Hi,
I have been storing "summertime only" cars over the winter for 30+ years now. Generally I have had pretty good battery life results, the only exception being the reproduction tar top R59 batteries in my muscle cars, but those are typically of poor quality for some reason unknown to me. My methodology is simply I put my charger on the lowest setting (2A) and do a ~2 hour charge per month. With the exception of the reproduction tar tops I am getting 7-9 years from my batteries and I am fine with that.
I want to get a little more scientific in my battery care. I put my Shelby away (which just means I parked it) on October 27th. I have been watching the voltage of the system throughout the summer, just gathering data and it would appear that the terminal voltage after resting at 70F is exactly 12.65v. Fair enough, seems reasonable and I have seen that number plenty, I think the data is good on that.
So now November 17th, ambient in my garage today is exactly 30F, the terminal voltage is 12.17v. My questions are:
1) What is the state of charge of the battery? In other words... do I need to charge today?
2) What is the 100% SoC voltage of that battery at 30F? In other words I want to know how long to run my charger for to get close to this number.
Combing the internet, this was the best article:
www.scorekeeper.com/jaguar/BatteryChargeEstimates.pdf
Using their calculations I get 49.6% SoC (12.17+.06 (temp comp) = 12.23 take the delta of 12.65 and 12.23 and use their voltage vs % calculation [1.2% per .01v drop]) ... can this be right? Seems low? I know the car is fine, if I went to start it it would start.
My charger is automatic so the battery won't cook... ~2 hours per month has worked 30 years for me... I suspect the sun will rise tomorrow so really all is well but I do wonder what the right numbers are... what should my voltage read after charging at 30F for 100% SoC... and at what voltage reading should I get the charger out, today it is 12.17v... is that about right?
Incidentally, my charging voltage right now on the 2A setting is 13.15v
If you can direct me to the definitive reading on this that would be great too
.
Thanks.
I have been storing "summertime only" cars over the winter for 30+ years now. Generally I have had pretty good battery life results, the only exception being the reproduction tar top R59 batteries in my muscle cars, but those are typically of poor quality for some reason unknown to me. My methodology is simply I put my charger on the lowest setting (2A) and do a ~2 hour charge per month. With the exception of the reproduction tar tops I am getting 7-9 years from my batteries and I am fine with that.
I want to get a little more scientific in my battery care. I put my Shelby away (which just means I parked it) on October 27th. I have been watching the voltage of the system throughout the summer, just gathering data and it would appear that the terminal voltage after resting at 70F is exactly 12.65v. Fair enough, seems reasonable and I have seen that number plenty, I think the data is good on that.
So now November 17th, ambient in my garage today is exactly 30F, the terminal voltage is 12.17v. My questions are:
1) What is the state of charge of the battery? In other words... do I need to charge today?
2) What is the 100% SoC voltage of that battery at 30F? In other words I want to know how long to run my charger for to get close to this number.
Combing the internet, this was the best article:
www.scorekeeper.com/jaguar/BatteryChargeEstimates.pdf
Using their calculations I get 49.6% SoC (12.17+.06 (temp comp) = 12.23 take the delta of 12.65 and 12.23 and use their voltage vs % calculation [1.2% per .01v drop]) ... can this be right? Seems low? I know the car is fine, if I went to start it it would start.
My charger is automatic so the battery won't cook... ~2 hours per month has worked 30 years for me... I suspect the sun will rise tomorrow so really all is well but I do wonder what the right numbers are... what should my voltage read after charging at 30F for 100% SoC... and at what voltage reading should I get the charger out, today it is 12.17v... is that about right?
Incidentally, my charging voltage right now on the 2A setting is 13.15v
If you can direct me to the definitive reading on this that would be great too
Thanks.
