101–110 of 515 posts
Earlier quoted context omitted.
I saw this on the Gears and Gasoline Youtube channel: https://youtu.be/XgOowUWbCdk?t=628 -- looks like a lot of work to trace a parasitic drain.
If you like watching amateur YouTubers rip out their hair chasing electrical problems, I recommend checking out Tavarish and Samcrac. It turns out cheap flooded auction cars have tons of those
South Main Auto
Watch Wes Work
musty1
Earlier quoted context omitted.
> Ammeter across the battery terminals and pulling each fuse to see when the drop goes away How does this compare with the way presented in the article based on measuring resistive voltage drop across each fuse in turn?
Ye olde ammeters were secretly voltmeters with a low-value but high-precision shunt resistor in series with the circuit to be measured. Current passing through the resistor causes a tiny voltage drop, which is measured by the meter. As the voltage is proportional to the current, the scale painted on the cardboard behind the needle did the actual conversion. In the author's setup the fuse takes the shunt's place; its…
Earlier quoted context omitted.
> 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.
> It should be fine with the car not "on" No. Not if the meter is in "Ammeter" mode (or is purely an ammeter only). An ammeter presents a very low resistance to the circuit you are attaching it to, low enough that for almost all circuits, it is effectively a "short". If one connects an ammeter across a low resistance voltage source (i.e., across the car battery) the ammeter will appear as a short circuit to the batte…
Yes. My first comment on this thread says not to do that, and suggesting an alternative is "Ammeter between a battery's terminal and the car's electrical system." instead. https://news.ycombinator.com/item?id=35514652
I was replying to "anywhere near large enough capacity" in the next post. The typical 10A range is massive overkill for typical parasitic loads in a car, and even things like the fuel pump deciding to kick on and run in most cars.
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.…
My experience is that a lot of independent mechanics will do what you ask them to do, so long as they think it’s not unsafe and have confidence that you’ll pay the bill without complaint when the task is done whether or not the problem is fixed.
Probably not a good “this is my first time meeting you, but please replace my flux capacitor” but if you’ve got a history with the shop, I’m surprised you couldn’t talk him into it. (I worked in a shop briefly in college. We’d do what the customer wanted, including installing parts they bought, but the only warranty was on a “we spent an hour; you paid for an hour; thus ends the transaction” basis.)
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…
Earlier quoted context omitted.
> 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
Earlier quoted context omitted.
> Ammeter across the battery terminals and pulling each fuse to see when the drop goes away How does this compare with the way presented in the article based on measuring resistive voltage drop across each fuse in turn?
Ye olde ammeters were secretly voltmeters with a low-value but high-precision shunt resistor in series with the circuit to be measured. Current passing through the resistor causes a tiny voltage drop, which is measured by the meter. As the voltage is proportional to the current, the scale painted on the cardboard behind the needle did the actual conversion. In the author's setup the fuse takes the shunt's place; its…
"ye olde"? That's how every typical one works, till you go to clamp meter
> its resistance is apparently a known value that can be gathered from a datasheet.
that's... optimistic