Gas out, induction in!

[Black Panther 1,589]

I think when the time comes it might be easier to let the insurance lapse.

[Frank 157]

9 hours ago, CarpeDiem said:

What sized cables do you have on that? To meet the standard @ 240amps/3kw you'd need 70mm2 for a 1m distance between battery and inverter.

That's some pretty hefty cable

Off the top of my head I cant say as that work was done by Half Moon Bay Electrical , they also did the AC side and organized the Inspector for the compliance sign off.. 

I will check  it out later and report back 

[K4309 263]

2 hours ago, khayyam said:

1000w of solar on a cat in a sunny place, sure. You'd have to work pretty hard to get that kind of input on a mono in NZ. 

Those were just the examples I have seen. Certainly much easier with the tennis court sized cat for solar, and tropical sun.

No reason it can't be done in NZ, it's just I haven't heard of it, which also appears to be the OP's question. Obviously a charge source other than solar would be a bigger factor in NZ. But in saying that, many boats already run generators or have alternators that are comedy large anyway. 

The basic concept has been proven and is very good on tropical cruising boats though.

[Frank 157]

4 minutes ago, K4309 said:

Those were just the examples I have seen. Certainly much easier with the tennis court sized cat for solar, and tropical sun.

No reason it can't be done in NZ, it's just I haven't heard of it, which also appears to be the OP's question. Obviously a charge source other than solar would be a bigger factor in NZ. But in saying that, many boats already run generators or have alternators that are comedy large anyway. 

The basic concept has been proven and is very good on tropical cruising boats though.

On your typical radar arch on say a 40 ft offshore cruising yacht you would have near enough real estate for 400W , even if a bit shy,wing panels could be added.

Lithium batteries have substantially lower internal resistance so charge quite a bit quicker than AGM 

[K4309 263]

2 hours ago, Black Panther said:

I think when the time comes it might be easier to let the insurance lapse.

What is the magic trick to places that require 3rd party and or public liability?

Specifically hauling out? (I can already hear you say "don't go to marina's", but sometimes you really need to do something that needs public liability ins).

[CarpeDiem 430]

8 hours ago, ballystick said:

Thanks, CD, there are some pretty good set ups out there, 48V would be ideal for a new build. I have seen a few with 12v if you can reduce your usage possibly. If the inverter was mounted close to the battery then the current path would be quite short reducing the problem of cable sizing loss, then the 230V can be distributed longer distances with smaller cabling

You can't escape the cable requirements. 

Even at 50mm between your battery and your 3kva inverter you still need a 240amp cable which will be 75mm2.

You could derate your inverter by installing a switch board with 10amp breakers, but this will drive your cost up fast as it requires an electrician and a inverter that can have a MEN configuration. Most inverters used in 12v cheap installations are IT, they have the plug/socket on them and you shouldn't run multiple devices off a single plug. 

I am yet to find a 12v LFP battery on the NZ market that is rated for 1C discharge. Most are 0.5C. Victron have a 0.7C at 24v.  So already your into more expensive battery tech. An incorrectly sized cable on a 35deg day under the bunk is a fire hazzard waiting to happen...

3kva at 12v is extremely inefficient. 

I am not saying it can not be done, just getting it right and making it safe needs some fore thought, you could end up finding that for an extra 10% spent a 24v or 48v system is the more efficient option requiring less solar, a smaller alternator and a smaller battery. 

 

 

 

[Lindsay 31]

Does anyone here have experience with a diesel stove?

[Ex Machina 366]

10 hours ago, CarpeDiem said:

You can't escape the cable requirements. 

Even at 50mm between your battery and your 3kva inverter you still need a 240amp cable which will be 75mm2.

You could derate your inverter by installing a switch board with 10amp breakers, but this will drive your cost up fast as it requires an electrician and a inverter that can have a MEN configuration. Most inverters used in 12v cheap installations are IT, they have the plug/socket on them and you shouldn't run multiple devices off a single plug. 

I am yet to find a 12v LFP battery on the NZ market that is rated for 1C discharge. Most are 0.5C. Victron have a 0.7C at 24v.  So already your into more expensive battery tech. An incorrectly sized cable on a 35deg day under the bunk is a fire hazzard waiting to happen...

3kva at 12v is extremely inefficient. 

I am not saying it can not be done, just getting it right and making it safe needs some fore thought, you could end up finding that for an extra 10% spent a 24v or 48v system is the more efficient option requiring less solar, a smaller alternator and a smaller battery. 

 

 

 

Interesting idea . We have 24v to 240v with lifepo4 at home only 3kW of solar and 400ah of batts and it works a treat .we can’t have a spa pool but we do everything else no problem .

it would be pricey but switching the boat over to fully 240v is very attractive with a 24v start battery and 24v running lights etc . Induction is something that has been on my mind awhile as I can’t hear gas alarms and have seen a shed load of land yachts with induction hobs . Actually a guy living next door to where I work has the very same cheapo plug in hob you are talking about running off his inverter in his large camper I don’t know the specifics of his solar system but I do know he’s running AGMs .

 

[Ex Machina 366]

25 minutes ago, Lindsay said:

Does anyone here have experience with a diesel stove?

No but I looked at them in earnest when the govt announced LPG was being phased out . You can also get diesel induction hobs , bloody spendy but no more than going full electrickery to run an induction hob 

[CarpeDiem 430]

40 minutes ago, Lindsay said:

Does anyone here have experience with a diesel stove?

I looked at them but found the exhaust flu/chimney requirements just wouldn't work for our boat layout. 

https://wallas.fi/product/87-d/

 

[Ladyhawk 37]

Se tried one of those two burner westinghouse induction cookers on our boat for a while, we have 360Ah Lithiums at 12v and used a 3000w inverter, and yup 95sq mm cable less than a metre long. It pulled 200A... so you can do the math on that, we took it out and went back to gas.

With a big bank and good gear, maybe at 48v and lots of charging capability would work, but we are just too small.

That cooker was noisy as hell too, weird cyclic buzzing sound that got on our nerves lol

 

[CarpeDiem 430]

37 minutes ago, Ladyhawk said:

That cooker was noisy as hell too, weird cyclic buzzing sound that got on our nerves lol

Magnetostriction. The amount of this is more about the cookware than the cooker. But it's pretty hard to eliminate altogether... 

[LBD 128]

14 hours ago, CarpeDiem said:

I looked at them but found the exhaust flu/chimney requirements just wouldn't work for our boat layout. 

https://wallas.fi/product/87-d/

 

I have been having a look at those... would love to know of any around NZ and how well thy are liked.... or diisliked.

I am also trying to see if they can be gimbled and if not, what is the maximum pitch and heel angles.

[CarpeDiem 430]

4 hours ago, LBD said:

I have been having a look at those... would love to know of any around NZ and how well thy are liked.... or diisliked.

I am also trying to see if they can be gimbled and if not, what is the maximum pitch and heel angles.

Apparently they can be gimbaled. But I am at a loss to understand how you'd gimbal it with the exhaust requirements...

[LBD 128]

9 hours ago, CarpeDiem said:

Apparently they can be gimbaled. But I am at a loss to understand how you'd gimbal it with the exhaust requirements...

 

That is what I have been pondering... I have asked the OEM about gimbling and maximum angles they can be used at, but if anything, the exhaust would need to route near the pivot to have a little flex. I spent a couple of hours looking at You Tube  and other reviews and info. No gimbled images,  butthere were  a couple of mentions of sail boat installations which were not gimbled. One owner opted for a small hanging/swinging hiking stoves for basic cooking when offshore, another opted for using the the stove on an angle.... but certainly they are not getting a lot of sail boat applications yet.

 

[Guest 75]

With induction cook top I guess you could run the motor when in use to alleviate  loss to battery. Still need 75m^2 to inverter tho. 2Kw for 15min is 40ish Ah, correct? Not allowing for invertor losses, and @12.8V

When is the target extinction date for LPG?

[CarpeDiem 430]

2 hours ago, Guest said:

With induction cook top I guess you could run the motor when in use to alleviate  loss to battery. Still need 75m^2 to inverter tho. 2Kw for 15min is 40ish Ah, correct? Not allowing for invertor losses, and @12.8V

When is the target extinction date for LPG?

There's not really a date... Reality is the date will come and go and the only thing that might change is the price of gas... 

LPG will be replaced with bioLPG which is chemically identical to LPG, but can approach net zero emissions.   You could replace your 9kg cylinder with bioLPG today and there'd be no difference, your appliances would operate exactly the same. 

The Government pipe dream of a 2050 net zero New Zealand signals that the transition will happen in the next 25 years

Yes, approximately 40Ah at 12v. 

 

[Adrianp 120]

We have 600ah of Lithium on 12v with a 3000w Victron inverter, 1.2kw of solar & 175A Balmar alternator. 

We've been cooking on a cheap single benchtop induction hob for about 3 years now and also recently added an air fryer. We haven't turn the gas bottle on for about a year now and are about to rip it out as I'm expecting the insurance company to ask us to get it certified.  

Yes we sometimes pull 200+ amps out of the batteries but that's what they are designed for. 2 x 50mm2 cables for both positive and negative side of the inverter cables.

Our setup gives us about 3 days on anchor with no solar, so need to motor to a new bay then!

 

[Black Panther 1,589]

A single hob isn't really cooking is it?

[raz88 96]

On 9/02/2024 at 9:36 AM, Bad Kitty said:

Bad Kitty has had a 2 element induction hob from day 1. Had AGM batteries, then Li ion, and did change the induction top to an off grid model that runs a max 2KW draw. If you crank one element up to high it drops the other one back to stay under the 2K. But even the original was fine. They are so grunty it's hard to imagine having 2 elements running on high.

They suck some power to get up to temp, but then consumption drops back quickly.

I was keen not to have gas inside the boat, then during construction was thinking I was being paranoid, and then a sailing cat at Opua has a gas explosion than peeled half a deck off & blew a guy into the water, and I let paranoia run free.

12v system & inverter, you don't need 48v as earlier suggested.

No regrets, I'd do it exactly the same again, but if you had a boat set up with low draw, low charging, and small battery capacity it may take some work/spend to get there? 

Assuming the cat in opua was 20 years ago this year or next, I had a workmate who was friends with owner and heavily involved in the recovery. Accident was caused by a freestanding lpg heater that wasn't part of the boats systems or anything to do with cooking (and the kind of thing that even a boat with a gas cert could have brought aboard with minimal thought about insurance/risk).

Another option rather than going lithium/large capacity battery bank is to consider a genset, and just run genset when cooking. Obviously impacts the serenity, but when done in conjunction with/as a backup to a completely outdoor bbq setup may be worth considering? I know of a few raceboats who've gone this way with a microwave.