Groups > sci.electronics.design > #460485

Re: Forever Power (almost)

Subject	Re: Forever Power (almost)
References	<4rblhc5ncr4rtco0ufjrg6subd7mtdjnmd@4ax.com>
Newsgroups	sci.electronics.design
From	Clifford Heath <clifford.heath@gmail.com>
Organization	Tell him he's dreaming
Message-ID	<g1ASA.103648$jo6.5086@fx33.iad> (permalink)
Date	2017-05-16 17:56 +1000

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On 16/05/17 18:11, oldschool@tubes.com wrote:
> This is just a stupid idea that I had, which will acomplish nothing,
> other than see how long it lasts.
>
> I dont know how much a standard 12V 5 amp battery charger requires from
> the 120Vac power line, but I read it was around 150 watts.

I wouldn't buy a charger that wastes twice as much power as it delivers.
It's very easy to do better than 30% efficiency, in fact, it's hard to
do that badly. The crappiest transformer-based charger will waste less
than 20 watts.

> So, lets say I connect a 200W inverter to a car battery. Then plug into
> that inverter, a 12V 5A battery charger, and connect the leads from that
> charger to the battery that is powering the inverter.

> So, it's an endless loop, the power being drained from the battery is
> being recharged by itself thru an inverter and battery charger.

> How long would this actually work? I know there is going to be some loss
> due to heat in the inverter and the charger too, so this really would
> not last forever, but just how long would it last????

You said the charger wastes 100W. The inverter will waste some too,
say 40W (80% efficient). So you have a net 140W drain on the battery,
or 12amps. A mid-sized car battery is 60 amp-hours, so it'll last
less than five hours, turning all the stored power into waste heat.

Clifford Heath.

Thread

Forever Power (almost) oldschool@tubes.com - 2017-05-16 04:11 -0400
  Re: Forever Power (almost) mike <ham789@netzero.net> - 2017-05-16 02:24 -0700
    Re: Forever Power (almost) Aussie <aussie@none.com.au> - 2017-05-16 19:36 +0800
  Re: Forever Power (almost) Clifford Heath <clifford.heath@gmail.com> - 2017-05-16 17:56 +1000
  Re: Forever Power (almost) John Larkin <jjlarkin@highlandtechnology.com> - 2017-05-16 07:06 -0700
    Re: Forever Power (almost) tabbypurr@gmail.com - 2017-05-16 07:10 -0700
      Re: Forever Power (almost) rickman <gnuarm@gmail.com> - 2017-05-16 10:14 -0400
    Re: Forever Power (almost) George Herold <gherold@teachspin.com> - 2017-05-16 08:48 -0700
      Re: Forever Power (almost) John Larkin <jjlarkin@highlandtechnology.com> - 2017-05-16 09:01 -0700
        Re: Forever Power (almost) tabbypurr@gmail.com - 2017-05-16 09:10 -0700
    Re: Forever Power (almost) bitrex <bitrex@de.lete.earthlink.net> - 2017-05-20 07:40 -0400
  Re: Forever Power (almost) Tim Wescott <tim@seemywebsite.really> - 2017-05-16 10:03 -0500
  Re: Forever Power (almost) krw@notreal.com - 2017-05-16 12:34 -0400
  Re: Forever Power (almost) Jon Elson <jmelson@wustl.edu> - 2017-05-16 13:28 -0500
    Re: Forever Power (almost) mike <ham789@netzero.net> - 2017-05-16 15:15 -0700
  Re: Forever Power (almost) bloggs.fredbloggs.fred@gmail.com - 2017-05-16 14:24 -0700
  Re: Forever Power (almost) Rheilly Phoull <rheilly@bigslong.com> - 2017-05-17 09:25 +0800
  Re: Forever Power (almost) Jasen Betts <jasen@xnet.co.nz> - 2017-05-18 20:38 +0000
  Re: Forever Power (almost) jurb6006@gmail.com - 2017-05-18 15:42 -0700
    Re: Forever Power (almost) Jon Elson <elson@pico-systems.com> - 2017-05-19 23:02 -0500
      Re: Forever Power (almost) mike <ham789@netzero.net> - 2017-05-19 22:05 -0700
      Re: Forever Power (almost) Neon John <no@never.com> - 2017-05-27 10:43 -0400
        Re: Forever Power (almost) tabbypurr@gmail.com - 2017-05-27 09:23 -0700
          Re: Forever Power (almost) krw@notreal.com - 2017-05-27 14:35 -0400
            Re: Forever Power (almost) tabbypurr@gmail.com - 2017-05-27 11:41 -0700
              Re: Forever Power (almost) krw@notreal.com - 2017-05-27 19:58 -0400
                Re: Forever Power (almost) tabbypurr@gmail.com - 2017-05-27 17:36 -0700
          Re: Forever Power (almost) Jim Thompson <To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> - 2017-05-27 12:15 -0700

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