Wiring an inverter

[Sailing Drummer]

I have a question about wiring a pure sine wave inverter - actually any inverter for my situation. I currently have a modified sine wave inverter and I plan on continuing to use it. I have it wired and fused properly to the house battery bank and it feeds a dedicated hard wired ground fault outlet. But I'd like to add a sine wave inverter for certain lower power AC devices that should be getting clean power.

I will be getting something in the range of 600 watts. The issue I've come across is none of the inverters I've looked at have the ability to be hardwired to an outlet (or the panel). If I put the inverter where I'll be using it the cable run to the battery bank will be about 25-30 feet. That will require some very heavy cable. If I put it close to the battery I'll be stuck using long extension cords. That doesn't seem very safe. Ether way I still have to plug into the inverter instead of an outlet.

So my question is have any of you had a situation similar to this? If so, how have you set yours up? If you haven't had this problem, what suggestions would you make. I can't spend what it costs for a larger inverter that has the hardwired outlet feature.

Thanks,
Larry

[roverhi]

Low voltage DC current has serious voltage drops/poser loss running long distances. You need to use really really big wires to compensate for that. AC travels way better so you can get by with much smaller wires/extension cords. That makes putting the inverter as close to the batteries as possible the way to go. If you anticipate using an AC powered device in a certain location that would require an extension cord, why not wire the inverter into the boats AC system, if it has one, or installing AC outlets where needed. Will need a switch so you can't accidentally hookup shore power with the inverter on the line and run wires to the outlets. Running the wires may involve creativity to keep them out of sight, away from anything that might chafe them and some boat yoga to do the install but no big deal.

[transmitterdan]

Larry,

I think your best choice is to run a properly sized extension cord from the inverter to where you want to plug in your devices. Keep the battery wires as short as you can for lots of reasons. I would strongly advise not to run battery wires 25-30 feet to an inverter. Try to keep these wires less than 6 feet and preferably 3 feet or less.

There are several reasons these small inverters don't have the option to hard wire into the boat's AC system. They are not designed for it and I can't recommend that you try that.

[smac999]

install outlet. run wire to inverter near batteries. put plug on end of wire. plug into inverter.

[Reefmagnet]

there are some models of inverter available with a changeover relay installed. Not sure if they could be found on a 600 w inverter, however. My 600w inverter is wired about 6 metres (20 feet) or so from the batteries without issue. I used 25mm2 cable (the stuff that's about 1/4" diameter - not sure of the gauge size) and it works fine with negligible voltage drop while operating as far as I can tell (it has a remote panel with source DC voltage displayed), although we aren't big AC users on board. Mainly just use it for chargers for cordless tools and the copious amounts of techno-wizardry we bring aboard.

As for change over, I've got a 3 pole double throw relay that I confess to not having installed yet, but it has an AC coil corresponding to the AC supply voltage. The plan is: The coil connects to shore power; The A/N/E wires from shore power connect to the N/O contacts; The inverter AC output connects to the N/C contacts; The common for the contacts is then connected to the outlets on the vessel. Nice and simple. Shore power goes on, relay closes N/O contacts and shore power is fed power outlets. Turn off shore power and N/C contacts close, allowing the inverter to supply AC to the same outlets. The relay I have is a readily available industrial relay with a DIN connector and locking clamp and is more than suitable for the purpose. For higher current applications, I would have used a contactor, but a relay is fine for my purpose. I may decide to hedge my bets at installation time and one outlet connected to shore power directly for both redundancy and if I ever need to draw more current than the relay will safely carry.

[deblen]

Originally Posted by smac999

install outlet. run wire to inverter near batteries. put plug on end of wire. plug into inverter.

smac999 would you agree to "install another GFCI outlet...."

OP already has one GFCI outlet fed by existing mod.sine wave inv.,which he intends to keep.

I would also add a caution-since you will now have 2 inverters aboard,be aware that the AC coming out of them is not & cannot be sync'd.
You MAY experience "interference" if you link 2 items together,fed from separate inverters.

[rwidman]

Originally Posted by smac999

install outlet. run wire to inverter near batteries. put plug on end of wire. plug into inverter.

That's how you do it and that's how I did it on my previous boat. Just be sure you wire the plug correctly and use the appropriate sized cable and you'll be fine..

[rwidman]

Originally Posted by deblen

........... I would also add a caution-since you will now have 2 inverters aboard,be aware that the AC coming out of them is not & cannot be sync'd.
You MAY experience "interference" if you link 2 items together,fed from separate inverters.

It doesn't appear he plans to do that but if he does, he won't get interference, he will damage one or both inverters.

[Stu Jackson]

Originally Posted by rwidman

That's how you do it and that's how I did it on my previous boat. Just be sure you wire the plug correctly and use the appropriate sized cable and you'll be fine..

I agree with Ron's post #7.

He doesn't intend to wire this new outlet into the boat's system, just one new receptacle.

To the OP: LABEL the new receptacle very clearly.

Good luck, this is easy.

[Sailing Drummer]

Thanks for the replies. I had thought about running wire to an outlet and then plugging it into the inverter. For some reason I was thinking I couldn't have it behind bulkheads, but I guess that's because I was thinking about an extension cord. I will run marine grade AC wire (just like what I have going from the other inverter) between the inverter and outlet but on this one I'll use a plug at the inverter end since I won't be able to hardwire it.

And there will be no connection between the two inverters or their respective outlets. And I will label them. At some point I will be running the old inverter through a switch and RCD to the panel instead of just the one outlet. But before I do that I have to run all new AC wiring to new (to be installed) outlets. And eventually I'll give some thought to adding shore power!

But for now I'll have to decide which inverter to get. And get the house sold and move aboard and get away from this cold!!!

Thanks all, Larry

[Matt Johnson]

One way to "label" them is to use different color outlets. Maybe white for the large inverter and black for the pure sine model.

Matt