Battery dead. Bought a new battery last year. Charged it over the winter installed it in the spring. First time I went sailing it was dead. Brought it home tried to charge it wouldn't take. got a new battery. went sailing everything was fine. went sailing again. at start everything was fine engine started we motored out a bit stopped the motor started it again all was well. after sailing for a while wanted to hear the weather... no dice no electricity. motor won't start either, no lights. Motor is OB started it with the pull cord and the radio started working the lights came on. Ran the motor for at least an hour but after that the battery still had no charge. Anyone have any idea what is killing the battery. The only change I made was to attach a compass to the auxillary switch so that it would be visable at night. One last fact no fuses were blown. Thanks
- Status
- Not open for further replies.
M
MArk
Troubleshooting electrics
Thomas, First, get yourself an inexpensive (less then $30 at RadioShack) multimeter. Measure the voltage at the battery posts, not on the connectors attached to the battery. This will show you what's going on at the battery itself as opposed to at what may be a bad battery terminal connection. With no load, the voltage on a charged battery must be between 12.2 and 14 volts. If it isn't, charge or replace the battery. During charging, the battery voltage should be 13 to 15 volts. More indicates a bad voltage regulator. Less voltage usually indicates a bad connector. Measure at the alternator/generator to make sure it's putting out more than 13 volts. The greatest battery load is while starting the motor. When the key is turned to start, the battery voltage (posts again) should not drop below 9 volts. If the volts stay up but the motor doesn't crank, a connector is bad. If voltage drops below 8 volts, the battery is not fully charged or is bad. Connectors are usually the problem. Soldier connectors where you can. I've had good success sealing connectors in RTV silicon to prevent corrosion. See article below on proper connections. Also read the linked article "Troubleshooting Your Electrical System". Happy sails *_/), MArk
Thomas, First, get yourself an inexpensive (less then $30 at RadioShack) multimeter. Measure the voltage at the battery posts, not on the connectors attached to the battery. This will show you what's going on at the battery itself as opposed to at what may be a bad battery terminal connection. With no load, the voltage on a charged battery must be between 12.2 and 14 volts. If it isn't, charge or replace the battery. During charging, the battery voltage should be 13 to 15 volts. More indicates a bad voltage regulator. Less voltage usually indicates a bad connector. Measure at the alternator/generator to make sure it's putting out more than 13 volts. The greatest battery load is while starting the motor. When the key is turned to start, the battery voltage (posts again) should not drop below 9 volts. If the volts stay up but the motor doesn't crank, a connector is bad. If voltage drops below 8 volts, the battery is not fully charged or is bad. Connectors are usually the problem. Soldier connectors where you can. I've had good success sealing connectors in RTV silicon to prevent corrosion. See article below on proper connections. Also read the linked article "Troubleshooting Your Electrical System". Happy sails *_/), MArk
B
Bob
Electrically Conductive Grease
Hi Tom, This stuff is geat - picked it up at an auto supply outlet. Clean battery posts and connectors coat- tighten and then cover with the grease. Used on a small skiff - battery located in a damp compartment (can sometimes 1/2 fill with sea water).
Hi Tom, This stuff is geat - picked it up at an auto supply outlet. Clean battery posts and connectors coat- tighten and then cover with the grease. Used on a small skiff - battery located in a damp compartment (can sometimes 1/2 fill with sea water).
B
Bayard Gross
I think one of the cells is faulty
A twelve voly battery consists of six cells with two volts per cell. I think your new battery has a bad cell which would reduce its power to 10 volts which will not power anything. The charger on your motor easily overides this problem by putting out close to 14 volts so you end up with about 12 in your system. It is not uncommon to have this occur with new batteries. Modern batteries are made with extremely close tolerances and thin plates to reduce size and weight, attributes more desirable for modern cars than for boats. If the battery is dropped, the plates on the inside can crash into each other and destroy one or more of the cells of the battery. There are two ways to test for a bad cell. One is to use a hydrometer in which the specific gravity of each cell is measured. If one, or more, of the cells is significantly different than the others, then that cell, or cells, is faulty and the battery should be replaced. A second method is to use a digital volt meter. Place the negative end of the meter on the negative post and the positive end into the fluid (elctrolate) in the nearest batter cell. You should read two volts. Then stick the positive end of the meter into the next cell, and you should read four volts. And so on and so forth reading 6, 8, 10 volts to the last cell where you should read 12 volts. If you do not get this progression of two volts, the cell where it does not read some multiple of two volts is faulty. And the battery should be replaced.
A twelve voly battery consists of six cells with two volts per cell. I think your new battery has a bad cell which would reduce its power to 10 volts which will not power anything. The charger on your motor easily overides this problem by putting out close to 14 volts so you end up with about 12 in your system. It is not uncommon to have this occur with new batteries. Modern batteries are made with extremely close tolerances and thin plates to reduce size and weight, attributes more desirable for modern cars than for boats. If the battery is dropped, the plates on the inside can crash into each other and destroy one or more of the cells of the battery. There are two ways to test for a bad cell. One is to use a hydrometer in which the specific gravity of each cell is measured. If one, or more, of the cells is significantly different than the others, then that cell, or cells, is faulty and the battery should be replaced. A second method is to use a digital volt meter. Place the negative end of the meter on the negative post and the positive end into the fluid (elctrolate) in the nearest batter cell. You should read two volts. Then stick the positive end of the meter into the next cell, and you should read four volts. And so on and so forth reading 6, 8, 10 volts to the last cell where you should read 12 volts. If you do not get this progression of two volts, the cell where it does not read some multiple of two volts is faulty. And the battery should be replaced.
J
john renfro
juice
hello thomas,( sounds like loose connections ) for about $ 2.00 at an auto parts store, you can get a small hydrometer to check the cells in the battery. they have five little balls in them that float. none float=dead, 1 float= 1/4 charge, 2= 1/2, 3= 3/4th, 4= full, 5= over charged. john
hello thomas,( sounds like loose connections ) for about $ 2.00 at an auto parts store, you can get a small hydrometer to check the cells in the battery. they have five little balls in them that float. none float=dead, 1 float= 1/4 charge, 2= 1/2, 3= 3/4th, 4= full, 5= over charged. john
D
Debra B
over-charged 1st battery
I agree with the loose connection scenario for the 2nd battery - but have it tested. If it is w/o charge, then you have a short or high draw fault somewhere that is either not fused, or is drawing current but not enough to short the fuse (as much as a cars headlights, which would drain a battery in a few hours.) The 1st battery was probably over charged. Only leave a battery on a charger that is so designed - NOT a trickle charge. These are fairly expensive You might remove your modification - just to be sure.
I agree with the loose connection scenario for the 2nd battery - but have it tested. If it is w/o charge, then you have a short or high draw fault somewhere that is either not fused, or is drawing current but not enough to short the fuse (as much as a cars headlights, which would drain a battery in a few hours.) The 1st battery was probably over charged. Only leave a battery on a charger that is so designed - NOT a trickle charge. These are fairly expensive You might remove your modification - just to be sure.
B
Bill
Another suggestion
Another thing or two to try that I didn't notice being mentioned. -Assuming you have a good battery and clean posts: -Disconnect either one of the battery post connectors and connect a 12V test light between the cable connector and the post. If you have a current drain somewhere on the boat, the light will light. Disconnect your loads one at a time till the light goes out. You can also use a DC ammeter to do the same thing, just keep your polarity correct when connecting the ammeter. Most multimeters have a current shunt that will handle up to 10 amps. Good Luck, Bill
Another thing or two to try that I didn't notice being mentioned. -Assuming you have a good battery and clean posts: -Disconnect either one of the battery post connectors and connect a 12V test light between the cable connector and the post. If you have a current drain somewhere on the boat, the light will light. Disconnect your loads one at a time till the light goes out. You can also use a DC ammeter to do the same thing, just keep your polarity correct when connecting the ammeter. Most multimeters have a current shunt that will handle up to 10 amps. Good Luck, Bill
- Status
- Not open for further replies.