HELP? -- Diagnosing a bad battery

[ZinFreak]

Well, maybe it was karma. I've never had a problem with my '06 LGT, that is until yesterday. Got in the car to go to Grandma's house yesterday for Turkey Day and I get "click-click-click" when I turn the key. Dead battery -- WTF? Jumped it off our old trusty '95 Tercel and the LGT springs to life. I'm 99% sure nothing was left on or open. However, I hadn't driven the car in two weeks due to travel and working from home.

 

So here's my plan once I get my Fluke multi-meter back from my office;

 

1) Now that I drove it yesterday and it has sat overnight, measure the Open Circuit Voltage -- Looking for 12.65+ Volts ( + 12 mV for each degree F below 70 F)

 

2) Check the parasitic draw on the battery by removing the battery terminal and putting the fluke in between to measure the mA drawn by the security system, clock, radio for the door locks, etc. I hope to see a small number of milli Amps. What is small?

 

Questions:

 

1) Has anyone characterized the parasitic load on the '05/'06 LGT? I'm assuming this would vary by model year depending on the stuff Subaru has attached to the car. Maybe we should compile a list

 

2) What is the chance I've got a bum (marginal) battery? Here's my thought. My car has a build date of Sep 05, I bought it in Mar 06. That's like 6 months of sitting around with the battery being nibbled away. Lead Acid batteries will undergo "sulfination" when they sit unused and drawn down. (Lead sulfate can not be converted back to charged material). So if my car sat for 6 months with a drawn down battery, there's a really good chance the battery is simply marginal and it doesn't have enough reserve capacity (RC) left to sit for 2 weeks. Compounding this problem, my commute is 5 miles (< 10 minutes), which is barely enough time for the charging system to start to replace the lost charge due to starting the car.

 

Any advice is welcome. I've seen a couple of people post with similar problems although I've never seen a definitive conclusion to why some people's batteries poop out early or have starting problems if the car sits for a couple of weeks.

 

If some folks could check the parasitic load with MY perhaps I can compile this and post it. I think I'm also going to make a WALKTHROUGH for checking battery health and selecting a new battery for trading off between CCA (cold cranking amps) and RC (reserve capacity).

 

If I find I have a bad battery I'm not sure I'm going to go through the hassle of having Subaru replace it under warranty. I think I will buy an expensive battery with a large RC, I don't need CCA because here in NorCal it just doesn't get cold.

 

TIA - Zin.

[outahere]

Check fluid level in battery.

Check charging circuit.

Check specific gravity in each cell.

 

Check out this battery site:

http://www.uuhome.de/william.darden/

[PhilT]

Check fluid level in battery.

Check specific gravity in each cell.

 

 

How do you do that in a sealed battery ?

[mccorry]

You can't.

 

Mesuring the current draw and voltage with your Fluke meter is a good start. If you don't find anything obvious... then your best bet is to put a good charge on the battery. Overnight if possible.... to top it off.

 

Then, take it to Autozone or similar. They will do a free load test on the battery.

 

My guess is that you have something pulling some current (light left on, amplifier, etc) and draining the battery.

[ZinFreak]

How do you do that in a sealed battery ?

 

My 06' LGT LTD has a non-sealed battery. Popped off the right cell cover off and immediately dropped it down the side of the car into a freakin' unreachable place. Thank God for flexible grabbers and swear words.

 

Water levels are fine in both sides, I don't have a hygrometer so I can't test the SG yet. Something to do this afternoon.

[outahere]

How do you do that in a sealed battery ?

 

My original equipment battery is not sealed.

[ZinFreak]

Well I finally got a chance to fully charge the battery yesterday, then let it sit for a couple of hours.

 

Open Circuit Voltage - 12.25 V (correlates to roughly a 50% State of Charge).

 

The battery fluid level is fine, I don't have a hygrometer, so I'm going to skip the S.G. test.

 

Charging looks good, slightly more that 14 V.

 

Bad battery. I'm guessing sitting for six months between build date (9/05) and delivery (3/06) caused premature battery death due to sulfination.

 

Off to purchase a new battery today. I just can't bear taking an entire day at the Subaru dealer for them to hem and haw over the battery.

 

Point of reference...

 

Using the following table, determine the battery's state-of-charge:

 

Open Circuit .. Approximate ... Average Cell

Battery Voltage State-of-charge Specific Gravity

12.65+ ........ 100% ........... 1.265+

12.45 ......... 75% ............ 1.225

12.24 ......... 50% ............ 1.190

12.06 ......... 25% ............ 1.155

11.89 ......... 0% ............. 1.120

 

[if the temperature of the electrolyte is below 70 degrees F (21.1 degrees C), then add .012 volts (12 millivolts) per degree below 70 degrees F to the reading.]

[outahere]

 

FWIW, CR tested batteries in the Nov edition, and of the group 35 batteries, the Duralast (from Autozone) was rated #2, behind the NAPA Legend. The NAPA had better CCA, but the Duralast was rated higher on the life test.

[ZinFreak]

FWIW, CR tested batteries in the Nov edition, and of the group 35 batteries, the Duralast (from Autozone) was rated #2, behind the NAPA Legend. The NAPA had better CCA, but the Duralast was rated higher on the life test.

 

Thanks for the info, but too late. I took the low road and since I was at The Cult of Costco today, I picked up a group 35 100 Month Kirkland Especiale for 48 ish green backs.

 

After sitting without a battery that first start since ECU clearing always gets my attention with an "Oh Shit", then it revs to life just about when you are ready to give up.

 

On the road again! --Zin

[Mookem]

ZinFreak: Any problems since the new battery? I have an 07 with 1400 miles on it and the battery was dead yesterday after the car was sitting for 3 days. Like you I jump started it up with my trusty old Honda. I went to the dealer this morning and they tested and said everything looks fine - and maybe my trunk was slightly ajar (no way). I argued but to no avail as they didn't find anything. I did tell them if it happens again I'm having it towed to them and they are paying for a loaner. This Legacy GT has been the worst new car I"ve ever had in 30+ years - problems with fit and finish and now the mysterious no startup - bumming me out big time.

[ZinFreak]

ZinFreak: Any problems since the new battery? I have an 07 with 1400 miles on it and the battery was dead yesterday after the car was sitting for 3 days. Like you I jump started it up with my trusty old Honda. I went to the dealer this morning and they tested and said everything looks fine - and maybe my trunk was slightly ajar (no way). I argued but to no avail as they didn't find anything. I did tell them if it happens again I'm having it towed to them and they are paying for a loaner. This Legacy GT has been the worst new car I"ve ever had in 30+ years - problems with fit and finish and now the mysterious no startup - bumming me out big time.

 

Sorry to hear of your travails, my LGT has been perfect up to Thanksgiving. I've had really nothing to complain about except a little seat sqwak when I'm carving up Highway One. My Tool CD's mask that pretty well.

 

We'll see how the new battery holds up, I dropped it in on Saturday. I haven't driven it since then, used the Forester today, it was crappy weather and my wife is off. I decided I get her car dirty....

 

Check your battery for its OCV (disconnect the negative lead, measure across the battery) with a voltmeter, then refer to the chart I put in this thread. Do this after a long drive and let the battery sit for 2-3 hours for the chemistry to equilabrate. If you see 12.65 V (temperature compensated), it is OK.

 

Reconnect the battery, start the car up, it will start hard because the ECU may reset. Measure the charging voltage across the battery. You should see about 14 V (mine was 14.02 V, that's 14 in my book).

 

Also take a look at the manufacture date on your battery, the build date of your car from the window sticker, and your delivery date.

 

Unfortunately my craptastic Fluke only measures micro Amps, so I can't measure the parasitic draw off all the equipment sucking on the battery. So I can't help you there. (Yet) I will do this at work this week with a better meter.

 

Good luck.

[kenchan]

my old 02 wrx was like this too in the winter time. it was fine until it got cold.

 

i know it's a chunk of money, but you might want to swap it out with a Optima

Red top while you have the car. when you're ready to trade it in/sell it, put the

factory battery back in, charge it, and sell it. that's wat i did in my case with

the rex.