Im sure this is a silly question, but I am about to take a 4 hour drive with my Volt. What would be a good battery strategy? Ive got 3 miles of stop and go to drive before hitting the highway. I figure once I am down to 20 miles electric, switch to hold for the remainder of highway. Ill be going down a decent grade for a couple miles, I figure switch to low but keep it in hold mode. All that downhill would regen into the batteries right? Once back to city stop and go, switch to normal.
About to take my first trip in my 14 Volt, anything I need to know?
1 - 19 of 19 Posts
Use Hold Mode for steady highway driving. Use Normal EV mode for everything else, including any highway traffic.
Also, don't engage Hold Mode with a full battery, since a long downhill grade with a lot of regenerative braking would want to overcharge the battery. I always wait till the battery goes down a few miles before using Hold Mode.
And obviously, use Normal EV mode for the last part of the trip, to make sure you use up the full EV range.
Also, don't engage Hold Mode with a full battery, since a long downhill grade with a lot of regenerative braking would want to overcharge the battery. I always wait till the battery goes down a few miles before using Hold Mode.
And obviously, use Normal EV mode for the last part of the trip, to make sure you use up the full EV range.
Joined
·
131 Posts
I don't think the computer will let the car overcharge the traction battery. But it "might" be good to give it some headroom to take advantage of a long stretch of regenerative charging though.
2014 Volt Premium - Safety pkg 1 and 2, Navigation
Unless you're planning on attempting a long extended climb, you really don't have to do much of anything. Personally when I first got my '13 last year and took my first trip I actually put it in hold right from the get go to maintain as much battery as I could to act like a reserve. The Volt does much better on the highway in gas mode than it does in EV. Any power that is gained through regen is put back into the battery so you will recover some electrons while regenerating downhill. However, your hold set point doesn't increase to reflect the newly captured energy. If the engine turns off because an excess of power is available above your hold point, you will use that extra power before the engine turns back on.
I find driving in D provides sufficient regen for most drops in elevation. Just keep your cruise control set and it will capture as much power without decreasing or increasing speed. If however you find your speed increasing, you can drop into low. My '13 regens to about 13kW at freeway speeds on a decline in D and will maintain 65-70 with myself only. If I have passengers, the added weight does require a drop into L to avoid gaining speed.
Aside from any technique, I would otherwise just recommend the usual steps such as checking air in the tires, fluid levels, etc.
If you choose to keep a reserve in the battery, try to time your arrival and switch back to normal to use the remaining battery for the final few miles to your destination. This will help you minimize actual fuel used while giving you the peace of mind that should something happen to the ICE while driving you aren't stuck but have at least a small reserve of power to proceed either to your destination or somewhere that can help.
I find driving in D provides sufficient regen for most drops in elevation. Just keep your cruise control set and it will capture as much power without decreasing or increasing speed. If however you find your speed increasing, you can drop into low. My '13 regens to about 13kW at freeway speeds on a decline in D and will maintain 65-70 with myself only. If I have passengers, the added weight does require a drop into L to avoid gaining speed.
Aside from any technique, I would otherwise just recommend the usual steps such as checking air in the tires, fluid levels, etc.
If you choose to keep a reserve in the battery, try to time your arrival and switch back to normal to use the remaining battery for the final few miles to your destination. This will help you minimize actual fuel used while giving you the peace of mind that should something happen to the ICE while driving you aren't stuck but have at least a small reserve of power to proceed either to your destination or somewhere that can help.
On the '13 it will not overchange the battery in regen mode. I actually tested this theory on a recent trip to LA coming into Castaic on the 5 south. I had a mostly full battery beginning the descent and filled the last bar about 1/4 of the way down. By about 2/3 of the way down I noticed regen in D wasn't as strong and switched to L. At this point I heard the engine begin to spin up. I turned the mygreevolt app on and noticed the engine RPM field indicated the engine was operating at 3000 RPM, but the meter in the DIC did not reflect engine operation. Apparently the drive train spins up the engine without actually starting it in order to gain additional resistance when the battery is determined to be fully charged. I found that to be an impressive means of preserving battery life by not over charging and quite effective.
This answered my next question. I have wondered what it would do if the battery was full and there was a regen command.
For a trip like that there really isn’t much to worry about. You could just switch to mountain mode when you leave your driveway, the car will do the rest. The red line will show on the battery level the top half turns gray and you will run on EV until you eventually get to the red line, at which point you will effectively be in hold mode. This will leave plenty of head room for downhill regeneration.
Glad I could answer your question. I actually was curious what the car would actually do in the case of high regen on a full battery since it doesn't seem like there is much answer. I read somewhere that it just bleeds off the excess energy through a resistive system. Perhaps some is, but it definitely spun the engine on mine to add additional "engine braking" it would seem. I did notice while in D the regen wasn't as strong once the battery was at 100% usable which is why I decided to drop into L and discovered after about a minute at the higher regen that the engine clearly was spinning as evident from additional noise and confirmed with an RPM reading in the MGV app.
Normally not too many things surprise me, but the Volt definitely has a lot of surprises in how it protects itself and deals with what one might consider abnormal operating conditions.
Joined
·
400 Posts
Drive it to zero EV miles and don't worry about the rest. Done. That's what makes the Volt so great.
Joined
·
10,014 Posts
This^^
There is zero reason to worry about drive modes except play. In ELR, I get a small power boost when the battery is drained. Handy for passing.
Actually, this is a really good point. The best way to maximize EV effectiveness is to use it and not leave any on the table by the time you reach your (beyond EV range) long distance destination. The system will regen and consume any excess energy before running the ICE automatically. This really shows up when you come into populated in town driving. It’s certainly common slow to a stop with regen and the accelerate from top for quite a distance before the ICE comes on again.
I tend to put it into hold mode at 3/4 to 1/2 a charge on a trip way beyond EV range and switch back to normal to use the remaining charge when coming to a place I'll plug in. That's usually back home.
On a trip where I may or may not make it on a charge I just drive and finish in CS mode if I run out.
On a trip where I may or may not make it on a charge I just drive and finish in CS mode if I run out.
There is little to be gained from playing with the modes, and it is a distraction from driving, so I would not recommend playing with it much or having a complicated plan for using the modes. When I go out of town, I switch to hold mode when I reach the freeway, and keep it there until I reach my destination. After that, I let it default into normal mode. This is very little playing, but it does preserve my battery for short trips at the destination.
As for other trip planning, I would air up the tires and make sure you have a plan for dealing with a flat tire, since the car does not come with a spare tire (have the roadside service phone number handy, a tire plug kit, etc.)
As for other trip planning, I would air up the tires and make sure you have a plan for dealing with a flat tire, since the car does not come with a spare tire (have the roadside service phone number handy, a tire plug kit, etc.)
It normally doesn't spin the engine, it works MGA and MGB against each other.
I purposefully went down the mountain with a full battery this summer to test it and log with OBD. RPM zero the entire way.
I suspect your engine running was an unintended consequence of something else - was it exceptionally hot out? If the battery temp is too hot for the AC to control and the SOC Is high, the car will switch to engine operation to protect the battery as best it can (minimize the use of it until it is back in normal operating range)
^this. Even if you wanted to go speeding uphill in the mountains, this would also have you covered.
Otherwise, just drive and do nothing special. Enjoy the smooth ride. Volt is very pleasant for road tripping (I drove 2/3 of the continent and back this summer and no complaints).
Simple mode: Just drive and let the engine kick in once the battery is depleted.
Obsessive-Compulsive mode: Precondition three times before you leave. "Burp" the batter before leaving by unplugging the EVSE and plugging it back in 5 minutes before leaving. Drive on Normal Mode at speeds below 60 MPH and Hold Mode above 60 MPH. Ensure that the downhill stretch has enough battery headroom to capture ever single electron possible. Slow to stops using N to minimize energy losses when using regen. Switch to L when needing to stop faster than coasting. Ensure that ICE stays warm by not allowing it to cool during long stretches in Normal Mode. Overinflated the tires to 45PSI+, drive the speed limit. and draft semi trucks whenever possible. Absolutely ensure you arrive with no battery left.
Difference: ~1 to 2 MPGs. So whatever makes you happy...
Obsessive-Compulsive mode: Precondition three times before you leave. "Burp" the batter before leaving by unplugging the EVSE and plugging it back in 5 minutes before leaving. Drive on Normal Mode at speeds below 60 MPH and Hold Mode above 60 MPH. Ensure that the downhill stretch has enough battery headroom to capture ever single electron possible. Slow to stops using N to minimize energy losses when using regen. Switch to L when needing to stop faster than coasting. Ensure that ICE stays warm by not allowing it to cool during long stretches in Normal Mode. Overinflated the tires to 45PSI+, drive the speed limit. and draft semi trucks whenever possible. Absolutely ensure you arrive with no battery left.
Difference: ~1 to 2 MPGs. So whatever makes you happy...
I'll have to reconfirm. It wasn't hot or cold outside....and it was in the evening. Perhaps it was the MGs operating against themselves but I really thought I remembered seeing the "engine RPM" figure increase to 3000 then drop back to zero when I disengaged L and went back to D. I don't recall what the battery temp was during this so that may have been a factor. All in all though it's quite impressive what steps are programmed into the whole car to preserve itself.
The motors are quite audible when running in this mode - basically both are running at max. Could easily be confused for engine running at low idle.
But seeing RPM on OBD is something else entirely, if that's what happened
I'll have to try to recreate the conditions. I do know it was quite noticeable and I really thought I saw an RPM reading. I was however driving alone and paying more attention to the road than the app and only glanced to see what reading I was getting. I may have just misread.
Joined
·
388 Posts
I start in EV until I hit the highway, about 4 miles. Then I put it in Mountain Mode until I'm within about 25 miles from my destination. .switch back to EV and finish trip with 0 electric miles left.
1 - 19 of 19 Posts
