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I fixed a parasitic drain on my car in 408 days

davidmuller.github.io

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Re: I fixed a parasitic drain on my car in 408 days

#71

Post by ryukafalz »

KMnO4 wrote: post #48
kccqzy wrote: post #7

Earlier quoted context omitted.

> it's normal for the battery to die if you don't drive it for 3 days I've heard this nonsense a couple times now. I was incredulous at first but everyone seems to say this. What are anyone's suggestions for a weekend-only car? (I bike to work so I don't need a car on weekdays.) Trickle charge the car battery on weekdays?

You should see if there are carshare options around you. Even if you’re spending $50/weekend (which is a fair amount of driving — Communauto is as low as $3/hr), that’s still quite a bit cheaper than owning a depreciating asset with lifetime maintenance costs (not to even mention insurance and fuel).

Oh do I wish there were carshare options near me. Just moved from Philadelphia where ZipCar seems to be the only remaining contender, and you're lucky if there's one within a half hour's walk in the part of the city I was in. It's even worse in the town I moved to. There used to be a few at the nearby train station, but those seem to have disappeared. (This reminds me, I should go cancel my membership.)

I'm jealous of the carshare options that seem to be available elsewhere. If it were as easy here as in this NJB video, it'd be a no-brainer: https://youtu.be/OObwqreAJ48

Re: I fixed a parasitic drain on my car in 408 days

#72

Post by rootusrootus »

flibbityflob wrote: post #21
sokoloff wrote: post #14

Earlier quoted context omitted.

I’ve had unknown draws before and many times they’re not constant draws. A constant draw is easy and quick to find. A draw that only happens when some module or other wakes up is a lot harder to find.

As an example, my 2017 Corolla runs the fuel pump for a while 5 hours after shutdown to test fuel system pressurization. I didn’t even know until I recently started parking it inside and I finally heard it running.

Yeah that's pretty normal across different manufacturers, and you only hear it if you park in a quiet garage and happen to be in the garage at the moment it turns on to do it's thing. It's testing the seal of the fuel cap to make sure you aren't just venting gasoline fumes.

Re: I fixed a parasitic drain on my car in 408 days

#73

Post by rootusrootus »

fxtentacle wrote: post #22
overthrow wrote: post #3

Well this is timely. I have a parasitic draw on my NC Miata. The first mechanic just replaced the battery. The second told me it's normal for the battery to die if you don't drive it for 3 days (because "cars have computers now"). It seems like mechanics really don't like digging into the electrical part of the car... but these days that encompasses more and more of what can go wrong. Without time to dig into it myse…

Wow. My German car handles being parked for 3 months just fine.

So does my American car.

Re: I fixed a parasitic drain on my car in 408 days

#74

Post by gooseyard »

ceautery wrote: post #40

This is type of thing I've seen Eric O. over at South Main Auto[1] fix in dozens of videos. Mad troubleshooting skills, works hard to find root causes of things. He's pretty amazing, hidden away in some no-account town in upstate NY. 1 - https://www.youtube.com/@SouthMainAuto

I really enjoy his channel- another good one is the Pine Hollow Auto Diagnostics channel, which has dozens of really involved parasitic draw diagnoses, have learned a great deal from that one.

Re: I fixed a parasitic drain on my car in 408 days

#75

Post by rzzzt »

dylan604 wrote: post #67
kybernetyk wrote: post #27

Earlier quoted context omitted.

>It seems like mechanics really don't like digging into the electrical part of the car. If you've ever seen a car's complete wiring harness you'll know why. It's not only because there's three gazillions of wires - they're also heavily insulated with tape that makes it a nightmare to access those wires in the first place.

>there's three gazillions of wires My old math teacher would deduct points for not listing the units.

"Number of wires" is a unitless quantity.

Re: I fixed a parasitic drain on my car in 408 days

#76

Post by cloudripper »

dylan604 wrote: post #67
kybernetyk wrote: post #27

Earlier quoted context omitted.

>It seems like mechanics really don't like digging into the electrical part of the car. If you've ever seen a car's complete wiring harness you'll know why. It's not only because there's three gazillions of wires - they're also heavily insulated with tape that makes it a nightmare to access those wires in the first place.

>there's three gazillions of wires My old math teacher would deduct points for not listing the units.

My former English teacher would question why the age of your math teacher is relevant in this post.

Re: I fixed a parasitic drain on my car in 408 days

#77

Post by rootusrootus »

jws wrote: post #2

I have failed to find the parasitic draw on an RV (slower than this one, it takes a couple weeks to kill the battery). I finally got a "Top Post Battery Master Disconnect Switch", which is a little dinglebob that goes between the battery post and cable and lets you easily break the circuit. I highly recommend the $12 solution for an intermittently used vehicle.

> RV

I'm reminded how often people come to the RV forum trying to figure out parasitic draw. The answer almost always ends up being the propane detector. People forget it's even there.

Less of an issue on newer RVs that come with at least one basic solar panel installed from the factory.

Re: I fixed a parasitic drain on my car in 408 days

#78

Post by Eumenes »

lylejantzi3rd wrote: post #28
overthrow wrote: post #3

Well this is timely. I have a parasitic draw on my NC Miata. The first mechanic just replaced the battery. The second told me it's normal for the battery to die if you don't drive it for 3 days (because "cars have computers now"). It seems like mechanics really don't like digging into the electrical part of the car... but these days that encompasses more and more of what can go wrong. Without time to dig into it myse…

> It seems like mechanics really don't like digging into the electrical part of the car... Tell me about it. I'm in a similar boat. My audi a4 has had a parasitic draw for the past 10 years. My mechanic didn't want to take the time to address it because that sort of thing takes a serious amount of time and he's always backed up. I got out my fluke and narrowed the cause to what I believe is the comfort control unit.…

I'm looking into buying a reliable older vehicle, pre 2000, and just rebuilding the engine

Re: I fixed a parasitic drain on my car in 408 days

#79

Post by duskwuff »

mlyle wrote: post #59
johnwalkr wrote: post #54

Earlier quoted context omitted.

I think the mistake may have actually been writing ammeter instead of voltmeter. Ammeter is not safe as general advice as a typical one won’t be anywhere near large enough capacity for working with a car battery and should come with a lot of disclaimers about how to hook it up. Measuring voltage drop would work but only for fairly high loads.

> Measuring voltage drop would work but only for fairly high loads. Yah, that doesn't really make sense for small parasitic loads. > Ammeter is not safe as general advice as a typical one won’t be anywhere near large enough capacity for working with a car battery It should be fine with the car not "on", but the general level of danger of doing anything near a car battery requires caution.

> Yah, that doesn't really make sense for small parasitic loads.

If your multimeter has a sub-mV range -- which a decent meter should -- you can measure a voltage drop across the battery ground lead. I've successfully done that to diagnose a battery draw in my car.

Re: I fixed a parasitic drain on my car in 408 days

#80

Post by Scoundreller »

BoorishBears wrote: post #55
addisonl wrote: post #38

Earlier quoted context omitted.

Probably should get a brand more reliable than Audi...

I hear people say that about my BMW, and realistically the hassle of some reliability issues is nothing compared to driving the lifeless husks of cars they recommend instead. (there are reliable sports cars, but it significantly limits the pool you can select from)

I feel like I’ve lucked out in life with an ‘08 6MT N52 e90 and an ‘05 Corolla with a 1ZZFE.
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