Thanks Main Sail-
I don't even use my refrigeration because of the lack of battery capacity. I also carry a jump start pack just in case and I have used it. Do you think just 2-6volt batteries is enough? Would excessive amperage be a potential problem or just more than needed?
I plan to take my time to get a good fit. I know it is going to be tight.
Greg
First I would focus on how you can conserve energy such as LED lighting and not using an inverter to charge items such as iPads, cell phones etc. that can easily be powered from 12V DC.
Second I would run an
energy budget and compare that to how many days you want to be able to be engine or charge source "free".
Third would be to consider some solar so your overall bank capacity does not require tons of space. I would also look at your alternator's capabilities. Hint, a 55A stock alternator is really more like 25-30A, after it heats up.....
Fourth is how many days per year, in a row, will you be using the boat. 5 day stints? 2 day stints etc..? If just a typical one week vacation then a smaller bank can often suffice. Are you at a dock during the week with charging or on a mooring with no charging?
Fifth is when you go find the Ah capacity to deliver what you want or need to do based on your design criteria.
Sixth is that I would not waste
all your space on a house bank and much prefer to see an AUX or starting bank for reserve or emergency use. If your alternator or charge source should go tits up, a jump pack won't get you but a mile or so......
A reserve or start bank is not just about starting the engine in an emergency it can be about becoming the
reserve or emergency BANK especially when you've lost all charge sources and depleted the house bank already. Treat it like an
emergency bank not just a jump start....
Batteries, there are many options - As it is 2 T105 6V GC batteries are already 225 Ah's or approx 30-65 Ah's larger than two G-27 batteries. You could also move up to the T125 which is 240Ah's in the same case size.
Two Trojan T1275's, which are Trojan's 12V Golf Car batteries, would yield 300Ah's (150Ah's each) and they are very slightly shorter than the 6V T105/T125's..
Look at specs measure them out and figure our what you
actually need. Remember you are only discharging to 50% SOC so your bank needs to be double your use to 50% SOC... In other words if you use 100Ah between recharging you will want a bank of at least 200Ah's.
The main point here is don't negate having a good
reserve bank and to
do the math....