We have a new battery charger!

[Daftmare]

Hi all,

 

We have just had a Sterling battery charger fitted to our boat. Excitement all round.

 

On arrival back at our mooring, we hooked up the landline and off started the battery charger - great I thought, when we come back tomorrow morning, the charger will be on "float" and our batteries will be as good as new !!

 

Well no. Not exactly.

 

We used our trusty(?) multimeter to check the charge across the batteries and they were 12.8 for the two leisure batteries and 13.1 or something across all three (i.e. including the starter battery). I might be a bit out on the numbers, but the point being that the "miracle" I was expecting was that the charger would charge all our batteries up to 14 or 13 point something high.

 

The batteries are 2 years old, so maybe its because of that?

Is it something to do with our alternator?

 

Thanks

Jo.

[MoominPapa]

We used our trusty(?) multimeter to check the charge across the batteries and they were 12.8 for the two leisure batteries and 13.1 or something across all three (i.e. including the starter battery). I might be a bit out on the numbers, but the point being that the "miracle" I was expecting was that the charger would charge all our batteries up to 14 or 13 point something high.

 

It's not quite clear from the above when you did the measurement, but if you plugged in the charger to discharged batteries and then tested the voltage then those are fine: the voltage will rise as the batteries charge. The voltage should go above 14 as the charge progresses, and then drop down to 13.6 once the charger goes into float.

 

MP.

[Daftmare]

It's not quite clear from the above when you did the measurement, but if you plugged in the charger to discharged batteries and then tested the voltage then those are fine: the voltage will rise as the batteries charge. The voltage should go above 14 as the charge progresses, and then drop down to 13.6 once the charger goes into float.

 

MP.

 

 

Hi MP, we did not test the voltage until next day when the charger said it was on float. I expected 13 point something from them all at that point, but they were not.

 

Jo.

[RLWP]

Hi MP, we did not test the voltage until next day when the charger said it was on float. I expected 13 point something from them all at that point, but they were not.

 

Jo.

 

I'm a bit unclear about what you measured too. Did you take those readings (12.8 volts and 13.1 volts) with the battery charger connected and charging?

 

Richard

[Evo]

It all sounds OK to me. The charger has gone to float so it assumes bats are charged. Whats the problem.?

 

Give it a bit more time for it all to settle down, overnight is asking a bit for 3 batteries to fully charge and stabilise..

[Daftmare]

I'm a bit unclear about what you measured too. Did you take those readings (12.8 volts and 13.1 volts) with the battery charger connected and charging?

 

Richard

 

 

We disconnected the landline, so the charger was not connected, and then we took the readings.

Jo.

[bottle]

Ho Jo

 

There so many if's and but's with batteries.

 

May I recommend. two sites for your perusal

 

http://www.batteryfaq.org/

 

and of course Gibbo's site.

 

http://www.smartgaug...technical1.html

 

To test state of charge etc with a voltmeter is difficult, the volt meter needs to be very accurate, the batteries need to have been rested (not touched and disconnected from each other and every thing else) for 24 Hrs.

Edited August 31, 2010 by bottle

[WotEver]

To test state of charge etc with a voltmeter is difficult...

So if they're wet cells, use a hydrometer.

 

Tony

[bottle]

Agreed but even that method needs a certain amount of knowledge and interpretation.