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Battery Draining When Car Not in Use
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Lonestar
Novice
Jan 20, 2021, 9:38 AM
Post #1 of 13
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Battery Draining When Car Not in Use
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Hi... the 1.5 yr old OEM battery, replaced when the original OEM battery failed prematurely, is losing it's charge. I have a good charger that shows % charged. 2-3 days after charging to 100%, it can get as low as 65% before I go ahead a recharge it again. I have a technical background, so researched parasitic drain troubleshooting and did so. I thought I found something and addressed it, but today the charge was down to 70% again, from 95% 24 hours ago, which was 24 hours post charging. So, 48 hours to get to 70%. (Temp is in the mid 40s to mid 50s.) The current across the battery is less than 50ma with everything turned OFF. I had the battery 'tested' at Interstate Battery store and they found no indication of a problem. Nevertheless, it continues to drain.
I guess my next step is to disconnect the battery and see if it continues to drain on its own. I tried this once but apparently didn't let it sit long enough, maybe only 24 hours.
Oh, when I charged it this morning, it took no more than an hour to get up to 100%.
Any other thoughts? Thanks!
2017
Subaru
Forester
2.5L
38000 mi
(This post was edited by Lonestar on Jan 20, 2021, 10:22 AM)
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Lonestar
Novice
Jan 20, 2021, 10:30 AM
Post #3 of 13
(902 views)
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Re: Battery Draining When Car Not in Use
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The current across the battery is less than 50ma with everything turned OFF. Thanks! Yup, sorry about that. Poorly stated. I meant, from + terminal through meter (on DC ma) to - terminal, as you have indicated. The reading is less than 50ma, like 20-30ma. I took reading across the fuses and initially thought I found one dropping 2.3v. It said 'Steering/Heater' which I don't have but have heated seats. One of the switches was on Low setting but of course the ignition was not on. Sorry, not clear on the measurements and events following turning off that switch but still there appears to be no parasitic draw at this point and battery dropping to 70% in 48 hours.
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Hammer Time
Ultimate Carjunky
/ Moderator
Jan 20, 2021, 10:35 AM
Post #4 of 13
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Re: Battery Draining When Car Not in Use
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As I already stated, you only have 2 options here so one of your tests is faulty.
You should not be measuring terminal to terminal. It should be terminal to cable.
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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.
(This post was edited by Hammer Time on Jan 20, 2021, 10:36 AM)
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Tom Greenleaf
Ultimate Carjunky
/ Moderator
Jan 20, 2021, 11:08 AM
Post #5 of 13
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Re: Battery Draining When Car Not in Use
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? It drops in 48 hours by your device to 70%? OK, I'll take that it should just start up and you not be aware of it. If you keep charging a "Flooded Lead Acid" battery that goes low it will kill it. IF THEY go totally dead once it's iffy to recover what it was rated at. More it's done with again.
They don't take being low like "phone things" and come back 1,000 times.
In short if it's the car it's killing the battery so do the tests HT spent a lot of time to write out.
Whacked other is a dirty or wet (outside case) battery will self drain - you can measure that with your DVOM try it something you can wash off it really does especially if you add a pinch of salt to water and spray it,
T
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Tom Greenleaf
Ultimate Carjunky
/ Moderator
Jan 20, 2021, 3:19 PM
Post #7 of 13
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Re: Battery Draining When Car Not in Use
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For the fuse test and battery disconnected make sure you don't open a door or if a hood light, trunk light that it's off or unplugged.
Glove boxes and the like are all areas you don't know if lights go out (certain model of whatever) so if unsure take bulbs out. If too hard see which fuse those things are on in manual pull that one but probably more than one and get lost with the test.
Dumb stuff depending on type of bulb LED or incandescent cute lighting small as some are will wipe out a car battery!
T
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Lonestar
Novice
Jan 20, 2021, 6:57 PM
Post #8 of 13
(847 views)
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Re: Battery Draining When Car Not in Use
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Thanks Tom... I'm feeling bad that there are details I inadvertently left out that, after your and other's comments, I am now recalling. The 70% was just one day, one scenario. It has at other times dropped to 65% and once even close to 50%, whereby it hesitates to start of course. The only reason I even got onto it is because it did NOT start at all one morning a couple weeks ago. That, a day or two after I noticed the common hesitant turn-over that is often indicative of a low battery.
This all reeks of the same prior issue when Subaru said it was a bad battery and replaced it under warranty. Maybe their batteries aren't all that good.(?) This one isn't covered by warranty because we've surpassed the 3 yrs/36K miles. Not really important though.
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Tom Greenleaf
Ultimate Carjunky
/ Moderator
Jan 21, 2021, 2:47 AM
Post #9 of 13
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Re: Battery Draining When Car Not in Use
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OK, This battery is off warranty so it's probably time anyway to go new AGAIN seems soon for a third on a 2017 anything - the first could be from 2015 for all we know. Batteries are marked and age from that date when filled - know that.
You keep speaking of % of charge left? IDK what assorted meters and chargers you have or are used to? It's some % of what it might be capable of which changes (lower each day) for the life of one. If the best it could do is run (amp power) some toy thing vs a car both are in %s the toy isn't gong to start your Forester.
Basics: It's a perishable item to start vehicles not run on them not to go low much or at all it's whole life. They don't like heat, cold vibrations or being charged. OMG that stinks and always did with the damn things.
The testers, equipment for them isn't always so great but we're stuck with that too. Now with a "lockdown" state cars (vehicles all over) just sit longer and hate that.
Do more tests for a drain so a new one isn't just going to wipe out on you and can make sure you check the date it was made!
Good luck it's just a hunch you need a new one not conclusive yet though, Tom
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Note semi off topic: Cars are either used all the time never cool down or sit way too long more of that now. Virtually everything is on battery memory back up controlled by "computer" is a slight draw not going to last years without use.
Most are still liquid filled lead/acid not sealed units a drift to called AGM type is helpful but think for a longer run we (the people) need sealed things more tolerant of extremes.
*******************
Seen locally just driving by many new car dealers YARDS (acres upon acres of cars) not an empty spot! Folks running out with jumper boxes most were new and dead! Problems will start before these cars get a new owner and be all hell for a while.
Onward - the point is batteries are a weak spot in vehicles perish like produce is almost exact. Lettuce is closest you peel off outer layers till it's the good stuff to find it's not as large as it was when you got it. It never will be again, Tom
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Lonestar
Novice
Jan 21, 2021, 5:20 PM
Post #10 of 13
(822 views)
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Re: Battery Draining When Car Not in Use
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% charge indicated on Shumacher Extreme Heavy Duty Charger (woo hoo!) When you start the charging, momentarily the % of full charge shows up. Not sure how accurate, but when it didn't start and I hooked it up, It has read from just above 50% to 95% depending how long it sits before I check it. Goes up to 100% when done charging so it SEEMS to be taking a full charge, at least in it's own electronic mind.
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Tom Greenleaf
Ultimate Carjunky
/ Moderator
Jan 21, 2021, 6:53 PM
Post #11 of 13
(817 views)
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Re: Battery Draining When Car Not in Use
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Lonestar: Seem that super duper charger is like others. It might tell you how many amps it's putting out or not?
THIS IS ONE OF MY NOVELS KNOWN FOR THAT HERE WANT YOU TO SUCCEED AND UNDERSTAND THIS.
Hope this doesn't add to the confusion about the thing (charger) and what and why it tells you %s of things. It has no clue how huge AMPS wise what it's charging best bet IMO just knows voltage it sees. May back off if that goes to high while charging IDK, and doubt you do no harm meant.
For example the sealer but still lead/acid batteries for a motor scooter has a 12v battery to start the dang things! If you hooked up your charger on that tiny battery it probably would give you info like you get now.
Sure, it would say "all done, 100% charged" and good to go. For the scooter maybe not same battery in your Subaru - right? That take amps delivered which declines by the month and temperature it is at the time. Vehicle batteries should save CCA on them is what it could do at least new at 32F. Say for your car 500-CCA and should be marked. At 80F it might put out 650 AMPS! Below 32F the amps drop off on a graph really plummet. It can and usually get well below zeroF where I am. Batteries are fine the CCA is in the toilet! Can't start it.
So it's hard to tell actual AMPS it has when reading 100% so would that scooter.
As explained to me comparisons with something else. Take a garden hose has PRESSURE (volts) and AMPS (volume) so if you need to fill a 10 gallon bucket how much time would it take. You add pressure more goes thru. If you add diameter of hose you are adding volume.
Your battery loses it with already said, time*, and a shred is lost with each start.
It's a bouncing ball perfectly but never recovers to bounce as high at the first time in the case of batteries it's real close for a couple years then falls off.
*Time: A battery ages just sitting there before you bought it! What? Yes - a good battery outlet will NOT sell a battery after one full year, new but unsold. It isn't was it was rated at on the shelf anymore.
Why: The plates are in acid an flake is why at the bottom there's room for them to pile up. Those flakes are loss of AMPS over time and with heavy, fast drain like using the starter. CCA is for "cranking" is a hard fast load on a battery is why and the most a battery should sustain. It will quickly when running be back to 100% by car's alternator and stay there the alternator runs the features when you drive the battery just smooths it out.
Those flakes are loss of power happens fast and furious with charging fast after running low. Some new batteries only go super low to near dead once or twice have ruined themselves from that. Charging should be slow and steady plus auto shut off when chargers do their thing. The more powerful the faster but lots more harm to the battery!
Feel the heat come off a charger or in car an alternator working really hard will get too hot to touch it's trying too hard but told to.
All this kills the common lead/acid battery.
A test of a good battery because it's hard to know just power it has (AMPS) is it will crank and start, quick shut off no time to charge at least 20 times before it complains! Don't do that fast wait if you wish to do that it just makes a point. Bet yours can't now when it say 100% charged.
That means it's no longer enough for your car but still a battery with something.
Back to the drain? If it's draining more than the 50mAh the car's alternator was killing it all along so you did well.
If this sustained lots of vibrations, bumps and not fastened nicely held in place that too a problem you are shaking off those flakes faster and faster.
They make rough service batteries and ones that tolerate going real low like battery powered things also use DEEP CYCLE types. They can take it not common ones. Good for two years at best still!
We mere mortals would refuse to pay a FORTUNE for a battery like your common cell phones everywhere today that could start your Subaru! Those cost enough for phones!
I want to help you find a problem if there is one and probably do need a new battery again. It's too soon IMO and yours - I'm about sure of that.
Rule out the parasitic drain and quit charging fast if you do now or with any.
Buying new: Check how old it is before you buy it! It's marked or ask for one not over 3 months old they'll look at you cross-eyed but it's your $ and car plus this aggravation you don't need this often. Bad luck can happen I dare say more now than even 10-15 years ago?
Test some more hope this didn't confuse you and please forgive me for typos I try but web connection is so lousy where I am I'm rushing while it works it just cuts out and this freaking novel would be lost,
Tom
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Lonestar
Novice
Jan 21, 2021, 7:54 PM
Post #12 of 13
(812 views)
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Re: Battery Draining When Car Not in Use
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Tom, thanks very much for all your input. I appreciate it. What I need to do, I think, is disconnect battery for a few days to see how much it drops or doesn't drop. If it does just like connected, then I think the battery is bad... like to 65% or 52%. If it stays high, then I reconnect and see if it drops in circuit, indicating a leak. :-)
Thanks again! I will update later just for the heck of it since this is all out there now. Maybe it will help someone else.
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Tom Greenleaf
Ultimate Carjunky
/ Moderator
Jan 22, 2021, 1:30 AM
Post #13 of 13
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Re: Battery Draining When Car Not in Use
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RIGHT! If it can lose anything in a day or week should be marginal if noticed at all. Disconnected bat is on it's own. YES they can internally discharge by those flakes I spoke of. If or when those touch the bottom of the plates, just a hair or a lot it's self discharging up to a furious show of it shorting (not often to me) can outright explode. See warnings all over the place on batteries. On that too many warnings on anything all around us, this one is real.
That isolates the problem to do your test.
I'd like to suggest play (kind of but not kidding) with batteries outside of a close space! Don't store them where it can freeze even outside (new or dead ones) don't belong where they can hurt you or anyone,
Tom
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