Inverter advice wanted

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Gene

We just bought a new (to us) Sailboat. 1981 Watkins27 Pilothouse Sloop. New 18hp Yanmar 2GM20F diesel engine. Currently it has 2 series 24 batteries, but I am going to add a 3rd battery, so I will have one series 24 starting battery and 2 series 27 house batteries. I want to add an inverter to run a small 600W microwave, 9" ac/dc TV/VC, and the usual smaller appliances. What size inverter should I get ?? 1000W, 1500W, 2000W ?? Any brands to stay away from ??
 
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Ed Schenck

Do you have a charger?

Love my Heart Freedom 20 Inverter/Charger. Runs all the appliances that you mention and keeps the batteries charged. See Link below. It canNOT compensate for the very high amps of AC appliances. Fifteen minutes of a microwave away from shorepower will cost you 10-12 battery amps. A hair dryer maybe twice that much.
 
Dec 2, 1999
15,184
Hunter Vision-36 Rio Vista, CA.
You may want some more power.

Gene: You may want some more power. You can eat up a battery in short order by not having enough capacity. Check out your total requirements before you decide on which batteries and inverter to get. Check out the Xantrex/Statpower site. They have inverters, charger etc. They also had some packages (including the microwave) that you can look at.
 
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Derek Rowell

Battery drain

Remember that 1200 watts is 100 amps at 12 volts. Thats a huge amount for a Group 27 battery (probably 105 amp-hour capacity at most). The common wisdom is that you should not drain a deep-cycle cycle battery to more than 50% of its rating - meaning that you would have at most 30 minutes at 1200 watts. Also remember that the amp-hour rating is based on a much lower discharge rate, so you may in fact have considerably less than that time. You would need at least a 1000 watts inverter to run a microwave. We have a 1700 watt inverter (Xantrex/Statpower) on our 42 ft. boat, with two 4D batteries in the house bank (400 amp-hours). Although we have a microwave we do not use it away from the dock on a regular basis. I recommend you think it through whether it is a good idea to marry a microwave to such a small battery. In my mind it is not a good idea... Derek
 
Jul 1, 1998
3,062
Hunter Legend 35 Poulsbo/Semiahmoo WA
Microwaves Like True Sine Wave

Microwaves, cell phone chargers, and some other electrical appliances like and some even need true sine wave current. We have a 600W Microwave run by a Heart 1000W inverter (modified step sine wave) but I have to run it at reduced 70% power. Any more than that and the Microwave "groans". If you want to set things up like at home the whole electrical system will need to be revamped: High output alternator and three-step regulator, battery cables changed to 00 or better, upgrade battery switches to high amperage, these are a few things I can think of. While the batteries you want "could" run the Microwave at reduced power it's going to be rough on them at best. I use 4 golf carts switched together and I know they're "working" hard. Remember that all the current that you demand has to go through the battery plates so that's a LOT of current per plate! What happens when the plates heat up? Charge Mode: Also, my inverter puts out 50 amps in the charge mode and a larger inverter will put out even more so the batteries will be stressed not only during discharge but again during the charge cycle. Some inverters may have the ability to decrease the charging rate which is something to check into. Based on my experience, four heavy-duty golf carts really isn't all that much and, for me, I wouldn't want any less ampacity for the microwave. Our cell phone charges on the Heart but not all do - something to check out.
 
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Larry W.

inverter

Gene; I agree with what's been said. Re-think your need for a microwave. We have one on our boat, but rarely use it. No hair dryer either.
 
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Don Alexander

Heart 1000W

I use a Heart 1000 Watt inverter charger and have a 600 Watt microwave. I do run the microwave on full power okay. Because the battery drain is about 75 amps I always run the engine at about 1250 rpm whilst the microwave is on - which is usually only for a few minutes anyway. I have the standard 55 amp alternator and it offsets the inverter current so the discharge is only about 35 amps. I know the figures don't quite add up but the alternator does its best! Have increased the batteries to 360 Ah to handle all this plus coldbox. What I have to be careful about is to ensure my immersion heater in the calorifier is off. That really does make the inverter groan and the current hits about 155 amps. Re the modified sinewave output from the Heart, I have not found anything that it gives trouble to. This includes a laptop, TV, mobile phone charger, battery drill charger, mains power drill, hairdryer, iron - we use a travel dryer and a travel iron which only take about 600W, toaster, sandwich maker etc. etc. but no kettle or coffee pot as these can take 2 KW. Today's technology is to go to pure sine wave but the modified seems okay. Also have a Link 1000 battery monitor which serves both domestic and engine batts (voltage only on the engine batt). Its worth its weight in gold.
 
Jul 1, 1998
3,062
Hunter Legend 35 Poulsbo/Semiahmoo WA
Check Out the Xantrex Web Site

As Steve suggested, the Xantrex web site can answer a lot of your questions about inverter selection. The link is below. "A modified sine wave inverter can adequetely power most household appliances and power tools. It is more economical, but may present certain compromises with some loads such as microwave ovens, laser printers, clocks and cordless tool chargers." http://www.xantrex.com/support/readfaq.asp?did=265&p=546 The main "product" url is below.
 
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Brian

microwave? TV?

I usually go sailing to get away from the house. Can't you turn off the TV for a weekend? I can't recall anytime on my boat I thought of watching TV. Maybe not having an inverter is a good thing. Maybe spend the money on a cooking without a Microwave class would be good too. Sorry, I just like it simple when I am on my boat.
 
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Andy Howard

can't leave home without it

Sorry Brian, but your post kind of made me laugh. While the idea of leaving the world behind is noble, in the real world or at least my little reality (or nightmare); the TV, along with a nintendo player, and a VCR, at least a crate of GI Joes, Dolls, Coloring books, Lego's, Pirate Ships, Soccer Balls, Kites, Hot Wheels, etc., etc. are as necessary as life jackets and flares. And while my little tribe or crew are not oblivious to whats going on, they love to steer, are learning the basics of navigation and sail trim and enjoy a sunset, a bald eagle diving for it's dinner, and dolphins dancing on the bow, it's just that their young minds need more stimulation. BTW, I consider the TV a very helpful tool on board during July and August. The local stations Doppler radar has helped avoid or prepare for many late summer squalls. Like Don, we have a 1000 watt inverter and usally run the engine while the popcorn pops but mostly use the Microwave while at dock. Gene, since you said the boat is new to you, I'd suggest you add the group 27 battery and anchor out a few times before buying the inverter to get a better idea of what you need and want while away from shore.
 
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Gene

thanks for the advice

Space-wise for batteries, I think I'm stuck using the 27's for now. I don't have room for 4D's. We've sailed for 15 years, locally and bareboat chartering in BVI's, Greece, and Thailand. We plan on daysailing, coastal cruising, and a few longer cruises to the Bahamas, and Cuba. Our boat has only a propane cooktop, and no oven. We will have a propane BBQ grill. We won't use the microwave a lot while anchored, but, it's quick for potatos, veggies and such. We won't cook meals with it. We enjoy a TV for the news and weather, but we're not after a steady diet of TV while sailing. A 5" or 9" will certainly suffice. I have a friend who has a 45" bigscreen TV on his 36' EndeavorCat!! We don't use a hair dryer. We recharge camcorder and digital camera batteries. I think we could get by with a 1000W inverter, but, prices are still good for 1500W-1800W.
 
Dec 2, 1999
15,184
Hunter Vision-36 Rio Vista, CA.
Check out Grp 31 too.

Gene: You may want to check out Group 31's. A little more power in the same size case.
 
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