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Discussion Starter #1 (Edited)
It seems the ICE comes on at around 30% batt ..... If at that point your driving habits are allowing a charge, not just supplementing the drive....
When would it "shut off" ?
If the Batt reaches 50%? does it leave the ICE running & try to get all the way to 100%?
 

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It never goes to 100%, it is meant to stay between 20~30% to 70~80%. The battery will last longer if it stays betwen these numbers. my guess is the ICE will dhut off at 70% unless there is a driver override.
 

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The idea is to keep the batteries at a healthy state of charge with as little gas as possible. Why use the range extender to fully recharge the batteries when you can just plug in?
 

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I hope GM gets the hardware and/or software right so that it is almost impreceptable when the ICE shuts on and off. My ride in a Prius today was very enlightening about how poorly Toyota implemented this part of the Prius.
 

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I hope GM gets the hardware and/or software right so that it is almost impreceptable when the ICE shuts on and off. My ride in a Prius today was very enlightening about how poorly Toyota implemented this part of the Prius.
The advantage GM has with the Volt in this case is that since the drive is all-electric all the time, there's no mechanical shock to manage such as when the Prius shifts between drive modes. GM will just have to manage the NVH of engine start and operation, and since the small engine's connections to the car can all be isolated (soft mounts, dampers, etc) it should be a pretty smooth, quiet experience.
 

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I have owned two Lexus hybrids [2007 RX400H & GS450H] and I had a hard time telling if the RX engine was running but I could never tell if the engine was on or off with the GS. Lexus has a dashboard display to let you know what the engine is doing. The Toyota has a`4 cylinder engine and both of the Lexus have a 6 cylinder. The GS is more expensive and powerful than the RX so maybe they put more effort in keeping the GS quiet.

I have never been in a Prius so I can't compare the two systems even though they are almost the same with a larger engine in the Lexus
 

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But the subject was considered regarding a driver override to allow the driver to top off the battery well above 30%, perhaps up to 80% if the driver was approaching a mountain with a long steep climb. There was also a suggestion of having it tied into a GPS that would tell the computer to start topping off the battery so you cold have maximum assist on a long climb
 

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Discussion Starter #9
silvercorvette guesses that the ICE will shut off when batt hits around 70%.

Joshua Bretz seems to indicate the ICE can't charge the battery at all, but simply maintains the aprrox 30% state.

It is my understanding that the ICE, once activated at 30%, can & will add charge to the battery under many driving conditions, .. but it is still unclear at what state, or % of charge, will cause the engine to then shut off ...
 

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We'll just have to wait and see what the engineers come up with. My guess is by default it'll keep the batteries at 30-35% and there will be other modes for uphill driving etc.
 

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We'll just have to wait and see what the engineers come up with. My guess is by default it'll keep the batteries at 30-35% and there will be other modes for uphill driving etc.
But the reason for the charge not to go below 20~30% is to extend battery life. If the ICE needs to raw power from the battery to get up a long steep hill and it allows the charge to drop way below 30% battery life will be reduced. I would guess for the sake of extending battery life it would be better to have a driver override to et the battery up to 70% before starting a long steep climb.

I am assuming that the ICE alone will not have the power to climb a long hill and a battery assist will need needed.

The reason for the asumption is the ICE that was chosen by GM is only slightly larger than a Honda or Harley motorcycle engine, so I can't believe the ICE alone will be able to get a car with 4 people up a mountian
 

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silvercorvette guesses that the ICE will shut off when batt hits around 70%.

Joshua Bretz seems to indicate the ICE can't charge the battery at all, but simply maintains the aprrox 30% state.

It is my understanding that the ICE, once activated at 30%, can & will add charge to the battery under many driving conditions, .. but it is still unclear at what state, or % of charge, will cause the engine to then shut off ...
Joshua isn't saying that it CAN'T charge the battery, he's saying that (based on the powerpoint slide in his posting) the ICE is currently planned to be programmed to charge the battery for a while when the state of charge falls below a preset limit (let's call it 27%) until it reaches say 33%, then the ICE will shut off. That's the squiggly line in the chart, where the ICE charges is up a bit, you drive along and consume energy stored in the battery, and the ICE will start up again to charge up to whatever its cutoff point is.

I can see why they'd do this, and I can also see the point of people wishing for a way to tell the ICE to stay on, consuming more fuel than its software thinks it should, so they can build up charge for a long climb. If no such an override is be provided by GM, I'm sure some hacker will start working on it as soon as the Volt hits the streets.
 

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Hard to find a long enough extension cord when you're on the road.
You're missing the point. The range extender should keep the batteries at a healthy state of charge using as little gas as possible. The whole point of the volt is that it's electric, you get your power from the grid, which is way more efficient than an ICE.
 

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Discussion Starter #16
Joshua isn't saying that it CAN'T charge the battery, he's saying that (based on the powerpoint slide in his posting) the ICE is currently planned to be programmed to charge the battery for a while when the state of charge falls below a preset limit (let's call it 27%) until it reaches say 33%, then the ICE will shut off. ........"
I wonder if this will actually be the case, since it would "seem" that the ICE would be constantly on/off cycling "too often" in such a narrow on/off range (27-33%), as well as causing the car to stay way too close to the "critical low levels" on a long trip ....
I would think that at least 38-44% would be a safer top end "off" point.
 

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City street parking

Range extender maintains ~30% SOC - chart explains all:

In the chart the car is parked and plugged in at some point, being a city driver and hoping to park on the street some times, the question is will the ICE charge the batteries if they reach the low threshold overnight and away from a plug in source?
 

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Off line charging

Thanks,

My understnading of the technology is the motor is never actually attached to the wheels, but only charges the batteries... I don't see it as problem, but as a solution that would maximize the battery use and life.
 

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Discussion Starter #20
Thanks,

My understnading of the technology is the motor is never actually attached to the wheels, but only charges the batteries... I don't see it as problem, but as a solution that would maximize the battery use and life.
According to most of the info here ... the motor actually rarely charges the batteries, & only as a secondary function. The primary job of the motor (ICE) is to supply electricity for driving, when the car is in motion/on and the batteries have fallen to the depletion point, & to hold the battery's charge state at ,or just above, that depletion point..
The questions that arise in this thread are wondering what sort of "user overrides" will be available for people who WANT to turn on the gas motor to more fully charge that batteries, for various reasons ....
 
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