I'm getting tired of carrying my dead batteries to shore to recharge. Tested the batteries with the alternator running. I got readings of 12.0 and 12.0 at the batteries. I also got 12.0 off the back of the alternator. The instrument panel in the cockpit isn't working, so no drain there. Got a new alternator - same readings. I give up... any body out there know? Gene Kinney S/v Kin-Ship h40
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are you at a mooring?
Gene: Are you at a mooring? If you are, maybe you need to upgrade your alternator. I thought that the alternator should be putting out something more in the 13-13.5 amp mark. Marathon Diesel has a 100 & 120 amp unit at a very good price you should look at. If you are not on a mooring, then you need to look at your battery charger aboard the boat. Also get your batteries load tested next time you have them off the boat. Ours had the voltage but could not hold the charge (10 years old).
Gene: Are you at a mooring? If you are, maybe you need to upgrade your alternator. I thought that the alternator should be putting out something more in the 13-13.5 amp mark. Marathon Diesel has a 100 & 120 amp unit at a very good price you should look at. If you are not on a mooring, then you need to look at your battery charger aboard the boat. Also get your batteries load tested next time you have them off the boat. Ours had the voltage but could not hold the charge (10 years old).
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Bryan C.
Hmmmm
First, I'd buy a book that tells you how to do specific tests for the DC charging circuit, like Nigel Calder's book: "Boat Owners Mechanical and Electrical Manual." The $30 you pay for the book could save you hundreds in new equipment. It contains step by step tests you do to specifically isolate the source of your problems (plus has tons of other useful stuff to know about your boat). Other books will have this info as well. Steve is right (as usual), a charging alternator should be putting out about 13.5 volts. If your alternator isn't putting it out, you may be testing it improperly or perhaps your (new) alternator is shot. Would think that is unlikely -- unless you are doing something to burn it up, like turning the battery selector switch off (or its shorting to a broken circuit) which will blow an alternator if the alternator output is wired to the selector switch. The other source of your problem may be that your current batteries are shot and just can't take a charge. A 12.0v reading is just about a dead battery. (Charged is 12.6+). If your batts are reading 12.0v after they have been charged with a working charger your batts are probably dead. Have you tested them with a specific gravity tester? Don't know what type of batts you have, but it sounds like you've drained them a few times, and if you completely drain batteries repeatedly, even heavy duty "recycleable" batteries (but especially auto type starting batteries) you will kill them. A typical auto or "starting" battery can only be fully drained maybe a dozen times (depending on the quality of the battery) before it is killed. Good luck.nh
First, I'd buy a book that tells you how to do specific tests for the DC charging circuit, like Nigel Calder's book: "Boat Owners Mechanical and Electrical Manual." The $30 you pay for the book could save you hundreds in new equipment. It contains step by step tests you do to specifically isolate the source of your problems (plus has tons of other useful stuff to know about your boat). Other books will have this info as well. Steve is right (as usual), a charging alternator should be putting out about 13.5 volts. If your alternator isn't putting it out, you may be testing it improperly or perhaps your (new) alternator is shot. Would think that is unlikely -- unless you are doing something to burn it up, like turning the battery selector switch off (or its shorting to a broken circuit) which will blow an alternator if the alternator output is wired to the selector switch. The other source of your problem may be that your current batteries are shot and just can't take a charge. A 12.0v reading is just about a dead battery. (Charged is 12.6+). If your batts are reading 12.0v after they have been charged with a working charger your batts are probably dead. Have you tested them with a specific gravity tester? Don't know what type of batts you have, but it sounds like you've drained them a few times, and if you completely drain batteries repeatedly, even heavy duty "recycleable" batteries (but especially auto type starting batteries) you will kill them. A typical auto or "starting" battery can only be fully drained maybe a dozen times (depending on the quality of the battery) before it is killed. Good luck.nh
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Bryan C.
Clarification
Switch the bat selector to "off" will blow the diodes of an alternator if the alternator's output goes ot the switch (as opposed to a battery bank) and the engine is running.
Switch the bat selector to "off" will blow the diodes of an alternator if the alternator's output goes ot the switch (as opposed to a battery bank) and the engine is running.
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Doug Margison
batteries are likely shot
It seems to me your batteries are shot. The test of a battery is whether can support a load. Even if it measures 12V, as soon as you put a load to it nothing happens if the batteries at bad. A hydrometer will provide a better indication of the battery condition. All wet cell batteries should be tested occasionally. Not possible with sealed units though.
It seems to me your batteries are shot. The test of a battery is whether can support a load. Even if it measures 12V, as soon as you put a load to it nothing happens if the batteries at bad. A hydrometer will provide a better indication of the battery condition. All wet cell batteries should be tested occasionally. Not possible with sealed units though.
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Gordon Torresen
Alternator problem!
Your alternator should be putting out somewhere between 13.5 and 14.2 volts. You should read this at the back of the alternator if the alternator is good. This is regardless of battery condition. If the battery is sick, the alternator tries to make it well even if it is terminal. You state that you take the batteries ashore to charge them. It is to be assumed that they take the charge and do their job after installation. Take that alternator to a reliable auto electric repair shop and at least have it tested. They can probably rebuild it in short order. Diode damage to and alternator is almost instantaneous if a battery is connected backwards. Also check for other things that may have caused the failure, loose or broken wires, worn insulation, etc.
Your alternator should be putting out somewhere between 13.5 and 14.2 volts. You should read this at the back of the alternator if the alternator is good. This is regardless of battery condition. If the battery is sick, the alternator tries to make it well even if it is terminal. You state that you take the batteries ashore to charge them. It is to be assumed that they take the charge and do their job after installation. Take that alternator to a reliable auto electric repair shop and at least have it tested. They can probably rebuild it in short order. Diode damage to and alternator is almost instantaneous if a battery is connected backwards. Also check for other things that may have caused the failure, loose or broken wires, worn insulation, etc.
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Gene Kinney
Fixed the alternator Problem
Hi folks, Finally have a charging alternator. here's what I did: 1. took off the old one and had it tested. It was dead. 2. Put a rebuilt one on. Still didn't work. 3. Traced the wires TO the cockpit instrument panel. The harness connections were corroded near the engine. Replaced the connectors. 4. Traced the wires FROM the instrument panel. Found two wires that had been taped together and had rusted off their connection TO THE STARTER. 5. Reconnected them and Voila the cockpit panel and ccockpit ignition wroks. Plus the Alternator kicked in! That circuit was critical to putting a load on the alternator so that it would work. Thanks for the support. We even put the name on her this past weekend. I'm ready for some sailing.
Hi folks, Finally have a charging alternator. here's what I did: 1. took off the old one and had it tested. It was dead. 2. Put a rebuilt one on. Still didn't work. 3. Traced the wires TO the cockpit instrument panel. The harness connections were corroded near the engine. Replaced the connectors. 4. Traced the wires FROM the instrument panel. Found two wires that had been taped together and had rusted off their connection TO THE STARTER. 5. Reconnected them and Voila the cockpit panel and ccockpit ignition wroks. Plus the Alternator kicked in! That circuit was critical to putting a load on the alternator so that it would work. Thanks for the support. We even put the name on her this past weekend. I'm ready for some sailing.
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