Inverter Tips

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Tom.B

Tom.B

Moderator Emeritus
Joined
Jul 30, 2009
Messages
5,839
Location
USA
Vessel Name
Skinny Dippin'
Vessel Make
Navigator 4200 Classic
Any tips y'all can give meanwhile shopping for an inverter? During the upcoming winter overhaul of Skinny Dippin's charging system, I want to add a small-ish inverter (1000W-1500W) to use at anchor for small things like TV's, lamps, laptop charging, maybe a microwave, etc without firing up the genset. I'm thinking about not wiring it into the panel, but only have the inverter in the engine bay with a power strip in the salon within reach of the occasional extension cord.

Which brands are good and which should I avoid? Keep in mind, I don't really need a full-bore high end device, but from what I have read, Xantrex is one I should avoid, but I have not totally written them off. I was looking at Go Power! or Pro Mariner devices. Maybe Magnum, but they are pretty pricey.

I'd like to keep it well under $1000. $500 would be more like it. It's really going to be use so infrequently and I just can't justify $1500+ for something like this.

*NOTE* We currently (<- PUN!) have only about 440Ah in our 4 golfcart batteries, but I am looking to add two more for about 660Ah when I do the upgrade. Not for sure yet, but it's relevant to the conversation I suppose.

Thanks!

Tom-


-- Edited by GonzoF1 on Tuesday 15th of November 2011 09:04:49 AM
 
In reading the T&T list, Victron seems to be the way to go. No personal experience with the product.
 
After some research, I went with Magnum (2812). I saved quite a bit by buying a refurbished unit from Wholesale Solar http://www.wholesalesolar.com/products.folder/inverter-folder/refurbishedmagnuminverters.html

I bought the larger size primarily because I wanted the battery charging to put a good load on the genset. I also bought the ME-RC 50 remote, which was the best $150 I've spent on the boat (it looks like they're $180 now).

When I bough the unit, I didn't think I needed the extra AC power (above 1kw), but have managed to find uses for it -- like making toast and coffee while on the hook.

So far, the yards I've spoken to all say the Magnum is a good unit and that they haven't had any problems with them. They all say to stay away from Xantrex.
 
First decide the 1) max watts required. *2) a pure or modified sine wave, and 3) stand alone or combine inverter/charger is required.* The maxim watt required is calculated using the formula, Volts X amps = watts, and 1 amp AC 120 volts is = to 10 amps DC 12 volts.
*
You can buy a stand alone Prowatt 3000 watts, maximum 5000 watts, modified sine inverter for $500 to $600 which I installed in 1996.* Better to over size the inverters watts than under size.* The real question is do you need a PURE or MODIFIED sine wave inverter?* I found most of the things work fine on the modified sine wave and I wanted a stand alone inverter. *
 
chiropaul wrote:
In reading the T&T list, Victron seems to be the way to go. No personal experience with the product.
Click to expand...
*Looks like Victrons are limited in supply to the US market. Jamestown Distributors are about the only place that carries them.
 
I was looking at a smaller pure sine wave unit. 3000 watts will quickly kill the batteries should I find the load for it, and anything with ANY quality at that size is WAY out of my budget. That said, I don't have any experience with Prowatt (or any others for that matter), so If it's reliable enough and inexpensive enough, I shouldn't rule them out. Keep in mind, this is more of a it's-nice-to-have-but-I-don't-NEED-it item. I don't HAVE to have one that runs 100% for 24/7/365. Just one for a few knick-knacks while tooling around eastern NC.
 
These folks have several models and seem inexpensive. They are not a marine outfit but may suit your purpose, I'd look for customer reviews on the internet to see what ratings they have.

www2.northerntool.com/power-inverters.htm

Steve W
 
Tom,

If you're looking for an inverter on a budget, check out this 2000W inverter. This is a marine version that's available for under $300. I'm not familiar with the Power Bright brand, but the non-marine versions are sold at Costco.com and they usually carry quality stuff. I like the fact that they include an RF remote control.
 
Go big on the power strip cord and keep the run as short as possible. *Otherwise it will be the weakest link.

*

cheers,
 
Capn Chuck wrote:
Here is ours, http://trawler-beach-house.blogspot.com/2010/02/installing-power-inverter.html . It does everything we need it to do, microwave, coffee pot, toaster and even hot water heater, The HW only needs to be on for about 15 minutes to heat the water and uses very few amps. It powers the TV, sat receiver, DVD player, fans, you name it. Hope this helps. Chuck
Click to expand...
*Yea Chuck, read it yesterday and I am headed that direction, however, ProMarimer doesn't seem to make a 2000W hard-wired inverter anymore. At least I can't seem to find one. I'll keep looking. Perhaps a suitable alternative will surface. What surprises me about your rig is that your battery bank is so "small". I figured you would have more that 440Ah,but it is the exact same size as ours. I thought I would need far more to do what you do. Good to know I am at least in the ballpark.
 
I have had 2 Victron Inverter/chargers so far and they come in tops with the research I have done.
I have read recently about the magnums and they are supposed to be pretty good but to my knowledge they are no available in Aus.
The outback Marine inverters also rate highly.
Just ensure you get a full sine wave inverter so that everything you have can run smoothly.
Be warey of modified sine wave inverters which a lot of the cheaper units are.
 
GonzoF1 wrote:Capn Chuck wrote:
Here is ours, http://trawler-beach-house.blogspot.com/2010/02/installing-power-inverter.html . It does everything we need it to do, microwave, coffee pot, toaster and even hot water heater, The HW only needs to be on for about 15 minutes to heat the water and uses very few amps. It powers the TV, sat receiver, DVD player, fans, you name it. Hope this helps. Chuck
Click to expand...
ProMarimer doesn't seem to make a 2000W hard-wired inverter anymore. At least I can't seem to find one. I'll keep looking.

*I take it back... I actually DID find them for sale... My bad.
 
My battery bank is also 440AH. More than enough. My coffee pot has an insulated carafe, so it and the toaster only run for a few minutes at a time. One of the jobs I hope to tackle in the next couple of weeks is to get the hot water heater off of the inverter circuit. The inverter will run the water heater, but I only know that because I've accidentally left the switch on, heard the fan kick on, and then noticed the display panel showing 100+ amp draw from the batteries. If I want hot water that bad I'll start the generator.

Unlike diesel engines, it's usually better to oversize an inverter because the enemy of power electronics is heat. The only drawback to over sizing is that you may lose some efficiency on small loads. Larger inverters have larger heat sinks, or try to cool with more air flow. One thing to consider about the cheaper inverters is that they use small fans turning at higher speeds. In other words, they can make a fair amount of noise. The larger units tend to have larger, quieter, variable-speed fans with larger heat sinks, and can often handle the lighter loads without making much, if any noise.
 
I installed a 2800 Magnum Energy inverter/charger with a remote control to 8 AGM golf cart batteries. The Magnum system does an excellent job of monitoring and charging the battery bank and is adjustable to any setup. Including adjustable low battery cut out, adjustable charger amp draw, adjustable battery bank size and battery types, battery temperature and condition......real good stuff and worth the extra money. Do it once.

Here is the MS model http://www.magnumenergy.com/Literat...ters/MS Series Data Sheet (64-0200 Rev F).pdf

I found it the cheapest here http://www.boatandrvaccessories.com/

I found the best prices on marine wiring and lugs here http://shop.genuinedealz.com/ , great people to work with. You do not want to skimp on the wiring gauge or quality, very important.

Great winter project, good luck.

David
 
GonzoF1 wrote:GonzoF1 wrote:Capn Chuck wrote:
Here is ours, http://trawler-beach-house.blogspot.com/2010/02/installing-power-inverter.html . It does everything we need it to do, microwave, coffee pot, toaster and even hot water heater, The HW only needs to be on for about 15 minutes to heat the water and uses very few amps. It powers the TV, sat receiver, DVD player, fans, you name it. Hope this helps. Chuck
Click to expand...
ProMarimer doesn't seem to make a 2000W hard-wired inverter anymore. At least I can't seem to find one. I'll keep looking.

*I take it back... I actually DID find them for sale... My bad.

*Wrong again... Promariner HAS discontinued the Truepower 2000... I might find someone that has one still in stock, but I would rather deal with one vendor for all of my needs associated with this project. Defender.

Tom-
 
I'm leaning towards this:

http://www.aimscorp.net/2000-watt-pure-sine-power-inverter-12-volt/

Seems powerful enough and inexpensive enough for our current (<- another pun) purpose. However, I'm wondering about an automatic transfer switch. Are the necessary? Does anyone have an inverter rig without one? I understand the need, but I don't want my shore power to go off when I am away and have my circulating fans, fridge, and some other small drain kill my batteries.
 
I had a "PortaWatz" 1600 W set up for manual operation only on my previous boat. I had to turn the inverter on (with a remote switch) and unplug the fridge from the shore outlet and plug it into the inverter which was a heavy duty extension cord.

Many times I forgot to make the*change when I left the dock.

My current boat is automatic and I like it much better.
 
GonzoF1 wrote:
However, I'm wondering about an automatic transfer switch. Are the necessary? Does anyone have an inverter rig without one? I understand the need, but I don't want my shore power to go off when I am away and have my circulating fans, fridge, and some other small drain kill my batteries.

*

Tom:* The automatic transfer switch*passes through*AC when connected to shore or generator power for the inverter AC loads only.* This way the*inverter does not have to "invert" 12 VDC to 110 VAC for the inverter loads when there is an AC source available.*
Click to expand...
 
GonzoF1 wrote:
Click to expand...
*Yea Chuck, read it yesterday and I am headed that direction, however, ProMarimer doesn't seem to make a 2000W hard-wired inverter anymore. At least I can't seem to find one. I'll keep looking. Perhaps a suitable alternative will surface. What surprises me about your rig is that your battery bank is so "small". I figured you would have more that 440Ah,but it is the exact same size as ours. I thought I would need far more to do what you do. Good to know I am at least in the ballpark.

*I don't understand, here and here is the same unit I have and it can esily be hardwired. And here again on ebay . I was not aware that they have discontinued this one. Chuck
 
Thanks Chuck... I called BoatBandit and they were out of stock, but I didn't think to check eBay. DOH!
 
Where have you installed your inverter? Have you had any problems?

The guy who installed my Magnum 2812 insisted on putting it in the hanging locker. I didn't like the idea because of the very real possibility of blocked airflow from clothes in the hanging locker. The yard electrician claimed there would be too many problems with heat and moisture if I installed it in the engine room. I'm thinking of moving it. What do you think?
 
bobc wrote:
What do you think?
Click to expand...
*Mine is in the ER and right next to the 3-8D AGMs. The boat is 7 years old now and -0- problems with the inverter in that location.
 

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How hot does it get in there? I want mine in the engine bay too.
 
My Freedom 20 is in the engine room.* I don't have a thermometer in there but it must get well into the 90s when we're underway.* I don't know how long its been onboard but its an old inverter, predates the Xantrex era.* Having seen inside the Heart series inverters and some of the newer Xantrex "equivalents" I'd be looking for an old Heart if I wanted another inverter.* We have a Heart 25 on the bus.* I had the relays replaced in it about 2 years ago.* Its hard to find somebody who actually knows how to work on them but they are rugged.
 
Bare in mind that the hotter the battery (above 80 F) the quicker it will self discharge and the less amp hours it will be capable of producing. Check the battery manufacturers charts.
 
I'll just make some random comments on the subject:

In most cases, it's more efficient to use 12 volt appliances than 120 volt appliances powered by an inverter and 12 volt batteries. Fans, lights, TVs, refrigeration, etc. There is at least a 10% loss through the inverter. The exception would be a 12 volt coffee maker. These seem to be incredibly slow.

Some appliances will function just fine powered by a "modified sine wave (it's really a square wave with the corners filtered off)" inverter, but some do best with a pure sine wave inverter.

An inverter needs to be installed as close to the batteries as possible to minimize the voltage drop between the batteries and the inverter. Given the choice, the leads between the batteries and inverter should be as short as possible and the 120 volt circuit can be as long as necessary. An inverter will need ventillation and may have to be installed in a specific orientation.

The power (in amps) drawn from the batteries is more than ten times the power (in amps) produced at 120 volts AC.

An inverter is probably not ignition proteced and should not be installed in the engine room of a gasoline powered boat.

The advertised power rating of a microwave oven is the "cooking power, not the power consumption. The power consumption will be listed on the label near the power cord connection and will be considerable more than the cooking power. A "700 watt" microwave oven draws over 1,000 watts 0f 120 volt AC power. That is over 100 amps from a 12 volt battery bank.

Heating water with an electric water heater or heating the cabin with an electric heater powered by batteries and an inverter will draw too much power for too long a period to be practical. The same goes for air conditioning.

An inverter will have a standby current of up to one amp or so even with no load connected so it needs to be turned off when not in use or when it won't be used for a day or more to avoid unecessary drain on the batteries. Get one with a remote switch.
 
rwidman wrote:
The advertised power rating of a microwave oven is the "cooking power, not the power consumption. The power consumption will be listed on the label near the power cord connection and will be considerable more than the cooking power. A "700 watt" microwave oven draws over 1,000 watts 0f 120 volt AC power. That is over 100 amps from a 12 volt battery bank.
Click to expand...
According to the inverter's control panel, the 900W microwave on my boat draws 150A out of the batteries.*

That's not the whole story.* The oven's magentron doesn't conduct over the entire AC cycle, it only draws current during a fraction of one-half of one cycle.* It's off during the other half (half-wave rectified).* So, the peak current loads on the inverter are quite a bit higher than you might think.*

My microwave sounds a bit different when I'm on the inverter, so I'm not sure the 900W microwave would work very well with anything smaller than the 2800W inverter I'm using.
 
Unless its a quite expensive true sine wave inverter,

ALL inverters will take longer than dockside or big noisemaker (Over 10KW) 120V current to produce the same cooking result.

Home Power suggested heating a Pirex held quart of water with line 120 , and then again with the inverter.

Then its simple to add 10% to 30% to cook times when on the batteries.

Might be an interesting experiment with a 4KW or 6KW noisemaker too.

Refrigeration IS better with DC as the compressor speed can be easily controlled.

With lighting , fans and the rest I have found cheap thin DC wiring looses as much as a reasonable inverter working.

Newer inverters are way better than those from only a decade ago.
 
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