Different Charging After Battery Drain
09-01-2005, 03:30 PM
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Different Charging After Battery Drain
For the past two years I've had the boat, the voltmeters move in perfect unison, pegged at 16 at startup, then settle down to 13-14 for the most part, but then jump again to 16 occassionally for a minute and repeat. I thought the charging system was supposed to run at a steady 13.8 volts. The gauges are moving around enough to remind me more of the ammeter I had in a Corvette once. It sure seemed peculiar, but everything worked fine so I didn't question it.
That changed drastically when I recently left the bilge pump on docked for 2 weeks and completely drained the batteries. It runs ok again now, but boy is the charging drastically different. Upon start, the meters show 0 or even a little negative at idle prompting me to want to gun them, then get up 12 or 12.5 at cruise, but then I have seen 13 on just a couple occassions too. They still move in unison, but no more wild fluctuations 16 to 13 and back like before. And the part where they idle BELOW 0 has me real concerned.
This seems like quite a bit of change just from killing the batteries one time.
By the way I don't think it's a battery issue because I got both new starting batteries at the beginning of the season.
In addition to help for why the sudden change, it would also help to know if proper charging is supposed to resemble the way it used to work, or if it sounds more like the way it's working now.
That changed drastically when I recently left the bilge pump on docked for 2 weeks and completely drained the batteries. It runs ok again now, but boy is the charging drastically different. Upon start, the meters show 0 or even a little negative at idle prompting me to want to gun them, then get up 12 or 12.5 at cruise, but then I have seen 13 on just a couple occassions too. They still move in unison, but no more wild fluctuations 16 to 13 and back like before. And the part where they idle BELOW 0 has me real concerned.
This seems like quite a bit of change just from killing the batteries one time.
By the way I don't think it's a battery issue because I got both new starting batteries at the beginning of the season.
In addition to help for why the sudden change, it would also help to know if proper charging is supposed to resemble the way it used to work, or if it sounds more like the way it's working now.
09-02-2005, 06:02 AM
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Re: Different Charging After Battery Drain
that is a strange one mate , all can put this down to is the old batteries may have been partially sulfated causing a slight short within your batteries ,, now that you've replaced them it seems to read fine , it would pay to check your running voltages with a multimeter just to be sure....an example of good voltages would be ,,,engine not running 12.2-12.6 volts ,,,engine cranking voltages should not drop bellow 10.6 volts ,,,engine running idle with good battery 12.6-13.8 volts , at higher rpms voltages may rise to 14.2- 14.6.....if you are experiencing voltages as high as 16 volts you are running the risk of cooking your batteries,and its best you get your alternator checked by sparky .......
