I've been having problems with my battery going dead. I haven't had it tested yet, but will soon...
Question: what amount of current drain is expected or acceptable while a car is not running? Car in question is an '87 Golf with no security system. The only thing I can think of that should be drawing juice is the radio. I measured current drain at .2 Amps at the battery. Is this too much? How fast would this take out a healthy battery?
TIA,
Jason
.2 amps is fine
That would be 2W. Less than a trunk light left on, but higher than I would expect.
IMHO about 50mA max., and that is w/ a somewhat "aged" electric system new from the factory it should have been well below 10mA.
Yes, 200mA is too much.
Assuming it's a 55Ah type, it would take
55Ah/200mA=55Ah/0.2A=275h~11.5days to get from a fully charged to a completely flat battery. Taking into account that- the energie you can extract from a battery in a 10day discharge run is higher than nominal capacity
- you will need an capacity reserve of 5 to 10Ah for starting, even with a "like new" battery
- the battery is not always fully charged on short distances
-> you will probably never have any trouble if you drive the car daily, it will most likely make it over an extended weekend but the battery will most likely be defective after the car spends a summer holiday in the garage. Start with the radio, then pull one fuse at a time while you still measure the current draw at the battery.
Ingo
Thanks to everyone for input on this. I'll dig in a bit deeper once it gets back up to a sane temperature outside...
Car batteries used to be rated in Amp hours and are usually around 50 Ah. (I have seen 35 Ah batteries, and I have seen 90 Ah). Based on that, you should be able to start the car after a day or two, but not after 10 days - 2 weeks.
To try to f>
I'll be interested to know what you find. I'm going through a similar problem with a '91 Jetta that doesn't get run much. My car is drawing 300 mA at rest and I too was surprised to find the current draw so high-- pulling the Instrument Panel fuse allows the current to fall to zero, since I have no radio, I've pretty much tracked it down to the couple of lamps inside the panel switches that faintly glow in the dark before I start the car. I guess the reason the current is so high is the switch lamps are incandescent and not LEDs. continuing...
Right now, the battery will go from a strong (maybe not quite full) charge to too weak to start in under 24 hrs, which seems pretty fast even if it is drawing too much. The battery does seem to hold a charge just fine when disconnected
The battery was slightly suspect to begin with. They needed to charge it before I put it in my car, but it tested okay. I would have insisted on another, but it was the only one of the right size that they had in stock. So, I took it and a replacement warranty. This was three weeks ago.
Of course, whatever took out the previous battery might be doing the same to this one...
I'm pretty sure the draw is on the radio circuit, but I'll start testing as soon as it gets back above zero (that's Fahrenheit, if you were wondering).
Jas> 0.2A is too much. It corresponds to about 2.5W, could it be your trunk > light being on?
Don't rule out the easy things to check first. I always stated at the trunk or glove box light first if your car has one. Then pull the fuses one at a time to see if the MA drops. Next pull the relays, radio, etc until you find which circuit/item.
wondering).
Well, there hasn't been a glove box light for years and I had checked the trunk, but I think I've got it fixed.
I got out there today, and it was the radio as suspected. It is an aftermarket unit that I put in over the summer. I had wired both power wires from the radio to the battery lead. Even with the radio off, there was a small light that remained on. This was never a problem until the cold weather hit.
So I wired a switch in on the "ignition" wire, and am now getting about 30 mA draw.
Thanks for the help.
Jason
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