1 or 2 inverters?

A good friend of mine and I, over a few beers were discussing whats better, 1 3000 watt inverter or 2 1500 watt inverters. And why. So what's y'all opinions? Thanks in advance

At first thought I like the redundancy if you could run both inverters in parallel.

Same thing with the charger functionality. If the inverters could communicate, and coordinate charging capability in parallel then you would gain redundancy.

If the chargers could Not be coordinated for parallel operation then I think the advantage wold be for a single inverter installation to utilize the larger charger capability built into the larger inverter/chrgers

Not all inverters are also battery chargers.


It would be simpler to have one inverter capable of handling all anticipated loads. Otherwise, you have to split up the wiring and transfer switches so that some loads operate from one inverter and others operate from the other.


For me, simplicity is best.

WesK said:

Not all inverters are also battery chargers.


It would be simpler to have one inverter capable of handling all anticipated loads. Otherwise, you have to split up the wiring and transfer switches so that some loads operate from one inverter and others operate from the other.


For me, simplicity is best.

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True, but in practicality almost all quality, permanently installed inverters used in a recreational marine enviroment are inverter/chargers.

Also, some inverters are stackable, in that they can have there outputs combined to increase capacity.

ksanders said:

True, but in practicality almost all quality, permanently installed inverters used in a recreational marine enviroment are inverter/chargers.

Also, some inverters are stackable, in that they can have there outputs combined to increase capacity.

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I don't think that is the case. Catalogs are full of inverters that are not also chargers. Sometimes, your boat already has a perfectly good charger and all you need is an inverter.

As far as stackable, perhaps high end inverters are. Lower priced ones are not.

It takes a very special inverter to be able to sync its output frequency with another one and not blow up when hooked up in parallel.

The bigger inverter will be able to run bigger than 1,800 watt loads, duh!!! But it will also be more efficient when it runs any smaller load. Inverters loose efficiency the higher their load percentage goes- bigger windings and components.

Other than some degree of redundancy with two that comes with complexity and expense, I would go with the bigger inverter. But if my biggest load was 1,800 watts, then I would only have one 1,800 watt inverter and bank the extra money for use if it craps out.

David

One inverter /charger. Buy a good one (Magnum Energy) and you won't need a backup. I use mine a lot when cruising including running a microwave and other appliances. I would rather have one big one generally running on half or less capacity, than trying to cook for 30 minutes or more at near 100% capacity.

Ted

O C Diver said:

One inverter /charger. Buy a good one (Magnum Energy) and you won't need a backup. I use mine a lot when cruising including running a microwave and other appliances. I would rather have one big one generally running on half or less capacity, than trying to cook for 30 minutes or more at near 100% capacity.

Ted

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I don't see where they have inverters only. I don't need a charger

I just installed a Kisae 2000 watt inverter from West Marine in my boat and am pretty happy with it so far. I do need to upgrade my house battery bank to make full use of it but so far so good. We ran fans and the new Magic Chef refrigerator over night on the hook successfully last weekend.

Kevin

For 3000 watts or less I'd go with one properly sized inverter or inverter/charger. Over 3000 watts I'd parallel two or more quality inverters. Victron Energy makes several inverter/chargers designed to parallel.

I would try and determine the typical usage, and the inverter(s) loss at that load. A lot of times a big one has more loss at 1/2 power than 2 smaller ones at full power.
Appreciable? Maybe, maybe not but losses cost battery time.


Another thought is the issue of neutral grounding in the dual setup. Will you be able to touch loads powered from each inverter at the same time? GFCI' outlets only test a single AC branch, they cant test 2 branches at once. Could be a possible shock hazard.

Semi-Retired said:

I don't see where they have inverters only. I don't need a charger

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They are sold as Sensata Dimensions, and available up to 3,600 watts from a 12vdc battery supply. Not much of a savings over their pure sine wave 2,800 watt inverter charger.

Why do you think you don't need a programmable 4 stage 125 amp battery charger for almost no additional money?

Ted

Our boat has two legs of 120v breakers, so I have two inverters Magnum 2812. I like the dual chargers putting amps back in batteries. It does give me some redundancy should an inverter retire early.

I can heartily 2nd the Magnum recommendation. We cruise full-time, our 2812 was some of the best money we spent on boat gear. It is fitted with the battery monitor, it's great for keeping on top of what's happening with the system. Wholesale Solar was the vendor, very happy with them.

As OC pointed out, the inverter/charger is less complicated, particularly with the functions you gain with the Magnum remote & monitor. A standalone charger can't be interfaced with the Magnum remote. If you install the battery monitor, it will monitor a standalone charger but only the voltage of the bank and amps in/out. Not nearly as versatile.

Keep in mind that every inverter has standby loss just being turned on. The 2812 is about 6A @ 12VDC. Two inverters will double that. That's around 140 AH per day! (less time powered by genset/engine charging).

Whether you end up with one or two, you should probably engage a good MARINE electrician to do the install or at a minimum, design it and finalize/inspect it. With the evolution of ELCI shore power protection, inverters can create a nuisance trip if there's any sort of co-mingling of neutrals/grounds.

Semi-Retired said:

I don't see where they have inverters only. I don't need a charger

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We had a decent working charger...

But as I've added (and am still adding) battery capacity over time, when it came time to add an inverter... it became useful to make that an inverter charger.

I have two main battery banks, so the original charger now services only one of those banks, and the new inverter/charger services the other bank.

Even so, I still don't have enough charging capacity to exactly match the battery manufacturer's optimum recommendations abut charging capacity, on either bank. I'll be closer on the bank with the new inverter/charger, once I replace those batteries this year. I'll be closer on the other bank when I eventually replace that charger... assuming it craps out sometime... but in the meantime, we'll be close enough.

Just some thoughts...

-Chris

I am a two inverter/charger proponent (for my situation). I use the two chargers daily to cut generator run time (200 amps output when combined).

Since we cruise where the local power is 240 European, I use one charger/inverter for charging as it accepts European power and the 50 hertz frequency, and the second supplies North American 110 and 60 hertz throughout the boat.

My third use (not needed so far) is as a backup if the normally used inverter fails.

Bay Pelican said:

I am a two inverter/charger proponent (for my situation). I use the two chargers daily to cut generator run time (200 amps output when combined).

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That's an unplanned benefit to our having two chargers now. That should mean we can take better advantage of the higher AGM charge acceptance rate... so our normal 2 hours of genset charging in morning and late afternoon can have a much greater effect.

-Chris

IMHO not about redundancy but efficiency. Some inverters have a idle draw that is proportional to the the capacity. All inverters operate most efficiently at near peak.

400W - 600W guy to run more constant loads (for me really just the laptop and wifi booster) then however many kW unit to run peak, with an easy to get to on-off switch.

PS: getting chargers to coordinate together outside the bulk phase that aren't designed to do so is non trivial.

Some inverters have a idle draw ..............

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They all do but some have an available remote switch so you can turn them off when they are not needed.

I have 3000 watt MSW inverter, it runs everything except the heat pump.
I have a second small inverter wired into the outlet circuit from the electrical panel with an DPDT on-off-on 20 amp switch. So I can if everything sort of dies, have some AC for lights, etc..., completely isolated from all other AC power sources and wiring if need be, like who knows some weird catastrophe.

What this does is switch over to the small inverter all AC power to outlets or in center 'off' position, all outlets are off, or back to other side of 'on' whatever power is incoming going to all outlets, as from shore, gen or 3000 watt inverter.

I have all outlets on one 20 amp panel breaker. Except microwave and the fridge which are each on their own circuit breakers.

kev_rm said:

PS: getting chargers to coordinate together outside the bulk phase that aren't designed to do so is non trivial.

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To avoid the two chargers conflicting I installed a Blue Seas Remote Battery switch so that I can divide the house bank into two banks when charging from the generator. Each charger charges six 6 volt batteries.

I think you really need to ask yourself how important redundancy is. If you can live with a failed inverter until it can be replaced, I'd just get one. It's less space, less cost, less wiring, fewer fuses, etc.

But if redundancy matters, I'd install two specifically for that reason. Outback, magnum, victron, mastervolt can all operate in parallel with no issues. You get a better, more capable product, but it costs more.

twistedtree said:

I think you really need to ask yourself how important redundancy is. If you can live with a failed inverter until it can be replaced, I'd just get one. It's less space, less cost, less wiring, fewer fuses, etc.

But if redundancy matters, I'd install two specifically for that reason. Outback, magnum, victron, mastervolt can all operate in parallel with no issues. You get a better, more capable product, but it costs more.

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What we have right now is an inverter bypass switch for the loads, and a backup 40 amp charger.

If the inverter faults out, we just start the generator and turn a rotary switch to the "inverter bypass" position.

I have an OEM Charles 80 amp charger. I added a 2000watt/100amp Magnum Inverter/Charger. They can both charge the same bank at the same time. I have accidently deeply discharged the house bank(inverter set cutoff at 35%). When I turned on the "extra" Charles charger I could see 180amps into the batteries at the BMK. It actually was a little above 180....with cooling fans humming!!! I do think the Charles cut out when the absorption phase started but not immediately. I think the Magnum could handle all of the absorption charge needs so no need for the Charles to hang around.

AGM batteries actually need a good hard fast charge to help in desulphation since they do not vent. So I did not feel so bad for my mistake.

BTW, y'all keep mentioning the basic needs/uses of an inverter....no one mentioned the ICE MAKER!!!!! Come on now!!!...

twistedtree said:

I think you really need to ask yourself how important redundancy is .................

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There is a point where we cannot duplicate every mechanical or electrical component on our boats. We have to consider the possibility of failure, how critical the device is and the cost and space of the duplicate component.

Would a failed inverter cause you to cancel your cruise? Leave you stranded somewhere? Is it worth $1K to have backup for your inverter? Is your inverter really that unreliable and subject to failure that it needs a backup?

We have to answer these questions for our own situations and our answers will sometimes be different.

WesK said:

There is a point where we cannot duplicate every mechanical or electrical component on our boats. We have to consider the possibility of failure, how critical the device is and the cost and space of the duplicate component.

Would a failed inverter cause you to cancel your cruise? Leave you stranded somewhere? Is it worth $1K to have backup for your inverter? Is your inverter really that unreliable and subject to failure that it needs a backup?

We have to answer these questions for our own situations and our answers will sometimes be different.

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Agreed. Those are good examples of the questions one needs to consider when determining how important redundancy is.

I installed my first second inverter when my inverter failed the morning I was flying home for a week of work leaving my wife on a mooring ball in the harbor on Staten Island. At that time we had 110 refrigeration. It would take several days to repair the non-functioning inverter. Cost of dockage in NYC for eight days was a good portion of the cost of the new inverter so I opted for a second inverter. When the first one was fixed I installed it as well. Have continued with two inverters since then. Of course down in the Eastern Caribbean it is more important to have a backup as replacement and/or repair will take significant time and may require changing countries.

ksanders said:

What we have right now is an inverter bypass switch for the loads, and a backup 40 amp charger.



If the inverter faults out, we just start the generator and turn a rotary switch to the "inverter bypass" position.

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That's a great example of how to handle an inverter failure. Just run the generator. If you are OK running the generator for the rest of your trip and/or running without AÇ power, then I wouldn't feel a need for redundant inverters.

But what if you need AC all the time for basic boat operation? And what if you need to run for a month before the inverter can be repaired? Then redundancy starts to look more worth while.

Baker said:

I have an OEM Charles 80 amp charger. I added a 2000watt/100amp Magnum Inverter/Charger. They can both charge the same bank at the same time. I have accidently deeply discharged the house bank(inverter set cutoff at 35%). When I turned on the "extra" Charles charger I could see 180amps into the batteries at the BMK. It actually was a little above 180....with cooling fans humming!!!

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Similar situation on our previous boat. Wife hated the generator run time, so we stacked a Magnum ME 2012 on top of our MS 2812 just for the charging capabilities. The Magnum folks were a little nervous about it and had us de-rate the 2812 somewhat to balance the outputs. We turn off the 2012 when we get to the absorb phase. We've seen 190+ at times.