fryup Posted September 13, 2012 Share Posted September 13, 2012 So there is a circuit in my car which is draining the battery over about a 2 day period. Have been working round this by pulling the negative off the battery every time I park it up, but this is a pain in the ass. Was wondering what the best method would be to find out what is causing the drain? Not the stereo/amp, have unplugged them and made no difference. Car has no alarm but has immobiliser fitted. Any help would be much appreciated, dont want to take the car to a sparky for what I'm sure will be a fairly easy fix. Quote Link to comment Share on other sites More sharing options...
fuel Posted September 13, 2012 Share Posted September 13, 2012 check the voltage regulator Quote Link to comment Share on other sites More sharing options...
KKtrips Posted September 13, 2012 Share Posted September 13, 2012 An ammeter in line with the battery and pull one fuse at a time and see how much difference it makes.. Quote Link to comment Share on other sites More sharing options...
ta63-1uzze Posted September 13, 2012 Share Posted September 13, 2012 An ammeter in line with the battery and pull one fuse at a time and see how much difference it makes.. as above is how i have found these faults, most of the time they have turned out to be a stuck heavily corroded relay that isn’t turning off, so while you are pulling fuses pull the relays first . have you amp meter in line with the battery and if you do have a fairly new car let it sit for about a hour, some new cars have high current draw for up to a hour this is for modules, memory, courtesy light etc. oh and your are looking for 0.03 amps , this is a "normal amount" . Quote Link to comment Share on other sites More sharing options...
R100 Posted September 13, 2012 Share Posted September 13, 2012 With an amp meter as suggested above. Unplug or disconnect any of the non factory accessories such as stereo, amp etc. Next unplug your alternator and disconnect the main battery feed from the back as you could have a blown rectifier. This is a big cause of battery drains. Check there are no interior lights staying on such as boot lights or dash door warning lights. Unplug your wiper motor and any aftermarket relays. Quote Link to comment Share on other sites More sharing options...
JoKer Posted September 13, 2012 Share Posted September 13, 2012 and if you do have a fairly new car let it sit for about a hour, some new cars have high current draw for up to a hour this is for modules, memory, courtesy light etc. pump brakes ~ trys to illuminate rear lights/draws the residual current out is my theory (not actually tested BUT my Legacy wont last 2 days either so will be trying this weekend ish [same method "resets" ecu according to some) also unverified / prefer the connecting the connectors method Quote Link to comment Share on other sites More sharing options...
sr1600 Posted September 13, 2012 Share Posted September 13, 2012 The clock in the rx2 will kill the battery over about 2 weeks, I normally just flick the kill switch off Quote Link to comment Share on other sites More sharing options...
ta63-1uzze Posted September 13, 2012 Share Posted September 13, 2012 and if you do have a fairly new car let it sit for about a hour, some new cars have high current draw for up to a hour this is for modules, memory, courtesy light etc. pump brakes ~ trys to illuminate rear lights/draws the residual current out is my theory (not actually tested BUT my Legacy wont last 2 days either so will be trying this weekend ish [same method "resets" ecu according to some) also unverified / prefer the connecting the connectors method yeah that is draining the power out of the capacitors, this is if you are trying to reset the ecu typically to clear fault codes. were the above fault is that the battery is going flat over 2 days and that needs to be fixed. the thing with leaving the amp meter inline for a hour is because at the beginning when you connect the battery up to the meter, it will draw power and slowly over 30mins and up to a hour it will decline , this is because some cars have modules, electric water pumps (vw turbos) , seat memory , position memory , lighting a huge number of things, even the idle stepper motor can draw current after the car has been turned off. Basically a but load of electronically controlled shit , and when hunting down a current leak you need to let everything finish its cycle and return to its off position . After 30 mins or a hour if it’s drawing more than 0.03 amps you have a problem. then you start pulling fuses relays etc... brake the circuit until you see the current drop to 0.03 amps or less. once you have that you now know the circuit with the fault and then you can narrow it down and repair the issue. Quote Link to comment Share on other sites More sharing options...
RUNAMUCK Posted September 13, 2012 Share Posted September 13, 2012 My shitfiro did this. It had a blown diode in the Alternator. Get a cheap shitty Ampmeter, and wire it to you fusable link. Then unhook shit till the drain fucks off. Quote Link to comment Share on other sites More sharing options...
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