Remember that the Generator is AC voltage (unless you are planning to purchase
a 12VDC generator). It will be using the shore power battery charger to refill (charge) the batteries.
- - Inverters use 12VDC in large amounts - more than 10 to 1 for conversion the 120VAC and probably 20 to 1 for 220VAC. That is, for 1 amp of 220VAC you will suck 20 amps or more from the batteries. For a coffee maker or TV or computer you can easily consume some serious amperes from the batteries.
- - Normally the cost difference between the 12VDC - 20 amp output battery charger and the 40 amp output is very small.
- - Recharging your batteries up to "full" takes a varying amount of output from the battery charger. Oh! be sure the shore power battery charge is the new "smart" or computer controlled multi-step battery charger. Do not get an automobile type battery charger!
- - A "smart" battery charger will supply a high amount of amperes into the batteries to start the recharging and then reduce the amount of amperes it feeds to the batteries in - usually - two more steps. Typically you will see the three step "smart" chargers use words like: "Bulk charging
- Absorption Charge - Maintenance
Charge" or words similar to those to describe the 3 different steps in recharging the batteries.
- - Depending upon the "type" of batteries that will be installed in the boat - normal "liquid lead acid" or "AGM - absorbed Glass Mat" or "Gel" or the new "Lithium" - it is critical that your shore power battery charger - and - your engine alternator regulator
have the ability to properly recharge the particular battery type. Batteries are very expensive and using the wrong process to recharge them can quickly lead to significant decreases in the battery's life.
- - Depending upon where in the world you will be using the boat, solar and wind
power systems vary considerably in the amount of electrical
power you get from them.
- - If you look at the electrical threads on CF you will see that Solar Panels
only produce sufficient electrical power during 4 or 5 hours per day and in cloudless skies.
- - Likewise, Wind generators need significant wind - like the tradewinds in the eastern Caribbean
- to generate any usable electrical power to recharge batteries. And - cruisers tend to anchor
in areas with low winds for comfort in the boat. Wind generators need a lot of wind to put out significant power.
- - Towing electrical generators are a great idea - but - you have to set them up while sailing and then convert them back to wind after sailing. There is a tendency to just not want to do all that work so they are rarely used as towing generators. Beside which, anything you "tow" that is attached to the boat will slow the boat down unless you are sailing in high wind conditions.
- - All these things make up the "difference" between what the brochures and salesmen tell you and "real life" on a cruising boat. You will learn with time and experience that a lot of the brochures and salesman's information is quite different from "real life."