Mountain Mode?

[honoreitiscom]

OK I know the point of Mountian mode is to prepare for a long up-hill run so it will conserve more battery juice to help you get up that hill. But does it only work if you go in to mountain mode before the batterty range has dropped to 0? I went into Mountain mode today while on the highway with battery at 0, and I expected the battery range to grow but it never did.

[Stilgar99]

OK I know the point of Mountian mode is to prepare for a long up-hill run so it will conserve more battery juice to help you get up that hill. But does it only work if you go in to mountain mode before the batterty range has dropped to 0? I went into Mountain mode today while on the highway with battery at 0, and I expected the battery range to grow but it never did.

I believe it RESERVES charge....it does not create it...

Stilgar

[Rusty]

I went into Mountain mode today while on the highway with battery at 0, and I expected the battery range to grow but it never did.

I posted on a Mountain Mode test I did today (on an actual mountain) here. Yes, that's the behavior I saw. There was no indication of increased energy stored in the battery. When I switched from MM to NM the car continued on, running purely from the battery, for about 10-15 miles - even though it showed 0 range in the battery. The gas range errily crept UP over those miles as I headed back down the hill.

I've also tried the MM to NM mode on flat terrain, but this time turning the car off to make the switch. When I turned it back on? It had EV range... I think not showing the extra battery during MM is no big deal. But I think it should show the battery range available after a switch back to NM.

[Rusty]

And I found another abuse method for mountain mode this evening. We're starting our 3000 mile driving vacation tomorrow morning, and I wanted to gas up tonight so I wouldn't have to bother in the morning, and I was already running CS. In order to have a full tank in the morning I hit Mountain Mode when I left work. Around 10 minutes later pulled into the gas station (first time) and filled up.

Started the car again, and now I had 7 miles EV range to get home from the gas station without burning any of tomorrow's fuel :-)

Don't get me wrong, MM abuse burns through gas. So using it probably always (or almost always) hurts overall MPG performance. But it does seem to have some interesting possibly unintended uses.

Tomorrow I use it for what it was intended for. Biggest climb of the trip is about 30 miles from home, a ~4400' 15-20 mile climb. MM with a full charge straight from home won't burn any extra gas, as it'll just start running like normal CS mode sooner. Then I'll go normal mode either at or a bit before the first summit. No worries!

[ClarksonCote]

I've turned on mountain mode with 0 miles in the battery, and I'm pretty sure I saw some energy get put into the battery. The battery icon will still show 0 miles until you gain some meaningful amount of energy AND switch back out of mountain mode. It may take some time, which is why they say to do that at least 15 minutes prior to the mountains.

I noticed the engine revving higher than usual, and also the engine revving when my vehicle was stopped. So I'm pretty sure it does put energy back in, it just may take a long time to see that reflected on the battery/energy screen on the center display.

[kmoore]

I thought MM, if left on indefinitely, will get the battery back to about 45% SOC. And if you engage MM above 45% SOC, it won't actually run the ICE.

[hodginator]

I was curious about MM mode as well. I ran my batt to 0 then changed to MM and let it run until the engine turned off. When I switched to NM (after stop/start I believe) it read 10 miles of range on the batt.

Do date I haven't actually needed MM, but I've only had the car since Tuesday.

[ClarksonCote]

I thought MM, if left on indefinitely, will get the battery back to about 45% SOC. And if you engage MM above 45% SOC, it won't actually run the ICE.

That's my understanding too, and seems to match my observations.

[Rusty]

And if you engage MM above 45% SOC, it won't actually run the ICE.

That's my plan today. Start off in MM, let the SOC coast down from full charge to 45%, then run MM up the hill maintaining 45% to near the top. Should work well for me, since the mountain I'm hopping today happens to be fairly nearby.

[Jeff N]

I thought MM, if left on indefinitely, will get the battery back to about 45% SOC. And if you engage MM above 45% SOC, it won't actually run the ICE.

That's probably an obsolete percentage now that the Volt uses a 65% SOC range instead of the original 50% they had talked about in the past.

GM has said that MM adds an extra 15% to the minimum SOC (which means adding around 2.4 kWhs). Although GM has said they now utilize 65% of the native battery capacity when the car is new I think they have declined to state the specific upper and lower absolute SOC percentages. That means that the lower SOC is probably now 20-25% and MM changes it to 35-40%.