You CAN tow with a Prius

Thanks for expanding our notion of what these cars are capable of! And it makes sense that regen braking is going to charge the battery faster, that's alot more rolling weight to slow. Most of all please follow up with a post if you ever have to do any major evasive maneuvers or hard braking... It'll be good to get details on how the Prius handles when it's pushed so far beyond its recommended load limits!

 

Thanks for posting this, we're planning to tow small things with ours. This is very reassuring.

 

I have hauled lots in the Prius and it does fine. A few hundred pounds of wood, 600+ pounds of slate tile, and this weekend 25qty of 55lb concrete bags ~1400pounds and 20 bags of pea gravel at about 40lbs a piece 800lbs for a total of 2200lbs in the hatch. The rear suspension was NOT happy but I still had clearance between the wheel and wheel wells on my 15in tires.

I have not tried towing with a trailer but the same principles apply. The instant torque available from MG2 and the ICE together is pretty incredible.

This is for a GenIII after the gearing at the output of the ring gear:



So you get about 460ft-lbs of torque to the ground with the Prius compared to 600-ish with the big-a$$ truck? And with the Prius you get regen braking and friction braking. It is a truly remarkable vehicle.

I would suggest if you are towing often, then you should monitor the MG temperatures on a scangauge or android app. On a long incline the inverter temp and MG temps will increase. It will auto-correct by power reduction if it gets too hot, but it is nice to have a warning if you need it.

There is another member who has towed his airplane with the Prius...

 

You can't really make a graph based on RPM, because you have 3 RPMS, MG1, MG2, and the ICE.

The few times you need to tow 1000ft/lbs at high speeds, a rental is way more cost effective.

 

There are no android apps that can monitor the mg2 temps through an elm327 as that is not part of OBDII. You'll need a ScanGuage for that which is the most economical consumer device for that purpose.


Depending on the grade, you may need to use the engine brake "B" mode in order to reduce the load you put on the MG1 through the PSD.

The MG2 won't care.

 

What hitch are you guys using?

 

My hardware monitors everything available on the CAN network including the Prius specific codes and is readable from any bluetooth device. Or via USB in a PC, or generally I just have the OLED screen showing battery pack voltage and then current in/out to maximize regeneration.

 

I tow my 17' sailboat and have not had issues. Just like with towing in any vehicle you need to be alert and watch traffic so you can take it slow and easy. I was totally amazed - the one long highway trip that I took with it (about 200 miles) I was able to get mileage in the mid 30's.

 

What about adding an extra cooler? Maybe a GenI inverter radiator plumbed into the system?

 

What's all the hub-bub about? Camping in the Prius | Page 3 | PriusChat

My trailer's about 750# and braking distances are probably 3-4x what they are unloaded. There's no other way to put it... the Prius's brakes are crap.

I'd hate to think about trying to brake with double the weight.

 

460 lbs of torque to the ground? Thats big block Chevy territory. Truly a magical car lol....

 

Like Maestro says the scary part of towing is the brakes suck and it takes 3x longer to stop.
And get an android and monitor mg temps as thats how the trans is going to fail. Your going to overheat the windings of the mg's.

Easy way to tell right now how bad your stressing the trans and the trans cooling system is go to Home D and buy an IR Thermometer and take measurements of the Inverter and the reservoir and the trans body itself. Would love to see those numbers. Take it at the top of that 6000 foot hill.

But its a pretty tough little car. Right up to the point it throws a CEL.

 

While I think that my Prius is a very good vehicle and don't doubt that you can use it for light towing, this statement isn't accurate. You are comparing torque after multiplication through the PSD to engine torque for the "big-a$$ truck."

A more accurate comparison would be output torque from the truck's transmission. Most small block gas V8's would be around 1500 ft lbs while diesels would be around 3000 ft lbs depending on gearing and engine torque. If you account for final drive (differential) ratios the disparity between the Prius and the trucks gets even greater.

 

It's a good point that torque is a function of drivetrain just as much, if not more, than a function of the motor(s). I used to be a treeplanter and we'd drive around in forestry trucks that were designed for the most impossible terrain. Those things have the craziest low low granny gears ever. You could redline the engine and the wheels would barely be spinning. Now that's torque! Ain't no way a Prius could ever come close to that!

 

Something doesn't compute. That chart looks like MG2 torque at the ring gear at 106 mph is the same at ICE torque at the ring gear at that speed. If that's the claim, then the HP is also the same. The ICE HP is 98 hp and MG2 as installed and controlled MG net output in the Prius is about 40 HP.

The chart also shows MG2 with 8 times the torque as the ICE at 0 mph. If that were true it would be difficult to tell MG2 only acceleration from ICE plus MG2 acceleration.

The chart is a great idea, but need some refinement. It probably assumes that MG2 actually puts out its full rated torque under real world conditions.

I know I'm over simplifying things, but the chart still doesn't look right. Would you run through the numbers for a couple of speeds?

I'm off to Central America for close to 3 weeks, will report any Prius sightings.

 

Fool around with this and you'll see why.
http://ecomodder.com/forum/tool-aero-rolling-resistance.php
Any increase in energy required by a higher drag coefficient and more weight from the trailer is made up for by the lower speed.

 

Did you just have a stock Prius tow package put on?