The biggest PHEV myth

Let’s recap three important points about PHEVs:

1. They are a hybrid, which means two motors; petrol/diesel, and electric.
2. Three modes; electric only, petrol only, and both together.
3. The battery can be charged externally, by the engine, or by regen.

When you start a PHEV then the car will use electricty and petrol, and run down the battery unless you have a mode where you can tell it otherwise.

So what happens when the car gets to 0% battery power?  And here’s the myth.

The hybrid does not rely solely on its petrol engine.

What happens:

• Same as your car fuel light reads empty when there is actually fuel left.
• when the battery reads 0%, it’s not actually at 0%.  There’s still quite a bit of energy left, and the car does that so it doesn’t need to rely on its petrol engine only. 
• If you drive a PHEV at 0% you’ll still see it cut its engine and cruise on electric, usually at slow speeds.
• The PHEV will use spare cycles from the petrol engine to keep the EV battery charge up – for example, when idling, slowing down, any time you’re not at full throttle, and of course regen.

Now what if you’re towing up a steep hill, and deplete the battery completely?  Well, the only way that’s going to happen is if you’re full-throttle for a long, long, long time…minutes…enough to demand full power from both the petrol engine and electric motor.  But in the real world, that won’t happen.  Even on a steep climb you’ll need to back off for corners, and then the petrol motor can charge the battery.

And, try keeping a diesel or petrol engine flat-out, max throttle for minutes on end.  You’ll put it into limp mode.

So….when you have a PHEV, you’re not going to be relying just on your petrol engine.  You’ll always have the electric motor to help.