Re: Permanent 24 v to 12 v converter

Thomas Peacock

As part of putting in new instruments, I was able to shut down the “permanent” Sailor. Unfortunately, we do not have an on/off switch anywhere on our Sailors.

When I installed a new Raymarine Autohelm, the main box has a 12 volt output for networking instruments that includes a power supply. Therefore, the various gauges and chart plotter all get power from that. One could consider having a backup power source for instruments, in case the autohelm were to go bad. The instruments are all activated by the Autohelm breaker. The new Quantum radar also is wired into that breaker, 24 volts. Thus, one Sailor is now freed up.
Since the VHF is the most important of my present 12 volt devices, it has its own dedicated Sailor.
The second Sailor runs the FM/CD radio, as well as the 12 volt circuits for cigar lighters. Since cigar lighter plugs and receptacles are finicky, we don’t use them anymore. Instead, I installed a 24 v to 5 v USB hub for phone and other small device charging. However, be aware that very new laptops may use the new USB 3/USB-C type connectors to charge the computer battery. It is important to be aware of the total demand on your USB hub.
The third Sailor is inactivated by having pulled the fuse. However, I sleep well at night knowing that in case either of the other two Sailors were to go down, there is at least a spare.

I don’t really care about the radio storing stations. But, if important, one could run the dedicated wire from the radio to the 12 v starter battery, with an in-line fuse. That is what is done on automobiles. The power draw is negligible. Plus you could always just pull the fuse if leaving unattended for more than a few weeks.

Tom Peacock
SM #240 Aletes
Chesapeake Bay, US, leaving for Martinique November 3

On Oct 14, 2019, at 12:30 PM, Paul Osterberg <osterberg.paul.l@...> wrote:

I’m surprised about the function of the Permanent 24 v to 12 v converter. If I understand it right the only original function is to keep the memory in the FM/AM radio even when the main switch is off.
The current when it is on is ca 0,5 volt, that is a lot of Ah during a day, or during a two-week crossing it’s close to 165Ah. That is a lot of waste unless you regularly run your gen set but we try to rely on solar.
The only way to turn it off is to pull out the fuse. To me that is overkill to have such a heavy-duty converter for such a little use.
 When my friend changes his car battery, he connects an ordinary 9 volt battery to the stereo and that is enough to keep the memory.
I have connected some 12 v appliances to the permanent converter, 12v led light in the galley, and a few USB outlets.
Have I missed anything about the function of the Permanent converter?
Paul on SY Kerpa SAM#259 Lagos

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