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Discussion Starter #1
Hi all,
This morning when I started to go to the dealer I purposefully put the car on "hold mode" because I have a factory recall for the battery system.
The ICE ended up roaring most of the way and the energy display shows 11.6 mpg. I don't remember its ever being so bad.
I wonder if it's just because my battery system is malfunctioning and the ICE is trying to charge it. Or the ICE itself is having some problems.
When you put on the hold mode is the ICE allowed to charge the battery aside from the braking system?
 

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You sure you didn't put it in mountain mode? Hold mode will slightly recharge the battery, but the engine should cycle off and run off battery and "hold" the battery SOC ( state of charge, the level ).

Mountain mode will run at 2/3 duty until the SOC is ~ 45%. Then it will act like hold mode.
 

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The ICE should not be charging the battery in Hold mode above the level when you engaged Hold mode. I think that odd experience was due to your battery problem. I have never seen such low MPG from using hold. It is EPA rated at 37, which is pretty easy to get. My worst numbers come from running hold for just a few minutes at a time while the engine is warming up. This happens if I almost make it home on battery, but not quite. And these are rarely below 30.
 

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Your driving style will definitely affect your MPG, just like your range is similarly affected on battery. You will even notice that your remaining gas range fluctuates based on how you are driving while on pure batter. But 11.6 is unusually low, and likely due to your battery issue.
 

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The ICE will only rev up to supply extra demand like longer upgrades and charging the battery buffer when that is used up. Otherwise it will keep a steady low speed rpm that can be felt through the steering wheel. You can feel the engine shut off when coasting to up to a stop light and waiting for it to change to green. I suspect the computer was sensing the battery buffer was depleted (even though it might not have been) and rev'ed up the engine to charge it to no avail.
 

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If you've got a problem with your battery system, and can't tell us EXACTLY what the problem is, it's very difficult to regard any answers about why your fuel economy is what it is are ... imaginary. We'd literally have to make stuff up to answer it. USUALLY a 2013 with tires properly inflated on level ground will get about 50 MPG at 55, 42 MPG at 65 and about 35 at 75. If you're not driving about 90, the behavior of the engine almost has to be related to whatever your battery issue is and the car is trying desperately not to strand you.
 

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How long a drive are we talking here? Cold weather and cold engines lead to bad mileage, and something like that could be perfectly normal on a pretty short drive.
 

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The engine goes through a warmup phase. During this time you're using the battery buffer and the car keeps track. If you're driving hard or at high speed and using the climate control you can draw it down considerably. When the engine exits warmup it begins to supply driving current and begins to replenish the battery to the SOC it remembered when you entered "Hold" mode. If you've been easy on the car rpms are gentle but if the SOC has gotten low then the rpms get pretty high in order to meet the demand.

So in short, it varies, and it's normal.
 

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Discussion Starter #10
The ICE should not be charging the battery in Hold mode above the level when you engaged Hold mode. I think that odd experience was due to your battery problem. I have never seen such low MPG from using hold. It is EPA rated at 37, which is pretty easy to get. My worst numbers come from running hold for just a few minutes at a time while the engine is warming up. This happens if I almost make it home on battery, but not quite. And these are rarely below 30.
I think this post is the most accurate one in diagnosing the problem.
Please refer to my other post:
https://gm-volt.com/forum/showthread.php?327593-The-recall-almost-killed-me
for the details.
 
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