I appear to have developed a gremlin in our DC electric system. At one moment the batteries appear well charged 12 - 13 volts (which they are) then suddenly the lights will dim and pumps (e.g. water) will labor. If I check the volt meter it shows 10 volts (and the needle wobbles around =/- .5 volts.) I have discovered that to fix the problem, I go above and hit the switch for the electric winch, which draws alot of power, and it jolts the system right again (i.e., back to 12-13 volts) The problem occurs intermittantly every three or four days. I have not be able to determine what starts the problem. Only how to end it. Any of you electrical wizards out there have any ideas? Thanks, Peter Milne S/V Blue Heron
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Miles
Battery connections?
Have you checked you battery connections? I've had similar problems that were caused by slightly corroded connectors. When you say the voltage drops are you measuring directly at the battery with a voltmeter or with one that's wired in? You might take a look and be sure all the connection are VERY clean. When you "jolt" the system with the winch perhaps you are temporarily zapping through some of the gunk on the battery terminals... Or maybe it's Gremlins ;.)
Have you checked you battery connections? I've had similar problems that were caused by slightly corroded connectors. When you say the voltage drops are you measuring directly at the battery with a voltmeter or with one that's wired in? You might take a look and be sure all the connection are VERY clean. When you "jolt" the system with the winch perhaps you are temporarily zapping through some of the gunk on the battery terminals... Or maybe it's Gremlins ;.)
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Mike Kenny
Clean or replace the battery connectors.
Sounds like a bad connection to me. Standard lead battery posts are notorious for producing this type of symptom. If you have them, take them off and clean the posts and connectors with a battery post and terminal cleaning tool. The tool is a male and female wire brush combo. It costs about $5 at an auto parts store. You can use sand paper but the tool is much easier and does a better job. Clean and tighten all other high current connections.
Sounds like a bad connection to me. Standard lead battery posts are notorious for producing this type of symptom. If you have them, take them off and clean the posts and connectors with a battery post and terminal cleaning tool. The tool is a male and female wire brush combo. It costs about $5 at an auto parts store. You can use sand paper but the tool is much easier and does a better job. Clean and tighten all other high current connections.
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R.W.Landau
just a note
I think the other guys have answered it. Don't just look at the connections and say they are good. They may look great. Take them apart and clean them. If you are still having the problem, start at the ground bar then the hot side of your panel. Look for oxydation or corrosion. r.w.landau
I think the other guys have answered it. Don't just look at the connections and say they are good. They may look great. Take them apart and clean them. If you are still having the problem, start at the ground bar then the hot side of your panel. Look for oxydation or corrosion. r.w.landau
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Jay Beery
Connections
Don't forget to check the connections of the battery wires on the other ends. Most of all check the other end of the ground wire off the battery. Engine block? It too must be clean and secure. It sure sounds like a bad ground to me. Good Luck, Jay
Don't forget to check the connections of the battery wires on the other ends. Most of all check the other end of the ground wire off the battery. Engine block? It too must be clean and secure. It sure sounds like a bad ground to me. Good Luck, Jay
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Eric Lorgus
Maybe it's your winch switch or relay
Peter, I'm not sure what you meant about "hitting" the winch switch. If the switch or relay is allowing current to flow to the winch, that would explain your sudden drop in voltage. Have you tried disconnecting the winch to see if this isolates the problem? Eric Lorgus
Peter, I'm not sure what you meant about "hitting" the winch switch. If the switch or relay is allowing current to flow to the winch, that would explain your sudden drop in voltage. Have you tried disconnecting the winch to see if this isolates the problem? Eric Lorgus
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Rob
I'm with you Eric
This crossed my mind as well, but I was unsure if there was a relay in use or not. Agree with the diagnostic too. Rob
This crossed my mind as well, but I was unsure if there was a relay in use or not. Agree with the diagnostic too. Rob
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Jack
Sounds like the relay for the winch!
try eliminating power from the winch for a week or two, and see if the problem goes away. Jack
try eliminating power from the winch for a week or two, and see if the problem goes away. Jack
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R.W.Landau
not the winch
Peter, I don't think you will find that it is the winch. When you click the winch on,the demand load arcs through your corroded area and makes a tiny temporary connection. That is why your problem comes and goes. Something needs cleaned and my first bet is the battery leads. r.w.landau
Peter, I don't think you will find that it is the winch. When you click the winch on,the demand load arcs through your corroded area and makes a tiny temporary connection. That is why your problem comes and goes. Something needs cleaned and my first bet is the battery leads. r.w.landau
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hp
Suphated Batteries
I have had similar problems with older batteries that were allowed to sit for long periods of time. When placed under a heavy load the battery overcomes its internal resistance caused by sulphation. At low draw, this internal resistance blocks the flow, lights dim and flicker. If I am right you can progressively switch more load on the system by turning on bilge or macerator of refrigeration systems and watch the voltage actually climb. Regular cycling of a battery above a 50% charge level prevents this problem.
I have had similar problems with older batteries that were allowed to sit for long periods of time. When placed under a heavy load the battery overcomes its internal resistance caused by sulphation. At low draw, this internal resistance blocks the flow, lights dim and flicker. If I am right you can progressively switch more load on the system by turning on bilge or macerator of refrigeration systems and watch the voltage actually climb. Regular cycling of a battery above a 50% charge level prevents this problem.
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