There isn't much driving to report about today. Our 2007 Chevrolet Tahoe sat in the garage most of the day, for the previosly stated 3rd-seat reason. Dad and I did take it down to the beach for a few sunset photos. What could go wrong?
In an attempt to get "the look" I wanted, I put the headlights on...
Climbing in to fend off the cold while the jumpers cables arrived, I became obssessed with conserving power to save up for another try. When we opened the doors to climb into the truck, the navigation system began making disc access noises - and consuming power - even though the non-smart key was still in my pocket. This seemed to go on for two minutes until it finally figured out I wasn't going to start the truck and put itself back to sleep. This activity can't account for much juice, but I wonder what other parastic electrical demands are in play. Still, it's my fault. I should have left the motor running, and I shouldn't have overridden the headlight minder.
But I haven't heard navigation system disc acceess noises as loud as this one in other cars. Maybe all systems "pre-load" the map software - my unconfirmed theory - when a door is open so it's all booted up when the engine is fired. Maybe this one's just a bit noisier than others. For instance: Earlier in the trip, and on more than one occaision where we were stopped at signals, my wife had asked, "Do you hear dogs barking somewhere?" I couldn't understand what she was talking about until we realized it was this disc accessing noise.
All in all, it's a minor gripe. We're really enjoying the Tahoe. After last summer's Jeep Commander trip and 5 years of Land Cruiser experience before that, my wife was expecting to hate the ride. She doesn't. It's actually been quite smooth and quiet most of the time, and feels better planted than the Commander had on the same winding roads. And the four of us have plenty of space for ourselves and the junk we want to keep nearby. The wisdom of employing a column shifter, with the resultant gain in center console storage, is not lost on this crew.
Day 7 tally: About 15 miles driven, no fuel added
Dan Edmunds, Director of Vehicle Testing @ 4,692 miles
thebigal says:
09:19 PM, 12/30/06
I have to wonder why the battery went dead? Did you leave the ignition on and the lights on? Otherwise I wouldv't thought that a 50K Tahoe had a battery saver feature that cuts all power draining devices after a set amount of time - such as the lights "accidentilly" being left on. Or at least has a run-down protection that will always ensure enough juice to start the vehilce. I know that my 6 year old S-10 has it as well as my 2 year old base model Impala. If I leave the lights on - interior or exterior, the car shuts them off after 20 minutes or so. How long did you leave the lights on? If it was only for a few minutes I find it strange that the battery went dead. But then again, it is a factory Delco battery probably and only has the "required" amount of CCAs. I have replaced at least in my truck the factory battery with the largest battery I could fit into the engine bay and still properly bolt down. I have never had a problem since - even after running the subwoofer for 20-30 minute stretches with the ignition off, or the headlights on with the ignition off. I still find it strange though the battery went dead....
Come to think of it, the only lights I have ever left on in either of my vehicles have been interior lights. I have often forgotten to turn off the dome or map lights after using after the ignition is off. I'll then exit the vehicle and since they have a timed delay to turn off I often don't wait to see if they turn off, hence they stay on. But the since the vehicle turns them off after 20 minutes, I have never had a problem. I have never tried it with the headlights since both vehicles have auto headlights and I rarely manually switch them on. Plus the vehicles ding like crazy if the exterior lights are left on reminding you to tun them off. Maybe I'll see what happens if I leave the headlights on for 20 minutes and see if the vehicle shuts them off for me???
thebigal says:
10:01 PM, 12/30/06
okay - results of my test. Your dead battery got me to thinking so I went and just did a little test of my own with both vehicles. I turned the headlights on in both vehicles and left the ignition key out. I closed and locked the doors as if I had gone to town and accidentally left the lights on. The Impala had turned the lights off when I went back 20 minutes later. When it did it, I don't know since I didn't watch and time it. (That would be like watching water boil :D) The truck had not turned the lights off. The truck does however shut off the interior lights when left of though. However, I may have flawed my own test since when I turned the trucks lights on, I also turned the dash lights all the way off the shut off the constant dinging. The truck dings when the ignition is off and the lights are left on, but the ding quits if the dash lights are turned all the way off with the dimmer switch. The Impala only dings if the door is opened, the ignition off and the lights left on. So I wonder if by dimming the dash lights, I bypassed the battery-save feature, since I deliberately turned down the dash lights??
Who knows.... it just goes to show that if a base model sub 20K GM vehicle can have this battery save feature, shouldn't a 50K almost fully loaded GM vehicle also have this feature? Unless it wa somehow defeatable like my truck possibly is. Maybe I'll have to re-run the test in my truck just to see if I had indeed defeated it....
priuscrusher says:
11:44 PM, 12/30/06
I'm not gonna reread the post but i think he said he turned off the feature.
editor_karl says:
10:14 AM, 12/31/06
Another dead battery in a late-model GM car...in well under an hour. This happened to me two weeks ago in an XLR-V. Less than 45 minutes of sitting in the car while evaluating the interior (and the headlights weren't on, just the parking lights) and suddenly the message center is flashing "low-voltage" and when I try to start it I get nothing. I was driving old Mopars before I had my license 22 years ago, and those cars have horrible charging systems. However, assuming the battery was less than a year old and/or in good shape, I could certainly always get away with an hour or more of "accessory on" activity and still start the car (those cars had 10:1 compression engines displacing 7.2 liters, btw). And on more than one occasion I left the headlights on by accident (with no safety feature to shut them off after X-minutes, of course) and I'd still get the car started if it had only be a couple hours. Call me kooky, but these "can't leave the car's accessories/headlights on for 20-plus minutes or it won't start again" GM's are looking pretty lame.
priuscrusher says:
10:56 AM, 12/31/06
Between the seats, low battery life, and higher cost, I am glad I am following this long-term test. Looks like I'm still gonna go with the Acadia as soon as I can afford it.
I just hope InsideLine doesn't start claiming that the Miata has more storage than the Acadia. Haha. Just a joke for anyone who followed the Miata longterm editors posts.
firstwagon says:
12:35 PM, 12/31/06
I think the problem is more high current draw than weak batteries.
In the old days, there was very little in the way of electrically powered components in a car.
The amount of electronics and electric motors in a loaded Tahoe is staggering. Add to that electric engine cooling fans ( I'd guess 60 to 80 amps there) and it's not surprising that batteries get run down.
I'd be curious to see what the current draw is with the engine off and the key out.
thebigal says:
01:33 PM, 12/31/06
I am in agreeance with Karl in that I think that you should be able to run any accessory, including the headlights for more than 20 minutes with out worrying that the battery will go dead. I know that today's vehicles are loaded with electronics as compared to yesteryears (even my own), but still such short battery life is a little alarning.
Maybe it's time for regular vehicles to have two batterys like diesels do. One battery solely dedicated to keeping the electronic gizmos and such operating when the key is turned off and another soley dedicatedd to getting the vehicle started??
Or maybe it really is just a weak battery? I know that I changed from my 650 CCA factory battery to a 900 CCA and I have never ever had a problem since.... I can run my stereo at length (longest has been about an hour) with a 400 watt sub and still no drag on the starter to get started. My last nights test was longer than 20 minutes by the time I got back out to shut the lights off and again no problems....
mr_bots says:
12:40 PM, 01/ 1/07
Must just be a fluke, I've gone to the drive-in with the car off and radio on for upwards of two and half hours in a Yukon and have never needed a jump afterwards. Also, me and some friends have used the headlights on our cars to light up a field or park for football, frisbe, etc. for an hour or two and none of them needed a jump afterwards (GM vehicles included). Also, I haven't know GM to have a headlight shutoff after X minutes. I don't seem this necessary because how often does one actually need to manually turn the headlights on in a GM car? Don't most of their cars made within the last year or two even kick the headlights on 30 seconds after turning on the windshield wipers?
jerrywimer says:
05:53 AM, 01/ 3/07
Dunno about it being a fluke. One of the first things I did to my Avalanche after bring it home new from the dealership was kill the battery. I was in the garage that evening playing with the navigation system, "getting to know it", in preparation for a family trip the following week. I'd just finished figuring out the most important points and programming my parents' address as an address book entry when my wife called me into the house. I left the nav on, key in the ignition (at accessory), and stepped out to take care of business. I forgot about the Av for hours, and when I came back, predictably, everything was dead. I'll take credit (blame) for leaving the key in the ignition at the on position, since that'll more or less tell the "smart" (hah!) electronic system that you supposedly didn't *forget* and leave the offending drain on by accident (in other words, if the key wasn't left in, the door open would've killed power, and if it hadn't, the battery sentinel surely would have after the 20 minute or so default timeout). But I'd still expect the battery to deal with the draw of only the navigation unit (sound turned all the way down) for the amount of time I left it.
Is there a chance that you left the key in the ignition at the time you had the lights on Dan?
jerrywimer says:
06:00 AM, 01/ 3/07
I just read your reply on the other entry for the Tahoe where I criticized the need for removing the seats. I stand corrected for this case Dan. It looks like you had a larger load than I originally thought. Sorry.