power inverter 12vDC to 240vAC

Discussion in 'OnBoard Electronics & Controls' started by sebski, Jul 17, 2008.

  1. masalai
    Joined: Oct 2007
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    masalai masalai

    Thank you Landie & Fanie - - a good read and learning opportunity....

    Would you guys like to "pontificate" on a system of electric drives, gensets (DC? as per polar power?), batteries and solar panels - - - Starting with electric drives of 10kW each and in modular form to achieve the rest as technology improves?

    I am not keen to pirate this thread, so, - - How about on my old thread (almost dead through apathy) here - http://www.boatdesign.net/forums/showthread.php?t=20633&page=6
     
  2. Fanie
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    Location: Colonial "Sick Africa"

    Fanie Fanie

    Hi Lubby, sorry I didn't do it properly the first time :D

    So in all of this - it is better to use a LA battery for starters of power motors, while the rest should work off SLA. The problem for most is that they do not know there are substantial differences between the LA and SLA's, and then getting a decent SLA charger is another matter.

    The well known LM317 voltage regulator makes a very poor charger for the SLA's, but is used widely since it's cheap, another case of you pay for what you get.

    Unfortunately wrt boats there are no really efficient power source. We got somewhat spoiled with petrol engines, but that luxury is on the fade. Solar power is expensive and very unefficient, wind power may be slightly better if you're in a windy area, but still not efficient enough. The combination of them is a bit of relief.

    A better source of energy may be using a radio active source, they can have long half-lives and in generating power via steam could make for some efficiency. Problem is going to be getting gov's to release the cap they've placed on the use of sources and mostly to educate people in the use of them. It is not a visible 'thing' and for some difficult to grasp, making it deadly if not used with the right procedures. I can just see the die hard DIY bunch jumping in this one :D

    Another source of energy is hydrogen, not developed to the point where it can replace fuel... and the concept of using pistons on an engine got everyone stuck there. Hydrogen burns at a high temp, I think it's 1400 deg C and could make for some efficiency. Generating it fast enough is another matter.

    One thing is for sure, we are not using energy as efficient as we can, like heating shower water while BBQ-ing and so on. It seems that if we do experience an oil resource collaps more would be done for other ways of energy generation, but until then, the oil co's and gov's are happy taking their big cut out of your few bucks, and they're the only ones smiling.
     
  3. Fanie
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    Fanie Fanie

    Mas, if you talk about 10kW of power... man that is a LOT !!! To give you an idea... one sq meter of SA sunligh has about 1000W of power available in it (according to the clever people). To be able to sustain your 10 000W you will need 10sq meter of sunlight, not accounting for losses, which is limited to about 8 hours per day and only on good summer days. 10 000W will draw a modest 833 amp off your 12V ;) while if you install the looooong mains cable to your boat then current at 230V would be about 44 amp :D Get the idea ?

    Let me put it into another perspective for you. A radio needs a few watts to talk to someone on the other side of the world, and here we are blowing thousands of watts on something else. Granted, not the same thing but I keep thinking the way we use power is a bit like candy floss.

    I have obtained a small phosphor radio active source with half life of I think it is 15 years. It's been at my bedside for about 10 years now, still happily glowing away day and night, never gets switched off, no power source, no charging it up, no sun or wind required, no putting petrol in it... it just keeps going. Isn't this the thing we should look at ? We could do away with sails all together, reserving them for fun sailing only, your radio active motor can run 24 / 7 with no emissions other that steam. Power on demand.

    I'm considering hi-jacking one of these nu-ki-lear (George Bush) submarines and use those power sources in my cat :D I'm sick of running around with smelly and expensive petrol... it so... so... old.
     
  4. CDK
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    Location: Adriatic sea

    CDK retired engineer

    Long before GPS was available I did a project for a dredging company, involving exact positioning of the ships in a harbor under construction. Before that time, they always made the shipping lanes deeper and wider to avoid conflicts and subsequent payment delays. My people developed a system with transponders on land at known positions and a receiver/computer system that calculated the position with better than 1 mtr accuracy.
    The system was successfully used in Abu Dahbi and other Gulf states where solar panels were employed to power the transponders, but in Alaska there was a power problem. We used propane burners there to heat a thermocouple array that delivered the required energy. It worked, but the changing of bottles was a nuisance, so we went searching for a better solution.
    We found a small company that sold us nuclear generators! A fairly heavy lead container with some nuclear waste in it, a thermocouple array and a giant heat sink on top, delivering 12V at 3 Amp for several 100 years. Very difficult to transport because all documents had to be forged and the cylinders were disguised as machine parts with several items on and around them that had noting to do with it.
    What happened with them afterwards I don't know, they may still stand somewhere along the coast of Alaska.
     
  5. Fanie
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    Fanie Fanie

    That's more like it ! But thermocouples ? Actually on boats this could work quite well if you have a source to generate heat and use the water to cool the other side down, like a heat exchange. Peltier devices has been around for some time althought just as blooming insiufficient as solars. Heating water for steam would be about the best and most efficient.

    As for the screening with lead - which is really heavy - there may well be other lighter materials that can be used for screening... depending what type of emmision the source does.

    I think it's time ET comes back and bring a couple of containers of the right materials with :D
     
  6. CDK
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    CDK retired engineer

    Fanie, I used the word thermocouple so most understand what I mean, but in reality it was a stack of rare metal semiconductors or TED's. A large piece of metal separated them from the heat source and caught the radiation particles so they couldn't degrade the semiconductor material. The TED's could be removed without exposing the radiation source.
    A complete unit was approx. 65 kilogram and had 2 carrying handles. There was a blower mounted on top of the heat sink but for Alaska they removed it.
     
  7. Fanie
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    Fanie Fanie

    Probably where global warming is comong from :D

    One thing that frustrates me a lot is that we are surrounded with very powerful nature elements, yet we are unable to make use of these resources. The sun, wind, lightning, waves on the sea, just to name a few. One lightning strike is aparently powerfull enough to supply a city for a year. We only get fried equipment from it.

    Now if Masalai can tap some of that power he may well have his electric boat, although I can imagine his hair standing streight and away from him like he's a van de Graaf generator :D
     
  8. masalai
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    masalai masalai

    Fanie, It stands up now...... "Electrifying!"
     
  9. Fanie
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    Fanie Fanie

    He he... which one :p
     
  10. masalai
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    masalai masalai

    Hey, I been radiated and glow in the dark too - all of them.....
     
  11. Fanie
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    Fanie Fanie

    You mean like one of those glow in the dark condoms he he he :p
     

  12. masalai
    Joined: Oct 2007
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    Location: cruising, Australia

    masalai masalai

    Don't like insulators, got to get rid (discharge the energy) somehow....
     
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