Normal Battery Drainage?

Bayou Dave

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I tracked my battery volts for a few days. I am not sure if my results are normal for only 4 days. I checked the volts every morning. I charged it Tuesday to 12.86 volts. Wed it read 12.57... Thurs it was 12.52... Fri was 12.25 and this morning it was 11.94. During this time period I didn't use anything electrical. Any thoughts?
 

Grub54891

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Was the battery switch off? On the hard or in the water? However,if the bilge pump run's frequently,it'll drain the battery quicker than ya think.
Could be lots of things as a stereo with a memory wire or a mild short someplace. Pull the positive cable off the battery,hook a meter between the cable and battery post,with everything off,set meter to amps and it should read zero unless there is a problem. Even a bad battery will drain on it's own.
 

Bayou Dave

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Was the battery switch off? On the hard or in the water? However,if the bilge pump run's frequently,it'll drain the battery quicker than ya think.
Could be lots of things as a stereo with a memory wire or a mild short someplace. Pull the positive cable off the battery,hook a meter between the cable and battery post,with everything off,set meter to amps and it should read zero unless there is a problem. Even a bad battery will drain on it's own.

It doesn't have a battery switch. It is on the hard. The bilge pump is manual, not automatic. I assume you believe the amount of drainage is not normal? I will try your suggestion and see what happens. Thanks...
 

gm280

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I have to agree with grub1and grub2. The only way to know for certain is to charge the battery and then remove either the positive cable or the negative cable and then track the voltage over the same time period. If it still drains down, you could have something on the surface that is bleeding off some miniscule voltage. They use to call it surface discharge. So a good battery case wipe down and cleaning may help. If that doesn't help, remove the battery and take it to a parts store and have it load tested to see if it is going bad... Otherwise you have no known baseline to work from... JMHO
 

Bayou Dave

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I pulled the pos cable off and checked for amps and got a zero reading. Next step is to take it to Autozone and have them check the battery. I had a one year warranty on the battery that expired last month. Figures!
 

alldodge

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It doesn't have a battery switch. It is on the hard. The bilge pump is manual, not automatic. I assume you believe the amount of drainage is not normal? I will try your suggestion and see what happens. Thanks...

Just a point but the bilge pump should be automatic controlled by a float switch, with also a manual switch. This is most important if it sits in the water, if it sits on a trailer not so much.
 

Bayou Dave

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Just a point but the bilge pump should be automatic controlled by a float switch, with also a manual switch. This is most important if it sits in the water, if it sits on a trailer not so much.

I always trailer it, ramp is only 20 mintues away, so I am not too concerned about having it automatic.
 

jhebert

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Based on my own testing of 12-Volt storage batteries, and assuming there is no drain on your battery except itself, that is, the battery's self-discharge, the rate of discharge you have measured is abnormal. I recommend you re-test by disconnecting all loads and cleaning the top of the battery to remove any material that might be conductive and short-circuiting the battery terminals.

For comparison, I tested a 12-Volt battery for self-discharge over a period of 446-days and found the self discharge was at a rate of

0.000695-Volts/day

This particular battery began the test at 12.78-Volts and 446-days later measured 12.47-Volts. The battery was an AGM battery, which generally show excellent, that is, very low, rates of self-discharge. This same battery was tested after 671-days. Its terminal voltage was still 12.29-Volts. The battery under test was stored indoors in normal room ambient temperature. A battery stored in colder temperatures should have a lower rate of self-discharge. There was no load on the battery and it was not charged in any way during the test period.

I also tested a conventional SLA battery, a flooded cell lead-acid battery in good condition, over a shorter period. It showed a drop of 0.15 volts in 134 days, for a rate of

0.0011194 volts/day

Both of the test batteries were used batteries and both were several years old. Both had been in service before being tested. If interested, you can read more details of the testing at

http://continuouswave.com/ubb/Forum6/HTML/002630.html

and at

http://continuouswave.com/ubb/Forum6/HTML/002130.html
 
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Bayou Dave

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Jhebert.... you must be a battery expert! Very detailed testing. I'll have the battery tested first. If it is still good I willl charge it fully, leave all cables off and check it every day for a week. I'll see what happens and then go from there.
 

Bayou Dave

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Here is an update. Had Autozone check battery and it is good. What I found out is that the radio was in the on position and draining the battery. Turned it off, recharged the battery and now the problem is solved.
 

gm280

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Here is an update. Had Autozone check battery and it is good. What I found out is that the radio was in the on position and draining the battery. Turned it off, recharged the battery and now the problem is solved.

I have to say two things. First, great to hear you found your problem and solved it. That is always good to know. Second I want to thank you for taking your time to reply what you actually did and even that you located your problem and fixed it. Too many time we on here never hear from some posters about what they finally found out and tell us. That is what makes these type comment boards useful to so many when we can read about the problem, and then read the solution. So thanks again and happy boating... :thumb:
 

Bayou Dave

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I have to say two things. First, great to hear you found your problem and solved it. That is always good to know. Second I want to thank you for taking your time to reply what you actually did and even that you located your problem and fixed it. Too many time we on here never hear from some posters about what they finally found out and tell us. That is what makes these type comment boards useful to so many when we can read about the problem, and then read the solution. So thanks again and happy boating... :thumb:

Thanks GM280. There have been many posts that I have followed and then they stop cold. It always made me wonder "what happened?" My minor problem may or may not help someone else, but at least they will know the final result.
 

Outsider

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Another quick check for parasitic drain is to pull a cable in the dark, not everyone has an amp meter (at least I don't) ... ;)
 

airshot

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Glad to hear you found your problem and glad you posted your results. I was going to suggest another easy way to check it out would be to disconnect both terminals and then see how much your battery drops. If battery stays up then bat is good and you have another drain somewhere. But if battery drops on its own then you have a bad battery. I decided to post it anyway in case some else might be interested.
 
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