Installing an Inverter

[Mark Johnson]

For very occasional use... I have hardwired my very small 120W pure sine wave inverter into the boat. It is easy to do and works fine, but does require an EXPENSIVE three way "power in" switch, like made by Blue Sea. These select the boat to run on either the dock's AC OR the inverters AC, BUT NEVER BOTH!!! I also prefer to avoid "automatically on" designs when disconnecting from the dock, but only energize the AC system when using it. Just having the inverter on, uses power, even with NO AC load, And when the inverter is on, it is best to switch off all sockets except the one being used, to save amps. (Yep, empty sockets draw a small current!) I also avoid Charger / Inverter designs, because I have found dockside AC to DC chargers to be the MOST vulnerable electronic item on our boat... (been through 5 in 15 years) If it is a combination unit, when the dockside charger is out, so is the inverter. I use a "double pole" circuit breaker on the inverter's DC in lines as well, and this helps protect it from the AC spikes that come down the dockside umbilical chord. (and FRY the AC charger)! So far so good, we are on our original inverter...

Best of luck, Mark

[skipmac]

If you want the top of the line go with a Victron inverter. They have a wide range of models including standalone inverters, inverter/chargers, and models that allow you to connect the shore power and inverter in parallel to your boats AC system (without blowing up either system) so the Victron can act as a power booster if you have something like a compressor kick in that pulls a lot of amps on startup.

They are not cheap but have never heard a complaint from anyone that owned one. Also good tech support in my experience.

[senormechanico]

Originally Posted by JDGreenlee

Reader also beware: IMHO some of these forums are seeded/salted (depending on your viewpoint) with vested interests and not all of them acknowledge their formal relationships with manufacturers or dealers all of the time. Most do. Some do not. Just sayin'... That said, it is value-added here for those having it to contribute hard data and to correct errors - but please reveal potential conflicts of interest, if any.

FWIW, I have no financial interest in any companies mentioned.
I work at home fixing Bernina Sewing Machines and others, having retired from electronics repairs of TV's VCR's etc.

While cruising, I got talked into repairing all manner of other people's boats, mostly autopilots, radars and charging systems.

I will freely admit however, I am not well known for tact!

[F51]

Originally Posted by Mark Johnson

For very occasional use... I have hardwired my very small 120W pure sine wave inverter into the boat. It is easy to do and works fine, but does require an EXPENSIVE three way "power in" switch, like made by Blue Sea. These select the boat to run on either the dock's AC OR the inverters AC, BUT NEVER BOTH!!! I also prefer to avoid "automatically on" designs when disconnecting from the dock, but only energize the AC system when using it. Just having the inverter on, uses power, even with NO AC load, And when the inverter is on, it is best to switch off all sockets except the one being used, to save amps. (Yep, empty sockets draw a small current!) I also avoid Charger / Inverter designs, because I have found dockside AC to DC chargers to be the MOST vulnerable electronic item on our boat... (been through 5 in 15 years) If it is a combination unit, when the dockside charger is out, so is the inverter. I use a "double pole" circuit breaker on the inverter's DC in lines as well, and this helps protect it from the AC spikes that come down the dockside umbilical chord. (and FRY the AC charger)! So far so good, we are on our original inverter...

Best of luck, Mark

Mark,
I agree with everything you said except the bit about empty sockets drawing a small current. Can you please explain how you understand that?
Thanks,

[David M]

I agree that it is better to have a Ship-Shore-Generator-Off dual-pole switch on both the Hot and Neutral side than to allow the switching circuitry on an inverter to do the switching for you. It's safer for one thing. It also gives you more control over your AC system. Three sources can be done with two 3 position, two pole switches.

[DotDun]

Originally Posted by David M

I agree that it is better to have a Ship-Shore-Generator-Off dual-pole switch on both the Hot and Neutral side than to allow the switching circuitry on an inverter to do the switching for you. It's safer for one thing. It also gives you more control over your AC system. Three sources can be done with two switches.

I also agree. My inverter has the internal transfer relay which makes it very convenient to utilize the same receps throughout the boat. But I ALWAYS leave the inverter powered off until all other sources of AC are disconnected. The internal relay operates independently of inverter power, it simply connects the branch circuit to the shore/genset power when it senses power on that source. After shore/genset shutdown, I then use the remote inverter control panel to power on the inverter.

I don't like the idea of 'slamming' a different power source on any appliance that may be running during the transfer. I would rather the appliance loses power for a several seconds, eliminating any chance of problems with differences in voltage/freq/etc.

[David M]

I should have said an Inverter-Shore-Generator-Off switch.

[Mark Johnson]

F51... I have a Link 10 charge monitor that is VERY sensative and accurate. When I turn off all charging sorces, like the dock charger, engine alternator, or our normally 100% solar supply... Then that is "0" amps going in.

Next I turn off ALL sorces out, even the little LED backlights or the stereo's memory wire. Now the Link 10 reads "0" amps in or out!

Next, I turn on the inverter with NOTHING plugged in, but the AC sockets switched on at the AC panel. The Link 10 reads the load immediately. I forgot the exact amount, but think it is in the neighborhood of an amp... just to energize it!

NOW, I can one at the time, switch off the properly wired Ground fault sockets at the AC panel. One switch off and it goes down .1A, another socket off, and it goes down again, etc.

I can't explain it. Just that they do draw a small amount of amperage, just from being energized, so I only switch on the one that I need at the moment.

The only explination I can think of, is perhaps GROUND FAULT sockets, like mine, have a very small load in order to do what they do??? Maybe one of you electrical engineers can tackle that question?

Anyway, GF sockets is what most of us have in their boats, so this is worth considering for folks like us, who concentrate on conservation rather than more energy production. It really is the cheeper way to go in the long run.

Mark

[bazzer]

The inverter will draw some current from the battery when in standby mode, this is adjustable in my unit, it's normally a couple of amps, this is for fast inverter turn-on when a load is sensed. Check your manual for setting this up.
By the way, there certainly appears to be Trolls on these forums that like to knock Xantrex as well as Raymarine!

[senormechanico]

I have nothing personal against the company, it's just that I'd like it a lot more if the product could be trusted to work right out of the box and STAY working.
Is that too much to ask?

BTW, a previous poster's problem with GFCI outlets and the inverter sense circuit got me to set up a GFCI outlet on my bench with a Fluke 177 digital meter.

I set it to AC amps and hooked it in series with the hot lead to check for any draw which would turn on an inverter's load sense circuit.

The meter was set for 300 ma scale.

I could measure no draw at all except during the actual "trip" which of course is a disconnecting solenoid.

[Mark Johnson]

Steve, interesting experiment.. My "top of the line" pure sinewave 120W inverter, is not automatic. I either switch it on or off from its double pole DC circuit breaker input. Also, it has no sense circuit. I was measuring my current draw from the inverter by turning ALL power sources in or out of my house batteries off, EXCEPT the inverter. When I switched on the inverter, (with no loads), the house batteries' VERY sensitive "Link 10 battery monitor" went from "0" A (in or out), to about - 1.2A. Then I switched off a forward cabin "AC outlets" breaker, which turned off three GFIC sockets, then the power draw went down to between -1A, flashing to -1.1A. Then another AC breaker off, and it went down another tenth of an amp, etc.

It was a very small current, but having them all energized definitely used just a bit more power. (We actually pay attention to TENTHS of an amp!)
I haven't given it much thought, because solving the problem is as easy as flipping a switch, and we hardly ever use AC when anchored out. It might even be from my outlets being 15 years old in a salt air environment, or the 25' of AC wire X 5, has something to do with the difference in your results, VS mine???

Like Arsenio Hall used to say: "Things that make ya go hmmm".

Mark

[Bash]

Originally Posted by DotDun

I also agree. My inverter has the internal transfer relay which makes it very convenient to utilize the same receps throughout the boat. But I ALWAYS leave the inverter powered off until all other sources of AC are disconnected. The internal relay operates independently of inverter power, it simply connects the branch circuit to the shore/genset power when it senses power on that source. After shore/genset shutdown, I then use the remote inverter control panel to power on the inverter.

I don't like the idea of 'slamming' a different power source on any appliance that may be running during the transfer. I would rather the appliance loses power for a several seconds, eliminating any chance of problems with differences in voltage/freq/etc.

That's an important point. Those internal transfer relays can be the weak links within an inverter. I blew one out on my last boat because I hadn't installed the type of switch that David M suggests, and when the "slamming" that DotDun talks about happened, the relay couldn't handle it. Smoked the poor little fellow.

After which I installed the safety switch.

[senormechanico]

Mark,
It could be that your GFIC sockets have different circuitry than mine. Newer vs older?
Salt is a definite possibility, especially with high humidity.
Try disconnecting the sockets leaving wires hanging loose to eliminate any wiring leakages.
If that eliminates the load, replace 'em with new ones.

[sail2wind]

OP here, will anyone please answer my question

[capn_billl]

What I did on my boat was to take 1 circuit breaker , (appropriatly rated), and run directly to AC input power on inverter, (no other loads). Then I cut the buss bar from the AC main to the three breakers I was intending to run from inverter. I added a warning label that these breakers are operated by UPS and will have power on at all times. I also changed the breakers with a different brand that was a different color. The I wired the output of the inverter to the now shortened buss powering these three, (fridge, outlets, overhead ac lights). The sum of these three breakers is less than max output of inverter. 15 amps in breaker, (2000Watt inverter), three 5 amp breakers out. If you lose shore power turn off input breaker imediately. I did fry the transfer switch once when shore power turned off then back on when the fridge was starting up. (Yes it was a Xantrex), but they did honor the warranty.