Adding more Battery to the house Battery + Solar

[bernd rundel]

I would like to add one or two more 8D batteries to the 2 that are installed
on my 2012 Cruiser 45.
Question, is there anything to worry about like to change the Charger as well?
Should I wait until I have to replace all batteries and add then to have all new ones
and exactly the same model?

I am thinking of adding solar on top of the bimini. any recommendations?
Is there a way to find out how much the fridge, freezer, etc uses?
Thanks

[Spirit of Mary]

Bernd,
A difficult answer, because it depends on a lot of variables. About the batteries I can't tell much, only use the same models and the same age. The charger capacity recommendation is 10 - 25 % of the total battery capacity.
I have 200W solar panels for my Bav 38. The fridge consumption is very much depending on the thermal isolation , which is standard very bad on a Bavaria. I improved mine a lot by adding isolation on the top (was without isolation) and adding PU foam all around the box. I expect an improvement of more than 50%. Normally when the compressor runs, the consumption is about 60W. I will get the experience coming holiday till end of September. I also replaced the cabin lights to Led. Also the anchor light is now LED.
I have 2 x 140Ah batteries beside the starter battery.
regards,
Ger

[Stuart]

Hi Bernd I went through something similar to what you're going through back in 2007 I found Nigel Calders Electrical mechanical book invaluable. It is full of info regarding calculating power consumption battery sizing re inverters and chargers etc.
We also changed out the original refrigeration system and put a frigoboat system in, beefed up the insulation added seals in the lid etc. that is your big energy hog.
We added 340 Watts of solar a wind generator and when in Florida and Bahamas rarely have to crank the engine or the Honda.

Hope this helps

[Anthony]

On my Bav 40 I installed 6x 6volt 'golf buggy' lead-acid batteries which are designed for deep cycle use. These have the advantage of being lighter and easier to install, and are simply connected in series and parallel to create 12volts and around 700ah. Tie down is achieved by timber battens that are easily screwed to the underside of the battery compartment, allowing easy regular checking of levels and topping up when necessary.
The system is supported by 2x 80watt solar panels on a rear targa, but the best support is the 400watt German "Silentwind" wind generator which lives up to its promise of quiet high output, way better than the AirBreeze I used to have.
Frankly, solar panels are a dubious device on a moving yacht, their efficiency diminishes rapidly with the angle of incidence of the sun, or any shadows, while the wind generator works all night when you need that power most!

[Ziffius]

The more AH you install the bigger the charger will need to be unless you have frequent access to shore power as your original charger was probably matched to the size of your Original battery bank, more batteries will take longer to charge with the original charger (most likely scenario). Solar power - the more the better if your in sunny climes, being able to rotate/tilt them to track the sun will improve efficiency but makes them awkward to position on the boat. Panels on the Bimini or an arch I prefer, the ones on an arch can be made to tilt which helps. I am in the Ionian and my wind charger doesn't do much compared to the solar panels. So wind v solar much depends on your cruising area, having both hedges your bets.