Originally Posted by nauticalnomad
I am adding to my battery bank and was curious as to what other AH the other people are carrying.
I have a 45 ft boat and at moment have 1 x starter battery along with 2 x leisure batteries at 110AH each. I am looking to add another or another 2 batteries to it and i had the option of a single
220 AH big battery or 2 smaller 110AH batteries. The 220AH battery is not as big in physical size as the 2 x 110AH batteries.
We used to have two house banks but upon n-th incarnation I decided to convert to a single, bigger bank instead. Over time, by going LED and kicking out some useless electrical equipment
from the boat I was able to reduce our originally 240Ah bank to the present 110Ah.
I am also sailing and maintaining a biggi-sh 72'er now. This one also has a single house bank (of 660Ah / 24V).
I remember from (Calder's?) book a fascinating discussion of 2 house banks vs. 1 bank. Frankly, I never really understood that argument as I am always sailing simple sailing boats. I can imagine that a specific trawler
or some other type of boat calls for two banks rather than one.
In practical terms, onboard a small sailing boat, you may consider the following tricks:
- make the starter battery huge,
(because should your house bank go pop, you can still run the VHF
or a LED anchor
- make the house bank (assuming 12 Volt systems) of two smaller 12V batteries rather than one big (use 50Ah + 50Ah to make a single 100 bank rather than use a single 100Ah battery)
(reasoning same as above - should one of the twin house batteries kick the bucket, you remove it and keep on rolling, with half the capacity)
To sum this up, my take is:
- one oversize engine battery,
- one house bank (made out of 2, or more, batteries)
e.g. here (boat 26', LED, no fridges, no air, no micro, no plasma,)
- starter 90Ah, (engine 12hp),
- house 110Ah (= two batteries 55Ah each).
Make sure you can start the engine of any bank (a simple jump wire is enough).
An automatic overflow charging
is nice to have on the alternator
side (we have a simple relay system).
Our daily Ah consumption
is 10 to 25Ah (10 to 25% of our house bank cap), depending on whether we are offshore
or anchored (more consumption
We use a digital monitor
to look up the house bank and the charging
status (Bogart Engineering) - recommended.
We use 150W solars and a PWM to charge off the grid and a shore side 25A charger
at the dock
. We are in a super solar hours zone (Canary Islands or Caribbean). I am going to upgrade to MPPT
and add 50% of solar capacity, just in case.
We charge 100% daily as a rule
, with single only days when there was not enough sun on the passage
Cut/mix/paste and set up your perfect house bank! ;-)