Best Inverter for the Buck

[mitiempo]

Originally Posted by 44'cruisingcat

No, they are rated for 15 amps. At 240 volts.

I wasn't aware what voltage you were wired for.

[prroots]

Yes, this thread has taken on a life of its own! I've finally gotten up the courage to draw up a rather crude hand-drawn schematic. Comments welcome
Pete

[mitiempo]

Looks fine to me except for the breaker mentioned and a chassis ground for the inverter.

As Maine Sail posted on Sailboat Owners the breaker should be double pole as it is a source.

[s/v Jedi]

This might come a bit late but the bext inverter for the buck is made by Sinergex imho!

These are pure sine for reasonable price and rock solid. They have conformal coating of the circuit boards. I have treated a 400W version really bad with wild overloads etc. The worst I did resulted in some internal fuses blown. I have that 400W version 9 years now.

I also have a 1,500W version which comes with a small remote control panel.

These units are available worldwide and some other brands relabel these. I think I even saw them in Mastervolt colors and labels.


ciao!
Nick.

[jzk]

So how about this for a three way automatic transfer switch:

Rapid Mobile 3 Way Automatic Transfer Switch

[Stu Jackson]

Pete's looking for a manual transfer switch, although that's not what he shows on his diagram.

[mitiempo]

Originally Posted by jzk

So how about this for a three way automatic transfer switch:

Rapid Mobile 3 Way Automatic Transfer Switch

A bit expensive.

[prroots]

I'm satisfied with the concept developed so far as exhibited above in my crude sketch and appreciative of the mostly positive contributions. I've received recommendations for everything from galvanic isolators to switches to inverters. I've learned a lot and hopefully, others have as well. At the outset I wasn't even aware that galvanic isolators existed I will definitely use the recommended switch and galvanic isolator. I'm still actively evaluating standalone pure sine wave inverters and this will be my primary focus going forward. These inverters are not marine grade and in most cases are not even designed for integration into existing AC systems. I justify this, in part, on the fact that the inverter is to be use in a non-critical application as opposed to electronics that provide navigation or communications. With this in mind, I will focus on finding reputable companies that stand behind their products and warranties. My favorite of the moment is Samlex America.
Pete

[foggysail]

I have friends who get along well with inverters from Harbor Freight!

[prroots]

Originally Posted by foggysail

I have friends who get along well with inverters from Harbor Freight!

Thanks. Good idea. We have one right down the street; I'll check them out. At a certain price one could consider them disposable!
pete

[prroots]

I came across something interesting in the manual for the Samlex ST1500-112. This is a 1500 watt pure sine wave inverter with hardwired AC connections and transfer switch rated at 30A. Here is the quote:

When the unit is feeding the internally inverted voltage (Power Status LED is green, power from the AC input source is not available), the current carrying conductors connected to the “L” and “N” terminals of the AC output will be isolated from the metal chassis of the inverter. Hence, during this condition, when the metal chassis of the inverter is connected to the earth ground, the “N” terminal of the AC output will not be grounded (bonded) to the earth ground. Under this condition, the “N” terminal of the AC output will not be a Neutral in the true sense. Do not touch this terminal as it will be at an elevated voltage(almost half the value the AC output voltage) with respect to the metal chassis / earth ground and may produce an electrical shock when touched!

When the unit is transferring power from the AC input source (Power Source LED is orange), the grounding condition of the “N” terminal of the AC output will be the same as the condition of the “N” terminal of the AC input source. If the AC input source is the power supplied from the utility, the “N” terminal would be a Neutral in the true sense, will normally be bonded to the earth ground and will read almost 0 V with respect to the earth ground. In this case, touching this terminal will not be a shock hazard.

The second paragraph makes sense, but what about the first one? The inverter intentionally isolates neutral from ground. I understood that neutral should be connected to ground at source? BTW, the manual states that this inverter is suitable for marine use although no mention of ABYC.
Pete

[prroots]

I have revised my standalone inverter design (see attached sketch). Some of the notable changes are:

1. Show AC transfer switch before AC panel
2. Show AC inverter output wire size as AWG 10/3 conductors
3. Show DC positive fuse close to battery as a 250 Amp class ANL fuse
4. Show DC cable wire size as AWG 2/0
5. Show galvanic isolator protecting two shore power connections
6. Show breaker sizes for all 3 AC loads

Most importantly, Maine Sail has convinced me to locate transfer switch before the AC panel so as to decrease fault potential. The negative is that it is now possible to inadvertently drain battery by feeding battery charger and/or water heater from inverter. The output cabling from inverter through AC transfer switch to AC panel has been sized in such a way that it is protected by the existing 30 Amp breaker (of AC panel) making it unnecessary to add still another breaker. Of course the wiring from AC panel to AC outlets will be protected by the existing 15 Amp breaker. The inverter itself will have overload protection. I have tentatively selected the Xantrex Prowatt SW2000 inverter. Xantrex recommends a 250 Amp fuse on the positive DC cable. I calculate that an AWG 2/0 cable of less than 3 feet length (one way) will be sufficient. Finally, I show a galvanic isolator protecting both shore power connections with rating increased to 50/60 Amps. Comments welcome.
Pete

[s/v Jedi]

Xantrex?! Do yourself a favor and check my earlier post for Sinergex. Will keep you happy

What size boat do you have? This silly iPad app I'm using shows nothing of that info...

ciao!
Nick.

[prroots]

Originally Posted by s/v Jedi

Xantrex?! Do yourself a favor and check my earlier post for Sinergex. Will keep you happy

What size boat do you have? This silly iPad app I'm using shows nothing of that info...

ciao!
Nick.

Thanks. Yes, I did read your posting. My selection came down to a choice between the Xantrex Prowatt SW2000 and the Samlex SSW-1500-12A. Both had almost identical specs and prices in the range of $350. The final thing that cinched it was that Samlex tech support told me that for my application I should buy a Xantrex or ProMariner. Since the ProMariner was much more expensive, that left the Xantrex. BTW, Xantrex tech support told me that they have had a higher than desired failure rate on many products as part of new product introductions. They are tweaking the manufacturing process to reduce the number of returns. Anyway, I'm definitely taking a chance. At least I will have a two year warranty and besides this application is non-critical to be used mostly for occasional use of a few galley appliances such as microwave.

Having said all of that, I'll take another look at the Sinergex inverters. West Marine sells the PS2-1500-112 for $700 which is out of my budget. I've had trouble finding any with greater discount. Do you know of a better source?
Pete

[s/v Jedi]

Originally Posted by prroots

Thanks. Yes, I did read your posting. My selection came down to a choice between the Xantrex Prowatt SW2000 and the Samlex SSW-1500-12A. Both had almost identical specs and prices in the range of $350. The final thing that cinched it was that Samlex tech support told me that for my application I should buy a Xantrex or ProMariner. Since the ProMariner was much more expensive, that left the Xantrex. BTW, Xantrex tech support told me that they have had a higher than desired failure rate on many products as part of new product introductions. They are tweaking the manufacturing process to reduce the number of returns. Anyway, I'm definitely taking a chance. At least I will have a two year warranty and besides this application is non-critical to be used mostly for occasional use of a few galley appliances such as microwave.

Having said all of that, I'll take another look at the Sinergex inverters. West Marine sells the PS2-1500-112 for $700 which is out of my budget. I've had trouble finding any with greater discount. Do you know of a better source?
Pete

I know that the best way to kill your budget is to buy a Xantrex. You will so regret that, I would almost give you the difference with a Sinergex to save you from that. Search CF for the Xantrex problems and the opinions of all the engineer members here. Buying it means loosing the $350.- and warranty does NOT help.

Never ever believe (or even listen to) people who will take your money when you buy the product. They will never tell you what is best for you; only what is best for them. Head the warnings by those here who have nothing to gain financially from whatever you choose!

I have not even heard of Samlex and not much of ProMariner either. To make it simple: Victron, Outback, Mastervolt, Sterling, Sinergex. May be Sterling belongs higher on this list. Start with the first name and check if they have what you need and if it fits the budget. Go to next name if not. If you end with Sinergex and still not suitable, then it is better to end it there. Wait another year or how ever long it takes.

Whenever I am faced with budget constraints, I buy less items, not the same amount of bad or even lesser quality. It's cheaper.

cao!
Nick.