310 DC Current Draw Chart

[Ralph Johnstone]

Pull the battery. Take it to the nearest auto parts store and get it checked.

I suppose you sell medical trusses and supports on the side .

Why not just test the battery in place with the engine starter and avoid the hernia ?

 

[Crusty Ol Salt]

I suppose you sell medical trusses and supports on the side.

Why not just test the battery in place with the engine starter and avoid the hernia ?

I don't sell anything. I have just turned wrenches my whole life and the most accurate test for cranking amperage and voltage can be found at an auto parts store or garage.

If this issue is a loss of amps during cranking the engine and the issue just started after fall winter conditions set in, 9 times out of 10 the battery is going bad.

 

[Ralph Johnstone]

If this issue is a loss of amps during cranking the engine and the issue just started after fall winter conditions set in, 9 times out of 10 the battery is going bad.

Absolutely, couldn't agree with you more .

My point is, give your back a break (as in a rest, not a fracture) and test the battery in place as per posts #14 and #15.

 

[SycloneDriver]

An inexpensive load tester can be purchased for under $40. I use them frequently.

 

[Tom J]

I don't sell anything. I have just turned wrenches my whole life and the most accurate test for cranking amperage and voltage can be found at an auto parts store or garage.

If this issue is a loss of amps during cranking the engine and the issue just started after fall winter conditions set in, 9 times out of 10 the battery is going bad.

I think Ralph was pointing out that the original D4 batteries in the C310 weighed about 100 pounds, and were difficult to remove.

 

[Ted10028]

5. record the lowest voltage of the start battery while the engine is being cranked. Best if you prevent the engine from starting and crank it for a few or several (maybe 10-15)seconds and see what the voltage drop is. This puts a good load test on. If you do this make sure you don't overfill raw water in your exhaust and back up water into your engine.

Here's a bit on this from BoatUS

Battery load test. Although not a perfect test, you can perform a load test on your batteries by measuring voltage at the terminals while running a heavy load like an anchor windlass or starter motor (without starting the engine). Normal shop procedures for load testing dictate a load equivalent to 50% of the cold cranking amperage rating for the battery being tested. That requires a load of greater than 300 amps for even the smallest of marine batteries. You need to isolate the battery being tested from any others in the system to ensure that the data you gather is specific to the battery you are testing. So you may need to disconnect any cables connecting to paralleled batteries in a bank. Obviously, you'll need to have the battery being tested connected to the boat's DC loads.
The other challenge here is that if you are going to use the engine starter motor as the load, you will need to figure out how to ensure the engine won't start while you are performing the test. If you are using loads like an anchor windlass or electric winch, you're all set. With gasoline-fueled engines, you should be able to disable the ignition system by unplugging a gang plug that supplies power to the system. For diesels, you'll need to find out how to shut down the fuel injection system while you perform the test. I recommend consulting the engine manufacturer for advice on how to accomplish this before you attempt it on your own. There are just too many variables here to generalize.

In any event, by running the windlass, electric winch, or starter motor for 10 to 15 seconds while watching your multimeter set on the DC volts scale, you want to see no less than 11.1 volts as a reading. Less than that indicates that the battery you are testing is losing capacity and getting ready to let you down. Of course, the battery should be fully charged (12.6 volts or more) before you attempt the load test.

FYI: My Yanmar owners manual say that when you first start your engine in spring you should turn key and hit off button several times to distribute oil before engine starts. It says engine can seize if you don't. Perhaps that is helpful in doing battery load test?

 

[john2]

is that 1,7 amp always on? turn of stuf untill you find the source.
Check battery voltage before starting with digital meter. 12,00 volt is empty voltage must be over 12,5 volts.
john.

 

[Clydo]

Another consideration our Maxwell electric windless draws:

Normal working load 12 volt 80 vpolts

AT stall 12 volt 305 volts

From owners manual.

Clyde Thorington
C310 # 245
I LEAN TOO
San Jose, CA