Our 26X boat tour on the last day of our Powell trip

[Russ]

Oh and the outboard still needs 12v right? So how do you deliver that?

[tuxonpup]

You have given this much thought. That can be dangerous.

I wonder how many TRUE 12v devices we have on our boats. You are probably right about LEDs being tolerant of dual voltage.

I guess all this relies heavily on dual 12v batteries in a series. If one fails, the whole system might suffer. Or not if it just drops down in voltage.

VERY interesting ideas. I bet you wish the boat were close so you can work on it at your leisure and experiment.

What does the Starlink require for voltage?

The Mini runs off 12V-40V, the USB-C power supply puts out 20V, 5A. I suspect it's cigarette lighter > USB-C adaptor will work on a socket running 24V as well, but I'll need to test.
Being able to run everything at 12V is the backup plan should the batteries in series at 24V develop a problem.

[tuxonpup]

Oh and the outboard still needs 12v right? So how do you deliver that?

There is still a 12V lead acid starter battery connected directly to the motor, all the 24V house battery wiring would be run from the separate pair of LiFePO4s. Currently we just charge the starter battery from the alternator and the house battery from solar, but the DC-DC converter allows each battery bank to use either charging source.

[Be Free]

You have given this much thought. That can be dangerous.

I wonder how many TRUE 12v devices we have on our boats. You are probably right about LEDs being tolerant of dual voltage.

I guess all this relies heavily on dual 12v batteries in a series. If one fails, the whole system might suffer. Or not if it just drops down in voltage.

VERY interesting ideas. I bet you wish the boat were close so you can work on it at your leisure and experiment.

What does the Starlink require for voltage?

The Mini runs off 12V-40V, the USB-C power supply puts out 20V, 5A. I suspect it's cigarette lighter > USB-C adaptor will work on a socket running 24V as well, but I'll need to test.
Being able to run everything at 12V is the backup plan should the batteries in series at 24V develop a problem.

Russ,
Many (I would venture to say "most") marine devices are happy with 12V or 24V (or even 40V). A 24V (or higher) house bank is not unusual in larger boats.

Tuxonpup,

As I see it, the main benefit of running your devices at 24V is the ability to use smaller gauge wire (costs less, easier to pull). If you need to fall back to 12V due to a battery problem, those wires may be too small or may introduce too much voltage drop while simultaneously doubling the current (possibly blowing the fuse or tripping the breaker). It can be made to work but I can't think of a way to do it that is not at least as expensive as a 12V design. Are you sure that the "juice is worth the squeeze"?

[OverEasy]

Hi Tuxonpup!

Be Free brings up an interesting point about having a 24 VDC system vs. a 12 VDC system and wire sizing and the future…
While the higher voltage can allow for smaller wire sizes it might not be so obvious to those in the future which should someone bring it back to a 12 VDC system…maybe a note somewhere like in the battery compartment or on/near the switch panel a note to the effect that your boat has been wired for 24 VDC?

Just a thought….

Best Regards,
Over Easy

[tuxonpup]

Boat projects have been on the back burner for a while, but after two more weeks of the current Sister Act run, I'll actually have three days off over Labor Day weekend for the first time since our San Diego sailing trip. The plan is to install the new fridge, chart plotter and depth finder on this trip, supported by a second solar panel and additional 100Ah LiFePO4 battery. Actually hooked the system up at 24V for the first time tonight and everything's working as expected, the battery monitor displays 26.3V, the USB outlets convert down to 5V to charge the iPad, while the cigarette lighter socket works at 24V to power the connected fridge, which is displaying 26.3V on it's own display;



I checked out the Starlink's cigarette lighter to USB-C adaptor and it also works up to 24V, which is a bit closer to the Mini's native 30V operating voltage. I'm not looking to downsize any wiring to go 24V, but both the Starlink and fridge's proprietary DC cables seem fairly skimpy for a 12V run over any distance, the former actually failed last trip and I had to get a replacement.

We'll see how it goes, I still haven't connected the 12V lead acid starter battery to the DC-DC converter/MPPT solar controller the house batteries charge from. That could be available as a 12V only supply once the boost-buck DC-DC converter is prioritizing it's charging over the house system, will be interesting to experiment with once it's all being managed through a cross charging system.

[dlandersson]

Saw this on the Lake Powell water level

Oh and the outboard still needs 12v right? So how do you deliver that?

[Russ]

both the Starlink and fridge's proprietary DC cables seem fairly skimpy for a 12V run over any distance, the former actually failed last trip and I had to get a replacement.

They will both be happier with higher voltage. If the starlink native is 30v, then I agree that the up convert will be an easier task.

My fridge didn't like the long 12v power run despite heavy 12-gauge wire. When I moved it closer to the battery, it's much happier with less voltage drop.

This is very interesting because when I got the fridge I contemplated how to feed it 24v. My guess is it will run more efficiently as well.

Thanks for posting and keep us updated.

[tuxonpup]

Saw this on the Lake Powell water level

Yep, deadpool isn't just a soccer team owner.

The canyons we're exploring were mostly underwater the first time we visited Lake Powell. If the Colorado dries out South of the Utah border there will be a lot more ghost towns to explore out west. The CAP water reached Tucson about the same time I arrived and promptly destroyed everybody's plumbing with calcification, but there's no way the natural aquifer created by the mountain ranges surrounding town could support the overbuilding that's occurred since then.

[tuxonpup]

both the Starlink and fridge's proprietary DC cables seem fairly skimpy for a 12V run over any distance, the former actually failed last trip and I had to get a replacement.

They will both be happier with higher voltage. If the starlink native is 30v, then I agree that the up convert will be an easier task.

My fridge didn't like the long 12v power run despite heavy 12-gauge wire. When I moved it closer to the battery, it's much happier with less voltage drop.

This is very interesting because when I got the fridge I contemplated how to feed it 24v. My guess is it will run more efficiently as well.

Thanks for posting and keep us updated.

Will do, I just ordered the replacement LEDs for all the interior and running lights, plus a sail stop for our new main. I'm going to try out the 24V>12V converter tonight and decide if it's worth it for the .3V or so the running lights would draw, or if I just put them on the 12V starter battery once it's part of the recharging system.