Having dealt with the problem of charging a dedicated windlass battery bank located forward under the V-berth for some years now, I'd like to pass on a couple of things I've learned.
The basic design evolved when I installed the windlass some 10 years ago while in the Caribbean. In order to avoid a long run of very heavy battery cables, which would have been about 60' in my case, I chose to locate a dedicated anchor windlass battery bank forward, near the windlass itself. The windlass is a Lewmar Concept 2. The battery bank consists of 2 Trojan T-105's.
Over the years, I've managed to murder several sets of these batteries, through both inadequate engineering and neglect. I used to be away from my boat for several months at a time, and used a small solar panel to keep them charged. The panel was inadequate, there was no controller, etc., etc.
Wising up a bit, I decided to install a small battery charger. I got a good deal on a ProMariner 10-amp smart charger which fit nicely between the V-berths under the step. That little charger is still there, and still does a good job keeping the battery bank fully charged.
However, there are three problems. First, I'm an active ham and that charger is incredibly noisy in terms of RFI (like every other ProMariner product I've seen). Therefore, I turn it off when using the SSB. In the past, I've forgotten to turn it back on....sometimes for weeks or even months. And, as could be expected, I managed to kill another set of T-105s. This "last kill" is still in my basement where for the past 9 months or so I've tried to revive them with all manner of interventions. They still have only 60% capacity.
The second problem is that the little charger doesn't have the ability to do an equalization cycle...i.e., to hit the batteries periodically with 15.5 volts or more for a few hours to avoid plate sulfation.
The third problem isn't so much a problem, but a "would be nice" factor. The windlass operates very well from the batteries alone. Sometimes I think it would be nice, however, to be able to help them with a higher voltage when pulling in 200' of chain and a 60lb anchor under some load. The little battery charger doesn't have enough oomph to do the trick.
Solution for all three problems: install a smarter, quieter, larger battery charger, not because it's needed to charge the batteries but because it would solve all three of the above-cited problems.
Happily, there's a good and not very expensive solution somewhere in my future. As some may know from my earlier posts, I'm a big fan of Iota chargers. Industrial strength, very smart designs, very compact, and very affordable. I could replace the little ProMariner charger with an Iota 55A charger which is about the same physical size for about $165. See current eBay listing: eBay Motors: 55 AMP BATTERY CHARGER RV MARINE REMOTE CONTROL NEW (item 260106436855 end time Apr-19-07 23:00:52 PDT)
These chargers use PWM technology, and with the IQ-4 smart charge option ($35) are multistage, pulsing, and periodic equalizing chargers. I've been using one in my ham shack for over 2 years to maintain a similar bank of 2 T-105s with excellent results.
Bottom line: size the charger larger than needed to just charge the batteries, anc choose a charger which does everything you want, including not interfere with your radios.
Sorry to ramble on so long. Anybody want a lightly used ProMariner 10-amp "smart" charger? :-)