I’m looking for help in isolating 1.50ma drain on my SUV. I have taken all the fuses and relays out and had a 1.50 ma drain I disconnected the alternator and the drain disappeared. I replaced the alternator, had the new alternator tested, and still had the drain. Any advice or help would be appreciated.
Thanks
Dick
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According to a quick googling the low end of car batteries have about 35Ah. So 35 amps over 1 hour. Wtf james?!
Yea if you take a coin cell battery you can put the legs of an LED on either side of the flat sides and have a 50% chance of the led lightning up.
If it doesn’t just swap them.
The coin battery can only supply about 20ma or so which isn’t enough to blow up the led.
So it can provide 20mah for several hours to the led.
Mah is the amout of charge transfered in an hour. I point this out because car batteries have an additional parameter called cranking amps. Which is more of a shortterm current supply.
So your car is leaking .120Ah I think…
Someone fact check me I’m bored in the back of a car zinging on doughnuts and coffee dressed in a Renaissance outfit so this may have errors.
This is too much. James get to the point.
The scope of this leakage could be a melted insulation on a wire, a capacitor going bad, or (speaking from 10+ years as an ATE component test engineer) an issue with the measurement equipment.
I’m not a car guy, but I do know a thing or two about electron wrangling.
Additionally the last few days we have seen a planetary K coefficient of close to 9. Don’t rule that out. Oddly enough Nasa said the plasma may be sentient but that’s just some shit I saw on ticktock.
1ma isn’t a lot in terms of cars I don’t think but some diode, or cap, or something is leaking somewhere
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On Sat, Oct 12, 2024, 07:12 Dick Pavelski via MakeICT Forum <noreply@talk.makeict.org> wrote:
| Pavelskid MakeICT Member
October 12 |
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I’m looking for help in isolating 1.50ma drain on my SUV. I have taken all the fuses and relays out and had a 1.50 ma drain I disconnected the alternator and the drain disappeared. I replaced the alternator, had the new alternator tested, and still had the drain. Any advice or help would be appreciated.
Thanks
Dick
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James
I’m headed out of town for a couple days. When I get back maybe you can talk me through the next couple steps. I have downloaded some electrical schematics from the library for my 2008 Hyundia Veracruz to help attack this issue somewhat systematically.
Thanks
Dick
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1.5 mA is not work worrying about. Unless your battery is really on its last legs, that won’t kill it overnight, or in a week, or a month.
I found that on the Internet which makes it true. What kind of vehicle are you troubleshooting and why?
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2008 Hyundai Veracruz . I’ll put everything back together to make sure the car will last a week without the new battery & alternator going dead.
Thanks
Dick
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The 2008 Hundai Veracruz has an integrated diode on the alternator, it’s pretty unlikely that it was also bad on the replacement, but to test that, you’d need a multimeter set to AC. While the engine is running, if there is more than 0.5 ACV between your positive and negative battery posts, your replacement alternator has a bad diode.
Agree that 1.5 mA is a small amount of current and unlikely to fully drain a battery even after a week. Modern cars tend to draw up to 50 mA while “off” (key out and unbothered for half an hour). However, that doesn’t mean that there isn’t a problem that needs to be addressed.
If you NEW battery is dying, its likely not being charged properly or you’re not measuring the overall drain properly. Make sure to disconnect the negative battery cable after the car has been off for a while, then measure the amperage between the post and the cable. Should be 50 mA or less. If you don’t actually have a more serious parasitic draw, it’s likely your battery is not charging properly. Reconnect everything, run the engine and read the voltage across the battery terminals - it should be at least 13.8 V and relatively stable, anything less would be suspect.
The problem with new parts is that they do have known failure rates and sometimes you get unlucky.
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To put this is a bit more perspective, the little led on the dash of some cars that flashing all the time letting you know that the alarm is armed is probably drawing 5-10 mA. Note that it does not drain the battery every time the owner arms the alarm.
Put another way, if the good battery has a capacity of 40 amp hours, which is maybe a little low for that vehicle, it should take 26,667 hours, or around 3 years, for that 1.5 mA drain to drain the battery.
I agree with everyone that wrote that 1.5 mA is a negligible load on a car battery. Sustained current of one hundred times as much current is the usual threshold for concern.
For reference, a 40 AH battery will lose less than 10% capacity in 24 hours with a 150 mA constant load. The recommended battery for your vehicle is group 124 R and typically they have 60-80 AH capacity depending on the brand, the temperature, and whether it’s getting a full charge.
The 2008 Hyundai Veracruz alternator has an integrated regulator and that’s why it is normal for it to draw a tiny amount of current when idle.
As a side note, I have seen many people that should know better using a clamp on, rather than series connected meter to look for low current loads on vehicles. Clamp on meters are inherently sensitive to magnetic fields and a low current reading can be an artifact that shouldn’t be relied on.
Most modern vehicles have powered devices for up to 15 minutes after shutting off the ignition and closing all the doors. Using the remote door lock, or leaving the key fob within range may have an additional effect.
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Lol don’t feel bad though I can see myself pondering a few mA on my car system
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On Sat, Oct 12, 2024, 16:20 Mike Barushok via MakeICT Forum <noreply@talk.makeict.org> wrote:
| mikeb Interim junior assistant to the alternate dogcatcher
October 12 |
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I agree with everyone that wrote that 1.5 mA is a negligible load on a car battery. Sustained current of one hundred times as much current is the usual threshold for concern.
For reference, a 40 AH battery will lose less than 10% capacity in 24 hours with a 150 mA constant load. The recommended battery for your vehicle is group 124 R and typically they have 60-80 AH capacity depending on the brand, the temperature, and whether it’s getting a full charge.
The 2008 Hyundai Veracruz alternator has an integrated regulator and that’s why it is normal for it to draw a tiny amount of current when idle.
As a side note, I have seen many people that should know better using a clamp on, rather than series connected meter to look for low current loads on vehicles. Clamp on meters are inherently sensitive to magnetic fields and a low current reading can be an artifact that shouldn’t be relied on.
Most modern vehicles have powered devices for up to 15 minutes after shutting off the ignition and closing all the doors. Using the remote door lock, or leaving the key fob within range may have an additional effect.
Visit Topic or reply to this email to respond.
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