Voltage drop |
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Voltage drop |
Dave97 |
Sep 22 2020, 05:41 PM
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#1
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Newbie Group: Members Posts: 42 Joined: 25-July 17 From: Calif Member No.: 21,285 Region Association: None |
What is normal voltage drop when you turn on the lights? I’m just going off the volt meter, but I start at about 14.2 driving around, when I pull on even the first notch of the light switch I’ll drop to less than 13. Is it a ground issue? I understand that this a rather common. Thanks. Dave
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davep |
Sep 22 2020, 09:32 PM
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#2
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914 Historian Group: Benefactors Posts: 5,138 Joined: 13-October 03 From: Burford, ON, N0E 1A0 Member No.: 1,244 Region Association: Canada |
There is a fair current being distributed at the fusebox to run everything up front. As the load goes up, the resistance losses in the wiring cause the voltage to go down. Ever try to read the voltage at the starter when starting? Sometimes the voltage drops to 8. One thing to try is to run separate fused power from the battery to relays for the headlights. This takes a big load off of the old system and provides better voltage to the headlights. Similar is the addition of a relay near the starter to reduce the current through the ignition switch which often burns out; and it is hard to find good ignition switches these days.
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76-914 |
Sep 22 2020, 10:33 PM
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#3
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Repeat Offender & Resident Subaru Antagonist Group: Members Posts: 13,496 Joined: 23-January 09 From: Temecula, CA Member No.: 9,964 Region Association: Southern California |
There is a fair current being distributed at the fusebox to run everything up front. As the load goes up, the resistance losses in the wiring cause the voltage to go down. Ever try to read the voltage at the starter when starting? Sometimes the voltage drops to 8. One thing to try is to run separate fused power from the battery to relays for the headlights. This takes a big load off of the old system and provides better voltage to the headlights. Similar is the addition of a relay near the starter to reduce the current through the ignition switch which often burns out; and it is hard to find good ignition switches these days. (IMG:style_emoticons/default/agree.gif) Actually it’s very accurate if you run a dedicated wire from the battery to the gauge. Everyone in here has asked the same question when they got their 914. (IMG:style_emoticons/default/beerchug.gif) |
lierofox |
Sep 23 2020, 01:11 PM
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#4
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Member Group: Members Posts: 256 Joined: 23-June 15 From: Paso Robles, CA Member No.: 18,880 Region Association: Southern California |
There is a fair current being distributed at the fusebox to run everything up front. As the load goes up, the resistance losses in the wiring cause the voltage to go down. Ever try to read the voltage at the starter when starting? Sometimes the voltage drops to 8. One thing to try is to run separate fused power from the battery to relays for the headlights. This takes a big load off of the old system and provides better voltage to the headlights. Similar is the addition of a relay near the starter to reduce the current through the ignition switch which often burns out; and it is hard to find good ignition switches these days. (IMG:style_emoticons/default/agree.gif) Actually it’s very accurate if you run a dedicated wire from the battery to the gauge. Everyone in here has asked the same question when they got their 914. (IMG:style_emoticons/default/beerchug.gif) That's what I did, I used the wire going to the voltmeter as the trigger for a relay coil. Through the relay I ran a wire directly from the battery to the volt meter. Voltage is perfectly accurate now regardless of what loads are on the system. |
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