Join Date: Aug 2006
Location: Arlington, VA
Thanked 11 Times in 9 Posts
Rep Power: 11
I agree that your 6-year old flooded batteries are likely near the end of their useful life. And, since you don't know their history or how they have been treated, it would be best IMO to start with new batteries.
The Dolphin 40A charger is a high-end smart charger which should be able to maintain your batteries just fine at dockside. The important thing is to keep them as fully charged as you can when you're not actually using them while cruising.
There is a wide range of inverters available, both pure sine wave and modified sine wave types. You might examine your needs in some more detail to know exactly how you plan to use the inverter. That would drive your decision as to what kind you need and what capacity. For example, a laptop can draw a lot of current (6-8 amps or so at 12V...about the same as electric refrigeration). There are 12V power supplies available for most all laptops; one of these might be a better deal than trying to power the laptop with a generic inverter, as the losses would likely be less, and if you had this option you might get by with a smaller inverter.
Now, if money is no object, think about a high end inverter-charger like the Victron Phoenix Multi-Plus. It does just about everything, is pure sine wave, has a 120A smart charger built in, puts out 2,000 watts @ 110VAC continuous, smart relays, can be chained, etc., etc. and will only set you back about two boat units :-)
Last edited by btrayfors; 08-07-2008 at 07:27 PM.