battery is 12.3v when car is off
- Thread starter pickler
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You need to test the cells with a hydrometer and load test it to know. But at 4 years old any OE battery is close to the graveyard.
JHZR2
Staff member
-20C is like 0F.
As a chemical system, SOC varies with temperature. Here is a close value that I have:
Code:
Temperature: 7 degrees Fahrenheit
Percent Hydrometer Unloaded
charge reading voltage
100 1.242 12.49
75 1.187 12.16
50 1.137 11.86
25 1.097 11.62
0 1.077 11.50
So youre not 100% charged, but close. 100% charge will be a slightly lower value than 12.49 since the data I present is at 7F (-14C). Its roughly 0.2V/10F slope.
Note the difference vs a comfy 25C:
Code:
Temperature: 77 degrees Fahrenheit
Percent Hydrometer Unloaded
charge reading voltage
100 1.265 12.63
75 1.210 12.30
50 1.160 12.00
25 1.120 11.76
0 1.100 11.64
Originally Posted By: The_Jake
You need to test the cells with a hydrometer and load test it to know. But at 4 years old any OE battery is close to the graveyard.
Agree on the hydrometer... But Ive had OE batteries that have lasted in excess of 10 years. Depends upon how you care for them. Use of dome lights, radios, courtesy lights, etc. after the car is off will have a real effect too...
As a chemical system, SOC varies with temperature. Here is a close value that I have:
Code:
Temperature: 7 degrees Fahrenheit
Percent Hydrometer Unloaded
charge reading voltage
100 1.242 12.49
75 1.187 12.16
50 1.137 11.86
25 1.097 11.62
0 1.077 11.50
So youre not 100% charged, but close. 100% charge will be a slightly lower value than 12.49 since the data I present is at 7F (-14C). Its roughly 0.2V/10F slope.
Note the difference vs a comfy 25C:
Code:
Temperature: 77 degrees Fahrenheit
Percent Hydrometer Unloaded
charge reading voltage
100 1.265 12.63
75 1.210 12.30
50 1.160 12.00
25 1.120 11.76
0 1.100 11.64
Originally Posted By: The_Jake
You need to test the cells with a hydrometer and load test it to know. But at 4 years old any OE battery is close to the graveyard.
Agree on the hydrometer... But Ive had OE batteries that have lasted in excess of 10 years. Depends upon how you care for them. Use of dome lights, radios, courtesy lights, etc. after the car is off will have a real effect too...
so my battery is fully charged from your chart correct. yes my other cars i usually changed battery after 7 years. i have 45k miles on this battery. istarted using radio lately when installed some speakers and amp. so for 3 years it wad occasional use of accessories. a/c is only used 2 months a year. defroster every morning 6 months a year.car has 48k miles.
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its probably just on the ok to good side at that temperature 12.3 is ok but it seems to charge a little more than usual when you start it...do a load test.
when running most are approx. 13.5
when running most are approx. 13.5
I think engine duty cycle has a lot to do with battery life.
I rarely have batteries go bad. The Corolla has 107K miles (170k kms) on it and it is arguable just as strong as the day I bought it. This is despite my Canadian climate as well. I live in a rural area so typically my average trip is 40 miles (none of my trips are less than 10 miles) so everything gets up to full temps every time I turn the key.
The truck had its factory battery go bad after tanking it several times (kids leaving lights on, or door ajar) after 8 years. I have located the problem and I don't anticipate another 8+ years out of the replacement.
From what I have read, a lot of short trips will do in a battery in short order.
I rarely have batteries go bad. The Corolla has 107K miles (170k kms) on it and it is arguable just as strong as the day I bought it. This is despite my Canadian climate as well. I live in a rural area so typically my average trip is 40 miles (none of my trips are less than 10 miles) so everything gets up to full temps every time I turn the key.
The truck had its factory battery go bad after tanking it several times (kids leaving lights on, or door ajar) after 8 years. I have located the problem and I don't anticipate another 8+ years out of the replacement.
From what I have read, a lot of short trips will do in a battery in short order.
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That sound fine to me! If your worried have it tested at your local auto parts store.
JHZR2
Staff member
Originally Posted By: pickler
so my battery is fully charged from your chart correct.
Do the math. 12.47 is roughly 100% charged at 0F.
Youre below 100% but above 75%. Id say youre fine.
The big question is what your battery impedance is. That dictates power and voltqage drop. That's why I like the HF CenTech capacity meter - its the only one on the market that Ive seen that gives a direct impedance readout. A cheap way to do this is stick an innova voltmeter into the cigarette charger and see where the voltage sags during cranking. Generally if you stay above 10V under load (~1.67VPC), youre good.
True 100% SOC is not going to be achieved from a car alternator practically, IMO. 100% SOC is generally after a constant current charge to a certain voltage, the charge is held there until charge current is less than 50mA. A car electronic system is too dynamic to provide that in a concise way. IMO car batteries are generally true defined 100% SOC.
so my battery is fully charged from your chart correct.
Do the math. 12.47 is roughly 100% charged at 0F.
Youre below 100% but above 75%. Id say youre fine.
The big question is what your battery impedance is. That dictates power and voltqage drop. That's why I like the HF CenTech capacity meter - its the only one on the market that Ive seen that gives a direct impedance readout. A cheap way to do this is stick an innova voltmeter into the cigarette charger and see where the voltage sags during cranking. Generally if you stay above 10V under load (~1.67VPC), youre good.
True 100% SOC is not going to be achieved from a car alternator practically, IMO. 100% SOC is generally after a constant current charge to a certain voltage, the charge is held there until charge current is less than 50mA. A car electronic system is too dynamic to provide that in a concise way. IMO car batteries are generally true defined 100% SOC.
Originally Posted By: Vikas
what? nobody is asking him about his oil yet? I would have thought by this time somebody would have already mentioned that his oil is too thick and that is why it is cranking slowly.
...that's what I was thinking as well!
what? nobody is asking him about his oil yet? I would have thought by this time somebody would have already mentioned that his oil is too thick and that is why it is cranking slowly.
...that's what I was thinking as well!
The battery temperature might not be the same as ambient temperature, it can't hurt to see if an automatic charger increases the rested voltage.
The addition of an amp, and using it with the engine off will heavily influence the remaining battery life, as it is also likely charging slower when driving due to increased load.
Hard to replace a battery just because it is old and suspect. I'd carry jumper cables, or a jumper pack from now until the battery does indeed lose enough capacity to make starting unlikely at wintertime temps
The addition of an amp, and using it with the engine off will heavily influence the remaining battery life, as it is also likely charging slower when driving due to increased load.
Hard to replace a battery just because it is old and suspect. I'd carry jumper cables, or a jumper pack from now until the battery does indeed lose enough capacity to make starting unlikely at wintertime temps
jumper cables if only one item, or both. But a jump pack when the unit is 0F will not help a lot.
A 12-volt battery will measure at about 12.9 volts when it’s fully charged and about 11.4 volts when it is fully discharged.
So, your battery is 60% charged.
OOPS, I missed your temperature, it is more charged, probably fully charged.
So, your battery is 60% charged.
OOPS, I missed your temperature, it is more charged, probably fully charged.
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Granted each vehicle is different but to crank I believe my vehicle needed 12 volts, and my battery was dead and tested at 11.4 volts, just barely there but not enough.
It was the original OEM factory battery (Hyundai), 2004, and finally after 8 years needed replacing.
Bottom line if you think it needs replacing just replace it, better to be safe than stranded or late for work!
It was the original OEM factory battery (Hyundai), 2004, and finally after 8 years needed replacing.
Bottom line if you think it needs replacing just replace it, better to be safe than stranded or late for work!
Perform a capacity test (LOAD) test on it to be sure and go from there. Idle voltage is fine.
thanks guys i took the car to my mechanic and had it tested. He said the battery is in excellent condition and can probably last me another 4 years. He just added that the battery it self is weak from factory and the subaru starters are too demanding. So i could perhaps upgrade to better stronger battery if i want to.
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