Advice please, in choosing the right size of inverter to purchase which is better to have a 700 watt or a 2,000 watt. Normally more is better, but for now all I intend to power is a laptop computer. For repairs will a 700W unit run a drill or saw?
inverter sizing 700W v. 2000W
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Inverter Size
Look at the power tools you may want to use, they will have a label that indicates how many watts they need. Another factor to look at is 'surge output' (how many watts above the rating will it provide, and for how long). So is 700 watts the continuous output, or the surge? If a tool, or device needs 700 watts to run, it may need 800 or more to start up.
Look at the power tools you may want to use, they will have a label that indicates how many watts they need. Another factor to look at is 'surge output' (how many watts above the rating will it provide, and for how long). So is 700 watts the continuous output, or the surge? If a tool, or device needs 700 watts to run, it may need 800 or more to start up.
DC Power Adapter
If all you wanted to do was power the laptop, a DC Power Adapter is much more efficient than an inverter. See the related link. I have one and it draws less than 2A when running my laptop. Of course you won't be able to run the drill or saw from it, for those you can get portable versions.
If all you wanted to do was power the laptop, a DC Power Adapter is much more efficient than an inverter. See the related link. I have one and it draws less than 2A when running my laptop. Of course you won't be able to run the drill or saw from it, for those you can get portable versions.
go fore broke
would recommend going with the biggest you can afford and fit into the space. better to be over powered than not enough power when needed.
would recommend going with the biggest you can afford and fit into the space. better to be over powered than not enough power when needed.
Inverter
Again, go with the biggest you can afford. I went small first, and now have two inverters. A good place to look is ebay. I bought a 2000w Heart for around 50 bucks. Have had it in the boat for a year now with not a problem one. What I did was leave the inverter completely seperate from the shore power stuff. Mixing the outputs could pose a feedback problem. I didn't want to have to remember to turn on and turn off shore power, inverter etc. So I just ran a couple of wall plugs from the inverter. When ever it's on, they are hot. But there is no cross over. You do have to of course, switch your plug ins to which ever you are using. Phil Prater
Again, go with the biggest you can afford. I went small first, and now have two inverters. A good place to look is ebay. I bought a 2000w Heart for around 50 bucks. Have had it in the boat for a year now with not a problem one. What I did was leave the inverter completely seperate from the shore power stuff. Mixing the outputs could pose a feedback problem. I didn't want to have to remember to turn on and turn off shore power, inverter etc. So I just ran a couple of wall plugs from the inverter. When ever it's on, they are hot. But there is no cross over. You do have to of course, switch your plug ins to which ever you are using. Phil Prater
True sine wave or not ???
If you're installing an inverter for some types of delicate electroninc devices (I'm not sure about computers) you need a true sine wave inverter. They're more expensive per watt than what's commonly called a modified sine wave inverter. I know most battery chargers (like for my power tools) won't work with a modified sign wave. I have a small (I think 200 watt) true sine wave inverter, mostly just used to charge my power tool batteries. Then I have a big 2000 wat modified sine wave one to run AC power tools, etc. if needed. As Phiggins suggested, I also use a DC power adapter for my laptop, which is essentially a small use specific inverter. If I plug my computer into 120 volt AC power at home, the power goes through a transformer to give the computer 19 volts DC. So, if I used a big inverter to plug my computer into on the boat, I would be taking 12 volts DC, inverting it up to 120 volts AC, then transforming it back down to 19 volts DC. Very inefficient. I try to be as efficient as possible with electricity on my boat. Might be more than you wanted to know, but I hope this helps.
If you're installing an inverter for some types of delicate electroninc devices (I'm not sure about computers) you need a true sine wave inverter. They're more expensive per watt than what's commonly called a modified sine wave inverter. I know most battery chargers (like for my power tools) won't work with a modified sign wave. I have a small (I think 200 watt) true sine wave inverter, mostly just used to charge my power tool batteries. Then I have a big 2000 wat modified sine wave one to run AC power tools, etc. if needed. As Phiggins suggested, I also use a DC power adapter for my laptop, which is essentially a small use specific inverter. If I plug my computer into 120 volt AC power at home, the power goes through a transformer to give the computer 19 volts DC. So, if I used a big inverter to plug my computer into on the boat, I would be taking 12 volts DC, inverting it up to 120 volts AC, then transforming it back down to 19 volts DC. Very inefficient. I try to be as efficient as possible with electricity on my boat. Might be more than you wanted to know, but I hope this helps.
For the sake of diversity...
Paul, sometimes these threads are most helpful NOT when they provide agreement on a course of action but rather when they present alternatives and stretch your thinking...which is what motivates me to write. First, I'd recommend you consider NOT buying an inverter...or if you do, not one of the ones you are considering. Why? First, because you apparently don't need one yet. What Morrie was describing is normally called a voltage booster (IOW taking your 12V DC onboard power and bumping it up to the DC voltage needed by your computer) and that's apparently all you need right now. Perhaps it would make more sense to wait until you have other unplugged 120V needs before choosing an inverter, since you'd then be sizing the inverter to your own needs vs. operating on some general theme (bigger is better) or buying less than what you ultimately would want. Voltage boosters are offered by all the manufacturers and/or you can have one custom made for your computer for a whopping $65 USD...and it will be excellent quality and give off no interfering RF. OTOH if an inverter seems a practical addition but for only uncertain and low demand use right now, why leap into the marine market when you can pick up a 400W inverter, new, for $35 or so? (I found some excellent choices when Googling this topic a few months ago). This will support all tool battery charging & laptop use you have now, involve minimal installation effort, impose no significant decisions on whether or how to relate inverter 120V to your existing 120V system and, again, buy you time to see what your real AC needs become. Finally, I have many times seen/heard the generic cautionary note that Morrie offers about modified sine wave inverters being unsuitable for some uses, and I continue to doubt it's validity for most of us. We've been out cruising for 5 years now, installed a basic Freedom 1000 inverter before we left, and we've yet to find anything it does not power properly. We have many battery-powered applicances, a variety of tools, use a DVD player, vacuum and microwave regularly, have powered 3 laptops and misc. computer auxiliaries, and have yet to discover a single problem. It's not hard to find this advice about true sine wave inverters in the catalogs and ads...but out here in the real world, I'm still wondering what it is I will bring aboard - that I need to have aboard - that is going to prove incompatible with this basic inverter. I think this experience again makes the point that, for your needs, it might be better to wait until you KNOW what will require AC aboard your boat before you make product choices and perhaps pay more (for a true sine wave inverter...or for ANY specific inverter) than you need to. Jack
Paul, sometimes these threads are most helpful NOT when they provide agreement on a course of action but rather when they present alternatives and stretch your thinking...which is what motivates me to write. First, I'd recommend you consider NOT buying an inverter...or if you do, not one of the ones you are considering. Why? First, because you apparently don't need one yet. What Morrie was describing is normally called a voltage booster (IOW taking your 12V DC onboard power and bumping it up to the DC voltage needed by your computer) and that's apparently all you need right now. Perhaps it would make more sense to wait until you have other unplugged 120V needs before choosing an inverter, since you'd then be sizing the inverter to your own needs vs. operating on some general theme (bigger is better) or buying less than what you ultimately would want. Voltage boosters are offered by all the manufacturers and/or you can have one custom made for your computer for a whopping $65 USD...and it will be excellent quality and give off no interfering RF. OTOH if an inverter seems a practical addition but for only uncertain and low demand use right now, why leap into the marine market when you can pick up a 400W inverter, new, for $35 or so? (I found some excellent choices when Googling this topic a few months ago). This will support all tool battery charging & laptop use you have now, involve minimal installation effort, impose no significant decisions on whether or how to relate inverter 120V to your existing 120V system and, again, buy you time to see what your real AC needs become. Finally, I have many times seen/heard the generic cautionary note that Morrie offers about modified sine wave inverters being unsuitable for some uses, and I continue to doubt it's validity for most of us. We've been out cruising for 5 years now, installed a basic Freedom 1000 inverter before we left, and we've yet to find anything it does not power properly. We have many battery-powered applicances, a variety of tools, use a DVD player, vacuum and microwave regularly, have powered 3 laptops and misc. computer auxiliaries, and have yet to discover a single problem. It's not hard to find this advice about true sine wave inverters in the catalogs and ads...but out here in the real world, I'm still wondering what it is I will bring aboard - that I need to have aboard - that is going to prove incompatible with this basic inverter. I think this experience again makes the point that, for your needs, it might be better to wait until you KNOW what will require AC aboard your boat before you make product choices and perhaps pay more (for a true sine wave inverter...or for ANY specific inverter) than you need to. Jack
True Sine Wave Inverters
Like Jack, I have used a modified (not true) sine wave inverter for years as have nearly all of my friends. We have all used nearly every type of electronices aboard and as far as I know, never had a problem. So, out of curiosity, have any of you ever had a problem? What kind? What equipment? Also, I'd echo Jack's remarks about just how much you'll use an inverter. My current boat is set up with a lot of AC, but my prior ones were not and I used a small inverter for all the odd charging / power supply needs. One boat didn't even have shore power and I never missed it. Rick D.
Like Jack, I have used a modified (not true) sine wave inverter for years as have nearly all of my friends. We have all used nearly every type of electronices aboard and as far as I know, never had a problem. So, out of curiosity, have any of you ever had a problem? What kind? What equipment? Also, I'd echo Jack's remarks about just how much you'll use an inverter. My current boat is set up with a lot of AC, but my prior ones were not and I used a small inverter for all the odd charging / power supply needs. One boat didn't even have shore power and I never missed it. Rick D.
Mine's kinda like Morrie's, sorta,,,,
I use a ProSine 2.0. (two KW) It's the marine model from Xantrex. That means the shore power is routed to the inverter change-over switch, not the distribution panel. Then the change-over switch sends the shore power to the distribution breaker panel as normal. When on shore power, the ship gets shore power. The instant that power is interrupted, the inverter takes over. By 'instant', I mean the AC lights don't even flicker. When shore power returns the inverter computer syncs it's output to the shore power Hz and changes back again seamlessly. Then it charges the batteries up to 105 amps. All while monitoring power draw aboard so as not to exceed the dockside breaker capacity. Let's see, what else? Oh, the charger is 3 stage and will equalize and is programmable to ANY battery types. It has a full function display panel that can be mounted up to 70 feet away and all functions are user selectable/disable-abul (I know, that's not a word). The only thing to remember to do is disable the inverter when leaving the boat in case of a power outage. That would draw down the batteries and also heat water if the hot water heater was left on. Because it's a true sine wave inverter, all computers and chargers work flawlessly. But, again like Morrie, I've eliminated all of the 'bricks' used for electronics and wired directly to 12 volts. Just because we have power is no reason to waste it. P.S. Rick, in the old days with a square wave inverter the only problem I had was the computer monitor. It was AC and the screen had horizontal moving bars every two inches. It was annoying but never damaged the monitor, unless you count that new monitor that blew-up the day after we left Florida for the USVI. I had to fly back to the US with it from Nassau. Other than that we didn't have much AC stuff.
I use a ProSine 2.0. (two KW) It's the marine model from Xantrex. That means the shore power is routed to the inverter change-over switch, not the distribution panel. Then the change-over switch sends the shore power to the distribution breaker panel as normal. When on shore power, the ship gets shore power. The instant that power is interrupted, the inverter takes over. By 'instant', I mean the AC lights don't even flicker. When shore power returns the inverter computer syncs it's output to the shore power Hz and changes back again seamlessly. Then it charges the batteries up to 105 amps. All while monitoring power draw aboard so as not to exceed the dockside breaker capacity. Let's see, what else? Oh, the charger is 3 stage and will equalize and is programmable to ANY battery types. It has a full function display panel that can be mounted up to 70 feet away and all functions are user selectable/disable-abul (I know, that's not a word). The only thing to remember to do is disable the inverter when leaving the boat in case of a power outage. That would draw down the batteries and also heat water if the hot water heater was left on. Because it's a true sine wave inverter, all computers and chargers work flawlessly. But, again like Morrie, I've eliminated all of the 'bricks' used for electronics and wired directly to 12 volts. Just because we have power is no reason to waste it. P.S. Rick, in the old days with a square wave inverter the only problem I had was the computer monitor. It was AC and the screen had horizontal moving bars every two inches. It was annoying but never damaged the monitor, unless you count that new monitor that blew-up the day after we left Florida for the USVI. I had to fly back to the US with it from Nassau. Other than that we didn't have much AC stuff.
Had a problem once with modified sine
I had one of those full size rechargable flashlights where the slide switch pulls all the way back and two spades pop out to plug into the wall. After 10 minutes in my 200 watt inverter, the plastic started to melt and smoke. Needless to say, my favorite flashlight didn't work after that. *cry
I had one of those full size rechargable flashlights where the slide switch pulls all the way back and two spades pop out to plug into the wall. After 10 minutes in my 200 watt inverter, the plastic started to melt and smoke. Needless to say, my favorite flashlight didn't work after that. *cry
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