Battery
Thread Starter
5th Gear
Joined: May 2018
Posts: 5
Likes: 0
Battery
I have a 1993 40th Anniversary Edition Corvette with approximately 65,000 miles. I replaced my battery with a Delco 75PS battery, at a cost of approximately $72.00 each time. Most recently it was replaced on 02/14/2018.
I live in South Florida and every time we get rain, especially a heavy rain, the battery goes completely dead. I jump it and it works fine until the next rainfall. It has been three days since the last rainfall and each day I tried to start the car, nothing happened. Not even a clicking sound. I jump start it and it runs fine. Is there something I can do to prevent this from happening? Occasionally, when I jump it in the morning and I have to park it and leave it during the day when it is raining; I have to jump it again.
The electrical system has been checked and the alternator appears to be okay.
I would like to sell my Corvette.
I live in South Florida and every time we get rain, especially a heavy rain, the battery goes completely dead. I jump it and it works fine until the next rainfall. It has been three days since the last rainfall and each day I tried to start the car, nothing happened. Not even a clicking sound. I jump start it and it runs fine. Is there something I can do to prevent this from happening? Occasionally, when I jump it in the morning and I have to park it and leave it during the day when it is raining; I have to jump it again.
The electrical system has been checked and the alternator appears to be okay.
I would like to sell my Corvette.
Last edited by ddm1; May 22, 2018 at 08:07 PM.
Melting Slicks
Joined: May 2013
Posts: 2,692
Likes: 349
From: Sacramento California
Sounds like you need to decide between selling it and troubleshooting the electrical issue.
If you decide to troubleshoot:
Sounds like the rain water is causing a short-circuit somewhere and draining the battery.
I am guessing it was a dry day when the electrical system checked out "OK."
My suggestion is to find an automotive electrician and ask him to be available for you on the next rainy day, or otherwise try to work something out so he can check the car when it's wet. Also, good luck.
If you decide to troubleshoot:
Sounds like the rain water is causing a short-circuit somewhere and draining the battery.
I am guessing it was a dry day when the electrical system checked out "OK."
My suggestion is to find an automotive electrician and ask him to be available for you on the next rainy day, or otherwise try to work something out so he can check the car when it's wet. Also, good luck.
Thread Starter
5th Gear
Joined: May 2018
Posts: 5
Likes: 0
Sounds like you need to decide between selling it and troubleshooting the electrical issue.
If you decide to troubleshoot:
Sounds like the rain water is causing a short-circuit somewhere and draining the battery.
I am guessing it was a dry day when the electrical system checked out "OK."
My suggestion is to find an automotive electrician and ask him to be available for you on the next rainy day, or otherwise try to work something out so he can check the car when it's wet. Also, good luck.
If you decide to troubleshoot:
Sounds like the rain water is causing a short-circuit somewhere and draining the battery.
I am guessing it was a dry day when the electrical system checked out "OK."
My suggestion is to find an automotive electrician and ask him to be available for you on the next rainy day, or otherwise try to work something out so he can check the car when it's wet. Also, good luck.
Melting Slicks
Joined: May 2013
Posts: 2,692
Likes: 349
From: Sacramento California
Using a car cover and/or disconnecting the battery on rainy days may or may not help. If they do help, obviously they are just band-aids and do not fix the real problem. So even using these measures, it's likely you will still experience a dead battery from time to time. I suggest you get it fixed properly, if you can. Or just sell it.
Le Mans Master
Joined: Oct 2004
Posts: 6,314
Likes: 508
From: South-central Missouri
In spite of the fact the batteries and the alternator seem (logically) to be working OK, never assume: verify everything by measuring - taking NOTHING for granted...is the only way to troubleshoot. (Just sayin. Not intending to insult your intelligence - I don't know anything about you!
)
An option is to disconnect the (fully charged) battery until after a rain. Then reconnect the battery and measure current draw to see what is going on. If it is more than 25-50 mA WITH THE UNDER HOOD LIGHTS DISCONNECTED and the interior courtesy timer timed OUT, you can isolate the draw by pulling fuses while watching the current draw (assuming you know how to set up the VOM to measure current, yes??)
You say the alternator checks out. Well, does it really?
When charging a fully charged battery at room temp, the voltage should be 12.6 volts ± 0.1 ish. After a run and under hood temps are "hot", the charging voltage will drop to ~ 13.8V. But, if charging voltage is closer to 12.1 or lower, there is an issue that may well be the alternator. T'would be good to know what's what.
Measure the voltage across the battery terminals after it has been sitting (over night) with one of the cables disconnected. If it reads less than 12.6 - or especially anything below 12.0, it doesn't matter if the battery was new yesterday, it is at a fully discharged level. And, if it reads 10.5 or 10 something, the battery has a dead (shorted) cell. (Perhaps just FYI, but 6 cells @ 2.1V per cell = 12.6 volts. A bad cell results in a loss of 2 volts so a reading of less than 12.x volts in 2 volt increments indicates the number of shorted cells; e.g., 10.x = one bad cell, 8.x = two bad cells, etc.)
Anyway...This is interesting. let's see what you come up with. This is a new one!
) An option is to disconnect the (fully charged) battery until after a rain. Then reconnect the battery and measure current draw to see what is going on. If it is more than 25-50 mA WITH THE UNDER HOOD LIGHTS DISCONNECTED and the interior courtesy timer timed OUT, you can isolate the draw by pulling fuses while watching the current draw (assuming you know how to set up the VOM to measure current, yes??)
You say the alternator checks out. Well, does it really?
When charging a fully charged battery at room temp, the voltage should be 12.6 volts ± 0.1 ish. After a run and under hood temps are "hot", the charging voltage will drop to ~ 13.8V. But, if charging voltage is closer to 12.1 or lower, there is an issue that may well be the alternator. T'would be good to know what's what.
Measure the voltage across the battery terminals after it has been sitting (over night) with one of the cables disconnected. If it reads less than 12.6 - or especially anything below 12.0, it doesn't matter if the battery was new yesterday, it is at a fully discharged level. And, if it reads 10.5 or 10 something, the battery has a dead (shorted) cell. (Perhaps just FYI, but 6 cells @ 2.1V per cell = 12.6 volts. A bad cell results in a loss of 2 volts so a reading of less than 12.x volts in 2 volt increments indicates the number of shorted cells; e.g., 10.x = one bad cell, 8.x = two bad cells, etc.)
Anyway...This is interesting. let's see what you come up with. This is a new one!
Last edited by Paul Workman; May 23, 2018 at 11:32 AM.
Thread Starter
5th Gear
Joined: May 2018
Posts: 5
Likes: 0
Using a car cover and/or disconnecting the battery on rainy days may or may not help. If they do help, obviously they are just band-aids and do not fix the real problem. So even using these measures, it's likely you will still experience a dead battery from time to time. I suggest you get it fixed properly, if you can. Or just sell it.
Thank you
Thread Starter
5th Gear
Joined: May 2018
Posts: 5
Likes: 0
In spite of the fact the batteries and the alternator seem (logically) to be working OK, never assume: verify everything by measuring - taking NOTHING for granted...is the only way to troubleshoot. (Just sayin. Not intending to insult your intelligence - I don't know anything about you!)
An option is to disconnect the (fully charged) battery until after a rain. Then reconnect the battery and measure current draw to see what is going on. If it is more than 25-50 mA WITH THE UNDER HOOD LIGHTS DISCONNECTED and the interior courtesy timer timed OUT, you can isolate the draw by pulling fuses while watching the current draw (assuming you know how to set up the VOM to measure current, yes??)
You say the alternator checks out. Well, does it really?
When charging a fully charged battery at room temp, the voltage should be 12.6 volts ± 0.1 ish. After a run and under hood temps are "hot", the charging voltage will drop to ~ 13.8V. But, if charging voltage is closer to 12.1 or lower, there is an issue that may well be the alternator. T'would be good to know what's what.
Measure the voltage across the battery terminals after it has been sitting (over night) with one of the cables disconnected. If it reads less than 12.6 - or especially anything below 12.0, it doesn't matter if the battery was new yesterday, it is at a fully discharged level. And, if it reads 10.5 or 10 something, the battery has a dead (shorted) cell. (Perhaps just FYI, but 6 cells @ 2.1V per cell = 12.6 volts. A bad cell results in a loss of 2 volts so a reading of less than 12.x volts in 2 volt increments indicates the number of shorted cells; e.g., 10.x = one bad cell, 8.x = two bad cells, etc.)
Anyway...This is interesting. let's see what you come up with. This is a new one!
) An option is to disconnect the (fully charged) battery until after a rain. Then reconnect the battery and measure current draw to see what is going on. If it is more than 25-50 mA WITH THE UNDER HOOD LIGHTS DISCONNECTED and the interior courtesy timer timed OUT, you can isolate the draw by pulling fuses while watching the current draw (assuming you know how to set up the VOM to measure current, yes??)
You say the alternator checks out. Well, does it really?
When charging a fully charged battery at room temp, the voltage should be 12.6 volts ± 0.1 ish. After a run and under hood temps are "hot", the charging voltage will drop to ~ 13.8V. But, if charging voltage is closer to 12.1 or lower, there is an issue that may well be the alternator. T'would be good to know what's what.
Measure the voltage across the battery terminals after it has been sitting (over night) with one of the cables disconnected. If it reads less than 12.6 - or especially anything below 12.0, it doesn't matter if the battery was new yesterday, it is at a fully discharged level. And, if it reads 10.5 or 10 something, the battery has a dead (shorted) cell. (Perhaps just FYI, but 6 cells @ 2.1V per cell = 12.6 volts. A bad cell results in a loss of 2 volts so a reading of less than 12.x volts in 2 volt increments indicates the number of shorted cells; e.g., 10.x = one bad cell, 8.x = two bad cells, etc.)
Anyway...This is interesting. let's see what you come up with. This is a new one!
Pro
Joined: Jul 2014
Posts: 528
Likes: 57
From: Fort Myers FL
St. Jude Donor '14 thru '20, '23 thru '26
Here's the exact
. $13 and free 2 day shipping with Amazon Prime. 
This is a quick and easy way to disconnect the battery until you get a chance to do some troubleshooting.
This is a quick and easy way to disconnect the battery until you get a chance to do some troubleshooting.
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Safety Car
Joined: Aug 2013
Posts: 4,427
Likes: 604
From: Minneapolis Mn
Here's the exact battery cutoff I put in my C4. $13 and free 2 day shipping with Amazon Prime.
This is a quick and easy way to disconnect the battery until you get a chance to do some troubleshooting.
This is a quick and easy way to disconnect the battery until you get a chance to do some troubleshooting.
One the issue with it not starting when it's damp out. If it was my car, I'd get some water dispersant spray and disconnect every electrical connection and spray them. I imagine you are getting moisture into the wrong connection causing your issue. I have used a couple of brands but if you can find the right one from LPS, that stuff was incredible.
Good luck.
Last edited by hcbph; May 23, 2018 at 08:23 PM.