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jaime66

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  4. 240v power?

    in Boat Building & Maintenance

    Posted

    10 minutes ago, WotEver said:

    This is something I've never understood with the aircon industry. If a unit has 2.5kW of cooling power, how come it only draws 1kW? Where does the other 1.5kW come from?

    Its green energy ....you need 1kw to run compressor 

     

  5. 240v power?

    in Boat Building & Maintenance

    Posted

    1 hour ago, nicknorman said:

    Modern engines like Beta 43 have a 12v 175A or greater domestic alternator, that equates to around 7 or 8 A at 230v having been put through an inverter. However these types of alternators are automotive ones and not really designed to produce a high output for a long time - they run too hot and fail prematurely.

     

    A better idea is a TravelPower (as just mentioned). This is a high voltage alternator feeding a “magic box” out of which comes up to 3.5kW at 230v 50Hz. Because the alternator is running at around 300v the current is low and so even though it is a similar physical size to a 175A 12v alternator, it runs much cooler and can easily produce your 4 or 5 amps at 230v.

     

    Oh and the only other thing to consider is the startup current of the aircon compressor. Whilst it may only take 4A when it’s running, I bet the start up current will be much, much higher, maybe approaching 10 times higher. Just for an instant, but if the Inverter or Travelpower can’t start the motor without cutting out from overload, it ain’t going to work!

     

    We have a 2.5kw inverter but it struggled to start up our small dyson vacuum cleaner due to the startup current surge.

     

    More generally, I would concentrate mostly on getting the best insulation. The roof will be far too hot to touch on a hot sunny day and the less of that heat that gets through to the cabin ceiling, the better. Light coloured paint makes a big difference as well. I’ve always thought about a sprinkler system that pumps canal water over the roof to keep it cool, but never actually tried it.
     

    Finally, boating is about calm and relaxation and if you have your engine running all the time it will be a nuisance not only to you, but also to anyone else within earshot. Fine when you are cruising, not fine when you are moored up in the company of other boats or moored outside someone’s house on lovely summer’s day.

    All modern AC units run with inverter to power the compressor so no high amp draw on start up ....if they can build Pyramids  sure we can get a AC unit to work lol 

  6. 240v power?

    in Boat Building & Maintenance

    Posted

    Sorry  should have said unit would only run when engine is running not off battery also 2.5kw a/c unit would be drawing 4/5 amps and would make unit water cooled so no hot air blowing on anyone ....

    1 hour ago, nicknorman said:

    I did wonder about that. Anyway, shouldn’t it be -2.5kw as it is extracting heat, not delivering it?!

     

     I wouldn’t like to be moored next to that on a hot day, pumping 2.5kw of heat in my direction!

    Would make the unit water-cooled  so no hot air blowing on anyone 

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