First post here...

The not so short story: I have a 2011 XC90 6 cylinder AWD I've owned about a year. There have been many times when I thought it was cranking a little slow, but until recently, never any problem. I had the battery tested twice and it was pronounced good, but not great. A few weeks back, after it had been sitting for a week or so, I noticed it definitely cranked slower than usual, but it did start. I drove a short distance, less than a mile, and shut it off. I was waiting for my daughter at school, listening to the radio, when the radio shut off. There was a message in the message center about battery save mode, or something of that nature. I immediately restarted the car and was able to make several more short trips. Didn't think much of it until a few days later when I went to drive it again. Couldn't get the doors to unlock with the fob. Opened it with the key (I still hadn't caught on as we had had problems with the fob before...) set the alarm off, stuck the key in the steering column, shut the alarm off, and found the car was stone dead. When I finally got to the battery it was reading 3.5 volts.

(Is there any way to lock and unlock the tailgate when the battery is dead or not installed? )

Charged the battery up and everything was fine, for a couple of weeks. Had the car checked and the parasitic draw was "less than 20 ma". Then, I let it sit for a few days and found it stone dead again. Charged the battery and let it (the battery) sit, unconnected, for 5 days. The battery was pretty much fully charged at the end of the 5 days, so I don't think it is self discharging.

The car was new in 2011. The battery has a date code in 2013, so it's been replaced at least once. (I doubt if Volvo used Dekka batteries, anyhow...) The current battery is, I think, bigger than the original, which makes me wonder if maybe this was an issue back then. As far as I know, there is no aftermarket equipment installed other than light connections for the trailer hitch.

One more possibly related bit: In the winter (when it cranks slower) I get a warning that the stability control system is disabled. This happens pretty regularly when the temperature is below freezing. A scan indicated a problem with the steering wheel position sensor. Last time the battery went dead I had to jump it. Even though the temperature was well above freezing, I got the same warning. I'm thinking the low voltage may be causing the problems with the stability control.

But, what I really need to figure out is what's killing the battery. I found a similar thread, but it dealt with model year 2005 and 2006; I doubt the 2011 would have the same problems. (Someone mentioned the satellite radio; is there a known issue with it?) I haven't gotten a good handle on how long it takes to die, or if it is predictable.

Someone else suggested it might be the central locking and to leave the car unlocked. I'd rather not have to do that...

It has been suggested I take too many short trips, but, I don't think it's driving habits. We've had it for about a year and just started having issues recently. If I had to take a WAG, I'd say something is waking up and staying awake when it should be sleeping, or something, once in a while (but not always) doesn't sleep when it should. A friend suggested a gremlin is sneaking in at night and using the seat heaters.

I have access to a very sophisticated battery capacity tester. I tested the battery yesterday. It is supposed to have a 185 minute reserve capacity, but it only tested to 110 minutes. Not that impressive, so I'm going to replace it. However, I really don't think that's the problem. At a 25ma draw, and completely ignoring the fact that the slower you draw it down the greater the capacity, it still nets out to 76 days to draw it down to 10.5 volts, nowhere near what I'm seeing - 3 to 10 days to less than 4 volts.

If you're still reading this, I guess I'm already in your debt. Sorry for the long ramble, but I wanted to give as much information as I could. I'm actually a pretty good mechanic and also pretty good with electricity, but this one has me scratching my head. I am grateful for any insight you might add.

Oh, does anyone have a published procedure for checking the parasitic drain? If I take a battery cable off everything resets and I'm not sure I'm getting an accurate indication of the real world events.

TIA,
John

 

I would certainly start with replacing the battery. If the draw is under 20 milliamps, then there is not a draw problem.

To check draw, make sure all doors are closed and the alarm is on. For the trunk, manually push the latch to simulate it being closed. Set your meter to the highest amps setting. Use alligator clips on the leads. Loosen the 10mm for the negative cable but dont remove it yet. Slowly pull it up while keeping it in contact with the post until you can slide one alligator clip under it to clip to the post. Clip the other to the cable and disconnect. Watch your reading as it drops.

 

Thanks for the quick response. One of my concerns is that the draw doesn't stay at 20 ma, or doesn't always drop to 20 ma. Can't imagine how to catch it, though, without some sort of recording ammeter.

I found another post somewhere (maybe on a different board) saying that the HVAC blower resistor can cause the battery to go dead, but no specifics. Anyone heard of this?

 

If you think it is dropping below 20 mA and then going back up for no known reason, that would be pretty rare. And yes, you would need a meter that can record and graph the results, not just one that will display the high.

I've never had a blower motor resistor cause a draw.

My money is on the battery

 

OK, here's a little more info. I did a real good draw test on it (still going on). After about 5 minutes it had dropped to somewhere around 12 ma. However, by the time an hour had passed it was up to about 32 ma. The only spec I've found seems to indicate it should be less than 25ma, but I've also found a bulletin that says the sat. radio can draw up to 70 ma and still be "OK". Even if I'm averaging 35ma, I should still be OK for about 55 days and still have enough juice to open the doors. Clearly, something else is going on.

 

32mA is too high. I always see between 8 and 16 mA on those.

 

It was down that low for a while but it went back up sometime between 30 minutes and an hour after I shut it down.

 

Just checked it again. It's been about 5 hours. It's been staying around 30-35ma since that first half hour.

Where is the satellite radio? I'll just unplug it. It's not activated anyhow.

 

You've said:

-The battery has a date code in 2013
-I had the battery tested twice and it was pronounced good, but not great.
-after it had been sitting for a week or so
-. I drove a short distance, less than a mile, and shut it off.
-it has been suggested I take too many short trips.

Batteries have a life expectancy or 3 years. Sure they will warranty them longer (pro rated for length of ownership) and sure many people will tell you that they have had a battery for 7+ years...

Batteries are designed for daily drivers with 20+ minute
Commutes. If that's not you, and it doesn't sound like it is, expect 3 year max battery life, like you have received from it. To extend battery life you can buy and install a battery maintainer that you plug in when not in use to keep the battery charged. Along with checking your battery terminals for corrosion every oil change, cleaning them and using dielectric grease on them to prevent future corrosion.

Short trips, periods of non use, weather changes, poor connection (corrosion), age and vibration all kill batteries. If you want longer life, nurse it along.

PS those same things also kill engines... over a longer period of time sure, but kill them just the same.

Best advice, drive your car... frequently (minimum every 3 days) for more than 20-30 min. I get it, gas is expensive, but so are cars.

 

Can you select Sat1 or Sat2 as an input? Probably need an RDAR recovery and software update, and possibly a new battery as well.

 

I don't know. It is not active, so I never mess with it.

This AM, about 14 hrs after I shut it off, it was at about 30ma. (These are interpolations. It varies about 5-6 ma on a digital meter, so I report the average of the highest and lowest readings over a 10 second or so period. The readings agree with an analog meter where you can see the needle oscillate around an average reading.)

About an hour later it had dropped to something like 11ma. We're expecting rain soon, so I'll have to terminate the experiment so I can close the tailgate.

I'm starting to think maybe there is a gremlin inside the battery that eludes testing but still spontaneously drains the battery when no one is looking. A draw big enough to kill the battery would have to either be large in magnitude or long in duration. I'm not seeing either.

 

Prior to the first time it went dead it was my daily driver. It saw two 110 mile trips and at least one 26 mile trip every week.

I've only owned it for 1 year. The PO drove the cr@p out of it putting 112,000 miles on it in a little over 4 years. The first battery replacement occurred before we acquired the car.

I've been driving for over 50 years and I've never seen this behavior in a car (with a good charging system) with a battery that didn't test bad.

 

The RDAR is the most likely problem. Thats the module for the satellite radio. There is a bulletin requiring it to be recovered and then updated with new software. That should get your draw down under 20 mA and if your battery isn't already weakened too much, be the end of the problem. I wouldn't expect much more out of the battery. If you live in a cold climate, I'd probably replace it before winter.

You can also buy a MOST loop, which you can plug into the fiberoptic connector at the RDAR to bypass it. It's a dealer item but isn't too costly if I remember correctly. The RDAR should be behind the right rear cargo compartment panel.

 

You mean I can't just pull the power wire off it? On a different subject, can I unplug the antenna and route it to portable receiver that is activated?

 

Without power, it won't transmit the signals on the fiber optic network, so I'm fairly sure your radio won't work at all then.

Not sure on using the antenna

 

Just a quick update:

The issue is still unresolved. The battery draw test did not uncover anything unusual. I let it go for about 24 hours and never saw anything more than about 80 ma and whenever it was that high it didn't stay there for long. I'd think to kill the battery it would have to be either very high or very long and I saw no evidence of either.

I picked up a gizmo that plugs in the cigarette lighter and shows voltage. Nothing unusual there, either. After 30 seconds or so it's up around 14 volts and stays there.

Still can't come up with an explanation of how it could start one day and be stone dead a few days later, even if the battery was marginal the day it started. I'd think it'd at least have enough juice left to open the doors.

 

80mA is way too high.

Voltage when running isn't really telling you anything with regard to this problem. If the alternator wasn't charging, you would have a warning.