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Old 04-16-2014, 08:52 AM   #41
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What recharges the batteries at night? Wind generator / diesel generator? If recharging via diesel generator it doesn't make sense to me to run these big amperage loads through an inverter. Inverters are not 100% efficient so it would seem like you are losing efficiency with this method. What is the point?
ease of circuit wiring/distribution setup
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Old 04-16-2014, 11:37 AM   #42
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You won't do most of your re-charging at night (though some folks find a wind generator does help in this regard). People with decent inverter systems use these to get through the night noiselessly....recharging occurs in the morning when underway (alternators) or by running the genset in the morning to cook breakfast, heat water, power the washer/dryer...and of course, charge the batteries. For us and I think, many others the whole point of a good inverter system is that the evenings can be spent quietly.

ALSO: your post at #34 above is not correct. You said: The comment of inverter boost is somewhat misleading. The inverter design can sometimes allow short time peak wattages to exceed the wattage rating of the inverter. This is usually rated in seconds and probably is not good for the electronic components. Electronics do not respond well to overloads but hopefully they have accounted for this in the design.

Modern inverter/chargers like those by Victron & MasterVolt, are designed to parallel shorepower and/or gensets and supply inverter power to handle the demand peaks (usually brief). They can do so indefinitely with no damage to the inverter. Victron has produced a publication (not specific to their products) which discusses the various approaches to providing power aboard and I this answers most of the questions you are raising in this and associated posts.....I think you will enjoy reading it. It can be downloaded free at http://www.victronenergy.com/upload/...limited-EN.pdf
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Old 04-16-2014, 11:36 PM   #43
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Interesting

You mention that that these inverters parallel shore or generator power to handle peak loads. If this is the case I still do not get the point in running high loads through an inverter since either shore power or the generator would have to be applied to handle the load. In the case of being on the hook your generator "noise maker" would be running during these parallel situations. If that is the case why not just let the generator supply the full load? Why not just sound proof the generator? A person can burn a lot of diesel for the price of these sophisticated inverters. I see the advantage of inverted power in light loads that do not tax the battery capacity and make it where you do not have to utilize generator power. I guess we can agree to disagree. To me I guess it boils down to an ROI and I can burn a lot of diesel through my Northern Lights generator at a lower cost than the cost of these sophisticated inverter systems.
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Old 04-16-2014, 11:40 PM   #44
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You mention that that these inverters parallel shore or generator power to handle peak loads. If this is the case I still do not get the point in running high loads through an inverter since either shore power or the generator would have to be applied to handle the load. In the case of being on the hook your generator "noise maker" would be running during these parallel situations. If that is the case why not just let the generator supply the full load? Why not just sound proof the generator? A person can burn a lot of diesel for the price of these sophisticated inverters. I see the advantage of inverted power in light loads that do not tax the battery capacity and make it where you do not have to utilize generator power. I guess we can agree to disagree. To me I guess it boils down to an ROI and I can burn a lot of diesel through my Northern Lights generator at a lower cost than the cost of these sophisticated inverter systems.

We have both, we also prefer the genny.
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Old 04-17-2014, 01:36 AM   #45
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David: sometimes shorepower supplies are inadequate and the inverter can be used to compensate for this....of course not necessary where shorepower (or shorepower leads and breakers !) are up to the job. But the biggest benefit may be in genset sizing. Of course this may not apply to you, but for someone building a new boat or contemplating replacing a genset, the effect is this: traditionally, gensets for boats with air-con have been sized to cope with the peak load of the air-con units starting up. This peak load is brief but can be enormous. So you end up with a big genset that starts the air-con alright...but is then very difficult to keep properly loaded up. Reductions in genset size of 30-50% are possible....with the smaller genset operating at better average loads. It is not a matter of agreeing or disagreeing....I wasn't suggesting this approach is right for you as I don't know anything about your cruising profile. But again; check out the Victron publication- it describes different technical solutions for different power consumption profiles.
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Old 04-17-2014, 09:20 AM   #46
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The typical small boat inverter cannot be paralleled with shore power. This would damage it. If you want to parallel an inverter with shore power you need to buy one that's designed for this. It won't be inexpensive.
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Old 04-17-2014, 12:07 PM   #47
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David: sometimes shorepower supplies are inadequate and the inverter can be used to compensate for this....of course not necessary where shorepower (or shorepower leads and breakers !) are up to the job. But the biggest benefit may be in genset sizing. Of course this may not apply to you, but for someone building a new boat or contemplating replacing a genset, the effect is this: traditionally, gensets for boats with air-con have been sized to cope with the peak load of the air-con units starting up. This peak load is brief but can be enormous. So you end up with a big genset that starts the air-con alright...but is then very difficult to keep properly loaded up. Reductions in genset size of 30-50% are possible....with the smaller genset operating at better average loads. It is not a matter of agreeing or disagreeing....I wasn't suggesting this approach is right for you as I don't know anything about your cruising profile. But again; check out the Victron publication- it describes different technical solutions for different power consumption profiles.
This is exactly the point regarding inverters like the Victrons or Magnum Hybrids. Well said!
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Old 04-17-2014, 02:21 PM   #48
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Have you looked at MasterVolt units. I like their construction and Tec Reps to deal with for advice. BlueSeas and MasterVolt are always good to deal with and not have problems after installation. Make sure the area you mount your choice of inverter has a good air flow.
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Old 04-18-2014, 06:56 AM   #49
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>If that is the case why not just let the generator supply the full load?<

Installing a 4KW or 6KW noisemaker that is usually heavily loaded , and might need the assist of a smart load sharing inverter is a far better investment than installing a 10 -12KW that will almost never be at half load.

The service life and repair record of the hard working unit will be far better.

The fuel burn will also be about half , as lightly loaded diesels are not efficient at all.

For boats with 2 Air cond 4KW is fine 3 air units 6KW will work.

That $4,000 inverter is cheap compared with the price of a noisemaker 2x the size.

Add automatic load shedding at $60 a circuit and most cruisers can live very well with minor effort.
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Old 04-18-2014, 07:28 AM   #50
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Add automatic load shedding at $60 a circuit and most cruisers can live very well with minor effort.
Interesting. I looked into load shedding for my home generator and all I found was industrial-grade stuff (and prices).

$60 per circuit seems very reasonable. Who sells those?
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Old 04-18-2014, 07:59 AM   #51
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>If that is the case why not just let the generator supply the full load?<


The service life and repair record of the hard working unit will be far better.

The fuel burn will also be about half , as lightly loaded diesels are not efficient at all.


That $4,000 inverter is cheap compared with the price of a noisemaker 2x the size.
Actually those are not accurate statements. A modern diesel (heck that includes the 4 cylinder Cummins on my 20 year old, 6500 hour 20kw Onan, which just surveyed out perfectly.) just needs some load on it, 20, 25% is fine. It is no load that hurts them.

I was going through marine generator costs and specs with a friend the other day, and had gone through this fairly extensively a few years ago as well when considering installing a second, smaller generator.

Take a look at NorPro's site for instance and take a look at the fuel burn for their Isuzu and Yanmar generators at various loads. To put out the same KW requires virtually the same fuel burn. On the Yanmars, some are even less in the bigger genset delivering the same kw as a smaller one.

Then take a look at the price. A 15NY costs about 2100 more than a 7NY. This is not untypical among other brands as well. Westerbeke 10kw diesel about 3k more than a 5.5.

So you are really not buying a boosting inverter and all those batteries to save any money to reach a certain kw capacity. Yes, the slightly smaller genset offsets some of the cost of the inverter system. You have to know very precisely what those loads are that might put the genset over the top.
It is a nice bonus feature, no doubt. And if buying a new inverter for a boat that has had some loads added to an originally smaller genset, stressing it, it is superior solution than an inverter that doesn't have the feature. But the primary reason is that of getting any sort of inverter in the first place: a quieter, somewhat less expensive way to power small loads within it's capacity.
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Old 04-19-2014, 07:47 AM   #52
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>Interesting. I looked into load shedding for my home generator and all I found was industrial-grade stuff (and prices).

$60 per circuit seems very reasonable. Who sells those?<

I borrowed a Granger overpriced catalog and used 120V 30 A relays.

These were sold as NC or NO (normally Closed or Open) owner adjustable.

For load shedding a NC relay would be installed before say a hot water heater.

A very light line ( 16Ga) from perhaps the #2 air cond , that is powered only when the Air cond is on would kill the HW heater .

A list of start requirements for what is onboard is a big help in working out how to live off a modest source.

A simple switch to break the relay connection allows full juice living when the 240V 50A power pole is handy.
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Old 04-19-2014, 06:41 PM   #53
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............For load shedding a NC relay would be installed before say a hot water heater.............
Why would you need to heat hot water?

Load shedding can be done in an elegant and safe manner or it can be done in a haphazard and unsafe manner. Any relays either powered by or controlling 120 volt or 240 volt AC need to be in enclosures preferably built for the purpose. Any 120 wiring, even control wiring, needs appropriate circuit protection for the current carrying capacity of the conductors and needs to conform to ABYC 120 volt AC wiring standards and practices.

Ideally there would be a panel with lights indicating anything that has been shut down by the load shedding circuits to avoid confusion and help with troubleshooting. A tag on any appliance subject to load shedding would be a good idea for troubleshooting purposes and for the safety of anyone servicing the appliance.

And of course there should be a simple way of disabling load shedding and returning all appliances to normal operation.

Ideally the boat is equipped and wired so load shedding is not necessary.
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Old 04-19-2014, 09:03 PM   #54
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But most aren't wired to handle all loads at the same time....and what FF suggests is easy to do even with the proper safeguards.

I prefer the other alternative at the dock or genset...just go up to 50A 125/250 or even 100A service....
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Old 04-23-2014, 07:26 AM   #55
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>Take a look at NorPro's site for instance and take a look at the fuel burn for their Isuzu and Yanmar generators at various loads. To put out the same KW requires virtually the same fuel burn. On the Yanmars, some are even less in the bigger genset delivering the same kw as a smaller one. <

Looked and found the con.

They Only list at 100%, 75% and 50% loading.And offer no fuel map.

The problem comes when that big 12Kw or 20Kw is loaded with a batt charger , and perhaps the fridge.

A maybe 1KW load , much ungood to operate any diesel at 5% load .

A 4KW at 25% load is still light , but many of the engine donors are from yard equipment , so are built for it.
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Old 04-23-2014, 11:58 AM   #56
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5% load for an hour or two won't hurt a modern diesel. And by modern I mean the last 25 years. If you get paranoid, throw something else on while you are at it. Cruising boats do this all the time to recharge the inverter bank; there is typically a hot water heater that will kick in after being off for awhile, and so on.

But heck, most big boats come with only a generator, sized to run the whole thing, but often asked to run light. Mine was that way when I bought the boat and the 20kw genset, which had about 2500 hours on it, surveyed out just dandy. 4000 hours later, still dandy. And that little Cummins is positively antediluvian by todays standards.
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Old 04-23-2014, 12:20 PM   #57
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The show-stopper for me on this 3000W inverter would be that it only has a 30A charger. I didn't look at options for a remote panel, but I'd definitely want the option to display amps in, amps out, voltage and any other goodies a remote usually gives you.

otherwise, you can't beat the price.
That's why I went with the Magnum. I wanted to load the genset. The truth is, the high-current portion of the charge doesn't last that long.

The Magnum allows you to set the battery type and total capacity through the control panel. This helps to optimize the 4-stage charging program. How much this helps I don't know, but I do know that a poor (cheap) charger can quickly kill a set of expensive batteries.
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Old 04-24-2014, 07:23 AM   #58
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If the batt set were large enough a 100A charge rate at 14V is still 1500W , about one small electric heater .

4000W noisemaker a small load

20,000W noisemaker ,,,,,,
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Old 05-06-2014, 08:29 PM   #59
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I haven't looked at the AIMs inverter but all true marine grade inverters separate the neutral and the ground. The only point these should ever be common with a boat should be at the dock pedestal. Typical non marine inexpensive inverters may tie these together this has the potential to create a real problem or hazard in the marine environment.
I would just use caution making sure the AIMs inverter does keep the ground and neutral separated.
Let me clarify the only time these are combined is when the inverter is supplying power, when it is not they should be separated.

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Old 05-06-2014, 08:45 PM   #60
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I haven't looked at the AIMs inverter but all true marine grade inverters separate the neutral and the ground. The only point these should ever be common with a boat should be at the dock pedestal. Typical non marine inexpensive inverters may tie these together this has the potential to create a real problem or hazard in the marine environment.
I would just use caution making sure the AIMs inverter does keep the ground and neutral separated.
Let me clearify the only time these are combined is when the inverter is supplying power, when it is not they should be separated.
Bill

Our ground is binded at the panel.
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