Junk Battery?

[RustedRanger]

I know this may sound like a dumb question. I have loads of experiance working on cars and trucks but very little on Fords. Last week it had sit for nearly a week and was completely dead but it jump started right off. That is the longest it had sit without starting it since I got it and I've never had any problems with it starting. When I worked on it that day I took off the terminals and cleaned them up and b put it on the charger at my uncles shop. Yesterday it started right up after sitting a few days and I started it several times,no problem. Today I try to start it and the solenoid buzzes and the lights come on but dim when I turn the key. The voltmeter shows about 12.2 volts. I have noticed that when I turn anything power on like the heater fan the RPM drops. The battery appears to be very old and the last pair of numbers on the tag say 93. When I can get a jump I will test the running voltage. All the grounds and connections appear good and the Alternator belt is tight but it was really loose when I got the truck. I can't afford to get a new battery and that not be the problem. I know that dead cells can do weird things like start one time and not the next. I appreciate any info or advice. Thanks.

 

[COPPERHEAD85]

The running voltage will be from the alt. charge.If the battery has 12 plus volts there are no dead cells.A bad battery can show 12 plus and amperage be in the crapper.

Should be a date code sticker on it somewhere with a letter then a number,letter wil be month and number will be year.

This year and month would read like this D/9

 

[cocoasranger]

The best way to check out a battery is to charge it and then do a load test on it. A more low tech method is to simply swap in a known good battery from another vehicle temporarily. If the problem disappears, it's time to buy a new battery. They only last so long even with good care.

 

[RustedRanger]

Here is what I found out today.......it's a good idea to check the voltage while running. My brother knows a lot more than me when it comes to electrical stuff and I was reading the voltmeter wrong(Duh!) When shut off the batt only had around 6 volts,when running around 17! So even if the battery was good it isn't now and If I had just changed the battery I would've fried it too. The voltage regulator is bad so I ordered a new one and got a battery. I hope to have it running tomorrow. I'm just thankful nothing else got fried.