inverter ?

jennykatz · Posted: Sat Feb 25, 2012 7:21 am Post subject: inverter ?

I bought a 1000 watt inverter from WM and thinking about putting it on the table side of a cc-23(venture) running a 10ft line back to lazerettes number 6 gauge wire with a 50 amp fuse next to a series 27 , 115 amp house battery the motor battery will be the same series 27

2 questions is 6 gauge 50 amp fuse enough . I will be using this for tv , computer, maybe coffer maker . very small microwave 600 watts or smaller

rogerbum · Posted: Sat Feb 25, 2012 8:09 am Post subject:

1 KW @12V is 83A and that assumes 100% efficiency in power transfer in the inverter. 600W@12V is 50A again assuming 100% efficiency. Actual efficiencies are probably closer to 90% so multiply the above amperage by 1.1 - e.g. 55A for 600W and 92A for 1KW.

As for the wiring you need, it depends on the round trip distance to the battery (e.g. twice the physical distance). For 92A, 10 feet away from the battery you need #2 wire, for 55A at the same distance #4 is recommended. See this chart for wire size recommendations. While I know your intention is to only use it to power a max of 600W, I'd wire it for the rating of the inverter (1KW) since the initial current draw for the 600W microwave may need more than 600W and since you or a future owner may decide to use the inverter at it's rated load later. Too narrow a gauge of wire is a fire hazard and fiberglass burns really well, so make sure you do it right.

thataway · Posted: Sat Feb 25, 2012 10:41 am Post subject:

Agree with Roger--although you can get by with #6, the less voltage drop you have on the 12 volt side, the better you are. So go with #4 wire.

However, one group 27 will not give you much reserve for running this inverter--I would have at least 2 group 27 or better yet 2 group 31 batteries (which is what I did for the 1000 watt inverter).

A group 27 battery (group # is case size--and not related to amount of capacity directly-there is a range of capacity). Basically inverters in our size boats are for either short term high draw items such as the microwave, or longer term for things like TV sets. It is more efficient to use a 150 amp inverter for the low draw items.

dave · Posted: Sat Feb 25, 2012 11:08 pm Post subject:

When I bought my boat, I had the dealer install an 1800 watt inverter. Our Keurig coffee maker draws 1400 watts. The dealer used #4 AWG.

jennykatz · Posted: Sun Feb 26, 2012 7:38 am Post subject: wire size

Yes I have 2 series 27 115 amp hour batteries . The 1000 watt came with 3ft of number 6 wire but going 10ft will require number 4 as your suggestions . Thanks I guess a 70 amp fuse breaker would work

Pat Anderson · Posted: Sun Feb 26, 2012 11:59 am Post subject:

Jim, according the instructions that came with my inverter (1000 watt also), the inverter should be as close as possible to the battery. Mine is under the motor well, with very short, very heavy cables to the battery (they were supplied with the inverter). Then I ran a normal heavy duty three wire extension cord attached with cable ties to the bundle tucked up under the gunwale, and wired it to an outlet in the cabin. I also wired a remote control switch for the inverter. Works like a charm.

dave · Posted: Sun Feb 26, 2012 10:10 pm Post subject: Re: wire size

jennykatz · Posted: Mon Feb 27, 2012 7:56 am Post subject: inverter

Pat what kind of remote control? I guess I could just put the inverter back at the battery box on the cc-23 and then just get a 10-3 wire and put on plugs ?

Pat Anderson · Posted: Mon Feb 27, 2012 8:53 am Post subject: Re: inverter

The remote switch is a wired remote with a long wire, it cost about $20 as an accessory to the inverter, and it just plugs right in to the rear of the inverter. The brand is Cobra. I will take a picture and post it here. It has a push off/on switch and an indicator light. Then it is exactly as you describe. Ideally it should go to a GFI out but mine is just an ordinary outlet.

journey on · Posted: Mon Feb 27, 2012 10:24 am Post subject:

Jennykatz,

What is the type and brand of your inverter? I hope it's a sine wave output, or else you'll waste a lot of power running anything but a resistive load.

That copper cable is expensive. Instead of rushing down to your local west marine store, search the internet for copper cable/wire.

Boris

Will-C · Posted: Mon Feb 27, 2012 10:31 am Post subject: inverter ?

Marine wire is usually tinned to prevent corrosion from creeping up the wire leaving you with insulation and no copper wire left. In a salt water enviroment go with tinned copper worth the extra cost IMHO.
D.D.

rogerbum · Posted: Mon Feb 27, 2012 10:31 am Post subject:

If the installation of the 110V wire is even semi-permanent, I'd recommend that you do buy Marine grade tinned 3 conductor wire for the 110V run (as opposed to an extension cord or similar).

jennykatz · Posted: Tue Feb 28, 2012 7:39 am Post subject: inverter

The inverter is a slim 1000 w west marine its a modified sine wave .
I thought about putting it in the back by the batteries and then decided against it since there is the 10 micron gas filter and the gas switch back there also . If there ever was a leak it could be a problem .

So I will get awg 4 10ft and put the inverter in cabin probably better for corrosion then outside in battery box.
I sometimes wonder if all this is worth it .

Now do I really need a switch or a fuse if not loading it down with 1000 watts ?

rogerbum · Posted: Tue Feb 28, 2012 11:11 am Post subject: Re: inverter

journey on · Posted: Tue Feb 28, 2012 12:09 pm Post subject:

OK, my suggestion as to finding the wire on the internet concerns the fact that WM is rather an expensive place to buy wire. If you want tinned wire, that's on the internet also.

A few comments on "modified sine wave" are in order. First we all agree that our normal AC is a sine wave with a frequency of 60 Hz (cps, for those of us who are elderly.) Well a modified sine wave is really a stepped square wave, and instead of a single frequency it contains a 60 Hz fundamental and an infinite series of higher frequencies (Fourier series,) which go to make up the square form of the modified wave.

What does this mean to us? Glad you asked. For a coffee pot, which is pure resistance, not much. But if you want to run a microwave, or a TV or anything that isn't pure resistance, it's somewhat of a problem. I ran a microwave from a Freedom inverter (modified sine) which made a lot of noise as the higher frequencies rattled through got lost and the unit took longer to cook anything. The microwave was rejecting the higher frequencies and losing power.

I installed a sine wave inverter on Journey On in the cabin to keep it out of the elements, and am very happy with the performance. A PROwatt SW1000 Inverter (sine wave) is $220 on the internet. My, how prices have come down. Buy the cable and unit off the internet and the total cost would not be much more that a modified wave installation from WM.

Also, using an inverter/battery combination to heat water via a coffee pot is a very inefficient use of battery power, especially with a single series 27 battery. To heat water quickly, get on of those single burner, butane cartridge stoves. They're really great in the morning.

Every circuit should have a breaker between the device and the power source, somewhere. They may not be cheap, but they're cheaper than ANY fire on the boat.

Boris