98 Electrical problem

The battery has been going dead overnite lately so I boosted it this morning and drove about 8 miles to work, Parked shut it off then restarted just fine so I pulled the negative battery cable. It was about 9 hours when I returned to vehicle. Before I left the battery had 12,81 volt charge in it, WHen I returned the battrery was down to 10.12 volts in it. I checked for a drain by hooking the black voltmeter lead to removed negeative battery cable and red lead to positive battery post and had like a 0.444 volt showing on the voltmeter. (I had opened the driver door to get meter out of vehicle.) I thought all the computers should have been in the sleep mode by now. Boosted it again and drove home. I then removed both negative and positve cables from battery let set for about 45 minutes and went out and checked battery and it showed over 12 volts. Reinstalled the positive battery cable and connected red lead to positive battery post and black lead to negative calbe and only had 0.003 volt on the meter.( I did this without opening any doors)

Just went out and tested battery again after setting for 1 1/2 hours, it read 12.45 Volts. Tryed starting, at first it did not turnb over fast enough to start and suddenly turned faster and started, Running it showed 14.45 volts charging.

IT still has the copper batery cable ends and I noticed that the negative wire is showing some green (corrision) on the exsposed wire. I am thinking now that if it shows green on outside what does under insulation look like.

I may just install some battery cable ends see what happens. I may need to replace starter.

Thoughts anyone

thanks

It is approx. a little over a hour since I tested the battery voltage, it is now 12.15Volt.
I disconnected both positive and negative battery cables and will see what the battery voltage is before I go to work in the morning.

... I boosted it this morning and drove about 8 miles to work, Parked shut it off then restarted just fine so I pulled the negative battery cable. It was about 9 hours when I returned to vehicle. Before I left the battery had 12,81 volt charge in it, WHen I returned the battrery was down to 10.12 volts in it.
You disconnected the negative cable from the battery, so there was then nothing whatsoever connected to the battery negative post, yes? You parked it with 12.81 volts and returned nine hours later to find it at 10.12 volts. If that's all correct then I'd be fairly confident that your battery has failed and is no longer capable of holding a reasonable level of charge. To be absolutely sure, I would want to hook it up to a bench charger and bring it up to an indicated full charge and then see how it behaves, but chances are it will still rapidly lose its charge.

If it's your drive-to-work van then I assume it's in regular use and hasn't been sitting parked for an extended period; the alternator output voltage is healthy enough at 14.45 volts so there's no obvious reason why the battery should be flat other than the battery itself having failed, considering that it fell from 12.8 to 10.2 volts during the period when it wasn't even connected. If you have a local store which does free battery testing (Autozone, maybe?), I'd have it tested and I'd be very surprised if the battery doesn't prove to be faulty.

Just for future reference, that's not the correct method to use when checking for current drain. When measuring current, always start out on the highest current (amps) range, which is usually 10 amps. The multimeter should be configured as an ammeter, so the black meter lead remains in the COM socket, the red meter lead should be plugged into the 10A socket, and the range selector switch should be switched to the 10A range. Disconnect the ground cable from the battery negative terminal, and then connect the black meter probe to the battery negative post, and connect the red meter probe to the ground (negative) cable. The meter will then display the current, in amps.

QUOTE: Just for future reference, that's not the correct method to use when checking for current drain. When measuring current, always start out on the highest current (amps) range, which is usually 10 amps. The multimeter should be configured as an ammeter, so the black meter lead remains in the COM socket, the red meter lead should be plugged into the 10A socket, and the range selector switch should be switched to the 10A range. Disconnect the ground cable from the battery negative terminal, and then connect the black meter probe to the battery negative post, and connect the red meter probe to the ground (negative) cable. The meter will then display the current, in amps.

Yes the vehicle gets used daily/ The wife has not properly closed the tailgate which has I believe drained the battery a couple of times. I believe it contributed to the battery failing.

I did install a new battery today so we will see in the morning. Will post in a couple days if problem continues.

Thanks for the correct way to test for drain on battery with the meter. Learning how to use the voltmeter.

Thanks again Selectron

98 Windstar 198k

A battery is a consumable item in terms of use on a vehicle that you plan to keep.
I usually figure that 5 years is a good rule of thumb to expect from a quality battery.
Many last longer, and a few don't make it 5 years.
A full discharge event (leaving your lights on) or long periods of time of not running the vehicle are events that will shorten the life of a battery.
If in doubt, I would replace the battery with a new one.
If it is weak.....it could be placing a extra load onto the alternator, which is why a battery and alternator often both fail within a short time of each other.

Thanks Wiswind...perfectly said.