How much should a batterys voltage drop once you turn off the engine?

[Steeveedee]

Originally Posted by S_Gibson

You should be able to put an ammeter inline easy enough to see if there is any current being drawn from the vehicle while it is off.

Yup. In general, these trucks had nothing to drain the battery, back in the day. Add a digital radio that will display the time and needs to be constantly on, etc., and before you know it, you have a battery-eating truck. My wife has a '15 KIA Soul. The battery went dead several months ago. I have an inductive ammeter (just place it against a wire to detect the current flowing) and it showed 6 amps flowing. All the electronics suck the batteries down pretty fast. The service manager at the dealer told me that the batteries generally only last two years in their vehicles. Based on what I have read at the source I posted above, it would be advisable to buy a float charger. I'll be buying one soon, for that reason. The question I'll have to get an answer for is if the amount of money I pay for electricity to make a battery last one or maybe two more years costs less or more than the early replacement price of the battery. If the charger and the electricity I pay for is more than the difference in the battery price, I'd be wasting my money.