120 Volts away from shore power

[Jaspell]

I have what is probably a very dumb question. When I upgrade to a larger boat, either in Island Packet 31 or 32 or a mid 30's Cabo Rico, I plan to do the ICW and hopefully some offshore work to the Bahamas or farther east into the trades.

The boat would likely have a single 100 watt solar panel, at least based on most of the boats I am looking at. Most of them also seem to have a 1000 watt inverter. My dumb question is,while away from the dock, is there a way I can use 120 volts to say, run a microwave for 5 minutes to heat a meal, or charge a cell phone or laptop without killing my batteries? How do I do that, systems wise? My gut tells me no, but my head tells me ask CF and see what people say.

[skipmac]

That's pretty much the deal. Might want to check the power requirements of the microwave and make sure the inverter you buy can handle it.

Second part of the solution is to have enough battery to supply the power for whatever it is you want to run. Microwave sucks a good bit but it only runs for a couple of minutes so not a big problem. Charging phones take longer but used very little power. Some laptops can use a bit more so depends on how much you would use it over the day.

The secret is to work up an energy budget. Add up the power requirements for everything you plan to run. Then make sure you have enough battery AND enough charging to keep them going.

[K_V_B]

I always found this on line book very helpfull:
http://www.victronenergy.com/upload/...limited-EN.pdf
Basically contains most what you need to know in order to estimate your energy needs, and determine how to meet them.
It's by the guy who owns Victron Energy. He's Dutch, so his examples assume 220V, but I think it is useful for 120V country as well...

[smac999]

You might need a 2000w inverter for Mircowave

Charge cell phones from battery through 12v cig plug. Using ac is a waste of power

You need a decent size battery bank (400ah min)

[Cheechako]

Yes, just use the invertor for the micro wave, when the morning's starting to heat up, it's handy for heating a cup of water for tea or oatmeal etc. I used a MW on a 1000 watt freedom invertor way back when.... albeit a small MW... Keep in mind you should have a good size battery bank for the invertor loads....

[skipmac]

Just keep in mind, unless you have an AC generator, everything electric you use will ultimately go back to the batteries. So when calculating the 120V AC loads you need to also add lights, pumps and everything else you will use when you decide how much battery capacity you need.

Also if you have an inverter make sure you hook it up with large cables.

Second the recommendation to use DC cigarette lighter plugs for cell phones and laptops. Much more efficient.

[SV THIRD DAY]

As much as I hate to admit it...we have a 700w Iron aboard that we use through the inverter while living without shore power on the mooring. I tell my wife to just show up at work with winkled clothes but I do like the microwave (750w unit) so fair is fair I guess.

Nothing can quite kill a battery bank as big heavy loads, so if you want to make some microwave popcorn...do it when the engine is running putting power into the batteries.

[onestepcsy37]

what everyone else says.

get the biggest box of golf cart batteries you can comfortably hold.
get appliances, like microwaves, that use the least amount of power to do what you need.
get the smallest inverter that will handle all the devices that will be used at the same time.

get additional ways to charge the battery bank. remember that your biggest draw will probably be your refrigerator, and that runs on/off all the time, although not off your inverter.

we use solar panel, honda generator with large battery charger, and main engine. i have a 700W inverter because that will run my power tools and shop vac, but not my wifes hair dryer!

[Stu Jackson]

You mgiht want to read the Electrical section here:

West Advisor Articles | West Marine

What one needs to do is to design & install a balanced electrical system: batteries for storage of energy, solar/shorepower/alternator for charging, DC loads and AC loads from the inverter take energy OUT of the batteries.

The link in reply #3 is also excellent.

[leftbrainstuff]

Microwaves are a huge power hog and are very non linear in their startup power requirements. You'll need a decent sized house battery 600+ A and a decent inverter say 2000+ W. We prefer gas for cooking. 2 gas bottles last us 6 months and we cook everything.

There is very little need for always on 110V these days. We charge and run everything off of 12V including a NAS, directional wifi and an internal network. We run 12V to 110V 300W inverters to charge laptops and run the tv when on the hook. This removes the always on parasitic load from our 3000W inverter providing 110V to the outlets 24/7.

If you can fit enough solar 300+W you'll find you can avoid running a generator most days.

Sent from my SM-N900T using Cruisers Sailing Forum mobile app

[dlymn]

Start with inverter rated at twice the maximum of your largest load. So 1000w microwave
, 2000w inverter. This micro will use 100-150 amps of 12 volt power to operate for an hour, so 8-20 amps for 5 minute. Including inefficiencies. That's replaced with 1-3 hours of solar charging or running the engine for up to 20 minutes
We do our energy demand stuff as we head out to the wind after an anchorage. The motor also heats the water and so it' s time to top n tail. In the Med, there's always motor time.
We even run a washing machine then. It's rocky sometimes, but it works.
For cooking or boiling, gas is the way to go.

[rwidman]

Originally Posted by smac999

You might need a 2000w inverter for Mircowave

Charge cell phones from battery through 12v cig plug. Using ac is a waste of power

You need a decent size battery bank (400ah min)

That is pretty much how it works. Look on the label on the microwave. What you need to know is the power consumption of the microwave, not the "cooking power". For example, a microwave advertised as "1,000 watts" will consume close to 1500 watts of power.

On my boat I do much like what the OP is considering doing. I have a 2000 watt inverter and a 400 AH house battery bank. I use the inverter to power the microwave and a coffee pot (but not at the same time). Keep in mind that you have to run the engine to recharge the battery bank and that you shouldn't discharge it more than 50% before recharging it.

[Cadence]

Originally Posted by Jaspell

I have what is probably a very dumb question. When I upgrade to a larger boat, either in Island Packet 31 or 32 or a mid 30's Cabo Rico, I plan to do the ICW and hopefully some offshore work to the Bahamas or farther east into the trades.

The boat would likely have a single 100 watt solar panel, at least based on most of the boats I am looking at. Most of them also seem to have a 1000 watt inverter. My dumb question is,while away from the dock, is there a way I can use 120 volts to say, run a microwave for 5 minutes to heat a meal, or charge a cell phone or laptop without killing my batteries? How do I do that, systems wise? My gut tells me no, but my head tells me ask CF and see what people say.

Sounds like you have received a bunch of good advice. The question may come down to no. of crew and the extent of your voyages, away from shore power. A 100W panel sounds very light to me if your relying on that alone.

[Mikado]

A common thread in most advice you have received is to plan for more power than you think you will use right now. Chances are you will add on to your electrical needs and you don't want to re-invest in your power related equipment. I would consider a wind generator as well as a solar panel so you can recharge 24hrs/day. Also, buy the best batteries you can afford. I have two 8D AGM batteries for my house bank which can provide 20 hours of 25amp power to my Heart Freedom 30 inverter, and with my AirX wind generator running I have enough juice to run fridge, freezer, AC, washer/dryer, watermaker, etc. continuously without worrying about over usage.