5411 Charging

[Chris Gonzales]

The AMP meter needle on my 5411 Universal diesel engine shows only a very slight inclination into the positive charge area when my engine is running. With engine off and the blower switch on it shows a little more discharge on the meter than that but never shows discharge when running. I have used the motor little since buying the boat and have charged the two batteries at the dock with shore power, so how the batteries are charged isn't a good indicator of the engine charging them properly.Can anyone tell me how to test the alternator for charge? It is difficult to tell what wire is what and the thing has been painted a few times. Also, when charging the batteries with a charger using shore power, is it critical to disconnect the ground to protect the alternator diodes?Thanks!Chris

 

[Tim Dranttel]

Checking for charge

Chris,What you are seeing is not abnormal for a boat that spends alot of time on shore power keeping the batteries fully charged. There are really two ways to check that your alternator is putting out juice. The easiest way to see if your alternator is working is to take a screw driver and hold the blade on the back of the alternator where the bearing cap is and test for a magnetic pull. If you feel a pull then your alternator is working. What this test does not tell you is how much charge is being produced and whether or not this energy is even getting to your batteries. That is why the second test is even better. The more precise way to check for proper charging involves the use of a digital voltmeter. Check the battery's charge with the engine stopped and no load on the batteries. You should see about 12 - 12.5 volts on a fully charged battery. Then start your motor and set about 1000 RPM. Measure the voltage again AT THE BATTERY. If your alternator is working correctly you should see a 1.5 to 2.5 volt increase. Somewhere between 13 and 14 volts. These numbers are based on wet cells. If you have gels the charging numbers are to be lower I think to keep from over charging and evaporating the gel. Nigel Calder's book, I think called "The Boat Owners Electrical and Maintenance" explains this all in much better detail.Tim

 

[Chris Gonzales]

Thanks Tim!

I'll give it a try tomorrow and see what it says. THANKS!Chris

 

[michael w]

CHRIS I REPLACED MY AMP METER WITH A VOLT METER,SO WITH THE ENGINE RUNNING YOU CAN TELL HOW MANY VOLTS ARE COMING FROM THE ALTERNATER.TEST YOUR BATTERIES WITH NO DRAW (EVERYTHING OFF).THEN START YOUR ENGINE LOOK AT VOLT METER,THEN CHECK YOUR BATTERIES AGAIN THEIR SHOULD BE AN INCREASE IN AMPS (1-2)AT THE BATTERIES.I ALSO PURCHASED A LINK 10 MONITOR (INTERFACE).ITS A $200 DOLLAR GADGET BUT WELL WORTH THE MONEY.