Inverters, AC Power, etc... What would you do?

[GordMay]

1. Ideally an inverter should be installed within 10 feet of the battery bank, and smaller 120VAC wiring run the longer distance to the AC load location(s).

2. A 200 A/H battery bank is probably more appropriate to a more modest cruising style than your high-end charter mode. You can expect to consume as much as a third of your total usable capacity (30 A/H consumed of 80-100 A/H usable capacity) in just a single 2 Hour TV night (Colour TV @ about 300Watts + DVD @ 50W).
I’d highly recommend a much larger House Battery Bank - at least 400 - 600 Amp/Hours installed.

3. I think that the Generator can power “tool time”. You’re not likely to be overly concerned with tranquility when using power tools.

4. In this instance, I’d consider acquiring a second Inverter, closely sized to the entertainment centre loads.
The efficiency of an inverter varies with the load. Typically, it will be highest (‘peak efficiency’) at about two thirds of the inverter's capacity. The inverter requires some power (‘idle power’) just to run itself, so the efficiency of a larger inverter will be low when running very smaller loads. The full story is told by a graph of efficiency vs. load, as published by the inverter manufacturer. This is called the "efficiency curve." Size your “Entertainment” Inverter to accommodate the connected load at the “Peak Efficiency”

FWIW,
Gord

[ssullivan]

Good input, Gord. To comment back:

#1 - No question about it. It makes more sense economically, asthetically, and for safety to install the inverter close to the batteries and do the run across the boat with the smaller amp AC.

#2 - True. I have calculated actual values for TV, PS2 (plays DVDs, games, audio CDs, etc...), and amplifier. These are respectively: 65W, 79W and 125W. In 12V, this equals 23 Amps drawn per hour, plus losses related to an inverter, so 30 Amps drawn per hour of use is a very good estimate. Since I am switching over to 120VAC refrigeration with holding plate, I now have an extra 100 AH battery and will add another into the existing bank, for a total of 400 AH. I am going to add them in paralell to the existing bank of 2 100 AH house batteries, doubling the capacity of the bank. This should give me 4 hours of time per day to use this system, to get to 1/3 battery drain, using your calculation from your previous post. If this is still not enough, I will buy 2 more 100AH batteries and add them in parallel as well. I have a nice long empy bilge area adjacent to the battery bank (inches away). Bank expansion should be simple. In trying to reason out the inverter issue, I had lost site of the "big picture" to some extent. Thank you for reminding me.

#3 I think the genset will be just fine for "tool time" as well. Plus... many projects that require extensive power tool use also require a dock so you can haul things on and off the boat and have a little bit of sanity while doing the work.

[irwinsailor]

Does anyone use a Charles inverter? The boat electronics company that I am renting a slip from tells me that they use Charles because they have found them to be less troblesome that xantrex. I need to by a new unit and I want one with a large charger so when I run the genset it will charge faster and I will need the genset running less. I also have a 2800 watt heard with charger that I will sell cheep. I have not been able to get it to work, it could be something simple.

[H/V Vega]

Hi Mate,

OK this might not be the cheapest solution but it might be the smartest in the long term.

1. Xanterx make the kit you can trust. I have known them them controller inverter inverter and used their stuff for ages and it has NEVER failed me. I also have the 2500 with the Link 2000R controller. The 2500 is a work horse that has been proven for years. It is worth every single penny mate, and you have a great charger as well a power tools and cold beers.

2. Yes separate your nav supply from your happy time stuff. If something goes wrong you want that computer to keep working no matter what. I even have a separate battery I can switch into that line should I need to isolate the entire main DC system for some reason.

3. Forget running long DC lines just run short DC lines and long AC ones to your kit. Makes for better engineering and saves a bomb on heavy DC cable.

this a very wise idea from Makai, "For the laptop we had a dc-dc 12 volt to 19 volt inverter made. It has even a lower over head as it plugs directly to the battery system. Huge losses occur when using the inverter to go from 12 to 110 and 110 to 19 volts (most computer charge rates). A good inverter losses 20 percent or more from 12 to 110 and then again from 110 to 19 volts." Mine is 15 volts DC but WTH anything that works and keeps working, right?

Now some everyday stuff you might want to think about. We are all over the place and spend most of our anchor time away from marinas. In fact there are usually no marinas around the places we go. Running the gen set to pay an inverter to keep the beer cold is a real, repeat REAL, costly pain in the back side! We have used house chest freezers for years on the inverter and they work fine its just that the overhead is massive. Think fuel for the gen set mate plus spares, oil, filters, all that stuff. Take a look at another thread on here about Sterling coleman coolers there are some great thoughts in there about efficient cooling.

[sck5]

Many computers have 12v plugs as an accessory you can buy from the manufacturer - I powered my old Sony laptop with one but the manufacturer doesnt sell one for my current machine. It is worth looking at the manufacturer website for your computer to see if they sell one - a 12v adapter custom made for your computer may well be the most efficient way to do this of all of the options.

[James S]

Some previous posts talk about ac TVs that are actually 12v (or close enough) when you chop off the transformer....you may not need to convert to AC for the goodies

[donradcliffe]

I agree that sizing the inverters to the load is much more efficient for small loads. Small inverters tend to have more RF noise however.

I have run a sander or grinder all day long when power was cut to the boatyard. Not a noticible load on my 500AH battery bank compared to the 70A shopvac, which the admiral can use for hours.