Plan of attack for keeping my marine battery topped off

[wrcsixeight]

If you are serious about using the alternator to recharge, I think you will be disappointed. Alternators can do bulk charging fairly well upto 80% state of charge if wired adequately, but that last 20% takes forever, no matter what charging source you use.

Seeing as how this thread is about "topping up" a battery, the alternator is an unwise choice. If you were to take specific gravity readings during recharge and had a baseline to compare it to. I believe at about the 12 hour mark you will be in the 95 to 97% range. If you were able to measure the current passing to the battery, you might find less than 10 amps.

Recharging or discharging a battery is not simple math, and alternators are not the magical instant battery chargers the general public believes them to be

Some other factors to think about is even if the alternator at idle speed is going to do much, and if so, how long will it be able to do it as it heats up.

Peukert cannot be ignored either

 

[WagoneerSX4]

http://en.wikipedia.org/wiki/Peukert's_law

Good read - Never learned about that in all my engineering classes.

So I've read up on a bunch of stuff since posting and, you're right, using the alternator I don't think will help me. It will if I completely drain the battery and get it up enough to get some useful CCA, but if I want it completely topped off it looks like I'm stuck with trickle charging it. I think I'm back to square one with the 160W panel idea. I think as long as I don't overuse the battery it should keep it topped off nicely.