Re: Batteries or Battery and onboard chargers???
Converting from a sailboat to a pontoon, I'm still hanging on the the theory that the more batteries the better. I got used to running the toys without running the motor. However now I'm moving over to a pontoon, and in the process of restoring a 24 foot Sundancer. I've been thinking about power for this thing as well, and support the toy habit! I'm planning on deploying three batteries, utilizing an A/B/All switch. I like to use the A bank for starting and running the motor. Use the B bank for all the accessories. After a while, run the motor on the B bank to charge it back up. The third battery, I just like to keep on board, and keep it hot. Occasionally I'll rotate the batteries around. After a battery reaches about 5 years old, I replace them.
A lot of it depends on how much you use them and for how long, and where you go boating. With the sailboat, I needed plenty of power for several days. Our sailing trips on Lake Erie would last two, three or four days, with a couple of times during the season, even a week long. And we were out where no land is in site.
I have used one of the solar trickle chargers (1.5A). It worked great. The one I had, I could plug into a cig lighter, so could put it on which ever battery with just some pig tails. However, it's no good when you got a dead battery. I mainly used it when I got back to the dock, and would just leave it on the battery I didn't use over the weekend, and would put the battery charger on the others.
I had a buddy there that put a 15w solar charger, and he swore by it. It's a nice size that you can easily remove when need to, and it's quite small.
Keep in mind though, we were out sailing for days on end. If your just hitting the lake on the weekend, I don't think it's worth it.