My $1.00's Worth!
Last Sat, 10/6/18: I changed our nearly 9 yr. old 4 batt battery bank [deep cycle 31M la wets] with exact same model new 4 batts. Cost of batts proper [$440 dollars in very early 2010] averaged out right at one dollar [$1.00] per every week for the entire duration of nearly 9 years. That's a cost I can live with and am pleased to announce! The new four similar batts were still under $500. I'm anticipating to experience approx $1 +/- per week house bank batt cost for the next 9 yrs!
I get all battery needs from local franchise of "Batteries Plus Bulbs". U.S. based - East Penn is the battery manufacturer.
I believe it is correct to appraise of these facts: Living 100 miles separated from marina in CA Delta, we only find time to use boat an average of 8 to 10 fairly-long-weekends per year. And, we do not very often spend more time at dock than what's required to on-load/off-load. We do spend much time at anchor swimming and playing/relaxing as well as running around in our tow-behind, quick and comfortable Crestliner o/b runabout. Additionally, I never leave boat plugged into shore power when we leave boat for any length of time. Also, our boat is rigged with mostly AC apparatus [stove, oven, fridge, microwave etc] that runs off gen set or shore power... so batt inverter is not required. In other words... our house bank power supply is not too often over taxed! As an aside - I don't let house bank drop below 50% charge before bringing it up to full charge again and I always keep batt distilled water level in correct position [usually check and add a little distilled once per year}.
In addition to house bank I also have specialized 24 starter batt for gen set and an isolated 'black box" 24 starter batt kept as emergency assist if needed [I like safety-redundancy aboard boat]. The emergency batt stays fairly new and fresh by getting cycled into gen set batt and/or runabout batt as may be required. These batts are both kept at 100% charge via AC trickle chargers and for the genset also hooked up is a small solar panel on fly bridge front.
BTW - Both engines start off the 4 paralleled 31M house bank batts. Starboard engine has big amp alternator that also charges house bank.
Soooo with no more explanation... I'll post photo of old batt bank just replaced. Then, new batt bank installed last Saturday. Then, emergency "black box" batt and gen set batt smart trickle chargers. Then 1977 60 amp
very dumb "Professional Mariner" batt charger [still works well]. Then,
very smart NOCO genius GEN 4 - 4 bank, 40 Amp 2018 charger [plan to install next visit to boat!].
https://no.co/gen4
There - That's my $1.00's Worth