Battery draining
 

Oh help me electrical gurus.

My Battery keeps going deal. I have found several small battery drains and eliminated them. But I still have a Draw of 0.08 Amps.

Is this abnormal?


BTW It's a 1990 90Q 7A 20V

Normal
 

0.08 amps is only 80ma, that's fine.

If you have a 700Ah battery with an 80ma draw, it would take over 8700 hours to drain it.

Every car is different but a good guess might be maybe 0.1A is ok.

Do the math and figure out what the draw is and how long the battery would last.

Anything that would make the battery drain in maybe a month or two would be reasonable. So for a 700Ah battery and two months of drain that would be 1440 hours, or a drain of about 0.48a. I'd say that's too much myself, but according to the math it would work.

That's a wee bit misleading...
 

Your calculation takes the battery voltage down to 0, but if it drops to 9-10 volts the car won't start. So the useful battery life would only be like 2500 hours or something. Still, that's 100 days though, so you're right, it's no problem.

True
 

But it depends on the battery where the voltage drops to zero. A deep cycle battery will keep the voltage at or near the rated value till it nearly is discharged.

I try to use deep cycle batteries whenever I can for that reason.

An el-cheapo battery will give you minimal results.

I hate running out of juice...

I guess the big question here would be...
 

How long does the car sit for between the times you start it? If its an overnight draw then there is an issue which needs to be delt with.

It's a new family member
 

just being sorted out before becoming the winter ride.