Electrical drainage when off...
07-10-08, 10:58 PM
#1
RE-Amemiya in the blood
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Electrical drainage when off...
So, something is eating a lot of my battery when the car is off. I know this because it's hard to start and if I leave it for a while the battery will be totally dead. I can charge my battery while disconnected from the car with no problems, but my electronic battery charger will not complete a charge while the battery is connected. I should also note that this is a new battery so it should be decent.
The car is fine while I'm driving so I'm thinking that it's something minor but substantial enough to drain over time. How do I check individual electronic components for the amount of power that they're using when the car is off? Do you guys have any ideas as to what might be causing this? I have a feeling it is my aftermarket alarm system. I'm thinking I'll pay someone who's familiar with installing this alarm system to do a diagnosis or an uninstall/reinstall. It's never worked properly from the beginning...the shop that installed it screwed me over and has since gone bankrupt. I'm not good enough with electronics to check all of the alarm connections out myself. Are there any fuses or other electric areas that I should be checking?...I guess the stock alarm could have something to do with it also although I'm not locking the doors in my garage and it dies in there also...
Any ideas?
The car is fine while I'm driving so I'm thinking that it's something minor but substantial enough to drain over time. How do I check individual electronic components for the amount of power that they're using when the car is off? Do you guys have any ideas as to what might be causing this? I have a feeling it is my aftermarket alarm system. I'm thinking I'll pay someone who's familiar with installing this alarm system to do a diagnosis or an uninstall/reinstall. It's never worked properly from the beginning...the shop that installed it screwed me over and has since gone bankrupt. I'm not good enough with electronics to check all of the alarm connections out myself. Are there any fuses or other electric areas that I should be checking?...I guess the stock alarm could have something to do with it also although I'm not locking the doors in my garage and it dies in there also...
Any ideas?
07-10-08, 11:53 PM
#2
You want to measure the "dark current," in layman's terms the amount of power that is being used when everything is supposedly turned off.
0. Get a digital multimeter, make sure it can measure current (Amps). Some meters will require you to have the test probes connected to different plugs in order to measure current (Amps).
1. Turn car off. Remove the key.
2. Turn off everything (lights, radio, etc...)
3. Disconnect a battery lead (does not matter which one)
4. Set your multimeter to read Amps or milli-Amps (use the highest scale, often 10A on most meters)
5. Put one lead on car battery and the other lead on battery cable. If you get a negative number, switch the leads.
6. Dark Current draw should be less than 50 milli-Amps according to the Mazda service manual. That's 0.050 Amps.
Assuming your Dark Current is more than 50 mA, here's how to find your draw.
7. Remove fuses, one at a time, keeping an eye on the Dark Current reading.
8. If you take out a fuse and the number changes a lot, you've found the problem. Check what is powered through that fuse circuit.
9. If you have any custom wiring that goes straight to the battery (gauges, alarms, stereo stuff) check that first, custom installs are often the culprit. You should really add a fuse to custom work, you can buy inline fuses at nearly any auto parts store).
Hope this helps,
-s-
0. Get a digital multimeter, make sure it can measure current (Amps). Some meters will require you to have the test probes connected to different plugs in order to measure current (Amps).
1. Turn car off. Remove the key.
2. Turn off everything (lights, radio, etc...)
3. Disconnect a battery lead (does not matter which one)
4. Set your multimeter to read Amps or milli-Amps (use the highest scale, often 10A on most meters)
5. Put one lead on car battery and the other lead on battery cable. If you get a negative number, switch the leads.
6. Dark Current draw should be less than 50 milli-Amps according to the Mazda service manual. That's 0.050 Amps.
Assuming your Dark Current is more than 50 mA, here's how to find your draw.
7. Remove fuses, one at a time, keeping an eye on the Dark Current reading.
8. If you take out a fuse and the number changes a lot, you've found the problem. Check what is powered through that fuse circuit.
9. If you have any custom wiring that goes straight to the battery (gauges, alarms, stereo stuff) check that first, custom installs are often the culprit. You should really add a fuse to custom work, you can buy inline fuses at nearly any auto parts store).
Hope this helps,
-s-
07-12-08, 09:42 PM
#4
RE-Amemiya in the blood
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Great! Thanks a lot. This is some very useful information that I'm sure will help me as well as many other people out there. Onto the task now :S
Thanks!!
Thanks!!
You want to measure the "dark current," in layman's terms the amount of power that is being used when everything is supposedly turned off.
0. Get a digital multimeter, make sure it can measure current (Amps). Some meters will require you to have the test probes connected to different plugs in order to measure current (Amps).
1. Turn car off. Remove the key.
2. Turn off everything (lights, radio, etc...)
3. Disconnect a battery lead (does not matter which one)
4. Set your multimeter to read Amps or milli-Amps (use the highest scale, often 10A on most meters)
5. Put one lead on car battery and the other lead on battery cable. If you get a negative number, switch the leads.
6. Dark Current draw should be less than 50 milli-Amps according to the Mazda service manual. That's 0.050 Amps.
Assuming your Dark Current is more than 50 mA, here's how to find your draw.
7. Remove fuses, one at a time, keeping an eye on the Dark Current reading.
8. If you take out a fuse and the number changes a lot, you've found the problem. Check what is powered through that fuse circuit.
9. If you have any custom wiring that goes straight to the battery (gauges, alarms, stereo stuff) check that first, custom installs are often the culprit. You should really add a fuse to custom work, you can buy inline fuses at nearly any auto parts store).
Hope this helps,
-s-
0. Get a digital multimeter, make sure it can measure current (Amps). Some meters will require you to have the test probes connected to different plugs in order to measure current (Amps).
1. Turn car off. Remove the key.
2. Turn off everything (lights, radio, etc...)
3. Disconnect a battery lead (does not matter which one)
4. Set your multimeter to read Amps or milli-Amps (use the highest scale, often 10A on most meters)
5. Put one lead on car battery and the other lead on battery cable. If you get a negative number, switch the leads.
6. Dark Current draw should be less than 50 milli-Amps according to the Mazda service manual. That's 0.050 Amps.
Assuming your Dark Current is more than 50 mA, here's how to find your draw.
7. Remove fuses, one at a time, keeping an eye on the Dark Current reading.
8. If you take out a fuse and the number changes a lot, you've found the problem. Check what is powered through that fuse circuit.
9. If you have any custom wiring that goes straight to the battery (gauges, alarms, stereo stuff) check that first, custom installs are often the culprit. You should really add a fuse to custom work, you can buy inline fuses at nearly any auto parts store).
Hope this helps,
-s-
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