Replacing on-board gas with lithium/solar & induction hob.

[Minerva]

There have been quite a few threads previously around replacing diesel propulsion with electric and the general consensus is not quite practicable.

However, on my dog walk today, I was wondering how practicable it would be to replace the gas system on board with electric/solar/induction hob? Presumbly we are much closer to that being suitable for UK based boats?

Let's set basis as an AWB, 35ft generic boat based in UK and occupied by a couple. Also assume that this is only to replace the gas system and all other domestic / fridge / instrument loads are already accounted for,

So in that case, how much wattage of solar panels and how many ah's of lithium would be expected to need to replace the gas system?

Thanks

 

[ctva]

Can you get a marine induction oven and grill?

 

[Minerva]

Can you get a marine induction oven and grill?

No idea! 2 'burner' induction hobs seem to cost the price of a couple of rounds in your local & there are a few Youtuber's who use them. For this cerebral exercise, lets assume you can.*


*This may be, in part, driven by the nuisance in trying to find gas last season...

 

[Keith-i]

This chap has done it. I'm not sure I've found exactly the video that details the battery and power considerations but it's there somewhere.

 

[lustyd]

Electric cooking is much, much less viable than electric propulsion unless you're living on shore power every day. The power required is simply too high unless you're on a very large catamaran covered in solar in a very hot place. Gas is fairly ubiquitous and convenient in most places, or alcohol stoves can work well too.

 

[srm]

I was recently on board a Canadian boat that used electric for cooking on an Atlantic crossing from Halifax to the Azores. They have a very large battery bank and ran a diesel generator every evening when cooking the main meal.

Do let us have feed back when you have your solar system up and running.

 

[geem]

How long does your gas bottle last at the moment? We have found some people hardly cook anything onboard whilst others are prolific cooks. If you are the former then you could convert to a lithium system at substantial cost and probably be ok. It's not just the batteries but the alternator and alternator regulator that cost substantial money. When you have spent several thousand pounds you may be asking yourself why you didn't keep the gas costing you probably less than £50 a season. On a 35ft boat you are unlikely to have space for sufficient solar to rely completely on solar for charging. You would need engine alternator charging. What you use with electric cooking you still need to put back.
For me the rush to lithium seems nonsense for the majority of people. Our true deep cycle batteries cost £600 and we expect to get several years out of them before we need to replace them. With lots of solar we make hot water for showers and washing up, we run an ice maker and every other domestic appliance through the inverter. All we lead acid batteries.
Give it five years and the lithium battery scene will be quite different and cheaper

 

[Minerva]

Electric cooking is much, much less viable than electric propulsion unless you're living on shore power every day. The power required is simply too high unless you're on a very large catamaran covered in solar in a very hot place. Gas is fairly ubiquitous and convenient in most places, or alcohol stoves can work well too.

But is it though?

I started at that thought, but lets say cooking for an hour total a day - that's probably near 2kw (through an inverter obviously). At 100% efficiency that's only 10 hours of 200w solar, so probably nearer 400w of solar.

My thinking was it may be more feasible than first presume.

 

[HissyFit]

This chap has done it. I'm not sure I've found exactly the video that details the battery and power considerations but it's there somewhere.

Sail Life haven't got their solar arch installed yet, and they are not starting their full time cruising life until that is sorted. In the meantime, they are continuing their fit-out in the marina.. For propulsion they are still Volvo Penta powered, and they have a generator for backup.

Sailing Uma, on the other hand, have been out there for a while, with various iterations of electric propulsion and an induction hob. I can't recall what other cooking facilities they have. They bought a diesel gen-set for their last escapade into the artic circle, where they were likely to be away from hook-up for extended periods.

The common denominator seems to be the need to return to shore-based supply every now and then.

 

[geem]

But is it though?

I started at that thought, but lets say cooking for an hour total a day - that's probably near 2kw (through an inverter obviously). At 100% efficiency that's only 10 hours of 200w solar, so probably nearer 400w of solar.

My thinking was it may be more feasible than first presume.

You forgot to add in all your other normal uses for solar. Recharging your batteries from overnight fridge use, etc. Our 740w of solar normally harvest about 2kw per day and we are not cooking on electric

 

[Minerva]

You forgot to add in all your other normal uses for solar. Recharging your batteries from overnight fridge use, etc. Our 740w of solar normally harvest about 2kw per day and we are not cooking on electric

Lets not go down that habit hole please.

As I said in my original post, my curiosity is around how much solar/batteries one would need to replace gas and that the 'normal' domestic load / solar was already accounted for.

 

[Hoolie]

... ... but lets say cooking for an hour total a day - that's probably near 2kw (through an inverter obviously). At 100% efficiency that's only 10 hours of 200w solar, so probably nearer 400w of solar.

You may be a bit pessimistic there. We have a single induction hob used when connected to mains power and I would say it is on a medium/high setting 1kW/1.2kW initially for a few minutes then gets turned down to 400W or even lower to complete cooking. I would guess no more than 0.8 kW/hr to cook a complete meal.

 

[syvictoria]

I was recently on board a Canadian boat that used electric for cooking on an Atlantic crossing from Halifax to the Azores. They have a very large battery bank and ran a diesel generator every evening when cooking the main meal.

So, they're actually cooking on diesel then!!!

 

[syvictoria]

Sailing Uma, on the other hand, have been out there for a while, with various iterations of electric propulsion and an induction hob. I can't recall what other cooking facilities they have. They bought a diesel gen-set for their last escapade into the artic circle, where they were likely to be away from hook-up for extended periods.

The common denominator seems to be the need to return to shore-based supply every now and then.

Don't Sailing Uma use an Origo (meths) ordinarily?

 

[bergie]

Sailing Uma, on the other hand, have been out there for a while, with various iterations of electric propulsion and an induction hob. I can't recall what other cooking facilities they have. They bought a diesel gen-set for their last escapade into the artic circle, where they were likely to be away from hook-up for extended periods.

Uma has an Origo alcohol stove as a backup.

 

[syvictoria]

Don't Sailing Uma use an Origo (meths) ordinarily?

Uma has an Origo alcohol stove as a backup.

There's an echo in here...!

I think the induction may actually be the backup?

 

[bergie]

I think the induction may actually be the backup?

Could well be. Our previous boat had a similar alcohol stove. Lovely to cook with.

 

[HissyFit]

Don't Sailing Uma use an Origo (meths) ordinarily?

Uma has an Origo alcohol stove as a backup.

There's an echo in here...!

I think the induction may actually be the backup?

It has been so long since they've been over their setup that I forgot that little detail. This makes more sense.

 

[rotrax]

Some Irish friends had the same model boat as we have. The first owner specified an electric oven and induction hob, powered by an 8KV Onan Genset.
When the cooker knob was turned, the Genset started.
The cooktop did not gimbal.
The whole thing, by the time they had the boat, was pretty poor. The Genset repair man was always out, they could not safely cook at sea and they both hated it.
I certainly would not consider it.
I totally replaced the 13 year old gas system on our boat in 2020, except the cooker. Nothing wrong with that.
Everything in the gas locker, right through to the cooker connection was replaced. Under 150 quid including a spare gas solenoid.
And I was within twenty feet of a boat that had a gas explosion on board once. The whole cabin top peeled off and chucked the owner into the Thames - with his beard on fire!
Gas does not frighten me, but I inspect frequently and ensure all is gastight after changing a bottle.

 

[Trident]

I have recently changed to all electric galley - 3kw inverter , 500Ah LifePo4 batteries and 1600w solar (at 38v with MPPT controllers so more like 2500w at 12v) I also had to up the internal 240v wiring to 32amp to the galley so that the induction hob, coffee maker, microwave and Ninja Foodie can all work happily

So far doesn't seem to be a problem - we've done away with a full oven as nothing has sensible power usage - the Ninja Foodie allows us to bake, air fry, slow cook, roast, pressure cook etc for 1400w and (other than the slow cook which uses less power) quite quickly so overall power use is minimal. We may have to change the microwave for one with a grill too as we can't now do cheese on toast etc but thats the only tweak we foresee so far.

We do have a small camping gas hob as our emergency back up if all electrics fail