Posted by Thom V (i) on December 09, 2001 at 16:37:27

In Reply to: electrics posted by nobby on December 09, 2001 at 07:47:09:

Hello,
OK, this is a little tough to answer not knowing more... However, if one was too bring a Laptop, a Digital Camera (geez, what battery eaters these nifty toys can be...), and a Mobile Phone (probably an essential item for safety in a small boat), I would look at a system built around a small Inverter. Too difficult to set up a system that would go DC to DC. Easier to use off the shelf DC to AC units and plug in your charging units for each bat pack like at home. One might check out some of the 125 to 300 watt units, being careful to see that each bat pack plug in charge module would go into the Inverter outputs. Get no bigger of an inverter unit than to make a timly charge of the biggest bat pack of the 3. Next is the problem of a main battery system to 'plug' the Inverter into... Here I would look at 2 Gel Cell type batteries (no lead acid to deal with) set up in a parellel configuration. This would allow some ease of handling and double the possible amps-a longer charge-one could deliver to the Inverter and then to the needy bat pack.

The last part of this system would be to charge the gel cell main batteries while out traveling in the boat. Most small outboards have small alternators that would do the job over time. One could augment this charge with a small 3 step charger system that would speed up the process. Also, one could add a small high voltage output solar panel to the main battery system. This might be helpfull if there is no charging system at all, for the mains, as it would help keep battery voltage up. Ohms law states that higher voltage uses less amps and amps is what batteries are all about. Of course if your planning on a bigger boat, the main battery system could be setup like the 1st paragraph and the rest of this might be moot...

Go to Google.com search engine and put in: west marine inverter, lots of info. there. Just put in the word - inverter - into Google and plan to spend some time...

Hope this is of some help. 'Nobby', please do tell us about your boatbuiding project...! What boat have you decided to build???