Energy solutions onboard a live aboard

[Simi 60]

Originally Posted by Reefmagnet

We've got 5v usb outlets all over the boat - the kind with dual outlets. My tip here is to buy the ones that glow red rather than other colours and make sure both outlets can supply 2.4 amps consecutively as some units have a 2.1/1.0 amp output only.

This sort of thing?
Considering pulling several of our dual PowerPoint's clogged with chargers and replacing.

https://www.auselectronicsdirect.com...AaAhiYEALw_wcB

Same same is cheaper on eBay.

[john61ct]

Most USians used to only get a passport for military service.

But now trending upwards. . .

1990 only 4%

1994 10%

1997 15%

Nowadays 42%!

[hellosailor]

Uncle Bob, on the East Coast, it is considered rude and unmannerly to whip out your voltmeter and stick it into the outlets on someone's boat, at least on the first visit, so we rarely know what their voltage actually is. just saying.

But John?
I got my passports for business or pleasure travel. Way before 1990, and I knew many other folks who were presumably passport holders for the same reason. Since only something like 10% of the population is or ever has been in military service...it wouldn't be hard to beat the number of passports that 10% needed (IF they needed it, did Uncle Sam pay the passport bills for draftees in Nam?) by the number of folks traveling for other purposes.
Where do your numbers come from? How do they compare to the number of international air travelers alone that we've had?

[Reefmagnet]

Originally Posted by Simi 60

This sort of thing?
Considering pulling several of our dual PowerPoint's clogged with chargers and replacing.

https://www.auselectronicsdirect.com...AaAhiYEALw_wcB

Same same is cheaper on eBay.

They need AC to power the USB. I was referring to the 12 volt models like below. The dual 2.4 amp are a little tricky to hunt down (they can be found on Ebay).

[Uncle Bob]

Originally Posted by hellosailor

Uncle Bob, on the East Coast, it is considered rude and unmannerly to whip out your voltmeter and stick it into the outlets on someone's boat, at least on the first visit, so we rarely know what their voltage actually is. just saying.

But John?
I got my passports for business or pleasure travel. Way before 1990, and I knew many other folks who were presumably passport holders for the same reason. Since only something like 10% of the population is or ever has been in military service...it wouldn't be hard to beat the number of passports that 10% needed (IF they needed it, did Uncle Sam pay the passport bills for draftees in Nam?) by the number of folks traveling for other purposes.
Where do your numbers come from? How do they compare to the number of international air travelers alone that we've had?

Hellosailor, the point that I was attempting to convey was that much of the world outside of good old US of A is 220-240 volts, single phase. To say that virtually no one has this voltage on a boat surely indicates a lack experience or knowledge beyond one's local boundaries.

[Simi 60]

Originally Posted by Reefmagnet

They need AC to power the USB. I was referring to the 12 volt models like below.

Fair enough.
We are predominantly AC powered.

[KTrout]

The budding electrical engineer in me is wondering if it’s possible (and reasonable in cost) to convert shore power (110-240vac 50-60hz) to 12vdc (nominal) and then run that straight to the “big” inverter? In this scenario, I’m imagining that bypassing the battery bank would prevent inadvertent charging/discharging that would excessively heat and cycle the battery.

This way, house AC is always from the inverter when on shore power. You can have one set of appliances that will always work, no matter what power source you plug into. No one has talked about this type of solution... am I missing something?

(For what it’s worth, my nautical electrical experience was as a EM2/SS [submarine] about 25 years ago. We didn’t worry too much about efficiency since we produced 4MW from two steam turbines—we had enough power to light a seaside town, if needed. We also had a kick ass battery that once literally scared the crap out of me. I had to toss that set of underwear.)

[john61ct]

Originally Posted by KTrout

convert shore power (110-240vac 50-60hz) to 12vdc (nominal) and then run that straight to the “big” inverter? In this scenario, I’m imagining that bypassing the battery bank would prevent inadvertent charging/discharging that would excessively heat and cycle the battery.

You are trying to "solve" a non-problem.

> This way, house AC is always from the inverter when on shore power. You can have one set of appliances that will always work, no matter what power source you plug into. No one has talked about this type of solution... am I missing something?

This is how many (most) larger boats are set up, but via auto transfer switches, these days usually built into "kombi" style inverter-chargers.

[KTrout]

Originally Posted by john61ct

You are trying to "solve" a non-problem.

This is how many (most) larger boats are set up, but via auto transfer switches, these days usually built into "kombi" style inverter-chargers.

Got it. I was wondering why no one brought up this solution in this thread, thanks.

[hellosailor]

"convert shore power (110-240vac 50-60hz) to 12vdc (nominal) and then run that straight to the “big” inverter? "
You can argue the numbers, or research specific equipment and load factors, but there's a ballpark 10% loss in each piece of equipment, so you'll be consuming 20% more AC than you need to, since you're trying to use AC to make the same AC.
You might also be stressing and prematurely burning out the DC to AC inverter, since the "DC" that it gets straight from the shorepower AC-to-DC converter probably will be nowhere near as clean as real DC from a battery, or DC that is being filtered through a battery.

[tanglewood]

Originally Posted by KTrout

Got it. I was wondering why no one brought up this solution in this thread, thanks.

What you have described is commonly done on large boats when operating with non-native shore power frequency. Hardly a non-issue, depending on the scope considered.

With native frequency, there is no reason to incur the power loss in conversion. But with non-native power, converting from shore to DC, then inverting, very effectively solves the problem.

[hellosailor]

"With native frequency, there is no reason to incur the power loss in conversion."
And all these years I'd been told conversion without loss would be perpetual motion. Not possible.
Apparently, as Rick said in Casablanca, I was misinformed.

[Dockhead]

Originally Posted by hellosailor

"With native frequency, there is no reason to incur the power loss in conversion."
And all these years I'd been told conversion without loss would be perpetual motion. Not possible.
Apparently, as Rick said in Casablanca, I was misinformed.

Why so snide? You might try for just a second to understand what he was saying.


He meant -- if the frequency is the same, then there is no reason to incur the loss in converting down to 12v (or 24v) and then inverting back up.


In that case, you just run it through a transformer, like my Victron isolation transformer.


If you need a different frequency, however, then Tanglewood is correct -- doing what the OP was asking about, is very common on larger boats, just like Tanglewood said.


On a boat for example with 230/24 50hz inverter/chargers (one, or a gang of them), you just add a large 110/24 battery charger (or several of them).


You isolate the inverter/chargers from the shore power system, connect to that ONLY the battery charger(s), and Bob's your uncle.



I think MOST large world cruising boats are set up like that.


On large loads, quality chargers and inverters can be more than 95% efficient, so the two-way loss might be only 10% or so. On small loads, you don't care, seeing as how you're on shore power. It's a fine solution.

[ohgary]

Just be carefull putting a bunch of USB charging ports around your boat unless you have a way to turn them off when not in use. They use a little power even when not being used.

Also for a laptop the most efficient way to charge them would be skip the inverted and use a "car" charger. Its just a DC-DC converter to take 12v to typically 19v the laptop needs.

[hellosailor]

Dockhead-
OK, if you have the right equipment and it is set up properly (which will also mean at least two inverters, because unless I was misinformed again, they are not efficient at partial especially light loads) you'll only have a 10% loss. That's still "real money".
And even a transformer, even a 1:1 transformer, surely still has SOME losses in it?

Using the shorepower direct, no losses except that of the wiring drop. Using conversions...not the same.