opinions on deep cycle battery

[cprince]

You could always have 4x6volts...2x series connected in paralell to the 2 other in series lol.....

I was just wondering about the charger because I have a 2 bank charger but I like to keep one on the crank battery!

Cprince do you have your paralell setup connected to your alternator for automatic charge? i've been thinking of doing that as well...

LOL!!

The only alternator I have is on my car!

I have one 15hp (Lost prop last Saturday!!!) and 2x 1971 Evinrude 18hps. One has an electric start.... but no alternator!!!

I do the parallel setup from time to time in my little tinny for the trolling motor. I hate clearing off the center bench to change over the batteries!!!

I have thought about this a lot and I would think that connecting it to the alternator would be fine... but the draw back is that the cranking battery would bot get *as charged* as it should, or otherwise would if it were alone. There must be a way to get a higher output alternator to be able to accommodate more than one battery.

People get hung up on volts... it is not hard to get the volts up on a battery... it is the AMPs that are key.

You could have a battery for your trolling motor that reads 12 or 13 volts on a multi meter, but wont push your boat long because it does not have enough AMPs.

When your battery is low on AMPs, this is what takes a while to charge "into" your battery. So... when you take a (for example) 10 AMP charger and put it on two batteries... each one is effectively getting 5 AMPs.

I do not know what type of amperage output a marine alternator (on average) puts out, but I cannot imagine that it would be as much as an automotive one. Those (I think) average from 45 to 75 AMPs.

Someone smarter than me can chime in and give us the Math behind all this to give us approximate times to charge at different amperage ratings... And fix anything I got wrong above! I think I got it right...

Craig

[Wrexxer]

The alternator on my 140 4 stroke is 40amp this why I thought it could cover the craking and 2 x paralell deep cycles seperare by an isolator...

I'm theory it should be good but I'm too chicken to try ahahaha

[cprince]

Paging mikemicropterus!!

See what he thinks.

Craig

[mblaney]

Like cprince said, doubling your batteries doubles your ampere-hours, like putting a second gas tank in your boat.

The only drawback with wiring two batteries in parallel is that you are only as good as the weakest one. If you have one old battery and add a second new one you will, in a relatively short time, have two old ones. Change them in pairs for best performance and life.
Similarly, if one battery fails (shorts) it takes the other one out with it.

To do it properly, parallel batteries require a little more care than handling them separately. Remember that if you remove one battery the wires are still hot (from the second battery). Always remove negative cables first (parallel system or not!)

[mblaney]

The alternator on my 140 4 stroke is 40amp this why I thought it could cover the craking and 2 x paralell deep cycles seperare by an isolator...

I'm theory it should be good but I'm too chicken to try ahahaha

Your alternator could be a 4 amp and it would still work but you would have to leave your motor running overnight to charge it . Your motor's ability to keep your bat's up will be mostly dependant on your running time (charging) vs trolling (drain); unless you are doing long high speed runs this would not work.

It makes the most sense to leave your cranking bat to the boat motor; do your deep cycles at home.