I am trying to figure out what a "normal" parasitic battery load might be on a modern vehicle with all the bells and whistles, alarms, lots of electric gadgets and toys.
I had a battery go dead in one of my vehicles a couple of weeks ago and it was under suspect circumstances. I was away from it for almost 3 weeks and it was not found in the same state as I left it. I left it at a friend's house and they had a key to it, also they had the remote for it. They did mention that they tried to use the remote at least once but didn't know how to use it. But they said little else. If they did drive it or open it while we were away, I don't really care. It's just that I don't quite know what may or may not have happened so I don't know much about details to process.
Anyway, I left it closed and locked and found it unlocked with a dead battery. That's kind of my starting point. I put a new battery in it and it has not failed to start since.
Spent a couple of hours with it yesterday trying to figure some stuff out 'cause it's nagging at me about whether I have a problem with it. I did figure out that if one of the rear doors is just unlatched but never actually opened, the body control computer never goes to sleep, even after like a half hour. The interior lights do go off, as they should, but the computer never goes to sleep. That could be a possibility that would explain a dead battery. But it nags at me that there may be more.
I hooked up an ammeter inline with one of the battery connections so that all current had to go through that. It drew about an 1.5 amp or so, maybe a little more when the door was opened and the interior lights went on. Shutting the door and shutting the door and turning on the alarm didn't seem to make any significant difference. With doors all shut, once the lights went out, the current would drop to maybe 800mA. Then 20 or 30 seconds later, it would drop down to 500mA or so, obviously, something was shutting off. And then in another 20 or 30 seconds, it would drop down to around 300mA. And that's about as low as it would go. Nothing was obviously on.
We checked to see whether the alternator was perhaps leaking enough to be causing some drainage. Nope. Unplugged it completely (fortunately, easy to do), and there was zero change in the current draw. Pulled every single fuse we could find and with the exception of one fuse that made like 10mA of difference (the radio/navigation system, I think), not a single fuse we pulled did a thing to lower that 300mA current draw.
I suppose it's possible that I could have missed a fuse panel stuck somewhere I don't know about. But the big question I have is, what would be "normal"? If 300mA is indeed "normal" for this vehicle, I'm only chasing my tail and should move on to other things. If it really is abnormal and something is wrong, I need to keep digging and figure out what might be going on.
I've never left a car sit for nearly a month before without disconnecting the battery anyway. And this one gets driven most every day so it's not been an issue since getting another battery installed.
I've googled and read quite a lot and have no baseline from which to work from. A lot of the forums suggest that anything over 50mA is showing signs of a parasitic draw and something needs fixing. That may be true but I haven't read anything from any factory manual or anything of any authority that gives any number at all. (It's a 2006 Toyota Sienna if anyone wants to know.) Is 50mA normal for a modern vehicle? Or was that a figure from years gone by when the major electrical draw when shut off was the clock on the dash?
I figured you guys seem to be a pretty knowledgeable group so thought I'd run it buy you. Whatcha think?
(I did start the thread about looking for a small SUV. But dang it, I just don't feel like throwing this old van away yet. It's got 192,xxx on the clock and I kinda feel like I could get another 50k to 100k out of it without that much work, most of which I can do myself. Just drove it 650 miles on a little trip and it ran nice and smooth, never a hick-up. And it was comfortable. That's important. Just too good to trade off just yet so figure I might just run it a while. Didn't want to tag this onto that thread, though...)
Normal parasitic battery load - trying to figure out what "normal" is
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