Mountain mode.

[kellybill52]

Just curious if anybody have tested running your car on depleted battery running on gasoline constantly on mountain mode regardless of were your going. Would this charge your battery back to full charge and would it be cost wise fuel efficient?

[saghost]

Just curious if anybody have tested running your car on depleted battery running on gasoline constantly on mountain mode regardless of were your going. Would this charge your battery back to full charge and would it be cost wise fuel efficient?

No, and no.

First of all - mountain mode doesn't necessarily recharge your battery. What it does is set the car's target battery state of charge 3.5 kWh higher - thus, if you enter mountain mode before getting to ~14 miles of range remaining, the only thing that happens is the engine comes on earlier. If you enter mountain mode with less than that remaining (like after the battery is drained,) the engine will recharge the battery up to that 3.5 kWh point - after which it stops charging the battery. There is no way to completely recharge your battery using mountain mode, even if there were some reason to want to.

But remember TANSTAAFL. Those electric miles aren't "free since the engine's running anyway," as some people seem to assume. To build those miles, the engine has to run longer, at higher RPMs, or both compared to what the engine would have done otherwise. This burns more fuel - about as much fuel as it would take to drive that distance on gasoline (might be a little more or less depending on the exact circumstances you're driving in.)

So for rough costs... the partial charge from mountain mode is 3.5 kWh from ~1/3 gallon of premium gas - call it $1.25 at typical current prices. 3.5 kWh from the wall - call it 4.5 with charging losses, at around $.13 per kWh typical any time of day rates - is a little under $.60 - less than half the cost. Except in places with tiered pricing and high marginal tier rates, or places with a shortage of plugs/wall power (like our off-grid solar users,) there's no argument for charging with gasoline. (And the places with high tiered rates mostly have special EV TOU plans available at much lower prices.

[Neromanceres]

It will not fully charge the battery.

It will try to build a charge to a higher charge sustain buffer state. Close to 40% I believe.

[Fulgerite]

I only charges the battery back up to about 35%... Then it just maintains the battery at 35%. The ICE will never charge the battery above 35%. As for economy... No it would be a waste of money. For example... In Los Angles where I live... I can charge my volt up for about 60 cents to drive 40 miles. A gallon of gasoline which also pushes the Volt about 40 miles costs me $3.85.

It's over 6 times more expensive for me drive the Volt on gasoline than Electric power.

[caronjeff]

I find mountain mode useful for those times the charge is low, I engage it during the 50MPH cruise into the City. When I'm in the dense stoplight to stoplight area then its back to normal mode and all EV for about 8-10 miles of quiet driving. Mountain mode will build up that 8-10 mile reserve, and yes it does burn way more gas than normal CS driving.

[Red Volt]

I recently took a 3600 mile trip, where charging was limited. I kept it in MM, and no it doesn't recahrge. Maybe this weekend I'll finally so a post with some fun numbers.