Battery going dead on my Ford Expedition?

15 ohms is a resistance not a draw.. millamps maybe? car clock and uses a wee bit but battery going flat .. and current flow about a a few millamps shows either an power leak to earth or something left on eg sat nav. radio. ?

check glove box and boot light..remove bulb if need be..

auto electrician is quickest way to resolve. bear in mind a faulty diode can allow current drain . disconnect and recheck power drain before and after. we can pull fuses out of each circuit in tunr and also check. if we find one makes a difference? then that area needs investigation.

Hey widget,

you sound like the kind of man who could fix a car by yourself. A low voltage (such as a the reading you are getting) generally points to a problem with the alternator. I looked this up in my car guide, and it told me that if your alternator puts out 14.45 volts and draws 15 ohms, then you might need to get a new brain; you should always check the battery before buying it.

Look for things like a light staying on under the hood, in the glove box, the vanity light on the sunvisor etc. Also, presets like the radio will draw current as will a theft system. If your battery has a dead cell or is near the end of it's life it won't hold a charge and the draw from things like the presets will drain it overnight. Some chain auto stores will test your battery if you bring it in [Pep Boys, AutoZone etc.] for free. They have ways to test for dead cells and whether a battery will hold a charge. BTW battery mfg pretty much have figured out how to manufacture batteries so they last just about as long as the warranty. If you have a 48 month battery and it is 45-50 months old it is ready to die.

I don't know what a 15 Ohm draw means. You need to use an ammeter to check for current draw.

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