7.4 charging issue

[jere1972]

took my boat out for the first time, since engine was installed, have some prop issues, but also noticed, during the most of the day the volt meter showed around 13.5=14v. then as we stopped more and more to fish, (running pumps, lights, and radio) the voltmeter would lessons as the engine was restarted, making the 20mile treck back the the ramp, @ idle it would sit @ 12v, not running it would be around 11v, under way around 12.5 a best, got back to the ramp, let it idle for about 20 min while we figured out what was wrong with the trailer, she went up to around 13v, 2hrs later during flushing, @ idle 12.2-12.5, turned battery switch off while running, guage went to 14v, turned switch back on back to 12.5, 13v @ rpm above 2k, next day 13.5-14v @ idle......im @ a loss or is this normal?. the altenator is just installed new....the batteries are 9 months old, wiring from the guage to the motor harness seems clean,

 

[pyrotek]

Re: 7.4 charging issue

Check battery voltage with engine on with a digital multimeter. Shou ld be more than 14 volts. Either gauge or alternator is not working.

 

[dingdongs]

Re: 7.4 charging issue

if your going to use a lot of power whilst stationary it may be better to get a 2nd battery installed so you have one for the starting and running and one for the accessories fitted.you nearly took all the power from your battery and one day it will not start your engine as too low and your going to need a tow home.

 

[tpenfield]

Re: 7.4 charging issue

I had a similar problem . . . it turned out to be a loose connection to the gauge.

 

[Silvertip]

Re: 7.4 charging issue

And if you want to screw up a perfectly good alternator, continue to turn the battery switch off with the engine running. DON'T DO THAT. 13.5 - 14 volts is a normal voltmeter reading at anything above 1500 - 2000 rpm. It is very possible to have the voltmeter read less than 12.6 volts at idle when you have a bunch of accessories operating. Why?? Because you are consuming more current than the alternator is putting out. The difference in those two values must come from the battery which in that case is discharging.

 

[EddiePetty]

Re: 7.4 charging issue

Your conditions, as described, may be normal. However, I would check ALL connection for cleanliness and tightness, the battery for low levels and the alternator belt for tension. Additionally I would verify the previous readings at the alternator output and at the battery using a DIGITAL multimeter.
Ensure that your connections are electrically 'tight' using the ohm scale.

And, repeating a previous warning: NEVER disconnect the battery (s) from a running alternator (all the smoke is prone to escape!)