Efficient electric boat

Discussion in 'Boat Design' started by Jeremy Harris, Jun 22, 2009.

  1. Boucaneer
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    Boucaneer Junior Member

    Thank you Dennis,

    I will certainly try the 12" x 12" prop, A good place to start, thank you.

    Well from my looking online at specs of cordless drills, the Dewalt 995 in a brushless heavy duty drill with metal gear mechanism that may be the best dewalt drill use for heavy duty use. This may mean nearly continuous use, I have yet to try.

    One can buy the bare drill, no battery's or case or charger for around £100 pounds. I have two Dewalt 18v 3 Amp hour batteries I can test it with first, and if any good invest in two new 5 hour lithium battery packs.

    I have also read that the batteries can be refurbish once worn out and dead by taking apart abd adding new battery cells, maybe 18560's possibly. I have yet to research it.
    T
    So to keep building ones own batteries for many years would be good with simple components one can buy from electrical factory's.

    I will have a look and learn about the Makita 480. I'm not sure if the Dewalt 995 has a cut out circuit, it certainly didn't say it in the specs.
     
  2. Boucaneer
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    Boucaneer Junior Member

    The Makita 480 looks good Dennis, with 1500 rpm is a good speed, and the drill driver version doesn't have a hammer drill mechanism, which we don't need for propulsion.

    So does the Makita cut out often or may I ask, have you converted the drill abd bypassed/turned off the cutout circuit.

    I know the Cordless drill electric boat competition mostly use Makitas, and I think they also sponsor the contest to.

    I have only seen one old Dewalt drill be used as a trolling motor abd it wasn't the Dewakt 995 version.

    I may take a chance with the dewalt 995 as I have a cordless Dewalt Jigsaw and angle grinder with batteries and charger that I can use. Still if the Makita 480 has been proven to be a good drill it would be silly to rescrict myself to a Dewalt.

    I shall have a think about which drill to try.
     
  3. portacruise
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    portacruise Senior Member

    Just about anything will work for awhile, it depends on what your goals are. You need to know how many watts your drill uses at CONTINUOUS duty cycle (most not designed for continuous), and the gear ratio, because going over that will burn it up or throw amps or heat breaker. If you are drag racing and need max speed for a very short period before the battery dies, then the aggressive 12X 12 might be ok if there is no breaker for amps or thermostat for heat. Troll motors run at about 1200 rpm no load and have been upgraded with 10 X 6 model props, but they designed for continuous use and have a huge mass of metal to wick away the heat. I don't know how that would compare to a geared thimble size motor used in a drill. Generally, (my guess) you would want the largest drill motor with the greatest reduction available, say to 600-400 rpm maximum design speed in a drill for any kind of efficiency- if you want to get you more than several hundred yards. This recent thread may help: http://www.boatdesign.net/forums/boat-design/efficient-solar-powered-electric-kayak-52833-4.html

    Jeremy also has some pics of drill setup for a race that is run in UK using cordless drills and tools on this particular forum- you might try a search to see if anything helpful comes up.

    OE


     
  4. kerosene
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    kerosene Senior Member

    I don't quite get your worry. Tesla unit is a battery and just allows the use as a buffer for local renewable source (solar or wind, in practice solar as small wind units are pretty useless) or as a buffer to store electricity when its cheaper. For example here in Finland you can get electricity priced on the electricity market price. Means that it fluctuates a lot during the day and the week, with simple programming you could draw from grid when its the cheapest and from the battery when its costly. This is beneficial for the power companies as the price pretty much follows the supply/demand. Its everyone's benefit that the supply and demand variations would match.

    As solar and wind in large scale too are cyclical and vary based on weather having storage capacity only makes them more viable.
     
  5. Pericles
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    Pericles Senior Member

    I'm not worried. Solar does not generate electricity at night & they are long nights in Finland in winter, but batteries can be expensive. The Mastervolt MLI Ultra 24/5000 in the UK costs £4,788.95 including Value Added Tax.

    http://www.cactusnav.com/mastervolt-...h-p-14511.html

    Eight years ago, there were hopes for an ultra capacitor from EEstor. Alas, poor Yorrick!

    http://www.stockhouse.com/news/newsw...r-year-excuses

    http://bariumtitanate.blogspot.co.uk/

    What's the market value for a Prius with life expired batteries?
     
  6. kerosene
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    kerosene Senior Member

    Prius batteries have outlived expectations and guarantees. There is a well alive aftermarket for used prius batteries (at reasonable price) for other uses ie. there is no lack of well working used spares. Battery expiration is not an issue on Prius.

    Batteries are expensive indeed but things like Tesla will put the economics of scale into play (+ the branding that helps sell the idea to mainstream users). This will put downward pressure on pricing and drive the manufacturing costs down.
     
  7. Pericles
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    Pericles Senior Member

    I looked Prius prices on Autotrader. 2006 model 95,000 miles automatic £990 or €1,342. New Prius today, just under £22,000 or €29,920. Why? Depreciation is horrendous. The cost of battery replacement is like the Sword of Damocles.

    Best move is to buy a petrol fueled BMW in UK. It's resale price after 3 years is 50% of purchase price. A Citroen looses 70% over same period.
     
  8. portacruise
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    portacruise Senior Member

    I was guessing maybe several factors besides depreciation cause the low resale prices of the Prius. Oil prices and resulting supply/ demand curve might be contributors. At one point when oil was very high, the used Prius was selling for MORE than what was originally paid by the owners. Some owners sold for a profit in the US, and pocketed or later bought new models with the proceeds when they became available. So it might be time to buy used if you can get one with a replaced battery....

    I'm wondering how the Tesla battery scheme will help with the endless price increases for electricity. Seems like just a trade off of endless price increases for batteries, as lithium is far from being a plentiful resource. Electricity derived from unstable priced fuels is used for the the manufacturing of just about everything. What would be the break even point for solar energy if all the supports and subsidies were removed, and cradle to grave costs of toxic materials used in their manufacturing is considered?

    PC
     
  9. kerosene
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    kerosene Senior Member

    This is not my experience with prius. See below:
    http://losangeles.craigslist.org/sgv/cto/4998064324.html

    9 year old car.
    more:
    http://losangeles.craigslist.org/search/sss?sort=rel&query=2006 prius


    compare:
    http://losangeles.craigslist.org/lac/cto/5008721765.html
    or:
    http://losangeles.craigslist.org/lac/cto/4988650946.html

    check what those cost new.



    - Prius batteries are not toast at 100k miles.
     
  10. Zulu40
    Joined: May 2015
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    Zulu40 Junior Member

    that Prius has to be a wreck, the same year car in Au would be A$10k at least

    Prius batteries are under transferable guarantee (a guarantee for the life of the car not the owner) for free replacement should they fail before 100k miles or 160k Km, or 8 years.
    Factory replacement outside of warranty is around A$3-4k.
    There is a market for renewing / reconditioning them from about $1200

    This because, the Prius battery which is physically around the size of a suit case, floats between 75%-85% charge.
    The secret (if thats what it is) to its long life is it never goes or runs to flat.

    Prius is a hybrid car not an electric car, theres a difference
     
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  11. rafaelcoelho
    Joined: Jun 2011
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    rafaelcoelho New Member

  12. BertKu
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    BertKu Senior Member

    Very interesting manufacturer. Any idea, what you pay in the UK for them? Also, any experience on minimum quantities? Bert
     
  13. rafaelcoelho
    Joined: Jun 2011
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    rafaelcoelho New Member

    The first pack I bought was 16cells of 60Ah. I am now buying a second pack of 10 x 100Ah cells. Never had problem with the first pack but we didn't cicle it too much. Prices can be found at: http://www.ev-power.eu/Sinopoly-40Ah-300Ah/?cur=1
     
  14. BertKu
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    Location: South Africa Little Brak River

    BertKu Senior Member

    Thank you for this valuable website. I am using at present 3,9 kwh a mixture between LiFePo4 and Deep charging SLAB's, total weight just under the 100 kg. It would be advantageous for me to change to those batteries. I could save 70 kg. Thanks Bert
     

  15. Jamie Kennedy
    Joined: Jun 2015
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    Jamie Kennedy Senior Member

    A small wind turbine would be nice to include in addition to the solar panels.
     
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