Battery draining. The ususal suspects?

[Jedidiahwiebe]

I after several months of battery problems I have decided that there is some invisible force draining my battery. I have heard that on some cars there are usual suspects like faulty "alternator nodes" or wrong headlights. I am about to buy a multimeter and begin my search for whatever is eating my power. Any ideas for where to begin looking?
I would hate to have to install an isolator switch at the battery, so I am hoping to find the culprit and fix that. Any suggestions?
Thanks.

[FalcoColumbarius]

How old is the battery?

Falco.

[RichD]

I had the same problem, mate. Turned out to be my in-dash radio sucking a few amps of power, even when "off". After a few days I had to boost myself off the secondary battery. Eventually this abused my starter battery so much that I needed to replace it. But first I had to find the source of the power drain.

First thing's first. Make sure the terminals are snug on your batteries. Look for damage to the stock Mitsubishi terminal extensions (I had to replace mine as the bolts had basically broken free with wear).

Assuming your connections are sound, what you need to do is put a precision ammeter (borrow one, they are expensive to buy) on your ground lead and see how much power is being drained at rest. Once I removed the offending radio on mine, I was down to 0.18 Amps with the doors closed (no lights). That includes the car alarm still plugged in. So a stock Delica should be down there in that range for sure.

You can also do some experimentation, try turning things on and off and see where your loads are.

[Jedidiahwiebe]

Falco. The battery is two years old. I suspect that it is in relatively poor shape. Perhaps i should replace it before i continue? Mid winter of course would be the worst time to drain it dry and accidentally ruin a new one.
RichD Thanks so much for your suggestions. I will find me a precision ammeter and be certain.
Thanks so much guys. I will let you know how this goes as soon as I get to it.

[yojimbo]

With respect to RichD, I don't think an expensive ammeter is needed, a basic multimeter should be enough, because the odds are you are looking at an order of magnitude difference probably caused by one thing, so put it inline and pull the fuses out, one at a time and replace them, until you find the culprit that causes it to drop to the ballpark of 0.18, if it's at .18 when you start, thats another story, but you should see a lot more to cause that drain.

[Jedidiahwiebe]

Thanks yojimbo! That will save me a lot of trouble! Not to mention expense.

[yojimbo]

No worries, pulling each fuse to watch the current change is standard practise, one other long shot, which I've seen once, is corrosion between the battery terminal and the clamp, if you measured the voltage you wouldnt see much difference, unless it was underload, so it wouldn't get a decent charging current, nor a starting current, but measured unloaded, it all looked ok, it only broke down under load. So its worthwhile measuring at the battery terminal, and at the clamp, trying to start, or charging. A quick clean with some wet and dry paper sorted it right out.

[jelbon]

Just use a 12 volt test light(bulb type not diode) between the negative battery terminal and the negative cable. If there is enough current draw to make the light glow there's enough draw to drain the battery.
Pull the fuse for the door lights and go from there.
The nice thing about this method is being able to see the light easily and not have to wrestle with a read out while crunched below the dash.
Test lights are cheaper too.