this on a Rav4 - 

[Bomber209]

Hi, I don't think you can physically fit a towbar to the hybrid, as the Battery pack etc is in the way.

[FROSTYBALLS]

Don't think a tow bar is needed - have a look at the first post of the following: 

 

[HSDish]

20 minutes ago, FROSTYBALLS said:

Don't think a tow bar is needed - have a look at the first post of the following: 

 

Think there should be some bar/rod/boom betwen the metal brackets in the pic (taken from my computer)

I asked the seller about more info about this but not got any answer yet

 

[Mick F]

12 hours ago, Bomber209 said:

Hi, I don't think you can physically fit a towbar to the hybrid, as the battery pack etc is in the way.

The Battery pack is under the rear seat.

I've not looked under the rear end of our Hybrid and even if I did I'd have to look under and conventional Yaris to see the difference ............... but I very much doubt there is a difference other than the exhaust perhaps.

Mick.

[Gerg]

44 minutes ago, Mick F said:

I've not looked under the rear end of our Hybrid and even if I did I'd have to look under and conventional Yaris to see the difference ............... but I very much doubt there is a difference other than the exhaust perhaps.

On the current Yaris hybrid the petrol tank is smaller than on a normal one - some bits have been changed to accommodate the batteries. I think there is a different floorpan for the hybrid to take some petrol tank space and give it to the underseat/battery space.  The back seat of a Yaris will normally sit on a big bump in the floor, so not like this picture (of an Auris hybrid, but yours will certainly be similar).  The petrol tank figures are 36 litres vs 42 litres.

HTH

 

[Mick F]

Here's the underseat area or ours.  I took the seat off to have a good look-see! 

Note that the Battery sits at the forward end of the "lump" and not the full depth of the seat.

Mick.

[Gerg]

An interesting picture.  I think on the regular Yaris the lump would extend to about the front (r/h in the picture) of the Battery and have some carpet put over it - I'm sure you knew that. 

I'm surprised that the tank isn't a bit smaller than it is (36l), unless they've moved some other bits around to give the tank more space in another direction.  But that would  be more expense for them, but then, they've already made a different shaped fuel tank and floor!

I'd forgotten that they've put the 12v Battery in there as well.

[Mick F]

I took a couple of more photos if you're interested!

Mick.

[Bomber209]

Mick F Hi,  I didn't mean the 12 volt Battery but the 360 volt lump.. Also a big lump of steel (towbar) in the main Battery sphere could possibly set up a substantial Magnetic Field. This could disrupt other systems ie ACE ???

[Mick F]

Yes, the BIG Battery.  It's actually far smaller than I thought it would be.  I expected it to occupy all of the underseat volume, whereas there's plenty void and unoccupied space under there.

As for a lump of steel, you could have a load of scrap iron in the boot to go to the scrap yard.  There's nothing in the handbook about carrying steel (and even magnets) about.

Towbars aren't big and lumpy either.  Just a few short lengths of steel angle, and in fact with some cars it's just a short bent length of hollow square section suitably bolted to the rear chassis.  Dunno what a Yaris towbar looks like, but I'll bet it's not so big that it'll effect the traction Battery equipment.

I think the inability for a Yaris Hybrid to tow, is down to human nature and exceeding the all-up weight allowance, so they don't homologate them to tow.  They always err on the safe-side despite people like me only wanting to tow a small camping trailer and would never get anywhere near the weight limits.

Mick.

[Mike J.]

1 hour ago, Bomber209 said:

Mick F Hi,  I didn't mean the 12 volt battery but the 360 volt lump.. Also a big lump of steel (towbar) in the main battery sphere could possibly set up a substantial Magnetic Field. This could disrupt other systems ie ACE ???

It is a 144V lump.

BTW, did you not view the pdf I linked to showing the fitting of a Toyota designed towbar to a Yaris Hybrid?

[Bomber209]

Mike J hi,

 I beg to differ. Owners Manual Page 34, 'Traction Battery when fully charged can be up to 520 volts'. As an in service item 360 volts is nearer the mark. If you access the service point on the Battery and use a suitable AVO check for yourself.

[Mick F]

On 5/16/2019 at 10:45 AM, Mike J. said:

 .............. view the pdf I linked to showing the fitting of a Toyota designed towbar to a Yaris Hybrid?

I was having a good look at the PDF to other day, and it struck me that if you had one fitted and then sold the car some years down the line, the new owner could easily fit a towball to it.

Hey presto, a Yaris Hybrid towing a trailer.  Illegal of course, but the new owner may not know.

Mick.

[Catlover]

It is up to the owner of a vehicle to know what the legal limits of his/her vehicle is, I would have thought.