On Sun, Jun 28, 2009 at 08:35:44AM -0400, [email protected] wrote: > > Once upon a time there was available at J C Whitney a relay just for that. > The Volkswagen of some vintage had two six-volt batteries under the back > seat wired in parallel. The relay would put them momentarily in series > (while disconnecting the six-volt feed) sending twelve volts to the starter > for cold-weather starting.
That was a cute idea on their part. Again, wiring it up wouldn't take much - here, I'll sketch it: http://okopnik.com/images/flip.pdf When the relay/switch is in the off/unpowered position, the two batteries are tied in parallel, and the watermaker is disconnected from the circuit. In the other position, the two batteries are connected in series, powering the watermaker. Do note that if you're charging while running the watermaker, only one of the batteries will get charged - which means that your total series voltage will start dropping after a while. Solving *that*, however, is quite a bit more complex (but does provide one possible answer to "why are there 12v-to-12v inverters?" :) > They may still have this relay available somewhere. If not, just look for a DPDT relay that can carry at least twice the current required by your watermaker. -- * Ben Okopnik * Editor-in-Chief, Linux Gazette * http://LinuxGazette.NET * _______________________________________________ Liveaboard mailing list [email protected] To adjust your membership settings over the web http://www.liveaboardnow.org/mailman/listinfo/liveaboard To subscribe send an email to [email protected] To unsubscribe send an email to [email protected] The archives are at http://www.liveaboardnow.org/pipermail/liveaboard/ To search the archives http://www.mail-archive.com/[email protected] The Mailman Users Guide can be found here http://www.gnu.org/software/mailman/mailman-member/index.html
