Battery’s charge

Before we get crazy with scenarios, what is your current average mpg?

 

It depends on conditions and what your car needs. If you do a lot of accelerating or climbing hills, battery energy is used for more power. If you live uphill from where you work, the battery will recharge going to work and discharge going home.

 

With that mpg, the topo of the land, and assuming your ICE is cycling on and off, it's sounding normal. I think the other guys were spot on.

 

That's normal behavior, then. We live in a mountainous area, about 1500 ft higher elevation than town. When going to town we get 80-99 mpg depending on the route we take, and 32-42 mpg coming home. Even the paltry 32 mpg is twice the average mileage we used to get in our truck.

 

welcome to priuschat! sounds perfectly normal. no worries and all the best!

 

I'm confused: in the morning, when you set out for work, state of charge is high. By the time you get home at night, it's depleted. And then the next morning, the state of charge is high again?

Something's missing: is someone else driving the car in the evening, with a more aggressive driving style?

The main thing I find that drives down our state of charge is my driving style. I have to tone it down: if I go out of my way to lift-off-and-reapply the gas pedal, to get it into stealth mode, I can quickly run down the charge.

 

There might be a problem with your battery, if the state of charge is consistently on the low side.

OTOH it could your driving style. The main thing that will deplete the charge is purposely getting the car into stealth (electric only propulsion) and then protracted running just below the threshold where the gas engine kicks in.

The Hybrid System Indicator (HSI) is a good display to use, for keeping an eye on things, if you've not already set it. Once you're in stealth mode, as long as you keep the bar to the left of center, the engine will stay off (unless the battery's really depleted). Your charge will be eaten up fastest when you're near that center point:




There's nothing wrong with stealth mode, and there's nothing wrong with running the charge down a bit, in my opinion. That's what it's there for. If you put the car in cruise control you'll see it doing the same behaviours. It's mainly a matter of degree, you just don't want to push it too hard.

There's a stretch of road I run fairly regularly, pretty flat, slight down grade, and almost without fail the charge starts dropping; it's too easy to slip into stealth. I'll stay in stealth, using light to moderate energy, 'till the state of charge drops nearly to half full. Then I'll purposely pulse the gas pedal to wake up the engine, and try to use pulse-and-glide more.

Regarding sitting and listening to the radio with the car off, I've pretty much given up on that behaviour since getting our Prius. But it's not the Hybrid Battery that's being used (at least I don't think so): it's the (diminutive) 12 volt that's employed when the car's off.

It's got a meagre capacity, so I avoid using it as much as possible when the car's off. Our model offers auto-headlights with delayed shut-off. I avoid using them. I also completely shut off the dome and hatch light systems, so they don't go on when doors/hatch are open.

 

At normal, around-town town speeds, with engine fully warmed (or close), with a decent state-of-charge, any time you lift right off the gas, then gently re-apply while taking care to stay to the left of that HSI bar center line, you should be in stealth, ie: engine stopped. The in-dash display showing your mpg graph will show mpg up at the top. (I'm assuming you're in the 'States). Step on the gas a little harder, pushing the HSI bar graph past the middle point, and you'll see the mpg graph react, as the engine starts up.



Note, at highway speeds, do the same behaviours and again that mpg graph will again show bars right up at the top. But in fact the engine will be at least idling (as indicated by a ScanGuage or similar, which can show rpm). I guess the engine's using very little gas though.

Any time you come to a stop (assume decently warmed up) the engine will shut off. Then when you start rolling again it'll stay off, as long as you're to the left of that HSI bar mid-point. I recall our first test drive of a Prius, getting back to the dealership there was a modest upgrade into their lot. I had to come to a near stop, then started fairly slowly up the ramp. I could hear that engine had stopped when I'd near-stopped, then stayed off going up that ramp.

Another case in point for me is a multi-story parking garage we use: I'll pull in with decent charge, reach out to get a ticket, then start spiralling up through the levels. It's at low speed and almost without fail the engine stays off. By the time I park the charge is quite a bit lower, or down to two bars (where the engine is forced to fire up).

 

You're welcome

 

If you want to use the radio or A/C while stopped, put the car in P but leave it in ready mode. The HV battery and engine will maintain the 12 volt battery level. This is NOT accessory mode...make sure the ready light is on. You can do this for extended periods if necessary.​