Installing basic inverter

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B

Brent

I just bought a sailboat that doesn't have an inverter and it seems like the kind of thing that would really come in handy. Since I don't have $1000 left over to drop a decent system, I picked up a $70 inverter from Costco and thought it would be worth a try. It's a Xantrex Xpower 1000 watt inverter (see link below for more info), and I was wondering about a couple things. I know it is not a charging inverter (I don't have shore power anyway) and it is not built for marine purposes, but I still think it should work alright... shouldn't it? Well I'm wondering about the installation, should I run it directly to my house battery, to the battery selecter switch, or to the breaker? I'm guessing the breaker would be the best bet, but in the instructions it says to wire it directly to the battery and to use less than 5 feet of 2 awg cable. Would it be best to wire the negative terminal to the negative on the battery and take the positive through the battery selecter switch (like how a light switch is wired)? But would this protect the system with a breaker? Should I install a DC fuse in the battery wire itself? Also, it has a chassis ground that in the instructions says to ground to the chassis. I saw in another post about inverters to ground that either to the negative battery terminal, to a ground bundle (if I can find it), or to the green wire from the shore power (which I don't have)... any clues on that one. The boat is a 1970 Columbia 26 mkII. Thanks! Brent
 
M

Miles

A few points...

A 1000 watt inverter will draw close to 100 amps from the DC (12v) side at max power. You probably don't have any breakers big enough to handle that load unless you've added one. You need to keep the wire run short and use a heavy gauge cable as specified otherwise the cable could overheat and melt. I'd probably hook it directly to the battery but you might be able to use your selector switch. In any case you need some kind of overcurrent protection (fuse or breaker) in the positive lead close to the battery or you could have a serious fire hazard. The switch won't provide this protection by itself. Sounds like an interesting project though, good luck!
 
Feb 26, 2004
23,315
Catalina 34 224 Maple Bay, BC, Canada
Be Verrrry Careful

Brent If you don't understand electricity, both DC and AC, this project may be way over your head. The green wire you're looking for is part of the AC side of the system. Do you already have AC power outlets on your boat? You know, like household outlets? If not, what are you going to connect the AC side of the inverter to? If not, and you're just going to use the plugs (receptacles) on the inverter itself, you don't need to worry about the green wire, since that's only for connecting to AC outlets on the boat, which requires opening the inverter, and connecting the three wires (black, white, green) inside the unit. The Xantrex instructions are very clear, I just put one in a friend's boat. What part of their instructions don't you get? You never want to connect an inverter to the starting bank, which will shortly kill the starting battery which isn't made for deep cycle discharge. So that means don't connect to the 1-2-B switch. A 1,000 watt inverter needs a 400 amp hour house bank, based on sizing rules of thumb. Do you have that kind of house bank capacity on your boat? Have you done an energy budget? I respectfully suggest you consider talking to someone who knows a lot about boat electrical systems, or spend lots of time with Nigel Calder's book before you do any damage to you, or your boat. You could also consider returning the unit, which seems way oversized for your possible AC load and ability to run it from your house bank, and just get a smaller portable inverter that you can connect to a cigarette lighter type plug, which will greatly reduce your wiring tasks, and give you the AC power you seem to want or need. Good luck, Stu
 
D

Dana Mega30 trailersailor

a 400 watt is ok for 26'

I use a 400watt,and it just plugs in liter,has is own fan and braker! work for small things fine!
 
B

Brian

Direct to the battery

I installed the prowatt 1750 and hooked it directly to the battery with a fused cable per the directions. BTW, I only have a house bank of 230 amps or so. But we don't leave it on all the time just, when we want to use a 110v appliance such as a blender. We keep up with the amps used via the battery monitor to as not to drain the batteries to much before recharging. So I wouldn't fret if you don't have a huge battery bank. Brian CREW REST
 
V

Vic

for a little perspective ...

the small honda or coleman gasoline generators put out about 1000W so you can get an idea of what you are looking for the batteries to duplicate. Vic "Seven"
 
B

Brent

I'll give it a try

Hey, Thank you all for responding. Stu- The reason I thought I could go through the battery selecter switch is because the instructions show that as one of the installation options (figure 3-1 is a diagram for installing on 'normal loads' that goes direct to the battery and figure 3-2 is a diagram for installing on 'heavy loads' that goes to through the battery selecter switch for the positive and straight to the battery for the neg). I'm not an expert at AC and DC circuits but I did do all the rewiring in my house and have done a great deal of car stereos, this particular project seems simple for pretty much anyone, what about it would be way over someones head? My confusion with the ground is that the instructions say to run the ground to the vehicle chasis (don't say anything about installing on a boat). I did see somewhere that marine inverters actually ground to the water... This is where I don't know what to do. If I was to exand to include other plugs on the boat I can see why I'd want to open up the inverter and connect up the wires there, but what good does it do to run a ground when the unit isn't grounded? I've considered using smaller units, but for the same price this one came up so I decided to go for it. I haven't done an energy budget, I actually just bought the boat last weekend and it is moored about 3 hours from my house (for a short while) so I haven't had time to go through and do my energy budget or even to calculate the size fuse I need... but I plan on using the unit like Brian was saying, just by watching the battery charge and only turning the unit on when in use.
 
P

Perry

Me Too!!

Brent, for Father's Day I got the same inverter from Costco!! (For my application, I was having a hard time figuring out/justifying the price difference between Costco and the boat stores). Haven't installed yet, but I think I'm gonna try the 2 battery switch setup.
 
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