fabius

So the electric shower is out then.... presumably that 86amps is only in the cabeling between the batteries and the invertor right? After that it's sent round the boat in 230v at 4.3 amps. Is that ampage a problem for the batteries or the wiring, i'm not planning on having an electric toaster but just so i know what the restrictions are. I'll have 230v sockets as most of my stuff for now is at that voltage. Is it normal for the ampage to get that high or do you just have to avoid high powered items all together.

The smaller of the donkeys it'll be then. I'll get onto the builder monday. You know when i think about it i already knew how efficient displacement craft were and it makes sense. The "stopping" bit however i had not thought of and your right about the mass so I wont want to go too small. I have the equation for the hull around here somewhere, i think it's the same one that we use to calculate handicaps in sailing races. As for hybrids well!! Sounds lovely but light bulbs a proving a challenge at the moment. It does seem like the logical way forward though with battery technology improving and getting cheaper. it would be uber efficient all right. Thanks for the help.

So if i'm factoring in 240v items does that mean that the amp's would be 20 times(ish) less than if they were 12 v. i.e........... a 12.8v item at 6amps = 76.8 watts the exact same same item 240v would be 240v x 0.32amps =76,8watts. ???? (Plus whatever power is lost in the inverter) THE MUD IS CLEARING...Here was me beginning to think that you somehow got something for nothing using 12v... Bloody Newton and his stupid laws!

Beyond me??? Well I never !!!! just kidding, actually i've just read the entire thing and the mud is beginning to clear and it's revealing more questions than answers. I have enough of it in though to start this power audit. Just one more question that the site doesn't explain(or i missed it). Whats the relationship between amps and watts?? Specifically i mean if bulbs are in watts why is the fridge in amps and how do i account for this. Cheers P.S. actually let me predict my next question and ask you to give me the formula for working it out too.... Maybe an example too.. Or would that be pushing it..

It needs another look so. I'd be happy to keep the £1500 for the upgrade in my pocket. It would go a long way towards other costs and the smaller engine would be cheaper to run. Any other opinions on the engine size??? Beta 55 or 75 on 60x12 widebeam keeping in mind it will have to be good for rivers and lakes. Anyone know if there are two alternators on Beta engines as Steelaway was saying. Would these be sufficient to charge a large bank??

I went with a 75hp upgrade from a 55hp (or something in that region because i'll be using it on rivers too and was worried that it will not make any headway up stream??? I could be way off as my backround is in marine craft and I don't have a huge amount of experience of displacement craft at that. 60x12 wide beam, I don't want to be screwing the engine the whole time to get anywhere.

thanks everyone for the contributions. Here is where i am so far.... with the power generation al least. 1.The petrol genny, used externally only, fed through the shoreline in 240v in principle will charge the batteries provided that the ampage on the charger is high enough. With lower amp charger this will not be practical because it will have to run for far too long each day and will cost a fortune in petrol. Correct??? 2.Of the other options an internal diesel genny is very expensive initially but cheaper to run and safer??? correct?/ 3.An altenator is a cheaper option but puts wear and tear on the main engine which is very expensive to replace but charges the batteries when under way. More questions so... I'm getting the idea that you are better spreading your eggs through a few baskets. Would i be best to continue with the external genny idea (with high enough charger ampage of course) and also get the mountings for an altenator installed so i can put it in when the cash is to hand? I could later (when the petrol one dies, or the petrol price kills me) add a diesel genny internally to the mix but for the moment cash is not in abundance. Does this seem like a reasonable way forward?? If so....How big should the altinator be?? Does it depend on the size of the engine?

Thank's for the post. I'm not mad on tow pathing it (it's very heavy) and it's not very nice to do either so i was thinking of mounting it internal and pulling the fuel tank off and placing it externally. I'm not new to boats and have some smarts about me as to the likely if not inevitable outcomes when petrol becomes a regular feature in your life but for the moment the petrol one is what i have and i'd like to use it if possible. I'm aware the petrol one is not a long term solution but this leads me to the question, Internal diesel genny or altinator off the main engine??? noise, reliability, cost, efficiency??? If i was to towpath the petrol should it be ran in through the shore power at 240v or should it go direct to the charger at 12v???? or do you need two shore power one 12v and one 240v?? Sooooo Mannny Questions So does this mean the genny would be best served feeding in through the shore power at 230v.??? It's a regular stand alone genny you'd find on any building site, the 12v connectors on it are quite small all right. Is this likely to effect the efficiency much??

ok power audit it is then.... how? I understand the principle of estimating useage over time but this is where i get lost. What info do i use, 1w led for 1 hr = ????. then there's the 5amp fridge on all day = ???. Do i work in amps, ahr, watts etc. Do i just get the information from the product i want to use or are there general rates for say a t.v. Cooking will be Gas Heating will be oil. Lighting will be led the fridge and the t.v. i would imagine will be the biggest draws. the laptop i'm sure could be charged in work. Also a friend told me that the bigger the battery bank the longer it will last because it will not drain as easily thus reducing the number of deep cycles it is likely to go through. Is there any truth in this? thanks again guys

Hi folks, I think this is my first post. I normally trawl through the forum archive for the answers to my questions (teadious but worthwhile) but in this case there is too much opinion, options and technobable for me to make any comfortable decisions. I have a 60x12 widebeam on order and i'll be fitting it out from sailaway myself. The one thing i'm really having trouble making progress on is the power system. At the moment i'm in the planning stage but have a good idea what i'll be doing with the rest of the boat systems but the power and batteries is just causing me confusion. As I said the boat is 60x12 widebeam and it will be used as a live aboard with little or no shore power available. There will be two people living on board and there will be the usual drain on the power from domestic items, lights, fridge, pumps. tv. laptop etc. nothing out of the ordinary. I'm planning on having 12v and 240v keeping the built in systems 12v to save on the inverter and the 240v for everything else. The principle i have followed generally with the rest of the boat system plans has been no waste.I've done this in the layout, heating and cooking systems, toilet(compost) and would like to do it with the power too. As such i would like to be able to charge off the main engine when it's running, the genny when it's not, shorepower where available and solar and wind panals would be nice in the future but i have no idea whats involved in this.What I have so far is... I have a lot of electrician friends to help assemble any system i decide upon, but they are the kind who scratch their heads when you mention batteries. I have a 2.5kw petrol(not ideal i know) generator with 12v and 240v feeds. The engine will be a Beta 75 with the regular altenator for the starter battery. The budget is limited(very) and I'd like to make use of the genny i already have if that is practical i'm aware of the safety implications of petrol The questions i suppose are.. What sort of batteries do i need and how many for a live aboard where we won't be listening to the genny all the time. We won't be regular cruisers. is it possible to have multipule sources feeding the batteries at once. If so how many and are there restrictions. Are there blueprints/ plans anywhere online for a system like this, the electrictian friends seem quite keen on these. Finally, how much and where?? If you've read this far, Thank you very much. Fabius. p.s. please keep the tech talk to a minimum or explain it if you have to thanks again.

Hello ther folks i'm new to the site. Is there any chance you could keep going naming off boatbuilders that you would recommend. I'm in a similar position and am looking to buy a widebeam to live aboard probably 60'x12.6'' and am looking to do some of the fit out ourselves (how much really depends on finances). We are looking at sailaways at the mo. Its our first boat so i'm thinking cheap as chips and learn my lessons from there but i don't want to be buying something thats flooded with quality control problems either just simple and reliable. Our first thought was the liverpool boat company but can't get in touch even after searching for details under their new name(i've read the differant comments about them but i'm still curious). I've looked at some other builders and prices vary considerably so it's all getting very confusing now and a bit'O'help wouldn't go a miss. Also some companies only do fully fitted. Is that very common? I'm not seeing how that makes sence. In short i'm looking for widebeam, sailaway builders who are reliable and at the lower end of the market? please help.