Hi -- On my sailboat, I have 3 Lifeline AGM batteries that are less than 2 years old. One battery is for the engine bank and a group 24 and a group 27 for the house bank and they are connected by a West Marine 50 combiner. I also have a Link 20 battery monitor. All the batteries were last fully charged about one month ago while the boat was stored on land for the winter. Since that time, the engine battery has maintained its charge at 12.7 volts, but the house bank voltage has dropped down to 11.7 volts, as measured by both the Link 20 and my own multimeter at the battery terminals. As far as I know nothing other than the Link 20 is directly connected to the house bank. My bilge pump is controlled by a circuit breaker and I have neither electronics nor a water heater on board. The Link 20 shows an amperage use at .1 amps and about 132 amps used since the last charge. I have confirmed with Xantrex tech support that the Link 20 by itself would not drain the house bank to that extent. I assume something is using current at a low rate but need some advice as to how to go about troubleshooting to solve this problem. Where and how do I begin, and is there an efficient process to follow? I will greatly appreciate your advice on this.
Mystery battery drain problem
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battery drain
Battery drain occurs due to the bidge pump running when you are'nt on the boat, also the bildge sensor draws a small amperage all the time and the battery switches do not turn this off.
Battery drain occurs due to the bidge pump running when you are'nt on the boat, also the bildge sensor draws a small amperage all the time and the battery switches do not turn this off.
Do you have a radio/CD player
Do you have a radio/CD player on board. These draw a slight current to keep the clock running and your pre sets in memory. An amp draw this low might be hard to find, and I would follow Stu's advice and start disconnecting things one at a time till you find it. Good luck, and keep us posted.
Do you have a radio/CD player on board. These draw a slight current to keep the clock running and your pre sets in memory. An amp draw this low might be hard to find, and I would follow Stu's advice and start disconnecting things one at a time till you find it. Good luck, and keep us posted.
The meter that you want to watch is ........
....your multimeter. Disconnect the feed from your house bank and insert your multimeter on a current-reading range. Start at a range of 2A and go down until you see a reading. I suspect that you will see a current drain of 2-10mA. You cannot use the Link 20 for this reading because the minimum reading of the Link 20 is 0.1A or 100mA. Since you are looking for a change in current that is about 1/10 of that value, you will never see it on the Link 20. Also, the Link 20 has a RESOLUTION of +- 0.1A and that means you can actually have zero current flowing and yet the Link 20 may read 0.1A flowing. If this is true in your case (units vary among themselves) you will accumulate AH of usage erroneously. Back to the troubleshooting. Stu is correct in his procedure to disconnect each circuit or item on the house bank and watch the meter to see if there is a difference. You should be able to do this with your main switch panel. Be aware that there are likely to be several "sneak" drains on your battery that your panel switches will not turn off. A couple of possibilities are (1) keep alive circuit on your stereo, (2) CO detectors, (3) propane detectors, (4) a dusk-activated anchor light, or (5) any kind of equipment that is connected to the battery that can be controlled with a remote. You may have other items that I haven't mentioned. If nothing causes a decrease in the current drain, I would then physically disconnect the output of the battery charger and the battery combiner. Failing that I would look at the bilge pump circuit. It should have a fuse that could be taken out to break that circuit. Assuming that your batteries are good, there has to be some measurable cause for the drain.
....your multimeter. Disconnect the feed from your house bank and insert your multimeter on a current-reading range. Start at a range of 2A and go down until you see a reading. I suspect that you will see a current drain of 2-10mA. You cannot use the Link 20 for this reading because the minimum reading of the Link 20 is 0.1A or 100mA. Since you are looking for a change in current that is about 1/10 of that value, you will never see it on the Link 20. Also, the Link 20 has a RESOLUTION of +- 0.1A and that means you can actually have zero current flowing and yet the Link 20 may read 0.1A flowing. If this is true in your case (units vary among themselves) you will accumulate AH of usage erroneously. Back to the troubleshooting. Stu is correct in his procedure to disconnect each circuit or item on the house bank and watch the meter to see if there is a difference. You should be able to do this with your main switch panel. Be aware that there are likely to be several "sneak" drains on your battery that your panel switches will not turn off. A couple of possibilities are (1) keep alive circuit on your stereo, (2) CO detectors, (3) propane detectors, (4) a dusk-activated anchor light, or (5) any kind of equipment that is connected to the battery that can be controlled with a remote. You may have other items that I haven't mentioned. If nothing causes a decrease in the current drain, I would then physically disconnect the output of the battery charger and the battery combiner. Failing that I would look at the bilge pump circuit. It should have a fuse that could be taken out to break that circuit. Assuming that your batteries are good, there has to be some measurable cause for the drain.
Phantom Loads
On my H34, I have a volt meter that is illuminated with an incandescant bulb. So, if I forget to turn my DC main switch off, that volt meter will draw current from the battery - about a watt or so to illuminate the meter. Could you have the same problem if you left your main switch in the "house battery" position??
On my H34, I have a volt meter that is illuminated with an incandescant bulb. So, if I forget to turn my DC main switch off, that volt meter will draw current from the battery - about a watt or so to illuminate the meter. Could you have the same problem if you left your main switch in the "house battery" position??
Thank you all very much for the suggestions. Just to clarify my electrical situation -- no bilge pump float switch, pump is either on or off by circuit breaker, no radio or cd player, co detector runs only when house bank switch, nothing that turns itself on, nothing to draw current that I know of, (and have been reassured of that by the installing tech). Could a "bad" battery charger or combiner result in this condition? A "bad" circuit breaker? A bad battery even though the Link shows current consumption? Thanks again for any and all suggestions. Steve
Some more answers
A battery charger usually has a diode to protect against reverse connection. This diode eliminates current flow from the battery to the charger. If that diode was bad and you had a faulty electrolytic capacitor or there was a bleed resistor connected to the capacitor (getting into the internals of the charger now), yes the charger could drain the battery. The combiner is a switch so it only works on the positive connections so highly unlikely it is drawing current. It needs an electrical path back to ground to discharge the battery. Same deal with the breaker. You could have one out of the two batteries defective which would cause the good one to get dragged down with it but, this does not usually happen with AGM style batteries. The AGM batteries predominant failure is seperator material drying up which acts like an open circuit. In rare cases, the plates will short through the AGM which will short out causing thermal run-away but if you had that problem, you would be talking about fires and major losses, not slow discharges. AGM batteries have a very very low self discharge - you can leave them uncharged up to a year and they will be just fine! Your batteries are discharging. Disconnect battery (+) and insert a sensitive current meter between the main cable and battery (+) with everything turned off. My guess is that something is drawing current. Good Luck
A battery charger usually has a diode to protect against reverse connection. This diode eliminates current flow from the battery to the charger. If that diode was bad and you had a faulty electrolytic capacitor or there was a bleed resistor connected to the capacitor (getting into the internals of the charger now), yes the charger could drain the battery. The combiner is a switch so it only works on the positive connections so highly unlikely it is drawing current. It needs an electrical path back to ground to discharge the battery. Same deal with the breaker. You could have one out of the two batteries defective which would cause the good one to get dragged down with it but, this does not usually happen with AGM style batteries. The AGM batteries predominant failure is seperator material drying up which acts like an open circuit. In rare cases, the plates will short through the AGM which will short out causing thermal run-away but if you had that problem, you would be talking about fires and major losses, not slow discharges. AGM batteries have a very very low self discharge - you can leave them uncharged up to a year and they will be just fine! Your batteries are discharging. Disconnect battery (+) and insert a sensitive current meter between the main cable and battery (+) with everything turned off. My guess is that something is drawing current. Good Luck
battery
the simple answer is; all batteries will self-discharge over time and the Link system itself, with all its wiring will, despite what tech support tells you, pull a charge from a battery. That's why you leave a trickle charge to it, to maintain that 13.5 voltage.
the simple answer is; all batteries will self-discharge over time and the Link system itself, with all its wiring will, despite what tech support tells you, pull a charge from a battery. That's why you leave a trickle charge to it, to maintain that 13.5 voltage.
Well...
assuming you DO actually test for a current drain as suggested above and find none as you seem to think...then the explanation will have to be a set of dead AGM's which can be caused by a bad charging system or regimen even within two years. Since that is unlikely I suggest you follow Rich's advice abov and get or borrow an ammeter that can actually measure what is going on and prove your assumptions right or wrong.
assuming you DO actually test for a current drain as suggested above and find none as you seem to think...then the explanation will have to be a set of dead AGM's which can be caused by a bad charging system or regimen even within two years. Since that is unlikely I suggest you follow Rich's advice abov and get or borrow an ammeter that can actually measure what is going on and prove your assumptions right or wrong.
Why no bilge pump float switch?
Scott -- removed the switch last month to simplify troubleshooting, but didn't impact the problem.
Scott -- removed the switch last month to simplify troubleshooting, but didn't impact the problem.
Why no bilge pump float switch?
Scott -- removed the switch last month to simplify troubleshooting, but didn't impact the problem.
Scott -- removed the switch last month to simplify troubleshooting, but didn't impact the problem.
xantrex is wrong!
OK SteveP, I did some math - are you ready? The Link 20 draws 25mA in the sleep mode. Thats continuous current drain! If you left it on for 1 month the amp hours that you took out of the battery are 0.025A(25mA) * 24Hrs * 30Days = 18 Amp Hours. After 1 month of powering up the Link 20, its like running a load of 18 amps for 1 hour. Your batteries and system are fine - no worries!
OK SteveP, I did some math - are you ready? The Link 20 draws 25mA in the sleep mode. Thats continuous current drain! If you left it on for 1 month the amp hours that you took out of the battery are 0.025A(25mA) * 24Hrs * 30Days = 18 Amp Hours. After 1 month of powering up the Link 20, its like running a load of 18 amps for 1 hour. Your batteries and system are fine - no worries!
xantrex is wrong!
OK SteveP, I did some math - are you ready? The Link 20 draws 25mA in the sleep mode. Thats continuous current drain! If you left it on for 1 month the amp hours that you took out of the battery are 0.025A(25mA) * 24Hrs * 30Days = 18 Amp Hours. After 1 month of powering up the Link 20, its like running a load of 18 amps for 1 hour. Your batteries and system are fine - no worries!
OK SteveP, I did some math - are you ready? The Link 20 draws 25mA in the sleep mode. Thats continuous current drain! If you left it on for 1 month the amp hours that you took out of the battery are 0.025A(25mA) * 24Hrs * 30Days = 18 Amp Hours. After 1 month of powering up the Link 20, its like running a load of 18 amps for 1 hour. Your batteries and system are fine - no worries!
The old low tech method
is to disconnect the positive battery terminals, then rub the wire over the battery connection. Even a tiny drain will make a spark. Disconnect suspect equipment (everything is suspect) one at a time, and do the spark test. When the spark doesn't appear, you have found the drain. Sorry, no meters or other toys necessary. Once you find the drain, you can use all the meters and equipment you like. I have plenty of equipment, but none of it works as well as the spark test.
is to disconnect the positive battery terminals, then rub the wire over the battery connection. Even a tiny drain will make a spark. Disconnect suspect equipment (everything is suspect) one at a time, and do the spark test. When the spark doesn't appear, you have found the drain. Sorry, no meters or other toys necessary. Once you find the drain, you can use all the meters and equipment you like. I have plenty of equipment, but none of it works as well as the spark test.
The old low tech method
is to disconnect the positive battery terminals, then rub the wire over the battery connection. Even a tiny drain will make a spark. Disconnect suspect equipment (everything is suspect) one at a time, and do the spark test. When the spark doesn't appear, you have found the drain. Sorry, no meters or other toys necessary. Once you find the drain, you can use all the meters and equipment you like. I have plenty of equipment, but none of it works as well as the spark test.
is to disconnect the positive battery terminals, then rub the wire over the battery connection. Even a tiny drain will make a spark. Disconnect suspect equipment (everything is suspect) one at a time, and do the spark test. When the spark doesn't appear, you have found the drain. Sorry, no meters or other toys necessary. Once you find the drain, you can use all the meters and equipment you like. I have plenty of equipment, but none of it works as well as the spark test.
Fred, could you elaborate on the 'Spark Test'?
First you say: "Even a tiny drain will make a spark.". Then you say: "... one at a time, and do the spark test. When the spark doesn't appear, you have found the drain. ". Is it the lack of spark that idicates a potential drain or the presence of a spark? I am asking because I may need to do this on a friends boat not because I am a nit picker. Thanks.
First you say: "Even a tiny drain will make a spark.". Then you say: "... one at a time, and do the spark test. When the spark doesn't appear, you have found the drain. ". Is it the lack of spark that idicates a potential drain or the presence of a spark? I am asking because I may need to do this on a friends boat not because I am a nit picker. Thanks.
Fred, could you elaborate on the 'Spark Test'?
First you say: "Even a tiny drain will make a spark.". Then you say: "... one at a time, and do the spark test. When the spark doesn't appear, you have found the drain. ". Is it the lack of spark that idicates a potential drain or the presence of a spark? I am asking because I may need to do this on a friends boat not because I am a nit picker. Thanks.
First you say: "Even a tiny drain will make a spark.". Then you say: "... one at a time, and do the spark test. When the spark doesn't appear, you have found the drain. ". Is it the lack of spark that idicates a potential drain or the presence of a spark? I am asking because I may need to do this on a friends boat not because I am a nit picker. Thanks.
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