Battery capacity Q

[Dave K]

I will have 3 amps in my boat powering my stereo. I am planning to have 3 independant batteries under the port side console with a on board 120V charger to plug in after each day.

I do not know if I should go 3-24 series DC batteries with a reserve capacity of 125a or go with 3-27 series batteries with a reserve of 160 each.

My question is if someone can help me out, is there a way to figure out how much play time you have based on amp rating (draw) of amps, and reserve capacity of batteries.

Do you really need to install in capacitor??

Thanks

[Ewok]

Just start adding up the amperage draw of your components, specifically the head unit and speakers to get a ball park of how long the batteries will last. I really have no idea about the amplifiers. I know the step up and clean up the power to the components and they transfer some of the energy to heat but I would start out thinking about where the electricity is ending up, in the HU and speakers. Also, when selecting batteries look at the reserve capacity for comparison and I would buy the highest RC you can fit in the boat. Keep in mind with higher RC it will take longer to charge them overnight, so you have to make sure you get a big enough charger to fill the batteries as fast as you need. I know bass boat shops around here have 30amp chargers they use for the trolling motor batteries.

[chpthril]

When building a stereo batter bank, I recommend sticking with a dedicated marine deep-cycle (when going with a traditional wet-cell battery) and not a starting or dual-purpose battery.

As far as specs go, the one to really concentrate on is "Ah" (amp hours). The rest - CCA (Cold Cranking Amps) CA (Cranking Amps) and RC (Reserve Capacity) are not all that important for stereo bank.

Each time you wire a battery in parallel with another, you are "stacking" the AH's together, example: two 80 Ah batteries wired in parallel = 160 Ah's. Add another and you have a 240 Ah battery bank.

Now, to answer your question. It comes down to a few things: What is your stereo's current draw, how long do you want to play, how much space do you have for batteries and how much money do you want to budget.

[Jason B]

FWIW: I had 3 bateries in my port locker and my boat leaned like I was weighted for surfing.(ok, maybe not that bad) Mine is a 20' so yours probably won't be as bad. Just something to think about if you can plan ahead for equal weight disbursement....

[Dave K]

Im 6'3" and 295 so the batteries should off set my fat a$$. LOL