GM Volt Forum banner

1 - 10 of 10 Posts

·
Registered
Joined
·
179 Posts
Discussion Starter #1
When I turn off the max and eco setting and it displays fan-only, I still see over 3kwh consumption while parked. Both rear or front defrost are also off. When I turn the hvac off, consumption is 0 - .5kwh. I was expecting fan-only to use much less power.
 

·
Registered
Joined
·
4,764 Posts
When I turn off the max and eco setting and it displays fan-only, I still see over 3kwh consumption while parked. Both rear or front defrost are also off. When I turn the hvac off, consumption is 0 - .5kwh. I was expecting fan-only to use much less power.
Check under Settings to see if Auto Defog is set to On. Auto Defog can cause the AC and/or electric heat to come on to clear the windshield.
 

·
Registered
Joined
·
179 Posts
Discussion Starter #3
Auto defog is on but both eco and max are off and display indicates fan-only. Maybe auto defog overrides this without any indication?

I'll turn it off
 

·
Registered
Joined
·
1,265 Posts
Yes -- auto-defog overrides, even in "fan only" mode. I purposefully keep auto-defog ON because I use fan only a lot, but it fogs up the windows in certain circumstances and I don't like always fidgeting with the controls. I have noticed that auto-defog tends to come on ONLY if you have solely the front window vents selected (and not any other).

Depending on temperature, you may also draw energy if any battery temp maintenance procedures are going on.
 

·
Registered
Joined
·
3,718 Posts
Rear window defogger draws quite a bit of power. Certain that it's off? My Gen 1 will apparently turn the rear defroster on during precondition if it's cold enough outside.
 

·
Registered
Joined
·
4,764 Posts
Rear window defogger draws quite a bit of power. Certain that it's off? My Gen 1 will apparently turn the rear defroster on during precondition if it's cold enough outside.
Quite a bit of power for a 12V system, i.e. 13V x 20 amp = ~250W, not a lot of power for the Volt's high voltage system. 250W of power use doesn't even register on the Driver Information Console.
 

·
Registered
Joined
·
419 Posts
...also the 12V battery could be somewhat discharged due to temperature/lights etc and the APM could be throwing many amps into your 12V battery.
 

·
Registered
Joined
·
790 Posts
More than likely it's the HVAC maintaining the battery. If you are in a cold region, it could be warming the pack. If a hot region, could be cooling. I notice that in the summer while driving with fan only mode selected, every so often the AC will come on and the car will start blowing significantly cooler air. I assume this is a side-effect of the battery maintenance/cooling taking place.
 

·
Registered
Joined
·
179 Posts
Discussion Starter #9
OK, I did some testing tonight. I think this confirms it is the auto defrost setting: (ambient 40F)

setting on and plugged in set to fan only - draws +3KW
setting off and plugged in set to fan only - draws -3 KW (the 240v 16a charge rate)

The DIC displaying fan-only is misleading, it should display "fan-only auto defrost on". All this time I was lead to believe no significant power was being used when fan-only was displayed.

Also, checked the rear defrost, when turned on there is no change on the DIC , so I assume its using the 12V battery.

Thanks for the help!
 

·
Registered
Joined
·
4,764 Posts
OK, I did some testing tonight. I think this confirms it is the auto defrost setting: (ambient 40F)

setting on and plugged in set to fan only - draws +3KW
setting off and plugged in set to fan only - draws -3 KW (the 240v 16a charge rate)

The DIC displaying fan-only is misleading, it should display "fan-only auto defrost on". All this time I was lead to believe no significant power was being used when fan-only was displayed.

Also, checked the rear defrost, when turned on there is no change on the DIC , so I assume its using the 12V battery.

Thanks for the help!
Just to clarify, the rear window defroster is powered by the Volt's 12V system but the 12V battery is not supplying the power. The Volt's accessory power system (APS) is a DC-to-DC converter that draws up to 1800W @ ~13V from the high voltage battery. The 12V battery only supplies power during start up of the Volt's systems.

The amount of power used by Auto Defrost varies, just like using the HVAC electric heat and air conditioning. 6kW is probably the maximum draw.
 
1 - 10 of 10 Posts
Top