Utility mode

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SkookumPete

SkookumPete

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I got to wondering today what practical difference there is between Utility and Run modes, other than the former ensuring that nobody drives off accidentally. When the manual says, "The high voltage battery is used instead of the 12V auxiliary battery for operating the convenient features of the vehicle", isn't this the same as the normal way the two batteries are linked to maintain the 12v system when the car is running (i.e. not in ACC)? The draw on the traction battery doesn't seem to differ between the two modes.

So you're spending an hour looking at the moon over the water, toasty warm and with your favourite crooner on the sound system. Is there any reason to prefer Utility Mode to just leaving it in Park, with the brake engaged to turn off the running lights?
 
Yeah, the little green car in the dashboard will draw a microamp, which will give you about a second more standby time since it is not illuminated. [emoji44][emoji1787][emoji2957]
 
SkookumPete said:
I got to wondering today what practical difference there is between Utility and Run modes, other than the former ensuring that nobody drives off accidentally. When the manual says, "The high voltage battery is used instead of the 12V auxiliary battery for operating the convenient features of the vehicle", isn't this the same as the normal way the two batteries are linked to maintain the 12v system when the car is running (i.e. not in ACC)? The draw on the traction battery doesn't seem to differ between the two modes.

So you're spending an hour looking at the moon over the water, toasty warm and with your favourite crooner on the sound system. Is there any reason to prefer Utility Mode to just leaving it in Park, with the brake engaged to turn off the running lights?
Click to expand...
I do this on a regular basis, even without the moon.
 
Well, the inverter and power steering being enabled are obvious differences. Add DRLs if the parking brake is not engaged.
 
KiwiME said:
Well, the inverter and power steering being enabled are obvious differences. Add DRLs if the parking brake is not engaged.
Click to expand...
Wouldn't the inverter and power steering only draw current if initiated by the driver? If sitting without those calling I would think it would be approx the same.
 
That surprised me as well when I first tried utility mode a year back. I checked it now and it stayed on for over 6 minutes but I know from other times using it that it does eventually give up. Torque Pro works too but doesn't show anything surprising. I could not get the current to spike by flicking the steering wheel, no idea why. LDC output power (just V x A in excel) settles to around 190 watts once the aux battery finishes accepting the bulk of a charge from the 14.8 V system voltage, and that was reflected on the media system's power draw menu.

utility mode.webp
Horizontal axis ticks are 5 seconds.
 
KiwiME said:
That surprised me as well when I first tried utility mode a year back. I checked it now and it stayed on for over 6 minutes but I know from other times using it that it does eventually give up. Torque Pro works too but doesn't show anything surprising. I could not get the current to spike by flicking the steering wheel, no idea why. LDC output power (just V x A in excel) settles to around 190 watts once the aux battery finishes accepting the bulk of a charge from the 14.8 V system voltage, and that was reflected on the media system's power draw menu.

View attachment 7646
Horizontal axis ticks are 5 seconds.
Click to expand...
Curious to see this graph parked in "run" mode w/ the emergency brake engaged (DRLs off) to see turning the steering wheel activation actual influence on the LDC power. (After the 6 minute settling period);)
 
I spent a little bit of time on this today. Between the various modes of Run PB on DRL off, Run PB off DRL on, Run PB off DRL on and in D or R, and Utility, I couldn't see any large differences until I allowed the car to roll and even then it only went up about 100 watts. I didn't have the patience to wait for the PS to go to sleep and I suspect that's where Utility mode might have an advantage, aside from the safety aspect. I'm fairly sure that the dash and media centre remain alight for the duration. Power steering movement did cause small spikes in the current if persistently held off centre.

Next I just did a few minutes in each mode with the PB on.
I'll post the graph with the disclaimer that there is a lack of data credibility because LDC output power appears to be higher than the power supplied from the traction battery. What I have is 5 second logging with a few minutes in Run mode at the start and a few minutes in Utility following. LDC output power is calculated in Excel by volts x amps. Traction battery output power is direct from TP and usually matches well with the dash readout. Because of the noisy nature of the data, I used a running average over 10 samples using an Excel trendline, and those lines are on bold while the source data are the fine lines. About all that can be seen is that LDC output is constant in both modes and traction battery load drops in Utility. If one were to assume that at least one data source has only a scaling error then we might be able to conclude that something is not drawing power from the traction battery in Utility mode. But I would not trust the data at this point.
This was done just at the end of an 'aux battery saver' charge event so there are no initial conditions to ignore.

RUN vs UTIL.webp
 
Yeah, the traction power looks sorta jumpy, so you might have a
granularity problem and rounding is throwing things off at such
low levels.

_H*
 
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