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#1
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Electric Outboard
Morning all,
I'm getting on good with this new hobby but we find that our old mercury 20 is damn noisy! We can spend 4-5 hours on the lake with a single tank of fuel so we're happy with that aspect. I've been looking at electric motors and note that to equal a 20hp petrol I will need some 400lbs of electric thrust. I think 6hp (120lbs) will do for our leisure time on the lake as there is a speed limit anyway. However, I am concerned about how long we will get out of a battery. Does anybody have experience of these things and how long a decent leisure battery will last with constant use? Is there anything else I could use? e.g. would an electric wheelchair motor give enough torque? How much torque would I need? I've considered looking around for a scrap seagul motor or similar and experimenting with different motors from the scrap yard. thanks in advance Tony Kenny |
#3
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Electric Outboard
Tony Kenny wrote:
("Paul E. Bennett") wrote in message ... In article "Tony Kenny" writes: snip So, a 12v 140 Amp-hour battery on a 4kW motor will last 0.336 hours? Or have I made a tits-up of the calculations there? At half speed that would give 1.344hours? Seems like I'll need an extension lead in the water with me try looking for heavy-duty milk float or oil rig batts. Or the larger yacht/boat batteries. I used to work with someone who was going to build an electrically powered canal boat. He was going to have a bank of oil rig batteries or the like, and an electric motor mounted inboard. His plan was to cover the roof with large sloar panels. He reckoned that for one days charging he could get one days cruising. This means either(a) travel every other day, then charge for a day or (b) travel at night and chage during the day. Look at solar and wind power to keep your batteries topped up. Simon |
#4
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Electric Outboard
In article
"Tony Kenny" writes: So, a 12v 140 Amp-hour battery on a 4kW motor will last 0.336 hours? Or have I made a tits-up of the calculations there? At half speed that would give 1.344hours? Seems like I'll need an extension lead in the water with me My bout is deep vee hull, 13' 6" long, 5' 6" beam I don't know what LOA, BWL and Draft are, sorry, I'm new to the whole boat thing, I usually stick with canoes and computers. If you have a displacement hull of those dimensions then the maximum theoretical speed would be 5.2kts. This speed would require an 800W motor to move it at that speed (assuming a reasonably efficient propellor. I think my outboard is worth about Ģ200 in its current state so it would be nice to be able to do all this within that budget or a little more, is electric going to prove v.expensive to get the same times on the lake that i do now? Ideally I'd like to get 10mph for 5 hours... mission impossible maybe? If you need to do that sort of speed at least a 4kW motor is needed. For that sort of duration then be prepared to put in a battery of about 20kWh capacity. This could be achieved with six Elecsol 270Ah batteries wired for 24 or 36V powering a LEM170 motor through a 4QD 300-36 motor controller. So the mission is possible only if you are into doing some quite intense engineering. I am sure you will find a suitable prop from the Piranha range. Angle gear-box need not be that complex. It will, though, all come at a price. The battery, motor, controller combination above is what I have on my 7 metre 2.1 beam 4-berth cruiser. I am not aiming for your high pace of travelthough and am expecting two days travel at a gentle 3 to 4 kts on most canals and rivers. The cost was about UKP2400 for all that including the bottom end of a Johnson 65 outboard leg. Mind you, I did get a good deal on the batteries. -- ************************************************** ****************** Paul E. Bennett Forth based HIDECS Consultancy .....http://www.amleth.demon.co.uk/ Mob: +44 (0)7811-639972 .........NOW AVAILABLE:- HIDECS COURSE...... Tel: +44 (0)1235-811095 .... see http://www.feabhas.com for details. Going Forth Safely ..... EBA. www.electric-boat-association.org.uk.. ************************************************** ****************** |
#5
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Electric Outboard
Now that the automobile industry reckon that fuel cell are the way forward,
and that by 2015, electric cars will be as common as diesels are now, long-term investment in electric boat conversions should bear this in mind. If fuel-cell electric cars become common, not only will an infrastructure of fuel and maintenance be available, but also both spares and retro-fit kits which would be ideal for boat conversions. |
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