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how many volts


spud150

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Can't make any proper sense of this - an ampmeter (do you mean ammeter) shows current (in amps), not volts. And, if it is a voltmeter, then if its so inaccurate/poorly scaled as to not show any decimal places......its virtually useless. If its an analogue gauge, it needs reading properly.

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It depends on several factors.

1 How accurate is your meter? A digital one is best for this as analogue isn't easy to read to any accuracy.

2 what sort of batteries do you have? Wet, sealed, AGM?

3 Where in the charge cycle it is.

With wet (flooded) cells you should rise to about 14.8 volts while charging, then drop to 13.2 for the float charge.

With sealed batteries the voltage should rise 14.4, then drop to 13.2 for float.

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It depends on several factors.

1 How accurate is your meter? A digital one is best for this as analogue isn't easy to read to any accuracy.

2 what sort of batteries do you have? Wet, sealed, AGM?

3 Where in the charge cycle it is.

With wet (flooded) cells you should rise to about 14.8 volts while charging, then drop to 13.2 for the float charge.

With sealed batteries the voltage should rise 14.4, then drop to 13.2 for float.

 

He said "when out cruising" NOT when shore line charging so in the majority of cases the last bit is just incorrect unless he has some fancy alternator controller fitted.

 

Typically alternator charging will start at something above 13 volts, probably above 13.5 volts depending upon the state of discharge of the batteries and gradually build to between 14.2 and 14.5 volts. Very old alternators may rise to between 13.8 and 14.2 volts.

 

In fact apart from the Sterling A to B charger I very much doubt any of the controllers can drop to a float of less than the normal regulated volatge unless they totally replace the alternator's own regulator.

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If it's the voltmeter on the engine panel it will probably be showing the engine/starter battery voltage and not the domestic battery voltage. Mine always shows just over 13 volts except for a few minutes after starting the engine.

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If it's the voltmeter on the engine panel it will probably be showing the engine/starter battery voltage and not the domestic battery voltage. Mine always shows just over 13 volts except for a few minutes after starting the engine.

 

On a split charge boat both battery voltages should be the same and on a twin alternator boat both alternators will have a similar regulated voltage of at least 13.8 volts and more likely over 14 volts. Discharged batteries would pull that voltage down for a while but it will rise over about half an hour or more.

 

If you have a split charge diode then that is possibly your problem but check for undersized cables and bad connections. Also check the output voltage at the alternator, preferably just before shutdown for the day.

 

Something is almost certainly wrong with your voltmeter or system. Check the voltmeter against a multimeter.

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Get yourself a little digital voltmeter from Amazon , under 10 quid , you probably have connections by the fuse box for it , it will give you the state of your leisure batteries .

 

<panto> O no it won't <panto off>

 

For that you need some knowledge and observations over time OR only checking the batteries after they have stood with virtually no load for a number of hours (overnight best). However even then the reading will depend upon how well charged the batteries were.

 

Even if the meter did show 12.7 to 12.8 volts after an overnight stand it still does not mean they are serviceable. A bank that is sulphated to a a very high degree will in effect be fully charged very quickly and give those readings but the dramatically reduced capacity will mean they discharge equally fast. The only way around this is to either conduct a timed discharge test or if open cell batteries a hydrometer test. In the latter case a sulphated battery would give a well charged voltage reading but a very poor hydrometer reading.

 

You can infer a lot from voltmeter and ammeter readings taken a periods throughout the week but thinking a voltmeter is all you need to assess battery condition will lead to problems.

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