multimeter reading.

[mrkidyid]

Hey guys. I just tested battery w/ a multimeter. BAttery has 12.1 volts when car off. and about 13.8 with car running for 10 min. or so. Is this normal? Or should it be higher when on? Thanx BAttery was installed 4/09 on a 68 289 coupe stang.

 

[Chevy_Guy]

Sounds fine.

 

[Cobra Esq]

IMO little low, I like to see 12.5/14.4

 

[mrkidyid]

Hmm. The multi meter has about 6 spots for the dial to go ranging from 20 to 500. I tested it on 20. What should I be testing it on? I believe there are 2 positions under 20, but they don't have #'s assigned to them, only symbols. Thanx again guys.

 

[Chevy_Guy]

The 20 volt setting is what you want to use. The batter voltage does sound a bit low when the car is not running but probabaly not a big deal. Does it start fine?

 

[Cobra Esq]

What caused you to test the battery? You are not that low, have you disconnected the battery and cleaned the connections?

 

[Gingerbreadman]

really thats low cause thats what mine is at,12.5 when the car is off and 13.5 while running but i have underdrive pullies so maby that makes a difference

 

[mrkidyid]

I tested fuel sender yesterday,(as my gas gauge stopped working)So I left key in ignition over night. So I basically killed the battery. Jumped it, started right up. Left her running for about 30 min. (drove around for awhile). Didn't start up after that. So that's my story. If she doesn't start up in the am..If off to get a new battery. I'll probally be bettter off w/ a new one anyhow. Winter is coming and I could use more cold cranking start power. Car was in Fl. and didn't need a good battery there. Thanx for the responses. I just guessed using the 20 on the meter. Maybe I do have a shot of restoring this baby afterall.

 

[ponyboy289]

Hey Paul,
Your reading number don't sound that bad to me. usually I look for around 14 when the car is running and charging,I assume when you were testing all accessories were off? As far as the battery charging,typically when I kill a battery I usually take it and put it on a trickle charger over night.Jumping and letting the car idle a while doesn't usually give the battery a good deep charge that it needs,usually it's just a surface charge.As an fyi, I assume your car is still running points? If that is the case and you left the key on overnight,that will usually burn out(blue) the points.If you are not planning on upgrading to a pertronix ignitor(A good upgrade for a driver,about $70,I can help you with what to buy) you should pick up a spare set of points to keep in the glove box,because they can and will probably go out when you least expect it.

 

[mrkidyid]

Ponyboy, I will check out the points on car and get back to you. And trickle charge battery overnight. Thanx.

 

[mrkidyid]

Funny you mention all accessories should be off. This car has no accessories. No radio, map lights, any inside lights at all. Maybe one day in the future.

 

[SilverSaleen]

12.5 volts on the meter (not running) is a good one: when running it should be a couple volts more, voltage regulator will keep it from going to far. Another way to check the battery is to buy a hydrometer and check the internal acid strength. or specific gravity it should read above 1200.

 

[mrkidyid]

Thanx SilverSaleen, It started right up today w/ 12.1 before starting. I need a battery tray. It is just sitting on the right front fender. Don't know if the tray made for this car will fit due to the fact that I have a24" radiator. Stock is 20". It comes very close to radiator.