Understanding 12v gel batteries voltage ?

[davethedog]

Hi all,

We have 5 x 102ah 12v gel batteries (rolls) as the "house bank". Trying to understand what is going on with them as in the morning, after being fully charged by the solar here in the Caribbean during the day, and running the fridge and freezer overnight (approx 5 amp hrs) as well as lights etc, in the morning they are reading about 12.7v. We have a Mastervolt system for battery monitoring (smartshunt and easy view 5 etc) which shows using about 80ahr overnight.

Does this seem to make sense as on previous boat we had AGM batteries and in the morning were down to about 12.3V?

Cheers

DTD

 

[geem]

Hi all,

We have 5 x 102ah 12v gel batteries (rolls) as the "house bank". Trying to understand what is going on with them as in the morning, after being fully charged by the solar here in the Caribbean during the day, and running the fridge and freezer overnight (approx 5 amp hrs) as well as lights etc, in the morning they are reading about 12.7v. We have a Mastervolt system for battery monitoring (smartshunt and easy view 5 etc) which shows using about 80ahr overnight.

Does this seem to make sense as on previous boat we had AGM batteries and in the morning were down to about 12.3V?

Cheers

DTD

Have you checked them with a voltmeter?

 

[davethedog]

Yes .with a voltmeter and also via the mastervolt shunt and the victron mppt controllers.

 

[[70521]]

How many hours of darkness are you having at the moment?

80/5 = would indicate 16 hours. What else it running?

What is the starting voltage of your batteries and what is the theoretical % usage at 12.7 volts?

 

[Tranona]

5 amps is just for the fridge - plus "lights etc" (as in the post) could easily be 80amps over 12 or 13 hours. The question is whether that usage (15% theoretical capacity) is consistent with a voltage of 12.7.

 

[davethedog]

Update to this, seems all is good and each morning the batteries are between 12.5 and 12.7v when we get up after tuning the fridge and freezer etc through the night.

Was just odd to sometimes see over 12.6v in the morning as precious boat it was down to about 12.3 each morning.