Induction cookers,fridge advice please

[delcrest]

Hi, I am currently in the process of doing a complete refit on a 12 meter cat, and would like to hear from fellow cruisers the good and the bad on my items below
1) induction heated cookers, ( adjustable heat range 400w to 2000watt current consumptions rises accordingly) obviously power hungry, but with Balmar alternators and smart chargers , 750 watt PV cells and a 750 amp/ hour battery bank 3 kw inverter think it could be done. Is anyone using induction heating and are you getting interference from the cooker i.e. RF noise etc on VHF / UHF radio, AIS, etc
2) most cruisers I believe use the microwave to store electronic item during thunder / lightening storms etc, would it not be better just line a storage locker on all sides with this s/steel , all sides electrically connected together , and grounded, to form a solid screen, to hold all items i.e. handheld GPS, Radio’s ,laptop, WI-FI modems etc etc
3) Small domestic refrigerator (220 watt 220v @.75 amps) rather than a Marine unit, which is 25% the cost of marine version, and cheap enough to dispose of and replace if gave problems after a while.
Thanking you all in advance

[dlymn]

Sailors tend to be energy misers and set their boats up to reduce electricity consumption to as little as possible. Gas cooking makes no demands on your batteries and a gas bottle lasts a long Tims. Gas is an energy dense storage system batteries are not. We use induction when we have shore power but really doesn't offer anything more than gsas. except we can carry the induction cooker outside.
Front opening fridges place greater demands on batteries compared with top loaders and their might be a risk of spillage in high seas.
Storage of gear in microwaves and ovens is more about using idle space that is storm safe than anything else. Most boaters wouldn't want to setup a dedicated storage space solely for the occasional lightning storm when general storage is usually at a premium on boats. Underlying all of this is setting up a boat for water sailing">blue water sailing. Now for coastal cruising, anything goes.

[onestepcsy37]

Small domestic fridge. Here in the USA they are known as 'dorm' fridges and cost about 10% of what an even low cost fixed marine fridge system would. One of our regular contributors - sailorchic34 - has such a setup (cheap 120v fridge and small inverter to power it from the battery bank) and she swears by it. And since she's an electrical engineer I tend to believe her.

If i hadn't already installed a marine fridge ten years ago I would be inclined to do the same....

[four winds]

A "dorm" fridge works fine for me as a live-aboard. Cost $78 new but it's the tiny one and all I need. Three years old now and working fine.

Must always remember to strap the door closed while under sail though. Forgot that a couple of times with predictable results.

[sparrowhawk1]

To answer your questions I would need to know how long you are going to be anchored vs. Tied to a dock. If you're planning on spending most your time at Anchorage using your main engines for charging is probably the worst way to go. With a cat you have plenty of real estate to put vast numbers of solar panels. windgen and small gen if your demands are very high. I think you're mistaken about your dorm fridge using.75 amps. I have used a dorm fridge in the past and currently own an Engel. That's a super efficient fridge that has one moving part. The simple answer is if you plan on using a generator or an engine to regularly charge batteries it might make sense to get a inefficient refrigerator but if you want to run it on solar and wind then the Engle (or equivalent) is well worth its money. Now a funny byproduct of having enough solar to get you through the cloudy days is sometimes having excessive solar on the sunny days. if my batteries are fully charged and then I have a sunny day I use my excess electricity on my induction cooktop or I use my food dehydrator but it's as a by-product it's much more efficient to use propane the rest of the time. Edit your .75a 220 sounds accurate. I didn't take the time to convert to 12 volts and I'm going to be lazy and just do a rough estimate of that being about 15 amps at 12 volts. that's a lot of electricity. And they're usually not well insulated so it's going to run more than 50 percent of the time. once again rough estimate. And you're going to have to have your inverter on full time which is probably at least another amp and you'll have to add inverter in efficiency which is at least 10%

[Austin]

Take a look at the Sundanzer refrigerators. They are top-opening, made for off-grid use and are very well insulated - best we could find. We have been very happy with ours. We tried an induction cooktop, but could not get it to operate reliably with our inverter. After the first one we got didn't work we talked with the tech staff for many different units and most commented that they may not work properly with an inverter. If you choose to go with an induction cooktop you may want to check on compatibility with your inverter first. Good luck with your refit.

[onestepcsy37]

Originally Posted by four winds

A "dorm" fridge works fine for me as a live-aboard. Cost $78 new but it's the tiny one and all I need. Three years old now and working fine.

What size inverter are you using? What is the smallest inverter that you think you could use?

[Agility]

Seems like too small a boat to justify but I'm planning something similar on a 47 cat.

1100 Watts of Solar Power = 350 Amp hours per day on average good day
SuperWind = 96 Amp hours on average good day
2 high output 165AMP alternators for total of 2 hours or 1 hour each = 265 Amp Hours per day

So about 750 Amp hours production per day. More or less engine time.

Induction Cooktop 1 hour = 200 Amp hours
Refer/Freezer high efficacy = 350 Amp hours
Watermaker, oven (Panasonic 4 way convection/microwave), electronics electric grill = 150 Amp hours

So about 700 Amp hours of usage per day and I bank 50 amps.

2 Victron Inverter/Chargers for 6,000 Watt but redundant capacity.
Isolation Transformer

Up to an additional 250 Amp hours used while cruising that would require running engine for about two more hours.

No genset.
760 Amp LifePo Genasun, might add another 380Amp Genasun

It's crazy but I still like the idea of no propane and all electric except for main engines.

On a good day, we make power even maybe on a crossing. On a bad day, run engines for a total of 4 hours - ouch.

When I write it down, I say hummmm. Anybody living like this and happy.

[delcrest]

Originally Posted by onestepcsy37

What size inverter are you using? What is the smallest inverter that you think you could use?

The boat had a 3kw pure sign wave installed already.Tried it on a friends induction unit(which I liked the look of) and worked Very well ie.it heated water with ease and the require temp and power was easily controlled from the units adjustable controller
agree gas is cheap but with all the "saftey" issues and the price to install a new installation exceeds by far the price of a two plate induction unit
I believe there are different types of solar panels, which type is the best valve for money, I am thinking 750W with mot controller
Thanks to all those that have commented
Should have mentioned earlier, I am 64 years old and and don't have that much cruising time left, although I currently am fit and well still able to scuba dive, do difficult beach launches with a RIB off the south African coastline to Aliwal shoal which has gotta be up there with the top hardest launches in the world and our coastline
thanks again for the valid comments

[Fog Bank]

We have a small dorm style fridge as well. It works well for our needs.

[K_V_B]

To get an idea of what a certain appliance will consume don't just multiply the power rating with the time you use it. When you cook something you will only put the hot plate on full power to bring it to the boil. Afterwards you turn it down, or even completely off...

Reinoud Vader, the owner/ceo of Victron Energy, has written a good book on electricity on board. You can download it here:
http://www.victronenergy.com/upload/...limited-EN.pdf

Vader has induction cooker in his boat, and his measurements show that you need about 50 to 60 Ah (at 24V) to prepare a 3 course meal for 4 persons. If the main purpose of your battery bank is going to be to drive an inverter going for 24V is probably a good idea. Otherwise on 12 V you're looking at 100 to 120 Ah.

For details see the book I linked to.

[rbrentp]

Been going through the same process an a similar size cat. Could not find a dorm fridge that fit available space with more than two cubic feet. Power through an inverter got the OMG from just about every one I talked to. My cat had 8 X 6V US batteries so a lot of storage but the weight on board was terrible (over 500 pounds). I opted to rebuild the drop in (about 5 cubic feet) surrounded with R-20 and best I can tell runs well off solar. (300watts @ 12V). Reduced batteries to 4.
Stove went with Gas. Did some checking and couldn't find a lot of people used an oven, at least in our climate...too freakin' hot in the cabin. Looked at induction...great on shorepower but need one of a narrow set of inverters. Between the electrical supply issues, cost of 8X battery, etc. it was cheaper to redo the drop in and less hassle over time.
Gas stove-- Generator is out of gas- cloudy for three days--no wind-- gas still works.

Living with Murphy prevents me from putting all my eggs in one basket.

[Imprezza72]

As far as induction cookers, a cruising couple on s/v Sea Wolf had this happen at the beginning of their trip...

[rjdives]

I also chose when doing our refit to take out the gas and go all electric. Did induction cooktops and oven. Been using them for 2 years now and we love them. Also went with a front load fridge/freezer. Is was costly but well worth it. Stainless construction, very well insulated, locking doors, 12volt and 120ac. Added 2" more insulation with a 3.2ah draw average. Lithium bank, 930 watt solar, 400 watt wind and 3000 watt pure shine wave inverter/charger. Main engine twin 150 amp high output alternators with serptine belts. 3kw diesel generator that I can parallel with the inverter if I need the extra power. Did I mention washer/dryer to on a 42' cat.


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[delcrest]

Thanks for your comments, have decided to go induction (amps and temp. Control) and a normal top opening domestic freezer .75 amps@220v, both items cheap enough to dispose of and replace if problematic!