GM Inside News Forum - View Single Post - IL Corrects Volt Story: Batteries Will NOT Charge When Driving; GM Website Differs

rob2299usa · 09-24-2008, 12:43 AM

Wow... ok, there is a ton of misconceptions in this thread. Ok here's my try at explaining this:

On ANY E-REV vehicle the point is to MINIMIZE fuel usage. You never want to use a drop of fuel more than you need to. For this reason, the gas engine in the Volt will be used only to maintain the minimum state of charge of the battery (in this case 30%). Charging the battery off of gasoline energy is not only less efficient than plugging it in, it completely defeats the purpose of this vehicle. Ideally you want to arrive at your destination with the batteries fully depleted so that you can maximize your off the grid energy usage.

The other point is battery life. You never want energy from the gas engine going "through" the battery. Not only are you suffering losses in energy due to the battery heating up (ever felt your cellphone or laptop battery after a good charge??), but you would also be needlessly cycling the battery. We should all know that batteries have a finite amount of charge/discharge cycles from our cellphone and laptop batteries dying after 6 months or whatever. It is MUCH more efficient to power the drive motor directly off of the energy coming from the generator connected to the gas engine.

Also, whoever said that "once you get to 600 miles your trip is done before you plug in again" is dead wrong. As long as you keep gasoline in the tank, the car will be able to continue to drive. Doing this often, however, would be stupid because then you're not taking advantage of the cheaper electric energy.

The author of that article does not know what he's talking about. Typical media... they just have no grasp of technology like this. The battery once depleted is not 400 lbs. of uselessness. It will be used as a buffer for high demand situations where additional energy is needed than the engine can provide, and it will also be used as a energy storage medium for regen. Theoretically you could regen enough if you were going down hill to kick back into engine off / ev mode so I would assume it will work something like that.

09-24-2008, 12:43 AM	#35 (permalink)
rob2299usa 2.4 Liter SIDI ECOTEC Join Date: Jul 2004 Location: Metro-Detroit, MI Posts: 217	Re: IL Corrects Volt Story: Batteries Will NOT Charge When Driving Wow... ok, there is a ton of misconceptions in this thread. Ok here's my try at explaining this: On ANY E-REV vehicle the point is to MINIMIZE fuel usage. You never want to use a drop of fuel more than you need to. For this reason, the gas engine in the Volt will be used only to maintain the minimum state of charge of the battery (in this case 30%). Charging the battery off of gasoline energy is not only less efficient than plugging it in, it completely defeats the purpose of this vehicle. Ideally you want to arrive at your destination with the batteries fully depleted so that you can maximize your off the grid energy usage. The other point is battery life. You never want energy from the gas engine going "through" the battery. Not only are you suffering losses in energy due to the battery heating up (ever felt your cellphone or laptop battery after a good charge??), but you would also be needlessly cycling the battery. We should all know that batteries have a finite amount of charge/discharge cycles from our cellphone and laptop batteries dying after 6 months or whatever. It is MUCH more efficient to power the drive motor directly off of the energy coming from the generator connected to the gas engine. Also, whoever said that "once you get to 600 miles your trip is done before you plug in again" is dead wrong. As long as you keep gasoline in the tank, the car will be able to continue to drive. Doing this often, however, would be stupid because then you're not taking advantage of the cheaper electric energy. The author of that article does not know what he's talking about. Typical media... they just have no grasp of technology like this. The battery once depleted is not 400 lbs. of uselessness. It will be used as a buffer for high demand situations where additional energy is needed than the engine can provide, and it will also be used as a energy storage medium for regen. Theoretically you could regen enough if you were going down hill to kick back into engine off / ev mode so I would assume it will work something like that. Last edited by rob2299usa : 09-24-2008 at 12:47 AM.