Sine Wave Inverter ??

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Ross

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Jun 15, 2004
14,693
Islander/Wayfairer 30 sail number 25 Perryville,Md.
Only a couple of them are really big and hard to handle from dink to boat. When I lived at Bangor we had a 10 or 11 foot tide range so I can see where a mooring is best. Hinged stairs and a floating pier are a bit pricey. ;)
The 2KW inverter is cheaper than i would have expected.
 
Dec 25, 2008
1,580
catalina 310 Elk River
Without physically re-wiring these products how do I run these 110v items off DC?

Fein Multimaster
Hitachi 1/2" drill
Porter Cable 690 router
Dirt Devil Vacuum
Port Cable RO Sander
Bosch Jig Saw
Nikon Camera Battery Charger
Panasonic Camera Battery Charger
JVC Video Cam Charger
Rigid Shop Vac
Makita Orbital Buffer
Vacuum Pump for refrigeration work


Everything that can easily be converted for use on 12V has been, TV, computer etc.. I don't want to physically re-wire these other items for use on the boat and fully understand the inefficiencies from 10% to 35+%....
Are you setting up shop on your boat away from shore power?
 
Feb 6, 1998
11,709
Canadian Sailcraft 36T Casco Bay, ME
Are you setting up shop on your boat away from shore power?
No, but I do and have used all those tools on the mooring for specific tasks or projects and may need to do so again at some point. I will be doing some interior refinishing this summer and will at least be using my Fein and RO sander as well as the vacuum.. I explained this earlier..see Post #20 (LINK)
 

druid

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Apr 22, 2009
837
Ontario 32 Pender Harbour
One little comment: I keep seeing this "Invertors are SO inefficient!" - anybody have any numbers? I'm seeing around 95%, which while greater than zero, is really not that bad. In fact, I wouldn't think a DC-DC converter is much better.

druid
 
Feb 6, 1998
11,709
Canadian Sailcraft 36T Casco Bay, ME
One little comment: I keep seeing this "Invertors are SO inefficient!" - anybody have any numbers? I'm seeing around 95%, which while greater than zero, is really not that bad. In fact, I wouldn't think a DC-DC converter is much better.

druid
Real world numbers:

ASUS Netbook eeePC

12V Adapter = 3.12 Amps
120V/150 Watt Inverter = 4.12 amps

Total Inefficiency With Inverter = 32.05%

Polaroid 19" TV

12V Direct = 3.9 Amps
120V/1200 Watt Inverter = 5.8 amps
120V/400 Watt Inverter = 5.2 amps

Total Inefficiency With 1200W Inverter = 32.8%
Total Inefficiency With 400W Inverter = 25%


Inverters are most efficient at close to their rated outputs but even at that inverters can vary widely in efficiency. The inverters used in the above scenarios all claim about 90% efficient and may be with an inductive load at close to the max rating..

A quote from Practical Sailor:


"Efficiency figures will vary based on demand load and battery voltage; most inverters’ efficiency will improve with higher loads. All test products were rated for efficiency using the same loads and voltage."

This batch of 8 inverters recently tested by PS ranged from a low of 73% efficient to a high of 93%, all with the same test scenarios and loads applied. These efficiencies are without any conversion inefficiencies like you would have running a computer or TV that is already internally DC off DC to AC and back to DC or the fact that you may be running it at well below its rating.

For the full article subscribe to Practical Sailor (LINK)..


Inverters can be quite inefficient but sometimes necessary if you can't find items that will run directly on DC.
 

Ross

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Jun 15, 2004
14,693
Islander/Wayfairer 30 sail number 25 Perryville,Md.
You can run your engine to drive the alternator to keep the battery up while you use the inverter and have nearly unlimited power/time availability. Your shop-vac uses about the same amount of power whether you are collecting sanding dust or saw dust and that is inefficient. Inverters wouldn't have those big heatsinks if they were 99 percent efficient. I wouldn't be troubled by a bit of wasted energy. If you want to save energy sand by hand. ;)
 
Jan 22, 2008
8,050
Beneteau 323 Annapolis MD
Okay, so each electrical component is inefficient. Lots of posts here just to debate if there is inefficiency- It's a given. Live with it. What the percentage of inefficienacy is doesn't really matter as long as sufficient power is available to do the task he wants to do. I calculate each tool is 100 percent inefficient if it's not usable.
 
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Ross

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Jun 15, 2004
14,693
Islander/Wayfairer 30 sail number 25 Perryville,Md.
I'm trying to imagine a shop vac on my boat.
even better! imagine a mess big enough to warrent it. ;)
Been there, done that, got the bruises to prove it.
 
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