Have used Golf Cart Batteries for years.
I prefer Dekas vs Trojans, but that is like Ford and Chevy, probably same thing.
Costco brand Golf Carts can be had for about $90.00 versus West Marine
at $235.00 a piece.
They weigh about the same, 60 to 65 pounds (27 to 30 kgs) and you pay for the lead, almost the same..215 or so amp hours @ 6 volts.
Don't take 'em below 50%, or if you really want them to last long, cut that in half and use only 25% of the capacity.
A rough guide is 1000 cycles at 50%, the less you take 'em down the longer they last.
To stay with the above religion I installed LED lights
down below, every one of them, also LED Anchor
light and Tri-Color.
Left the regular nav lights with old fashioned bulbs because the engine
is running with the nav lights. Tri-color only when you are sailing.
will also save the batteries and extend their life. 75% is the goal, but sometimes I go down to 70%.
Highly recommended a Battery Monitor
, it pays for itself over time:
Some folks get only 2 years on their batteries, with a Battery Monitor
and the above panels/75% rule
you can expect 5 to 7 years or more out of the Golf Cart Batteries. Spring for Rolls and shoot for 10 years or better.
Not a big deal for weekend warriors, but for full-time cruisers a good 12 volt system is the only way to go.
When I started with this sport I did not know much about all that and bought huge truck batteries for the boat and used them until the lights got dim, then I charged 'em up..Wrong and I paid for it.....
Do a deep cycle on a deep cycle battery and you do permanent damge to it although modern AC chargers can "equalize" the batteries and extend the life somehow, either way, get more batteries and use less of the capacity for a long and happy life.
If your daily load is 100 amp hours, and you have 4 Golf Cart Batteries, charge 'em every day to stay with the 75%, if you have panels
, they will put 50 amps back in so you only need to run the engine
every other day to stick with the 75%.
My load is about 60 Amp Hours and the panels
put in about 55 to 60 and if the sun is shining every day I can sit for anchor
every day and drink cold beer
, but in reality there is cloudy days that only yield 10 Amp Hours and there is a 20% loss from the solar panels
to the batteries and back out to the 12 Volt panel.
3 or 4 days without running the engine and keeping the 70% limit is about max.
Your milage may vary...