Pushing the limits of electric cooking

[StuM]

Originally Posted by Na Mara

I’ve given up on correcting people. Now I just translate what they have written into its least idiotic form and reply to that. Hopefully they do same for me.

The problem with that is that it encourages the sloppy misuse and results in more confusion through inexperienced people misunderstanding the basics and getting concepts wrong.

[hpeer]

Originally Posted by StuM

A meaningless statement!
This is why I keep on going on about units!
They averaged 465/400W in what time frames?

Is that the average of the highest peak output each day?
Or is that average over a standard time period.

A combined average of 432.5W ((465+400)/2) over the peak period 2hrs either side of noon would be possibly a total of around 2500 Wh per day.

An average of 432.5W over approximately 10 hours of daylight is 4,325 Wh per day.
An average of 432.5W in each 24 hour period is 10,325 Whper day.

(Or do you mean 465 Wh + 400 Wh = 865 Wh total per day.
Which would suggest maybe 30-40% of expected ouitput for 610 W at that latitude at that time of year in good conditions.)

Stu,

You are correct and I was sloppy in nomenclature.

It was WH not W.

So yes, 30% to 40% of expected in good conditions.

Please read my further explanations on why that is so.

Yesterday my production was 1,250 WH, even with normal cloud cover and some shading the batteries went out of bulk charge. Why so much higher? Someone accidentally changed the thermostat setting in the fridge which then ran far longer than normal, left more room in the batteries for more coulumbs of electrons. But no harm, it was windy last night so the wind gen actually held the load and charged a bit.

The average is total daily production over 30 days. The one panel gets some more shading than the other (wind gen and RADAR) depending upon how I lay relative to the sun. Peak on port is 189W, Starboard 219, HOWEVER I have seen much higher on both, very near theoretical max, with each panel producing over 1WH in a day.

The point remains, just because I have the CAPACITY to produce X amount does not guarantee I WILL produce that. Lots of squishy factors when looking at actual, on the hook, conditions. Moreover, I have SUFFICIENT capacity so that I only run the generator when needed for prolonged tool use.

[Pelagic]

Originally Posted by Na Mara

Om not arguing that induction is not more efficient. It is, but you are incorrect about there not being thermal losses from induction.

I am pretty sure with a gas flame that requires fresh air to combust the thermal transfer to surrounding air is considerably higher than induction. My comparative experience in the tropics with a gas stove and now induction only confirm that

[Pete7]

Originally Posted by Na Mara

It would have been great if there existed a gimbaling electric cooker 45cm in width with in built combi microwave convection oven WITH induction, but that product doesn’t exist so I settled for a little less hob efficiency to get everything else.

That's a real shame isn't it. I might suggest to Bolton Leisure they make a narrower double hob. They produce the Plastimo range of gas cookers often re-badged under other names.

Induction hobs

That Techimpex 2 does look nice though, but the price at E5800 ouch

The other thing to look at is other appliances. Whilst we have a 2kW kettle at home, on board we have a tiny 0.8L Russell Hobbs 1kW kettle. Half filled this is just the right amount for two cups of tea and draws 75A at night, less during the day any solar is used first to offset the draw from the batteries. You can see this on the inverter which draws say 65A instead. Use the kettle 9 or 10 times a day and it starts to mount up, so the little kettle encourages us to boil just what we need. Its also surprisingly stable when sailing:

https://www.argos.co.uk/product/4821...kettle:7:126:1

Add a small toaster, and sandwich maker again using less power. We are just thinking about this little rice cooker after recent posts on here were people said they were really good. Just can't work out if 1 cup is big enough for the two of us. That should be 280g which is about the size of two boil in the bag rice packets we normally use. Power is 250w and takes about 30 minutes, so a tiny amount. Set it off and then make the curry or chilli on a portable induction with a pan and lid (very important) and the amount of power needed is tiny.

https://www.lakeland.co.uk/62569/lak...ic-rice-cooker

[Loredo]

In my quest to find a induction hob that I could possibly have "sit" on top of my already existing gas one (build in would be nicer) I found this:
https://www.fosterspa.com/en-ww/cook...aspx?ndomain=6


Thought I'd share because it seems to me like it could be a very good candidate at an (almost) reasonable price. +/- 400 boat bucks.

[Na Mara]

I’m reviving this thread as I have had an idea and I want to test it on the forum.

So the 3.7kW cooker is arriving shortly and the 2.4kW inverter is having its last kink worked out by a Victron specialist so my whole new electrical system goes live in a few weeks. Now I had thought To deal with the mismatch in output from the inverter with the cooker by just load managing. The cooker has two 1.2kW hobs and a 1.3kW microwave combination oven. The jobs are resistance heaters so I should be able to use two of the three at any one time so long as they aren’t on full bore.

But then I got to thinking, what if I have a 1kWh power station on board as well. Then if I want to do heavy cooking I plug the thing in to the shore plug. With the cooker and the inverter on the Victron multiplus should use it’s pass through feature to send the 1.8kW at 230V ac from the power station directly through to the cooker, and if I then exceed what the power station can provide the Victron should then go into power assist mode adding another 2.4kW of power.

Unless I am missing something that should give me a full 4.2kW of ac power for about 35 minutes. It should let me run my cooker at full chat on the rare occasions that is needed even off grid. It’s a little bit of faff and the power station would need recharging off the inverter (or from its own panels) but it would also give me a totally separate backup electrical system.

Maybe I’d need a bigger power station, say 2kWh.

Of course I could just get another multiplus and parallel it to the existing one for the same money but the electrical cabinet is getting pretty packed and I’m running out of easy hookups on the distribution system. A power station just seems a much easier solution and it increases the amount and flexibility of my battery storage.

Anyway.
1. Would this work?
2. Is it optimal?

[Dockhead]

In my humble opinion, that's not a good idea.

Making up for lack of inverter capacity, by adding a large power station? Large power stations are something of fire hazards -- not a joke on a boat -- and it would be a lot of faff to charge and recharge one just for cooking, store, etc.

You've got enough battery capacity, why complicate it like this? Add inverter capacity if what you have is not enough. Victron charger-inverters can be ganged -- you can add another identical one and connect them together for double the output. Or just change your 2.5kW one for a larger one.

Do it right. Doing it right is always better in the long run.

You have a generator, don't you? If you don't want to add inverter capacity, why not just run the generator if you have heavy loads? One reason why I find electric cooking to not be a problem power wise, is because like most cruisers I time my generator runs to coincide with times of heavy loads, which for most is dinner time. I do laundry, make hot water, cook, charge batteries -- all at once during this time. When the cooking if finished, shut down the loads, shut down the generator, and have dinner. That way you don't touch your batteries during this time, which is a good thing (if you're using lead-acid batts as I am). I have the Victron Multiplus 3000/70/24 charger inverter, which doesn't manage much more than 2kW continuously (it is rated very ambitiously), and it's not been a problem, as cooking loads are light when the generator is not running.


EDIT: I seem to recall that you have lithium batteries. Lithium doesn't mind putting out current at large C rates, and doesn't mind charging at high C rates, so you want more than 2400 watts of charger/inverter in any case. Is that a 3000 VA model like mine? You can add a second one and gang them together, or replace with the 5000 VA model. You will not nearly realize the potential of lithium batteries with only 3000 VA of inverter.

[Russ]

Pardon My ignorance but Na Mara said they had access to shore power.
I assume there is a reason that they don't just cook using AC at the dock they never actually said that the concern was ONLY at sea re the need for the power station. If you can charge the power station to cook via shore power why not just plug it in period.
I quote:
But then I got to thinking, what if I have a 1kWh power station on board as well. Then if I want to do heavy cooking I plug the thing in to the shore plug.

I'm French and not too bright,Ha!
Russ

[Na Mara]

Of course when I have shore power I will just use that with the power assist on the inverter, being careful to disconnect the immersion heater so as not to blow shore fuses. But I meant that I could plug the power station into the shore power socket aboard to mimick having 8A of shore power even when not being on shore power.

Dockhead, I do get that I can parallel another Victron multiplus 3000 12V to the existing one but I would then use up the last two attachment points on my distribution system (I have a lynx distribution system with 8 attachment points for loads and chargers). I would then not have an easy option for connecting my new solar panels or other chargers. I could work around that but it’s neater not too ( and there is no space to extend the distribution system). I would probably also have to site the second inverter charger in the engine room with all the concerns that raises as it won’t fit anywhere else. In short J have my reasons for wanting to avoid a second inverter, particularly as it will be rarely needed.

I had not heard that LFP power stations were anymore of a fire risk than the 600Ah of LFP batteries I already have aboard.

I don’t have a generator. I could use a portable petrol generator instead of a power station, but it is loud, less reliable, and smelly. I would also have to ship petrol. Cheaper though.

Fitting a generator is very expensive and it would have to be a very small one to fit in my engine bay ( less than 48cm x 50cm x 95cm breadth, height, length). If I can avoid doing that I will.

[Dockhead]

Originally Posted by Na Mara

. . . I had not heard that LFP power stations were anymore of a fire risk than the 600Ah of LFP batteries I already have aboard.. . .

If the power station is LFP, then you're right and it's not more of a fire risk. Most of those are lithium ion, however.


If you can't add an inverter, I would just change it for the 5000VA model. The 3000VA one is obviously not big enough for your use case. This is the fundamental problem, and all these workarounds will not be a satisfactory solution. Do it right!

[JPA Cate]

Nice to see you back, Na Mara.

Imo, you should be paying more attention to what hpeer was trying to get across: that the weather gods do not always give you maximum output from your solar panels. They are affected not only by shading (which will lower your output always); they are also affected by cloud; and by dirt (just one cormorant defecating will take out a few cells till you wash it off--sometimes rain is your friend even though they may not put out anything in the rain--but it also keeps you from having to climb up to wash and rinse the solar panels.) Weather you experience over a year at sea can hand you surprises. We were navigating by celestial when we had 14 days and nights at sea, with no opportunity to get a sight due to overcast, getting nervous as we approached the west coast of the US. Your assumption of enough storage to get you 3 days would have had you not cooking for a long time, to say nothing of a hot beverage or two or a duck bath.

Still my opinion, but I think Dockhead's suggestion of the bus alternator should not be ignored, either, as it is an inexpensive addition that can really help you, and not a huge effort.

Finally, some energy spent in terms to considering how you can adjust the panels to take advantage of lower angle light than at midsummers day, will also help a lot in spring and in autumn. Our solar panels on our previous boat were more adjustable than on this one, and being adjustable proved itself to be quite useful to us.

Good luck with it.

Ann

[Na Mara]

I’m not totally ruling out the alternator upgrade Ann. It would involve a belt upgrade. I want to see how much I use the engine for charging once set up before doing this.

My present plan for panels is 220W of panels that can be orientated to any sun angle on two axis. 220W of panels that can be tilted on one axis. All of these are to be fitted to the pushpit. Then 200W of semi flex panels on the pilothouse roof. 640W total. I’ll max output with individual controllers and panel orientation and see how far that gets me.

Doing a bit of research into the power stations there is the Bluetti ac200max with 2kWh LFP battery and 2KW output. I could wire that up so it charges off the inverter and feeds into the 230V ac system. That would let it charge off the panels, alternator and so on. It would have to be off most of the time as otherwise it would charge the ships batteries whilst charging from them creating a very inefficient loop. But when more than 2400W is needed I could flick it on (and it’s charger off) and do as described above. It’s like running a 2kW generator whilst cooking only less noisy and rechargeable. I think this should work so long as I limit the current draw from shore power on the inverter to 9A. I could even have remote switches for the charger and ac connection to the station at the cooker to make life easier. The more I think about this the more I think it should work. It’s effectively like having a second battery system with inverter charger only much more flexible and with greater redundancy.

[PirateFoxy]

Is there some reason why a small camping stove wouldn't work as an 'emergency backup' non-electric option, should the electric system have an issue? You still would have to have a bit of gas on board, of course, since they mostly use those little bottles, but the whole set up seems small enough to find a place to stash where if there was any issue it wouldn't be likely to cause major trouble? We've been shifting away from gas in our RV and that's what we do - the little bottles seem to last quite well if you're only using them here or there when the electric system isn't an option. (My SO has been gradually improving the whole set up in our RV so we have intermittent periods when stuff isn't hooked up for use, rather than any actual failures.)

I mean, I think if you were using it regularly then your need for little bottles would get quite ridiculous, but like I said, it'd be an emergency back up sort of thing, not for regular use, so if you found yourself unable to fix the problem preventing you from using the electric cooking options, I'd think you'd need to be heading to somewhere with some civilization anyway?

In any event, we're quite happy with induction/electric in our RV - one thing that's particularly nice about the induction is we have a portable unit (not built in) and so if it's a hot day the whole thing can be set up outside instead of heating up the interior living space if you have a suitable place to put it.

It is a bit of planning to not be running too much stuff at once, but not impossible, you just have to think though the order of things before you get started. (Handy trick: if you want to keep something warm while you cook something else, wrap it up in a spare blanket or some towels, it'll insulate it so it doesn't cool as fast. Works pretty well to keep stuff a nice temperature while you quickly cook some vegetables, for example.)

We do have a meter (I want to say it's a Kil-A-Watt but I may be mis-remembering and that's just the name that stuck with me) that we use to test out the actual demand of any potential new item (induction burner, baby rice cooker, instant pot, kettle, whatever) at home just to get accurate numbers to work with for what things do when we use them how we'd typically do things, since things have not always read their own spec sheets, but I don't know how absolutely necessary that is. Still it's been helpful to get an idea of how much power different typical meals actually use, so you can adjust your menu plan a bit to suit battery/recharge status as needed. (And to make sure the whatever it is won't draw too much - like I said, they haven't all read their own documentation. If something is too much of a power hog for what it does, then we just don't bother putting it in the RV, which is easier than having it take up space in the RV that could have had something more useful in it. )

[Na Mara]

Yeap. Plan A foxy was just to load manage. I’m going to put a color GX on the cerbo gx so I can do this without using my phone. I was going to put that at the nav station but as the cooker it the only thing I have that can overload the inverter it probably makes more sense to have the screen in the galley. I’ll try that first as it’s (a lot!!!!) cheaper and see if I can cook within the 2.4kW restriction. If I find I really do need more flexibility to cook with multiple hobs, kettle and oven at the same time then I think I will try the power station.

You do make a valid point that I could use a camping stove if I need extra hobs. I have one as a backup anyway, why not also use it as a second hob when required. Damn sight cheaper solution but a bit more faff, also permits outdoor cooking when desired. I also have one of those flameless charcoal barbecues that can be used like an oven.

Too many options. Need to think about this more.

[Kd9truck]

Originally Posted by PirateFoxy

Is there some reason why a small camping stove wouldn't work as an 'emergency backup' non-electric option, should the electric system have an issue? You still would have to have a bit of gas on board, of course, since they mostly use those little bottles, but the whole set up seems small enough to find a place to stash where if there was any issue it wouldn't be likely to cause major trouble? We've been shifting away from gas in our RV and that's what we do - the little bottles seem to last quite well if you're only using them here or there when the electric system isn't an option. (My SO has been gradually improving the whole set up in our RV so we have intermittent periods when stuff isn't hooked up for use, rather than any actual failures.)

I mean, I think if you were using it regularly then your need for little bottles would get quite ridiculous, but like I said, it'd be an emergency back up sort of thing, not for regular use, so if you found yourself unable to fix the problem preventing you from using the electric cooking options, I'd think you'd need to be heading to somewhere with some civilization anyway?

In any event, we're quite happy with induction/electric in our RV - one thing that's particularly nice about the induction is we have a portable unit (not built in) and so if it's a hot day the whole thing can be set up outside instead of heating up the interior living space if you have a suitable place to put it.

It is a bit of planning to not be running too much stuff at once, but not impossible, you just have to think though the order of things before you get started. (Handy trick: if you want to keep something warm while you cook something else, wrap it up in a spare blanket or some towels, it'll insulate it so it doesn't cool as fast. Works pretty well to keep stuff a nice temperature while you quickly cook some vegetables, for example.)

We do have a meter (I want to say it's a Kil-A-Watt but I may be mis-remembering and that's just the name that stuck with me) that we use to test out the actual demand of any potential new item (induction burner, baby rice cooker, instant pot, kettle, whatever) at home just to get accurate numbers to work with for what things do when we use them how we'd typically do things, since things have not always read their own spec sheets, but I don't know how absolutely necessary that is. Still it's been helpful to get an idea of how much power different typical meals actually use, so you can adjust your menu plan a bit to suit battery/recharge status as needed. (And to make sure the whatever it is won't draw too much - like I said, they haven't all read their own documentation. If something is too much of a power hog for what it does, then we just don't bother putting it in the RV, which is easier than having it take up space in the RV that could have had something more useful in it. )

There are many camp stove options, but I think the most useful would be the multi-fuel stove like the MSR whisper light Internationale, it can run on many fuels whit gas would be the best for the stove but it can run on gasoline, and diesel, and you can get a kit to hang the stove so it will gimbal if for some reason you can’t place it on top of a gimbaling stove.
Cheers