Inverter Recomendations

G

Gene Morris

New member
I purchased an inexpensive 2kw inverter at Harbor Freight. It lasted 4 months with minimal use. Could someone recommend a good inverter 2KW. I have 2 sealed start batteries and 4 6V golf cart batteries for the house. What should I look for when installing? How do you tell if you have a reverse polarity issue. I have looked at the Xantrex Prowatt SW2000 True sine wave 2000 watt. It seems to be in my budget, any advise would be appreciated.

Gene
 
OK, I've had an Xantrex PROwatt™ SW 1000 Pure Sine Wave Inverter for 10 years and it has worked well. I'd recommend it.

But, why do you need 200 watts? In line with my view of the C-Dory: less is more, what would you use 2000 watts for? And do you have the batteries to back it up? 2000 W (2 KW) requires 200 amps of DC current. I have a set of golf cart batteries and I can't support that load for long. Also, the 1000 watt (1 kW) inverter is 30% less, $150.

Don't forget to include the DC wiring from your batteries to any inverter. I use 30 ft (round trip) of 4 ga wire, since I mounted the inverter in the cabin and the batteries are in the stern. I notice that 4 ga tinned wire is $164 on e-bay, West Marine may be higher. Use an appropriate breaker and switch.

A sine wave inverter is great, I beleive HF only sells square wave inverters ("Modified" sine wave.)

Boris
 
Have you calculated your power needs and include inverter inefficiency?

Electrical tester (reverse polarity and other conditions)
http://www.homedepot.com/p/Klein-Tools- ... /203195018


a few years ago I bought a Whistler 1200 from Amazon . It stopped working and out of warranty but I contacted Whistler and they repaired and tested it along with paying for return shipping.

I thought of them like Tabman from Bennett tabs
YMWV
 
While the Whistler 1200 may be a great inverter, it's a "modified" sine wave inverter. I be3leive that's either a square wave or a stepped sine wave. Either gives a lot of harmonics, which produce an interesting hum at times. Best for charging devices.

They're cheaper than Harbor Freight, tho.

Boris
 
One of the best inverters on the market to day is the Magnum. This unit is designed and built by the guys who started Heart and Trace (which were then sold out). It is a quality item. I have the MS2012-20B 12V Pure Sine Wave Inverter w/ 2-20A Breakers in the transfer switches. 33 5 sec surge power (real watts): 3300 30 sec surge power: 3100 watts 5 min surge power 2800 30 min surge power : 2200 watts Continuous power output at 25° C: Battery charger is 100 amps and there is a generator auto start, as well as the ability to alter charging profiles etc. This is probably overkill for your purpose. You have to decide if you really need the sine wave or MSW. I swapped my modified sine wave out (sold it to a friend, for his large cruising boat and the switch only cost me about $200.

I can run 2 large TV's, two satellite systems, a sound system, induction burner, microwave and 22 cu foot household refrigerator all at once from this inverter. No problems in the 7 years I have owned it. This runs off a bank of golf carts/series parallel.

Some of the other units are now made in Taiwan or China--and the reliability has not been as good in the past.

The question is do you really need 2000 watts (surge to real 3300 watts)? A microwave or induction burner? This is the most common use of an inverter in a small boat. Do you need a switching unit for the 110 volt mains power?

In my Tom Cat, I used a 1200 watt inverter, and to keep it simple I used a separate plug for the microwave or induction stove. That is, I had parallel 110 volt circuits in the boat--so I could plug into mains power or the inverter power, and avoid a 110 Volt switching relay.

Mastervolt and Victron also make very good alternators and charger combos.

Most of the good inverters will detect and show faults on the remote readout.

One thing is to listen to a microwave which is running on a MSW, vs a pure sine wave inverter. I have heard that the longevity of the microwave is less with the MSW, vs the Pure sine wave.

My
 
Thanks for the replies;

I do have a strong bank of 4 6v golf cart batteries "series/parallel" that produce approx. 500AH of current. I also have a good xantrex stand alone 3 bank 20 amp charger. All wiring is complete to the faulty converter. I also have separate outlets for inverter power vs shore power. I will run a coffee maker, toaster oven and possibly a microwave. And not all at the same time of course. My understanding is that the coffee makers draw about 1300 to 1500 watts. What is your experiences, obviously I would like to get by with a smaller (less expensive) inverter.

Gene
 
ow, 4 golph cart batteries, 2 banks? I had 4 of those batteries on Our Journey, but could only fit 2 on Journey On. You can certainly support the 2KW inverter, but I hope your outboards are up to the recharge. Our coffee maker is a butane stove with a coffeepot and the Honda puts out 40 A.

Xantrex is the company that bought out Heart. They're a Vancouver company, mfg in China. Trace makes/made commercial products was my experience. Anyway, I bought the Xantrex inverter because I have a Xantrex 20 amp charger which is in it's second boat and has worked well since 2001. It's also been sprayed with (fresh) water when the water heater failed.

And Bob, where do you put those golph cart batteries in a 22? That must be a study in ingenuity.

Boris
 
The Kill-O-Watt device (costs about $18) will measure the amp, or watt draw of an appliance, as well as line voltage, and frequency. Thus you can find out exactly what amount of current draw your appliance uses. (It is also usually stamped on the bottom, or on a sticker).

Not sure if the "automatic" timed feature of the coffee maker will work on MSW--the resistive heating element works fine.

I would suggest getting an inverter with a good warrantee, maybe even the extended plan. I have had some of the more common ones fail--but that was a few years ago.
 
Boris;

I have the house batteries on the deck of the hanging locker in my Tomcat. Of course they are sealed batteries. The run from the batteries to the inverter is less than 4 ft of cable.

Dr. Austin;

The electric coffee pot shows power requirements of 1350 watt. Microwave oven and toaster oven are less..


I have time to figure this out. Our next big cruise won't be until spring next year, when Margaret retires. Summer in SE Ak. Fall & winter East coast of US.
 
There are a bunch of MSW, 1500 to 2000 watt inverters on the market. I had 1500 watts on my Tom Cat, and C Dory 25. I didn't have any problems with the inverters, but didn't use them a lot. (Two group 31 batteries, to keep the weight down). The reason I am hesitant to recommend products like Xantrex, (which I had) is that I have heard of problems with them, in the last few years.

My current Inverter is in the RV and I did a lot of research before I swapped out the Magnum MSW for the PSW. Failures seemed very rare. My micro convection oven is difficult to replace, as well as being expensive, that is one of the reasons I went with the PSW (as well as a plasma TV, and the satellite dishes).

I probably would go to the off the grid sights and see which inverters are most highly recommended. There is a good chance you can find one of the good MSW inverters which will be less than $400.

By the way, the 4 golf carts only give you a "usable" 220 amp hours (approx). But that is more than enough for a microwave.
 
thataway":38i63klj said:
One of the best inverters on the market to day is the Magnum. This unit is designed and built by the guys who started Heart and Trace (which were then sold out). It is a quality item.
Click to expand...

Agree with Bob, the original Trace invertors are the standard by which others are measured. I bought mine in 2002. I believe the name was sold shortly after. Mine is a SW2512. It includes a 150amp charger, auto gen. start, etc. The SW series is no longer made because it was not included in the sale and according to the agreement with the new owners, the former owners had to pay a royalty to the new owners for each SW invertor they made. This along with pressure from Chinese imports priced it out of the market. Mine was over $4,000 in 2002.

However, the point to all this is - I would not hesitate to purchase one used if available. I would actually pay more for a used Trace than a new Chinese. They have excellent surge capacity. Not sure about invertors but I have noticed that some of the cheap generators on the market now call themselves XXXwatts - but if you read the fine print that is the surge capacity and the "continuous" capacity is much lower. Rather deceiving. I have had my invertor rebuilt twice in 13 years. It is one of the only invertors out there that anybody will even consider rebuilding. Mine gets used daily(off grid house).

Regards, Rob
 
would a modified 1500 watt inverter be able to supply a/c elec to a 700 watt microwave .or should i look at a pure sign wave ?
Is amamzon a good place to look or home depot,Lowes etc
 
Modified sine wave inverters will run most microwaves, and 1500 watt should be OK for a 700 watt "Output". Microwave. Probably 1200 watt input. But the microwave will run a little more slowly and make more noise--if it is digital, the timer may not be precise--most of the MSW are pretty good.

I have run microwaves off both MSW and PSW inverters--I switched the one in my RV for a PSW because of the way the microwave sounded--but many run the same on MSW.

Where to buy--also what brand to buy? There are a lot of cheap Chinese units flopping around. I tend to buy from someplace you can get a warrantee, and good return policy.

Also read up on them on the off the grid and solar power sites.
I happen to use Magnum, but that may be overkill for the C Dory. Same with Outback Mastervolt and Victron. Xantrex some have had good luck with--There have been changes in the company thru the years.

Some of the C Brats have the less expensive MSW inverters, and can give you better info on these.

I think that Magnum
 
jennykatz":2l813paf said:
would a modified 1500 watt inverter be able to supply a/c elec to a 700 watt microwave .or should i look at a pure sign wave ?
Click to expand...

As far as output goes I don't think MSW or PSW makes a difference.

From my experimenting with invertors on my boat I have discovered 2 things.
1/ A good quality invertor will have good surge capacity.
2/ Most small appliances will rarely draw their rated wattage.

We always used a coffee perc on the butane burner. A few years ago I decided to try our Tassimo. Coffee grounds are messy on a boat and the Tassimo is all contained. My invertor is a 800 watt model I bought over 20 years ago. I believe it is a Pro Watt. The Tassimo is rated at 1300 watts. It has no problem running the Tassimo.

I am NOT suggesting people overpower a small invertor. It needs to be properly wired for the length of run, amps and should be fused on the input side at its max. rated input current. I don't know how many watts the Tassimo actually draws but it is very quick so the invertor only has to supply surge for a short period. My invertor is fused for 100 amps and has a readout for input amps. When brewing the gauge hovers between 90 and 100 amps but has not blown the fuse. We have brewed as many as 6 cups and the next morning the resting voltage of our group 24 house battery had not dropped even a 10th of a volt.

If I had to start over I would get a PSW invertor/charger.

Rob
 
Rob brings up several good points, in that one needs to know the actual power draw of an appliance. The best tool for this is an inexpensive meter called Kill-A-Watt.
7258d563-c895-4b93-a51e-96a0ee8c115c_1000.jpg This is listed at less than $20 at Home depot.

I always check appliances with this device. It reads volt watts, amps and kilowatt hours over time. Plus frequency in Hz and mains line voltage. It plugs into the 110V mains outlet, and then the appliance plugs into it. It may not reflect the surge current, but most inverters are meant to handle at least twice their capacity in surge. Fortunately for microwaves this is a factor of 2, but many appliances such as a refrigeration compressor have a factor of 5. The heating element in the coffee maker inrush current is very short as the heating element comes to temperature--in microseconds. Some appliances may take longer periods to come to full power, and thus the inverter may have to be sized larger and / or have a higher surge capacity.

The Killowatt hours gives some idea of how much it will draw from the battery over a timed period (multiply by a factor of 10 for an approximation of the 12 volts to 120 volts.)

Some quick reading on the Tassimo coffee maker shows that it only runs the element for 30 seconds--it that is true, then that is why the group 24 battery has not significantly changed....but I would never suggest a group 24 battery for a load of 1000 watts. This may also be why the 800 watt inverter has not failed. Overloading puts both the inverter and appliance at risk.

In less than 20 minutes 100 amps out of the group 24 battery would take it to 50% discharge point--and any more would be harmful to the battery.....(a voltage of 12.2 volts, resting.) (Capacity of group 24 is generally about 60 amp hours, 20 minutes of 100 amps about 30 amps.)

Also the wiring for an inverter must be very robust. For 100 amp draw if the inverter is 10 feet from the battery (20 foot round trip) you should be using # 2 Gauge wire, and if 110 amps then # 1 wire. When I put the 1500 watt inverter in the Tom Cat for a microwave, I placed two group 31 AMG batteries into the cabin, only a couple of feet from the inverter under the aft dinette seat, and used #2 wire for the short run of only a couple of feet to the fuse, and the inverter.

Like the Meter I mentioned above, the DC amp meter may not fully reflect the inrush or surge current.
 
Bob, thanks I will be looking into buying one of those meters. Last year I switched to a group 31 house and moved it over to the port side.

One note re. positioning an invertor: It is best to keep the invertor as close to the batteries as feasible unless you are using flooded cells which are charged at high amps and are kept in an enclosed, poorly vented compartment. In this case the invertor should be separated from the batteries as its cooling fan can draw fumes from the off-gassing batteries past its circuit boards.

Regards, Rob
 
In pure sine wave inverters the voltage is a sine wave (sin Θ). In the US, this sine wave has a frequency of 60 Hz, or 60 cycles/sec. AC appliances are designed and operate with this in mind, TV's, microwaves; things that really need AC.

Modified sine wave inverters are square waves, sometimes a couple of square waves superimposed. They also run a 60 Hz.

If you look at their respective frequency content, the pure sine wave has only one frequency: 60 Hz. That's what the appliance expects and operation is smooth. The modified sine wave, however, has not only the main 60 Hz frequency but in addition an infinite series of harmonics, that is frequencies that are multiples of 60 Hz: 120 Hz, 240 Hz, etc. These are of lower amplitude than the main frequency, but still there. The MSW has these frequencies to give the square edges in the wave form. Coffee pots have a pure resistance heating unit so they aren't affected.


So, if you run an AC appliance on a modified sine wave, the appliance is only built to accept 60 Hz and the higher frequencies are rejected by the electrical circuit. For instance a microwave will hum and bang; that's the higher frequencies causing "reactance" in the input. Since part of the inverter output wave is rejected the power is lower for a MSW, but maybe 10%.

It's raining outside, waiting to finish painting the boat bottom. Now I feel better.

Boris
 
I agree with Boris (and Grandma): "On a small boat like C-Dory, less is more."

Inverters have a voracious appetite* for DC amps. Kiss your battery(ies) good
bye much earlier.

Aye.
* Swallow without chewing
 
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