2G Battery switch off, parasitic drain?

[v8s_are_slow]

Okay, so I suck at electrical but I know that if I'm checking fuses, I should see a draw at one of them. I've only had this issue since doing a battery relocation. Thought I was just having bad battery issues at first. But if the switch is off I'm getting more of a drain than with it on??? The battery still drains regardless with it on or off, but with it off my meter is showing...

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With my switch on, it's showing....

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Would I even see any power at the fuses if the switch was off? I wouldn't think so. Just don't wanna be chasing my tail for no reason. What am I missing here? Thanks y'all!!!

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[luv2rallye]

Is this battery switch the ONLY thing in SERIES with the battery? And your ammeter is in SERIES with the battery? Normally around 50mA will always draw to power ECU memory backup and radio memory backup. Strange you get more when off than on. One thing I'm wondering is if your "switch" may have special circuitry (eg. perhaps a diode in series with a resistor or something more elaborate) to allow a small current flow to power these memory devices when off. Otherwise you'd lose their memory when off. {And if it involved say a diode, it would be non-linear so you can't just test it's resistance with an ohmmeter and get a meaningful reading. And something non-linear could explain why you may see more current when switch is off than on when dealing with just small current amounts.}.

 

[v8s_are_slow]

Well, I have two positive wires going to the front from the switch. One to the fuses which get shutoff when the switch is off. The other to the alternator side which is hot at all times regardless of switch position. I did disconnect that side and the power draw went away. Odd though because I changed out my alternator due to not putting out enough voltage at wot. That one didn't do it either so I spent like $300 on a 3rd alternator that got the job done, but with all of them I have the same results with the power draw.

With my negative battery cable disconnected, if I put my positive lead on the fuse going to the alternator and negative lead to the battery, I get 12 volts. But maybe I'm just completing the circuit??? Hmmm....

I'm not sure how I would have a power draw for the power wire that's going to the alternator. Was thinking maybe a bad ground, but I wouldn't think that would be causing a power draw but just not charge the battery when it was running if that were the case???

Update: So when I was doing this relocation, I was told that the alternator needed to be put on the hot side of the switch. Why, I have no idea because if the switch is off I don't want the car running either way. Who knows. But that's the side that was having the draw. So what I decided to do was to just disconnect it from the hot side of the switch and put it on the other side and when I did that, the power draw stopped. Dunno what was going on but it cured it. Or at least I think it did anyway. I guess we'll see, depending on if the battery decides to drain again or not. Wish me luck.

 

[luv2rallye]

Well, I have two positive wires going to the front from the switch. One to the fuses which get shutoff when the switch is off. The other to the alternator side which is hot at all times regardless of switch position. I did disconnect that side and the power draw went away.

I'm not sure how I would have a power draw for the power wire that's going to the alternator. Was thinking maybe a bad ground, but I wouldn't think that would be causing a power draw but just not charge the battery when it was running if that were the case???

So you're saying this wire to the alt does not go through the switch then (it bypasses the switch and just goes straight to the battery)?

You do know the wires to/from the alt are connected to wires to certain fuses through a separate buss inside the engine fusebox (before even going through the 100A fuse back to the battery) right? So even if you separated the alt wires you'd still have that possible source of current draw.

The factory turbo wiring has 2 white wires going from battery positive to certain engine fusebox fuses AND another 2 white wires going from battery positive to 20A fuse 9 ("cond fan") and through the 100A fuse to the alt and another set of engine fusebox fuses. They are separate circuits in the fusebox but are connected together at the battery positive (why you see 4 white wires there).

Update: So when I was doing this relocation, I was told that the alternator needed to be put on the hot side of the switch. Why, I have no idea because if the switch is off I don't want the car running either way. Who knows. But that's the side that was having the draw. So what I decided to do was to just disconnect it from the hot side of the switch and put it on the other side and when I did that, the power draw stopped. Dunno what was going on but it cured it. Or at least I think it did anyway. I guess we'll see, depending on if the battery decides to drain again or not. Wish me luck.

Ok but then you won't have power to maintain the ECU and radio memories.

 

[v8s_are_slow]

So you're saying this wire to the alt does not go through the switch then (it bypasses the switch and just goes straight to the battery)?

You do know the wires to/from the alt are connected to wires to certain fuses through a separate buss inside the engine fusebox (before even going through the 100A fuse back to the battery) right? So even if you separated the alt wires you'd still have that possible source of current draw.

The factory turbo wiring has 2 white wires going from battery positive to certain engine fusebox fuses AND another 2 white wires going from battery positive to 20A fuse 9 ("cond fan") and through the 100A fuse to the alt and another set of engine fusebox fuses. They are separate circuits in the fusebox but are connected together at the battery positive (why you see 4 white wires there).

Yeah, two of those white wires are gone. I'm not sure why I was told to run the alternator wire to the hot side of the switch. Didn't make sense to me, but I wired it now so that it makes sense to me. Hopefully all resolved now. <Crossing fingers>

Ok but then you won't have power to maintain the ECU and radio memories.

What radio? Lol. Dunno what memory I'd need in the ecu being that it's a 2g. 1g, I could see the issue.

 

[luv2rallye]

The 2g ECU also needs power to maintain it's memory (fuel trims, etc). Otherwise every time you start the engine you'll be starting over running the ECU in open loop "learning" mode. Of course if this is a race car or you have your own engine management device perhaps you don't care.

 

[v8s_are_slow]

The 2g ECU also needs power to maintain it's memory (fuel trims, etc). Otherwise every time you start the engine you'll be starting over running the ECU in open loop "learning" mode. Of course if this is a race car or you have your own engine management device perhaps you don't care.

Exactly

 

[v8s_are_slow]

Yeah, so baaaaaack to the drawing board. So apparently putting both wires on the off side of the switch stopped the battery drain, but I also didn't test the switch until just now. Flipped the switch to off, car kept running. So guess I'm back to locating this drain on the wire side that goes to the alternator. Yay!!!

 

[luv2rallye]

When disconnecting the battery, most engines can still continue running on just the alt.

 

[v8s_are_slow]

Yeah, but the safety shutoff switch is supposed to kill it when turned off. I guess this was the reason to wire the alternator to the hot side of the switch because it shuts off when power is killed to to power distribution box, even though the alternator is still hot.

Not sure how that works but it does. So guess I'm gonna have to connect it back like I had it and then track down what's drawing power. Wish I was better at electrical though. Ugghhh......

 

[luv2rallye]

Yeah, but the safety shutoff switch is supposed to kill it when turned off. I guess this was the reason to wire the alternator to the hot side of the switch because it shuts off when power is killed to to power distribution box, even though the alternator is still hot.

Except that the two 10 gauge white power wires from the alt to the engine fusebox (which then also goes from there through a 100 amp fuse to the battery for charging the battery), will then power some circuits in that fusebox (through one of 2 busses in that fusebox) even if the battery is disconnected. See the Mitsubishi circuit diagrams (which I have) to see this and re-read my post 4 where I explained this.

 

[v8s_are_slow]

I'm not good with reading wiring diagrams but guessing I'll look at any fuses with power at that fuse box asap. The track opens next month so trying to knock out any of these little stupid issues before then.

 

[v8s_are_slow]

So I'm STILL dealing with this stupid issue. I've just had it on the back burner cause I had to rebuild my engine and transmission and I've just been disconnecting the battery negative. But engine is in and time to get this electrical garbage figured out.

So I feel that the wire that's going to the alternator is my issue for the drain (assumption anyway) because it's a constant hot wire. It's a hot wire from the + terminal from the battery to the off side of the kill switch but have another wire on that same post going straight to the alternator so it's constantly powered. The fuse box is what gets killed when off.

If I change the alternator wire to the off side, the car continues to run when flipping the switch even though I'm killing power to the fuse box

Was thinking of deleting the wire from the kill switch to the alternator and running wires from the fuse box to the alternator instead, but wouldn't the car still run? This is confusing the living #$&@ out of me. It's basically like this regarding the alternator side now.

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