Power Inverter

C

codicote

New Member
Mar 8, 2010
10
Australia
Boat Info
280 Sundancer
Engines
Twin 4.3l Mercruiser w/Bravo III Drives
Hi

Considering purchase on 2009 SEA RAY 2009 280. Boat in stock does not have a power inverter fitted. Should I add this ? Do you use it a lot away from dock?

Can I fit one later if I decide I want one later ? Cost is approx $2000 AUD

Regards

Paul
 
If you've never had one, you don't need it! If you've had one, you can't live without it. I'm guessing your boat doesn't have a generator? What items are you planning to run off the inverter? We don't have one and we don't need it either. We have a small inverter that plugs into the 12 V outlet to charge laptops or the kids games. We don't have a microwave or anything else that would require the use of an inverter. Our friends have one and they use it to power the coffee pot or the microwave for short bursts.
 
I added an inverter to our boat primarily to run a microwave. It is one of the most used items that I have ever added to our boat. From running the microwave and blender in the galley to powering small power tools for odd jobs, there is hardly a time that we don't use it for something when we are on our boat. Yes, add one. You will be surprised at how much you will use it. I can't imagine not having one.
 
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With a good marine mechanic adn electronics designer y ou can have inverters that can suppl;y enough power for just a TV, computer or large enough to easily handle an A/C Reverse Heat System. How much you wanna spend? That may be your only limitation.
 
If you stay at the docks with shore power, you won't need one. If you stay on the anchor you will need one with a couple of large deep cycle batteries to go with it.
 
I recommend for sine-wave inverters and have waeco 1500watt/peak 3000watt.

Buy a big deep cycle battery beacuse when you use an inverter you have to push the button of outlets/refrigirator on AC part of the MDP so your refrigirator will power simultaneously, altough you can power-off your refr.

When you use shore power or genny your refrigirator will drain 0,71amps(110volt) but when using battery power it drains 3amps(12volt), so inverter is just "fooling" the AC tool(110volt) and you will consume still 3amps.

This is only what I do by my electrical knowlegde, more experts would chime-in.

So make your amperage calculation for both refrigirator and which tool you're gonna operate with inverter.

Best regards.
Melida
 
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Henry Boyd said:
The question that should be asked is not how big an inverter, but how big a barge will be needed to tow to hold the batteries to power the inverter!
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Definitely. The inverter is not the issue; it's the battery bank. There are regularly inverter questions and once you start doing the calculations, the feasibility of running the larger AC items becomes a little more clear. Take the blender, for example. Assume a typical, decent blender that draws 5A (note that larger ones can draw up to 20A). Here's the simple math for an estimate:

5A x 110VAC = 550W
Presuming inverter efficiency at 90% (optimistic): 550W / 0.9 = ~610W
At 12V: 610W / 12VDC = ~51A
This is a huge draw from a single battery...it is hard to even get specs for most batteries at that discharge rate.

I'm not sure how much you have researched batteries, but they are typically rated for capacity at a specific discharge rate, often their 20 hour rate (meaning how many amp-hours of capacity the battery has if it was discharged over 20 hours), and the capacity decreases as discharge rate increases. So if you have a typical-quality run-of-the mill 100AH (20h rate) battery, its capacity is 5A for 20 hours, and it may be 80AH at 10A (8 hour rate), and 60AH at 20A (3 hour rate), for example. The derating is somewhat linear at the higher rates (it's an inverse power curve at lower currents). Note the semantics can be confusing...the 20 hour rate is sometimes wrongly referred to as the 20 AH rate, which is misleading...it infers the 20 hour AH rating. Also, some batteries are spec'd by reserve capacity (RC), which is the number of minutes at a specified current draw.

It's hard to say, but I would guess the capacity of the 100AH battery would need to be derated by at least half at 50A, so your 100AH battery is at best a 50AH battery at 50A. You could run your 5A blender for a total of 60 minutes in theory. In practice, the battery voltage would drop-off quickly causing the inverter efficiency to go down, heat in the bilge will derate the battery even further, and you might have enough battery for a couple margaritas! A microwave would use about double the power...you might cook a hot dog. Air conditioning is even more of a challenge. There are lower-power appliances available...not sure how well they work.

The way around this is to add multiple batteries in parallel to increase the AH and also decrease the discharge rate of any single battery. There are also some very high quality batteries available, but they can be expensive. Connecting deep-cycle 6V batteries in series pairs also is an option.

In a previous thread someone pointed out Rolls as being very good batteries: http://www.rollsbattery.com/. Maybe worth a look.
 
Four Turtles, someplace I have that exact picture from the same place looking at our boat parked at the same spot!!! I will try to dig it up, too funny. We have a 2000w max 4000w inverter on a two deepcycle battery bank and use it ALL the time with kids games, laptops, coffie pot, power tools, shopvac, ect... I have found when cruising for 3 or more days through Canada islands(no shorepower) that I def could not live with out it. As long as I run the boat to move locations everyday have no problems with the battery's draining down to much. I also have two more used for starting boat ect. I don't usually use microwave unless boat is running or on shore power except for short burst though.
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green anchors said:
Four Turtles, someplace I have that exact picture from the same place looking at our boat parked at the same spot!!!
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It's an awesome place to stop and explore. We stayed in A-Bay for a few days last summer and visited Bolt and Singer Castles. We had never been to Singer before. It was very impressive.

green anchors said:
We have a 2000w max 4000w inverter on a two deepcycle battery bank and use it ALL the time...
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This sounds like a good setup, and maybe what the OP may want to do. What is the highest-draw appliance you use regularly, the coffee pot or maybe the shop vac? What's the longest you have run the microwave? Real-world data points are better than theory any day! Out of interest, what type of deep cycle batteries do you have?
 
I think the blow dryer that is ran for 4 or 5 minutes, not sure what the watts are. The microwave is 1100 watts and runs for about the same amount of time maybe for popcorn or heat water. I have Deka master marine's with 200min at 23 amp. The shop vac is a small maybe 1gal type and does not draw too much(i think). The inverter is a Whistler 2000 continuous and 4000 max. I agree Singer was impressive, great dock with good water. The day we were there we had the whole place to ourselves. Canada has done a GREAT job with the park islands and we are working on the chore of spending alittle time on each one. So far Miltan(sp?) is one of our faves. PO of our boat said they would stay for 2 plus days at same spot and would start the boat for 20 to 30 mn a day and had no problem, Im not so sure about that. I feel much better running a bit after using the inverter for a night.
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green anchors said:
I think the blow dryer that is ran for 4 or 5 minutes, not sure what the watts are. The microwave is 1100 watts and runs for about the same amount of time maybe for popcorn or heat water. I have Deka master marine's with 200min at 23 amp. The shop vac is a small maybe 1gal type and does not draw too much(i think). The inverter is a Whistler 2000 continuous and 4000 max.
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Thanks, good data points. I'm curious how the Whistler inverter is installed and wired. I assume it's in the cabin since it's not ignition protected. Do you have an AC patch panel of some kind? I have been considering different options for my install...
 
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