Can You Run A Hybrid On Electricity When The Fuel Runs Dry?

When we asked our legion of YouTube subscribers what they wanted us to do with our long-term Toyota Yaris Hybrid, we were expecting some crazy, off the wall responses. And boy did we get some.

From "Mod it and then smoke V8 muscles" to "Take it off road!" to "Fill it with people and do a barrel roll" (think I'll sit that one out), there was the usual range of humour, sarcasm and deep thinking that we've come to love from our community. However, one question clearly stood out:

"What happens when the Yaris Hybrid runs out of fuel?"

Whilst pure electric vehicles like the Mitsubishi i-MiEV and Nissan Leaf have a simple battery range displayed on the dashboard, things get a tad more tricky with complicated hybrid systems that run off a combination of petrol and, in the case of the Yaris, nickel-metal hydride batteries.

So, can you simply revert back to electric power alone when the 1.5-litre VVT-i petrol engine runs out of juice? Can you still carry on for 1-2 miles more using the 120-cell battery pack?

The answer? From Head of Toyota UK PR, Scott Brownlee:

Yes, the range on just EV might be 1-2miles, but Toyota's Hybrid really works by coming in and out throughout a journey. So, for a 20 minute journey, you might only have the petrol engine on for 40-50% of the time. The idea is a little electricity out, and little back in, out and in and so on - not to go from fully charged to empty.

However, if you happen to be driving at slow speeds and the last drop of reserve fuel runs out, Toyota's Technical Team confirmed that the EV system will allow you to power the car for a small distance purely on electricity. That distance depends on the level of battery charge at that moment - for batteries close to the "recharge threshold" (the point at which the car turns on the petrol engine to recharge the batteries for fear of damaging them) this might be a few yards; for fully charged batteries, maybe a little more.

But the bottom line? Toyota's hybrid system is not designed to run with no fuel in the tank. Unlike a laptop battery, draining the car completely is not advised so as to maintain an acceptable battery lifetime. And unlike a normal car, the Yaris Hybrid - indeed any FWD hybrid - can't just be towed in neutral; you'd need to get a truck to tow with the front wheels off the ground so as to not generate electricity and overheat the motor.

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