Separate Inverter, Charger, or Combo ?

[Exile]

Originally Posted by john61ct

If you're not yet aware of Victron's *'Power*Assist'*feature check it out, **very useful** in allowing larger loads to run from a smaller gennie or mains source.

Especially handling startup or transient surges.

Yes, Dockhead has described those features well in other threads. My main a/c unit is quite old, and when it starts it is literally "off the meter." It hasn't resulted in tripped breakers while on shore power or the genset not being able to handle it, but I do try and be careful not to have anything else running on the 30A AC circuit when I go to start it. My inverter application would be much smaller, i.e. limited to electrical outlets only, which in turn would be for coffee pot, toaster, microwave, computer charging, occasional power tools, and probably not running more than one appliance at a time. So maybe 10-12A @120VAC continuous, but I'll size it for more of course. The features of the Victron you mention would probably be overkill, but then that's not necessarily a bad thing on a boat.

[Exile]

Thanks for your patience, and for hanging in there with me. Didn't mean to hijack the thread but hopefully this will also benefit others contemplating similar installations. The next challenge will be not screwing up the white neutral & green ground wiring, but I'm not there yet.

Originally Posted by travellerw

Alright, so to answer you first question. If you choose a sub panel wired only to the inverter, then you absolutely can use the existing wires. You would simply "unwire" them from the main panel and wire them into your subpanel. Of course you would need to ensure you put the subpanel close enough to the main panel that you didn't have wire length issues.

OK good. I'll be back onboard in a couple of weeks and so will check out fitment issues. Things are already pretty crowded in & around the main circuit panel, and hopefully the original installation left enough slack in the wires to reach a new sub-panel. I'm assuming that, other than a bit more work, whether or not I first run the inverter output through a transfer switch would make no difference to your analysis. I know it's unnecessary & redundant, but for whatever reason I'm liking the idea of being able to glance at a manual switch that immediately tells me what source of AC power I'm using.

I read the article you posted. They have essentially fed the inverter directly into the main panel through an AC rotary switch. So anything that can be powered from shore, can be powered from the inverter. They are relying on themselves to ensure those hi-cap devices are turned off before the inverter is turned on. My experience tells me this is not a good solution for "most" people. I have worked on numerous boats wired like that where the batteries had been killed because someone forgot to turn off one device.

Yes, that's how I understood their installation as well. Your personal observations about the downside of doing it this way are well taken.

That leads me to your final question. As long as everything is wired correctly with proper breakers then no damage should be done with the exception of dead batteries. However... The potential for damage to your batteries is fairly high. A couple of opps moments where you completely kill your batteries is all it takes. A new battery bank will most likely be in order.

It's enough of a challenge for me to keep up with everything when I don't screw up. So no unforced errors with my brand new battery banks, thanks.

Frankly, I think the safest, least complex and easiest solution is to have the AC circuits on an isolated subpanel powered by the inverter. On our boat, the inverter is pretty much left on as long as we are aboard (off at night). We have 110V AC all the time. If I start the generator, it doesn't matter, the plugs are still powered but now the inverter is being powered by the battery charger. There is no complex combined device to fail, there is not auto switcher to fail, its just simple.

I like simple. Especially since messing with the AC side of my boat's electrical system is new to me and so still looks all too complex. I have a couple of friends in the marine trades, one who is a surveyor, and they are both pretty down on inverters generally. They've seen it all, but I suspect problems which create hazards are mostly due to faulty installations and not necessarily the units themselves.

Btw, I assume you turn your inverter off at night because they draw on the batteries even when not being used? I think I read that somewhere. Some come with a remote switch you could mount in an accessible place so one doesn't forget.

Maybe this is just semantics, but I often read comments similar to yours above re: the inverter being powered by the battery charger when shore power or generator is on. Technically, isn't it the batteries that are actually powering the inverter, with the batteries in turn being charged by the battery charger through power supplied by either shore power or genset? I also often read this on the alternator side of things, namely suggesting that when the engine is running it's the alternator that's supplying power directly to appliances. Again, doesn't this get done directly through the batts. on the DC side, and through the batts. and inverter on the AC side? Or are there some cases, like in our vehicles perhaps, where the alternator is supplying power directly to appliances?

[Olddan1943]

Originally Posted by rgleason

Dockhead wrote:
Thanks, that confirmed my thoughts. We don't really use 120v at all as we are on a mooring, have no Microwave or TV (use cell phone for the occasional movie), etc. Using a Lind transformer for a laptop and MS SurfacePro has a 12vdc plug.

For such a small (2 receptacle) system, what is the minimum recommended for AC power from the AC inlet plug to the receptacles?
1 panel with two circuit breakers?
1 polarity sounders/alarm?
1 charger for charging the batteries (ProMariner ProNauticaP or Sterling)

Galvanic Isolation? or Transformer?

Is there some resource where I could read and understand what is required?

Our AC system is almost 40 years old, has a CB & polarity sounder in port locker. The article just below is very helpful, but I think we want to keep the two systems entirely separate and intuitive, as Dockhead suggested for small boats.


I like that mechanical lockout on the Pelagic's panel. Simple.

there have been numerous discussions about putting the A/C on a battery via the inverter.

The conclusion was, it cannot be done gracefully. the A/C is 120 vt and will suck your batteries down quickly.

You do not have any generator on board?

How long is your boat? Maybe you can find room for a Honda 2000?

[Exile]

Originally Posted by Pelagic

In Subic I have seen a number of Diesel Duck, who come here after China, experience numerous failures with twin Victron Multis/Combos wired to be the "master control" .
I think it is this "optional" feature which has caused a lot of problems.
Perhaps a lerning curve with the installers, or maybe some really funky and fluctuating shore power values, push the control system to the limit,....but most new ones experienced failures.

My Own Victron 24/3000/70 Multi was installed simply as a "Invertor" Source on the main AC Board in 2008 . (IE Shore/Gen/Invertor/ with mechanical lockout of each). It has performed flawlessly using the charger only function when on Gen or shore power.

I do still have the original stand alone 1800W Prosign invertor as a back up with Plug and extension cord to provide emergency AC power if needed and the original Victron Skylla 50a 24v Charger for bulk up and back up.

I think the Skylla must be 30 years old, still works great, but if I needed to replace, it would be with another Victron 24/3000/70 Multi

Curious, as I've seen this before, but what is the purpose of the "reverse polarity" switch, or is it an alarm? My panel does not have that, and I can only surmise that it's purpose is to alert you if battery polarity had somehow become reversed. I must be missing something.

[Pelagic]

Originally Posted by Olddan1943

there have been numerous discussions about putting the A/C on a battery via the inverter.

The conclusion was, it cannot be done gracefully. the A/C is 120 vt and will suck your batteries down quickly.

Actually not quite true [emoji4]

In my aft cabin, there was an access door to a large lazarette, which has a deck hatch behind cockpit
Cabin.jpg Views: 115 Size: 98.8 KB ID: 172588" style="margin: 2px" />deck access to lazarette.JPG Views: 118 Size: 57.3 KB ID: 172590" style="margin: 2px" />
I built a shelf on upper half of access for a small invertor style 240v Air Con and kept an emergency escape hatch on the lower part.

It works wonderfully on invertor and now with my Solar online and no shore power connected, my net loss with this Air Con, 3 fridges and fans running from 8am to 5pm is 3% SOC.
If not using the air con I am at 100% before noon.

Just love my 4 Sunpower panels!

[Olddan1943]

Originally Posted by Pelagic

Actually not quite true [emoji4]

In my aft cabin, there was an access door to a large lazarette, which has a deck hatch behind cockpit
Attachment 172588Attachment 172589Attachment 172590
I built a shelf on upper half of access for a small invertor style 240v Air Con and kept an emergency escape hatch on the lower part.
Attachment 172591
It works wonderfully on invertor and now with my Solar online and no shore power connected, my net loss with this Air Con, 3 fridges and fans running from 8am to 5pm is 3% SOC.
If not using the air con I am at 100% before noon.

Just love my 4 Sunpower panels!

Fantastic. You have figured out a solution that few if any others have figured out.
Now, at the risk of asking you to tell us all how you did that trick, please share your set up.

[Pelagic]

Well, I have 4 x 327w Solar panels and a large 24v House Bank (1040Ah)
The 1/2hp invertor Air Con has a soft start and registers very little AC load when running but my smart meter shows its drawing about 28amps on the house bank.

I made sure the air con installation was tight, so only return air came from cooled cabin. I thermally insulated the lazarette side of the bulkhead and with the deck hatch open, venting the hot air from compressor side, the unit cycles on and off at 26°C when its about 36°C outside.
But the real plus is a large enough Solar array that cranks out 25 to max 40A @24v all day long.

We have not moved back on board full time yet as just finishing up on some interior varnishing , so I expect our net loss will increase quite a bit with other loads, but once cruising, we rarely use AirCon.... It is more needed at the Marina

[ramblinrod]

Originally Posted by seapop

Buying a new used boat, and it only seems to have a trickle charger on the house batteries. I am thinking about upgrading to a more serious charger and also an inverter for the usual reasons. Question is, would it be better to have two separate units or one good combined unit.

Certainly cost is an issue, but more concerned about single-point-of-failure, and better overall management of the power system.

On smaller boats (up to 40 ft), I lean toward a charger/inverter combo.

You want both very near the batteries (<6 ft) , but not over the batteries (or even in the same compartment).

This kind of space is generally very limited especially on a smaller boat, so anything that can be more compact is beneficial.

A combo unit may be more compact.

The other issue is the combo unit likes to play with itself, meaning that it transfers shore power vs inverter power flawlessly, and switches between inverter and charge mode flawlessly when shore power is connected / disconnected.

A combo unit may be more automatic.

Another benefit is that the guts share the same enclosure and many of the same components, and wiring is common to both functions.

A combo unit may be less expensive.

What many people fail to realize is that marine electrical / electronic equipment has a life expectancy of about 10 years. At that point, it is either becoming unreliable and likely fail soon, or the features are outdated to what is currently available (and possibly desirable to those who embrace newer technology).

IOW, if one side fails after 10 years, it is likely time to replace both anyway.

On larger boats with lots of space and equipment / maintenance budgets to match, discrete devices are likely more desirable, giving the boater more options to fine tune features and functions to exacting needs.

Either way, in the last 10 years, pure sine inverter prices have plummeted to rock bottom. I steer everyone away from mod sine that I can. It just isn't sufficiently cheaper anymore to put up with the draw backs (GFCI hum, power supply heat, not playing nice with variable speed tools, etc.).

[Troutslayer]

I am not a marine electrician, just a solar electrician. If you have adequate battery and inverter capacity to handle the load and don't have any parasitic load I would tie it to my AC load center or if you have other large loads like AC I would move the needed circuits to a separate panel powered by the battery/inverter.

Resistive heating loads are generally not good loads to power with batteries but with ample storage and inverter capacity you should be OK for the time it takes to brew coffee. Don't leave it on though!

[a64pilot]

I haven’t read throughly everything here, but I think sometimes we get too complicated when it’s not necessary.
I have an automatic transfer switch for my generator / shorepower. 60 sec after generator starts producing power, the generator is automatically brought on line, even if there is shorepower, kill the generator and it switches back, automatically.
From there AC power is routed to my MS2812 Magnum inverter / Charger. On the remote there are charger buttons and inverter buttons, that of course control those functions.
All AC power is run through the Magnum and it then goes to the AC main breaker and panel.
I see no need for separate inverter panels, why would you do that?
Of course I don’t run my air conditioners or water heater from the inverter, but you can easily control what you power with the breakers.

As far as reliability, I have yet to meet someone with a failed Magnum, certainly it’s possible, but I have Solar, a second regular battery charger, and an alternator if it does fail. The Solar and alternator are enough I believe until you could get the inverter / charger repaired.

Why would reliability of a combo be any more or less important than standalones?

[Pelagic]

Originally Posted by a64pilot

I haven’t read throughly everything here, but I think sometimes we get too complicated when it’s not necessary.
I have an automatic transfer switch for my generator / shorepower. 60 sec after generator starts producing power, the generator is automatically brought on line, even if there is shorepower, kill the generator and it switches back, automatically.

I agree
In my earlier posts here, I advocated simple source controls, mechanical lockouts and to not use the combo to "manage" shore power.

But I also have the same KISS principal when it comes to automatic transfers on small yachts of power sources. Keep it linear and simple, because we really don't have the walk in engine rooms where a focussed engineer monitors the Generator while running and at startups.

I am familiar with specifying UMS (unmanned machinery spaces) to Loyds Maltese +100A UMS and the system and safeguards are considerably more stringent than what Victron or other small yacht suppliers, design for. Primarily on ramp ups and loading, the automatic non-preferent trips are far more sensitive and reliable than what we small yachts have available.

I guess, my biggest concern with automatic starts on my own yacht, is my own fallibility, that I have forgotten to do something that would damage the system.
I like to do the oil/water levels, check for any leaks from last shut down. Make sure no one has closed off the thru hull or exhaust, start, confirm cooling flow, then put on load.

Yes it takes a couple of minutes, but being mostly a DC boat and not having Billionaires as guests on my own boat...we can wait while I go thru my checks

[a64pilot]

I’m not saying auto start, I didn’t install that option as I don’t see the need.
However all RV’s that I have been on that aren’t 50 yrs old, have an auto transfer switch for the generator, start it up and a timer runs to let it stabilize, then the relay disconnects shorepower and connects generator power, without you having a switch mounted to do it, shut down the generator, relay opens and that reconnects shore power. Marine version
https://www.defender.com/product.jsp...042&id=1832843
Then the inverter / charger itself will pass through either shore power or generator output, it doesn’t know or care the difference. If AC power is present the charger function can operate of course, if no AC power is present, then you have the option to power the boat off of the inverter. The charger won’t function of course.
That’s it, no additional switches and everything is as automatic as it can be, without any complexity not required.
Adding a standalone inverter can and usually does result in more complexity ensuring that you can’t parallel the inverter and shorepower or generator power, and you can easily do nonsensical things, like power your battery charger with your inverter, I have done it 🤭

[Pelagic]

Originally Posted by a64pilot

Adding a standalone inverter can and usually does result in more complexity ensuring that you can’t parallel the inverter and shorepower or generator power, and you can easily do nonsensical things, like power your battery charger with your inverter, I have done it 🤭

Ok understand better... Good point about the added complexity of a stand alone Invertor and charger
When I first bought my boat and left Phuket for Philppines, I remember accidentally leaving the charger on when I switched from Gen to Inverter. Had that momentary thought.....have I discovered a free power source?

So your not alone![emoji57]

[rgleason]

Don't want to hyjack the thread... I was considering an inverter/charger, but no longer. I appreciate the fact that a big inverter will suck batteries. We have a very little 15amp receptacle inverter. Use it seldom.
Boat is 32' and extra room is very limited.

there have been numerous discussions about putting the A/C on a battery via the inverter.

The conclusion was, it cannot be done gracefully. the A/C is 120 vt and will suck your batteries down quickly.

You do not have any generator on board?

How long is your boat? Maybe you can find room for a Honda 2000?

[Olddan1943]

Originally Posted by rgleason

Don't want to hyjack the thread... I was considering an inverter/charger, but no longer. I appreciate the fact that a big inverter will suck batteries. We have a very little 15amp receptacle inverter. Use it seldom.
Boat is 32' and extra room is very limited.

I can understand that no 'extra room'. I am on a 34ft trawler. My 1500 amp inverter can run either the microwave or the coffee pot via switches. I would like more but, it ain't gonna happen.