SVX Network Forums Live Chat! SVX or Subaru Links Old Lockers Photo Post How-To Documents Message Archive SVX Shop Search |
IRC users: |
#1
|
|||
|
|||
typical battery life?
Fellers,
We replaced the battery on our '92 SVX LSL soon after we bought it about 18 months ago and yesterday the battery was dead again with the car sitting in the garage at about 40 degrees F. Is there a potential drainage source that i'm not aware of? Could this be alternator related? any info appreciated. thanks and Merry Christmas! Tdog |
#2
|
||||
|
||||
The quick, down and dirty way to check for a parasitic draw is to remove a battery cable while the engine is OFF (never remove it while the engine is running, no matter what the idjit at the parts store says - it'll fry the alternator) and all accessories, ignition, lights, etc. are also OFF (don't forget that big amp for your thumpers in the trunk.) Gently touch the cable to the battery and watch for any small sparks - that will indicate a load. Beyond that, doing the same but with a voltmeter between the battery and the cable ( one lead to the battery, the other to the cable) will indicate how much voltage is being drawn. The absolute correct way to check for parasitic draw is to use an inductive low-amp clamp around a battery cable in order to see exactly how many amps (or portions of an ampere) are being drawn - should be less than .02a . Some modern cars will draw a bit more until all systems 'go to sleep', typically a few minutes, some up to 45 minutes - but that draw will be low, typically less than 1amp.
If you don't see any spark and you don't have access to a meter, check the battery with a hydrometer. One bad/weak cell will draw down the other cells. You can usually buy a hydrometer at any parts store, K-Mart, WalMart, etc. for a buck or two. Downside - if you have a sealed battery...
__________________
ASE Certified Master Automotive Technician w/L1. ASE Certified Master Medium/Heavy Truck Technician. Certified EVT (Emergency Vehicle Technician) |
#3
|
||||
|
||||
Quote:
__________________
Andy ------------------------------------------------------------------------------------ If I would be a young man again and had to decide how to make my living, I would not try to become a scientist or scholar or teacher. I would rather choose to be a plumber or a peddler in the hope to find that modest degree of independence still available under present circumstances. -- Albert Einstein, The Reporter, November 18 1954 |
#4
|
||||
|
||||
Nope, a voltmeter. It will indicate how many volts are required to fulfill the load's requirement. Just don't try to start the car (or operate any other high-load devices - blower, cig lighter, etc.)while doing this, unless you want to let the smoke out of the meter...
Most parasitic draws are less than an amp or two and most ammeters would be useless at indicating that low of a current draw. I was just trying to offer up a reasonable method that would more likely be available to lightly equipped DIYers.
__________________
ASE Certified Master Automotive Technician w/L1. ASE Certified Master Medium/Heavy Truck Technician. Certified EVT (Emergency Vehicle Technician) Last edited by Beav; 12-26-2004 at 03:43 PM. |
#5
|
||||
|
||||
Quote:
Voltage cannot be drawn, it is purely a potential difference. I guess you are trying to measure the voltage on a closed circuit as opposed to an open circuit, which would not give a reading. Operating high load devices would not cause a voltmeter to smoke. It will only display the voltage, whether through components or straight across the battery.
__________________
Andy ------------------------------------------------------------------------------------ If I would be a young man again and had to decide how to make my living, I would not try to become a scientist or scholar or teacher. I would rather choose to be a plumber or a peddler in the hope to find that modest degree of independence still available under present circumstances. -- Albert Einstein, The Reporter, November 18 1954 |
#6
|
||||
|
||||
But if you try to draw a high current load through a voltmeter would it be able to handle the load? The leads and the meter itself aren't exactly built for that. I could be wrong, I never tried it.
If there is a parasitic draw it couldn't be an open circuit, therefore there would be a differential. No draw, no differential, no reading.
__________________
ASE Certified Master Automotive Technician w/L1. ASE Certified Master Medium/Heavy Truck Technician. Certified EVT (Emergency Vehicle Technician) |
#7
|
||||
|
||||
Quote:
Quote:
__________________
Andy ------------------------------------------------------------------------------------ If I would be a young man again and had to decide how to make my living, I would not try to become a scientist or scholar or teacher. I would rather choose to be a plumber or a peddler in the hope to find that modest degree of independence still available under present circumstances. -- Albert Einstein, The Reporter, November 18 1954 |
#8
|
|||
|
|||
If your SVX sits in the garage alot, remove the battery.
__________________
Larry III & The Beautiful Naviguesser '19 Tungsten Pearl Outback 3.6R Ltd...."AISHA" '08 Harvest Gold Outback 3.0L. L. L. Bean...."AIJOU" '07 Gray Diamond Pearl Outback XT Ltd..."AH SO" '05 White Pearl & Silver BAJA Turbo..."AH HA" '97 Bordeaux Pearl SVX LSi..."SUBYDOO" '94 White Pearl SVX LSi..."PEARLY" '92 White Pearl SVX LSL w/touring pkg..."SVXY" '92 Teal SVX LSL w/touring pkg..."ALCYONE" '96 Polo Green LSi ... "MIDORI" '00 Black Dodge VIPER RT-10... "VINNIE" Engineers do it with precision. English teachers are novel lovers. Home: larrysingeriii@comcast.net SVX FEVER, CATCH IT AT A MEET NEAR YOU !! |
#9
|
||||
|
||||
Quote:
I should have finished up with ".... no reading, no problem." 'No problem' would then equal a battery problem. Mechanics have been using the voltmeter method for years. A light bulb could also be used but if the draw is small the bulb may not illuminate. With a voltmeter a low voltage draw, such as a module not going to sleep or an analog clock with burnished contact points, would still be indicated. Watching the meter as you remove one fuse at a time would indicate the troubled circuit when the needle falls to zero. Not an absolute method with today's electronics but a handy substitute for those without access to a low amp measuring device.
__________________
ASE Certified Master Automotive Technician w/L1. ASE Certified Master Medium/Heavy Truck Technician. Certified EVT (Emergency Vehicle Technician) |
#10
|
||||
|
||||
Quote:
__________________
British vehicles are my last ditch attempt to keep the nasty Italian thoughts in my mind at bay. So far its working. |
#11
|
||||
|
||||
Quote:
As current cannot flow through a voltmeter, an electronic fault is unlikely to show itself, conversely a good circuit could appear to be faulty. The only way to be sure on a modern car is to use a low current ammeter. These tend to be rather pricey.
__________________
Andy ------------------------------------------------------------------------------------ If I would be a young man again and had to decide how to make my living, I would not try to become a scientist or scholar or teacher. I would rather choose to be a plumber or a peddler in the hope to find that modest degree of independence still available under present circumstances. -- Albert Einstein, The Reporter, November 18 1954 |
#12
|
|||
|
|||
the extent of my practical knowledge about electricity could be written on the head of a pin - using a crayon - nonetheless, I will press ahead.
I remember a high school science lab wherein we employed a galvanometer (low current ammeter) to build both a voltmeter and an ammeter - only difference had to do with parallel vice series placement (respectively) and the use of resistors. So, I assume Beav's use of the voltmeter in series effectively makes it an ammeter - or did I stray down the wrong road yet again? |
#13
|
||||
|
||||
Quote:
__________________
Andy ------------------------------------------------------------------------------------ If I would be a young man again and had to decide how to make my living, I would not try to become a scientist or scholar or teacher. I would rather choose to be a plumber or a peddler in the hope to find that modest degree of independence still available under present circumstances. -- Albert Einstein, The Reporter, November 18 1954 |
#14
|
||||
|
||||
Ya see, that's the problem with assumptions. They're usually made with just enough information to make one dangerous. With the advent of electronics in vehicles the old methods were abandoned without reasons given. This is another one of those times I wish the person(s) involved in deciding what we needed to know would have been a bit more generous.
__________________
ASE Certified Master Automotive Technician w/L1. ASE Certified Master Medium/Heavy Truck Technician. Certified EVT (Emergency Vehicle Technician) |
#15
|
|||
|
|||
Quote:
|
|
|