ballystick 72 Posted February 8 Share Posted February 8 Now insurance companies coming down hard on gas systems, requiring gas certificates for systems that have been present in boats including production boats since launch date, 30 years plus. After my last gas cert bill of $1600 plus I am contemplating switching to LiFePo4 batteries, incuction hobs and an air fryer oven in a solar/alternator combo, has anyone completed this changeover locally, what size inverter and battery Ah sizing etc? Quote Link to post Share on other sites
LBD 128 Posted February 8 Share Posted February 8 Does beg the question... does anyone have any stats on gas related accidents, explosions or fires on boats in NZ? I do know of one in Port Douglas 25 years back, we heard it at home 4 km away... it was violent, split the nice timber ketch stem to stern and lifted the deck off. No body on board luckily. But how often does it happen? 1 Quote Link to post Share on other sites
K4309 257 Posted February 8 Share Posted February 8 Which insurance co Bally? Mine has just given 6 months notice I need both a hull and rig survey to renew. No issues with that actually, as we've owned the boat for 26 ish years so I was thinking about getting a hull survey anyway, just for my own peace of mind, and to deal with any issues before they become a cluster. I always get mixed up with the name of my insurance co, it's either Mariner or Nautical. Based in Chch at any rate, and loads cheaper than anyone that is underwritten by Vero. On the gas thing, are all the kero stoves out of production? As in, to get one you have to watch TradeMe like a hawk and / or bastardise parts and what not? Quote Link to post Share on other sites
CarpeDiem 430 Posted February 8 Share Posted February 8 2 hours ago, ballystick said: Now insurance companies coming down hard on gas systems, requiring gas certificates for systems that have been present in boats including production boats since launch date, 30 years plus. After my last gas cert bill of $1600 plus I am contemplating switching to LiFePo4 batteries, incuction hobs and an air fryer oven in a solar/alternator combo, has anyone completed this changeover locally, what size inverter and battery Ah sizing etc? Depending on needs you'll probably want to consider a 48v system with 2 - 3kwh of available power. With this you will want a 48v alternator and a 48v inverter probably a 3kw inverter so you're not running it at its limit... Your induction cooktop (assuming dual hob) will easily pull 2.8kw of you're running an oven at the same time as boiling water you could expect to top out a 3kw inverter. At this point you're up around $10k (and that's being really generous). You also need an engine with enough power take off available so you can motor and charge the batteries at 2-3kw, if you don't have that much excess horse power available then you'll need a smart alternator regulator that backs off the charge current as you speed up while motoring. You could technically do it with 12v but you'll be pulling some big cables around to carry sufficient power and the feasibility of this would depend on the layout and location of all your components... You'd need a kick arse full frame alternator that might not fit in your engine bay. If you have space for enough solar panels to generate 2kwh/day then you'd be up for another chunk of cash. What I recommend doing is purchasing a watt meter, an el cheapo induction cooktop and actually try living off it for a week, cook all your meals on it, boil your water on it etc, if you have a little oven plug that into it. Get an idea of how many wh you can expect to use per day and then size your system from that. https://www.bunnings.co.nz/arlec-energy-cost-electrical-meter_p4410270?store=9491&gad_source=1&gclid=CjwKCAiAlJKuBhAdEiwAnZb7lW36d22bqOs5a6oxZVI4FOwlRrG07gFY6kg9idRIIasrKWGpCmPIdRoCQ_EQAvD_BwE&gclsrc=aw.ds 2 Quote Link to post Share on other sites
Frank 157 Posted February 8 Share Posted February 8 9 hours ago, ballystick said: Now insurance companies coming down hard on gas systems, requiring gas certificates for systems that have been present in boats including production boats since launch date, 30 years plus. After my last gas cert bill of $1600 plus I am contemplating switching to LiFePo4 batteries, incuction hobs and an air fryer oven in a solar/alternator combo, has anyone completed this changeover locally, what size inverter and battery Ah sizing etc? On our Campervan the specs are 330 Ah Lifepo Battery, 13 V 3KW Inverter 440 W Solar We run a 2100W Plug in Induction plate 800W Kettle 800W Microwave Isotherm 12 V fridge (has a small freezer compartment) Rooftop vent fan runs 24/7 Lighting, stereo etc etc This system barely breaks a sweat and we will be adding a dedicated freezer later. So far the DC to DC charger has never kicked in ie Solar has been sufficient. Caveat, we don't boil a kettle or use the microwave while cooking on the induction hob. We have used the kettle and MW simultaneously just for laughs, and it was obviously no problem. Induction hobs regulate power uniformly down to about half power and then they go into some kind of Cycle on - Cycle off mode. For the type of meals we prepare I don't see the power draw going anywhere near the full 2100W. The Induction hob is the fastest cooking system I have ever used. Needless to say the van does not have any LPG and if I ever built another boat I would install the above system in a heartbeat but it was expensive. On the boat we have an Alcohol stove so gas not an issue. On another boat im involved with we had to create a sealed gas Locker and replace all the plumbing with plastic sheaved copper tube except for the last bit where it couples to the stove, we did all the work ourselves except for the final hook up and certification. That piece of paper cost us $1200 5 years ago. 2 Quote Link to post Share on other sites
Frank 157 Posted February 8 Share Posted February 8 Foot Note A while back we calibrated the system monitor and needed to take the battery down to about 10% . From memory we had to boil 36 jugs of water (1L) together with a heat gun on low power and all the lights one etc it took well over an hour as I recall and the solar was disconnected. Day to day we have never sucked it below 75% but that might change when we are in the SI in Autumn. Quote Link to post Share on other sites
CarpeDiem 430 Posted February 8 Share Posted February 8 2 hours ago, Frank said: Foot Note A while back we calibrated the system monitor and needed to take the battery down to about 10% . From memory we had to boil 36 jugs of water (1L) together with a heat gun on low power and all the lights one etc it took well over an hour as I recall and the solar was disconnected. Day to day we have never sucked it below 75% but that might change when we are in the SI in Autumn. 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 Quote Link to post Share on other sites
Bad Kitty 252 Posted February 8 Share Posted February 8 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? 1 Quote Link to post Share on other sites
Bad Kitty 252 Posted February 8 Share Posted February 8 Ballystick if you want to take a look at our set up you're welcome. I'm broken currently after shoulder surgery, so boat is sitting in the marina doing nothing! Quote Link to post Share on other sites
waikiore 399 Posted February 8 Share Posted February 8 When speccing gensets for launches I always asked whether they were looking at an induction hob, if so we often had to double the size of generator just for that consumer-problem then was for the rest of the time the genset was not being loaded enough and you get all the problems with slobber and short engine life -they love to be at 80% normally. Quote Link to post Share on other sites
ballystick 72 Posted February 8 Author Share Posted February 8 13 hours ago, K4309 said: Which insurance co Bally? Mine has just given 6 months notice I need both a hull and rig survey to renew. No issues with that actually, as we've owned the boat for 26 ish years so I was thinking about getting a hull survey anyway, just for my own peace of mind, and to deal with any issues before they become a cluster. I always get mixed up with the name of my insurance co, it's either Mariner or Nautical. Based in Chch at any rate, and loads cheaper than anyone that is underwritten by Vero. On the gas thing, are all the kero stoves out of production? As in, to get one you have to watch TradeMe like a hawk and / or bastardise parts and what not? It is VERO who specify the Gas Cerificate, my 30 year old boat needed it, then I looked at insuring another and the cert was needed there too! Quote Link to post Share on other sites
ballystick 72 Posted February 8 Author Share Posted February 8 2 hours ago, Bad Kitty said: Ballystick if you want to take a look at our set up you're welcome. I'm broken currently after shoulder surgery, so boat is sitting in the marina doing nothing! I'm in Tauranga, are you in Auckland? I travel up that way sometimes. It would be good to have a look, thanks Quote Link to post Share on other sites
ballystick 72 Posted February 8 Author Share Posted February 8 3 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 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 Quote Link to post Share on other sites
khayyam 68 Posted February 8 Share Posted February 8 Interesting discussion. Induction hobs use so much juice compared with normal yacht electrics that I never would have dreamed of it. I would think a lot would depend on how much solar you can get, and thus how much charge you have to get off the engine. 1 Quote Link to post Share on other sites
K4309 257 Posted February 8 Share Posted February 8 53 minutes ago, khayyam said: Interesting discussion. Induction hobs use so much juice compared with normal yacht electrics that I never would have dreamed of it. I would think a lot would depend on how much solar you can get, and thus how much charge you have to get off the engine. I understand a lot of world cruiser types are doing it now, as gas (LPG) is so hard to get hold of in the islands, or the bottles / connections / certifications are all different between various jurisdictions. Was just reading an old article in Yachting World about a British family who sailed Atlantic / Panama / Pacific, they rated their favourite item onboard as an electric pressure cooker (had some fancy brand name or something). I think they had an electric kettle as well. Sited the difficulty of getting gas. Their set up was 1,000 w of solar and I think 300 A/h of Lithium. Was on a cat with 2 x 30hp engines, no generator. I've heard of one of those Patreon account video blogger cruisers doing it too (I don't follow that stuff so don't have the details). As far as I can tell the advent of Lithium batteries make the current draw achievable, as well as rapid recharge acceptance, and a sh*t-tonne of solar in a sunny place (i.e. the tropics) covers the overall energy demand. Gives full autonomous energy for cooking, i.e. no diesel for generators. The rest is technical details, like 12v or 48v, cable sizing, inverter sizing and overall system set up (like max capacity of the induction hob). What I don't know, how does the oven work? Or do you go for alternative oven cooking methods like a slow cooker or pressure cooker? (I'm thinking bread mainly for long term cruising, but pies, pizza etc are all staples on our boat). In terms of the ultimate in autonomy, all you'd need is a water maker in addition to the solar / induction cooking, and you could sail forever... Quote Link to post Share on other sites
ballystick 72 Posted February 9 Author Share Posted February 9 I was thinking that it is more achievable now with LiFePo4 batteries that have greater charging and discharging rates -C- and cooking time being short mostly, the expensive part are the batteries, but there seems to be lots of set ups that conflict, I was thinking a 400aH battery with a 2000W inverter with dual input DC-DC charger solar/alternator limiting charging integrated with a automatic changeover switch in my existing 230V system Quote Link to post Share on other sites
Black Panther 1,587 Posted February 9 Share Posted February 9 Cooking time short?.a good roast takes over an hour. Quote Link to post Share on other sites
ballystick 72 Posted February 9 Author Share Posted February 9 57 minutes ago, Black Panther said: Cooking time short?.a good roast takes over an hour. Maybe, I could microwave the roast, that would be quicker! 1 Quote Link to post Share on other sites
khayyam 68 Posted February 9 Share Posted February 9 2 hours ago, K4309 said: I understand a lot of world cruiser types are doing it now, as gas (LPG) is so hard to get hold of in the islands, or the bottles / connections / certifications are all different between various jurisdictions. Was just reading an old article in Yachting World about a British family who sailed Atlantic / Panama / Pacific, they rated their favourite item onboard as an electric pressure cooker (had some fancy brand name or something). I think they had an electric kettle as well. Sited the difficulty of getting gas. Their set up was 1,000 w of solar and I think 300 A/h of Lithium. Was on a cat with 2 x 30hp engines, no generator. I've heard of one of those Patreon account video blogger cruisers doing it too (I don't follow that stuff so don't have the details). As far as I can tell the advent of Lithium batteries make the current draw achievable, as well as rapid recharge acceptance, and a sh*t-tonne of solar in a sunny place (i.e. the tropics) covers the overall energy demand. Gives full autonomous energy for cooking, i.e. no diesel for generators. The rest is technical details, like 12v or 48v, cable sizing, inverter sizing and overall system set up (like max capacity of the induction hob). What I don't know, how does the oven work? Or do you go for alternative oven cooking methods like a slow cooker or pressure cooker? (I'm thinking bread mainly for long term cruising, but pies, pizza etc are all staples on our boat). In terms of the ultimate in autonomy, all you'd need is a water maker in addition to the solar / induction cooking, and you could sail forever... 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. Quote Link to post Share on other sites
aardvarkash10 960 Posted February 9 Share Posted February 9 52 minutes ago, ballystick said: Maybe, I could microwave the roast, that would be quicker! Blasphemy!! Quote Link to post Share on other sites
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