GM Volt Forum banner

Gen 2 Hold Mode -- weaker "grip" than Gen 1?

6755 Views 45 Replies 22 Participants Last post by  MikeyCVolt
My early impression--subject to revision--is that my Gen 2 does a worse job "holding" EV miles than my Gen 1 using it on the same commute.

I can't figure out if Gen 2 tries to "get back" to the held SOC setpoint, especially if it requires battery power beyond the ICE alone. On my Gen 1, the ICE (mostly) added charge to maintain the HOLD setpoint--but it also operated in a serial hybrid capacity. On my Gen 2, it seems that whenever it needs battery + ICE (like hard acceleration), it doesn't try to "replace" it. Maybe a characteristic of the parallel hybrid setup? Or maybe it tolerates more deviation?

It seems this member also noticed this issue on a 2000-mile trip where he used "hold" the whole time and lost half his EV miles.

What's going on here? Is the battery just augmenting the ICE in Hold mode? Do I need to drive within the (lower) power demands of the ICE alone in hold to avoid drain? Under what conditions (if any) will Gen 2 maintain the Hold setpoint?
1 - 5 of 46 Posts
No question the G2 in Hold mode will use battery whenever it needs it for hill climbing, or acceleration. Eventually the engine will attempt to replace some of that, but there don't seem to be any guarantees about how much will get replaced. If you are low on charge and need more of it for later, I suggest MM instead of hold to put some juice back in the battery. Otherwise in Hold mode you are susceptible to losing some.
I hate to sound like a broken record bringing this up so often, but using the ICE to add juice to the battery is horrible for efficiency; especially if the ICE is also moving the car at highway speeds. If you need the battery buffer because you are driving in the mountains, then that's fine ... and that's what Mountain mode is for. Otherwise I'm happy to trade electrons to keep the ICE operating at an efficient RPM/load range.

Obviously it's helpful to discuss differences between how the Gen 1 and Gen 2 operate under Hold mode and how the Gen 2 is less emphatic in keeping the SOC at a particular point so folks can manage their SOC for their desired outcome, but for almost any situation that I can think of, it's an improvement for the Gen 2 to be more aggressive in dipping into the battery while in Hold mode and an improvement that the Gen 2 waits for favorable conditions (deceleration, downhill, etc) to replace that charge.
No doubt that the implementation in G2 is an improvement. The bottom line is that the car needs it's battery under just about all circumstances. The concept of Mountain Mode is really a misnomer and designed to get someone thinking about this in the appropriate way. But the best way to drive the car is in Hold mode with a good deal of battery available for when it's needed (mountains or otherwise). If you are running low on battery, MM is there to help build it up -- since you need it all the time.

Reference the backfire issue in Hold mode when you have no battery left, it wouldn't surprise me if the engineers knew about this all along. The car can optionally run on engine, but it MUST have battery available all the time. If you are going on a long trip, be it to the mountains or the beach, you need to keep some battery in reserve. And if you run low, kick it into MM.

This highlights another point I've supported: that this car is not designed to be driven blindly.
It's an amazing car and for me, playing with the "system" to try and maximize EV miles is a great way to pass the time on longer trips. I always use "L" and I always try to arrive back home with as close to 1 or 2 EV miles left. The Volt is like a "teaser" vehicle for folks that aren't sure about a pure BEV. Once you experience electric only driving you really can't wait to get a pure BEV.
No disagreement there. That's why this car is not for the average clueless driver. Also, if you are a one car family, the Volt still makes sense over a pure BEV.
Works just the same for the average clueless driver. If you don't care about stuff, the only difference is "plug it in when you get home", and that's it. And the clueless will still get like 95% of the efficiency, performance, etc. that someone that obsesses about every detail of tire pressure and Hold Mode timing and when to use L instead, just by driving it as though it were any other car. The improvements available from fussing over things are so small, they barely matter. Even getting five miles of extra EV range amounts to, over the course of a commuting year, about fifty bucks in gas, if and only if you're already commuting enough to actually use up the whole range. Which most people aren't.
You have a point. The average clueless driver would barely notice the constant backfires anyway :)
I don't really agree with this. I'm guessing you probably have a Gen 1; the Gen 2 is designed differently and can really be driven as a normal hybrid without ever being plugged in or paying attention to the battery at all. Of course, why not charge it when you can? But in the Gen 2, the ICE should have plenty of power for climbing a mountain even with the EV range completely depleted. The engine is just as powerful as a Prius, and a Prius doesn't have any concept of mountain mode or anything.
I actually have a G2 ;) And while I enjoy my car immensely, between my own experiences and what I read on this forum, I appreciate the car's limitations. And I firmly believe that those limitations are represented in the delta between Prius sales and Volt sales. Chevy's plan was to build a capable electric car with additional range. Toyota just wanted to sell lots of cars to their known demographic of clueless drivers looking for reliable (and efficient) transportation. Much as it wouldn't be my choice, going forward I suspect we may see more and more cars in the Prius/hybrid mold, whereas the Voltec may ultimately disappear.
1 - 5 of 46 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.