Here's what happens when you don't use your Chevy Volt gas engine "enough"

[Voltdriver]

Hi All. You have referenced my blog. I was looking at the statistics and saw this URL as a referrer...

To answer a few questions above... The Volt is perfect for me. It actually makes more sense, in a lot of ways, than a Leaf. I make some longer distance trips from time to time (although in the last 6 months, I've only made about 6 80+ mile trips), and having that gas generator is a HUGE benefit. I have also noticed just how much range is affected in 100+ degree heat, and there have been situations where I would have been very nervous driving a Leaf to certain locations, unsure if I would have the juice to make it back. Having that piece of mind that you won't be stranded is great.

While I may be hauling around a small engine I don't need on a regular basis, conversely I have not hauling around another 9kWh of battery that I'll likely not need for daily commutes, so I say it evens itself out.

I don't really care too much about the cycling of the battery. I think most of you know that the Volt, while having a 16 kWh battery, only uses 10 of those for travel. 3 kWh is minimum state of charge (you aren't allowed to discharge to 0 like you are on a leaf) and 3 kWh are used when the original 10 start to not hold a charge. GM has warrantied no more than 30% loss at 100k miles, so I am not caring about the cycling of the battery, or they will replace cells. Plus, given the really high resale value of the car, and that I purchased it when the .9% financing was not available, I should actually be able to sell my car in about 6 months, take more money in to buy a new Volt, and get a lower finance rate.

I've actually traded my Volt with a Leaf owner for a day, and while the Leaf is a nice car, I wouldnt trade my car for it. I think the Volt is superior in every way, except having that 5th seat and a little extra leg room in the back seats.

During maintenance mode, the car just runs the engine to essentially kick the rust off. Fuel maintenance mode is completely different, and if your fuel gets old enough, it will force you to burn it so it won't go stale.

I have a lot more stuff at voltowner.blogspot.com. Feel free to ask me any questions.

[HydroJim]

Still confused as to what maintenance mode is for. I'd imagine the oil would all flow down to the bottom of the engine, and that the rubber pieces on the car would start to dry out, but you would think something like that would be done every week or so not 45 days?

[Diesel_Dave]

I suspect the "maintenence" has to do with oil films too. Many of the internal parts (camshaft, crankshaft, etc.) are steel I assume. When an engine shuts down, a thin layer of oil is going to cover all the wear surfaces. As the engine sits, however, that oil will slowly drain down, eventually leaving spots where the metal surfaces will be unprotected, potentially opening the door for rust to occur. I suspect that's a major part of the "maintenence".

Machinery, in general, doesn't like to sit idle for a long period of time. You can take an old beater car and drive it to work day after day without problems, but park it for a couple months and then go try and start it and you'll be suprised the problems that often arise.

[Voltdriver]

well, I think it is likely built a little more like a generator, and less like a normal engine. Generators sit idle for long periods of time, but are reliable and last a while. Will I get the same mileage out of this engine compared to an engine I exercised everyday? No. When I have 100,000 miles, and my engine has been running for less than 10k miles, do I expect a problem? No.

Still confused as to what maintenance mode is for. I'd imagine the oil would all flow down to the bottom of the engine, and that the rubber pieces on the car would start to dry out, but you would think something like that would be done every week or so not 45 days?

All it does it run the engine, instead of discharging the batteries. Its like driving the car beyond its electric range. The engine kicks in. Same there here, except it doesnt wait for a discharge.

By the way, I've only managed to get this 1 time. I went about 2800 miles without using any gas. Then we had a cold snap come through, and about .1 gallons ruined the streak. I have made a point to try to give the engine some good time to operate about once every month when I take it to the lake, instead of my wife's CRV.

Come winter time, it will be running every day for a couple of miles or so. I get about 30-34 miles of range in the winter, and my commute is 35 miles each way. This is just a summertime problem

[user removed]

I would think about keeping fuel in a sealed container and not filling the tank if I was going to drive without using any gasoline for extended periods of time. Add some fuel, say a couple of gallons a month to keep the mix as fresh as you could. Once you have a feel for your monthly consumption then you could just add enough to keep the fuel in the tank fresh to avoid problems due to fuel degradation.

That being said the fuel in my Altima sat for over 10 months between when the car was totalled and when it made it back on the road. I was concerned about the potential fuel degradation, but apparently the evaoprative emissions system does a good job of preserving the fuel quality.

Probably not a bad idea to take the Volt out for a higher speed trip every 3 months or so. You don't want psitons to not move at all for months on end, potential for surface corrosion on the cylinder wall in a cylinder that stopped with the exhaust valve open.

regards
Mech

[Daox]

I wouldn't be too concerned with old gas. I've fired up vehicles sitting with the same gas that is easily 2-3 years old without any issues.

[3-Wheeler]

Originally Posted by Old Tele man

...yeah, but here in Arizona, the Leafs have been "wilting" in the summer heat (pun intended)! Apparently cutting battery "life" the half or less!

I can 100% agree with that!

Typically, my li'l Insight HV battery is trickle charged every night, just before driving to work in the morning.

With all the heat we've had this summer in Wisconsin, my range has dropped probably close to 40%, maybe more.

Now at this point I'm not sure if this is attributed to the heat or some cells getting much weaker.

Will keep an eye on things and see what happens when it gets cooler this fall.

EDIT: My hunch is cells degrading.

Jim.

[Voltdriver]

GM recommends keeping your tank at about 3 gallons if you rarely use your engine. The system is pressurized and closed (no venting). Preserves the gas. This is my current savings chart. As you can deduce, depending on your circumstances, the payback period on the car can be pretty quick.

It won't let me link this due to my post count. Paste this in your browser.

[MetroMPG]

Voltdriver - thanks for chiming in & answering questions!

3-Wheeler - the Insight monitors cell temps, and restricts assist & regen if it gets too high. (I'm sure you know this.) That could be part of what you're seeing.

[Voltdriver]

BTW. I stayed away from it, but the Leaf having problems in Arizona helps illustrate one of the key differentiators between the 2 cars.

1) The Volt has an liquid cooled battery, in which the fluid is either warmed or cooled and circulated around the battery to keep its temperature in an acceptable range. This even happens when the car is in a parking lot unplugged. The Leaf, however, does not have this system and is strictly air cooled. A big help in minimizing battery degrredation to heat.

2) Leaf owners are allowed to fully charge and fully discharge their batteries. As previously stated, GM only allows the owner access to 10 kWh of 16 total. You aren't allowed to discharge the battery to empty. And since there are reserve cells, the range of the Volt will be constant for a longer period than a Leaf, as reserve cells come online when original cells degrade.

3) People in a car like a Volt dont have to worry as much about battery degredation. As their EV only miles diminish, they can still drive on gas. Not ideal, but in my case, it may change me from getting 800+ MPG to around 200+.