Jump to content


Photo

portable power supply losses

  • Please log in to reply
5 replies to this topic

#1 cavefrog

cavefrog

    Surveyor 1

  • *****
  • Posts: 1959
  • Joined: 11 Nov 2008
  • Loc: loozyanna

Posted 15 May 2009 - 12:05 AM

My lx200 mount uses 18v. my power supply (battery) is only
12v. so therefore I have to use the battery, supplying an inverter, supplying a 110v ac power supply putting out the required 18v. I know I have something in the neighborhood of 40% losses each time the power goes through a(n) inversion/conversion. so the losses are pretty significant.
anyone know of another way to do this ,so that I can have lower losses and make better use of the power besides making rising updrafts? :mrevil:

Theo

#2 jrcrilly

jrcrilly

    Refractor wienie no more

  • *****
  • Administrators
  • Posts: 33792
  • Joined: 30 Apr 2003
  • Loc: NE Ohio

Posted 15 May 2009 - 12:10 AM

I know I have something in the neighborhood of 40% losses each time the power goes through a(n) inversion/conversion. so the losses are pretty significant.


That sounds very pessimistic. If both the upconverter and the downconverter are switchers, the efficiency of each is probably above 90%. If you want to do it in one hop, though, there are readily-available laptop car converters that'll deliver 18VDC from a 12V source.

#3 Lane

Lane

    Soyuz

  • -----
  • Posts: 3591
  • Joined: 19 Nov 2007
  • Loc: Frisco, Texas

Posted 15 May 2009 - 03:24 AM

When I owned my meade LX200 it came with a battery connection that went from the 12v battery to the 18v plug on the mount. There was just this small box in the line that did the conversion and it never heated up that I can recall. I am surprised your mount did not come with one. The 110v power adapter was a option I had to buy separately for my scope.

#4 jrcrilly

jrcrilly

    Refractor wienie no more

  • *****
  • Administrators
  • Posts: 33792
  • Joined: 30 Apr 2003
  • Loc: NE Ohio

Posted 15 May 2009 - 06:30 AM

When I owned my meade LX200 it came with a battery connection that went from the 12v battery to the 18v plug on the mount. There was just this small box in the line that did the conversion and it never heated up that I can recall. I am surprised your mount did not come with one. The 110v power adapter was a option I had to buy separately for my scope.


When new, those models were shipped with an AC supply and the 12-18V inverter you mention was an option.

#5 cavefrog

cavefrog

    Surveyor 1

  • *****
  • Posts: 1959
  • Joined: 11 Nov 2008
  • Loc: loozyanna

Posted 16 May 2009 - 12:23 AM

allright ...thanks....I have never seen a converter that plugged into 12v and del 18, and I have owned, and modified a lot of electronic equipment. that dont mean much though,one cannot know it all. I guess I will try at radio shack (generally useless place) or autozone? I can guess that ordering a 12v power supply converter from meade would be expensive. I bought my lx200 preowned and only got the 110v power supply with it. Thanks again.

Theo

#6 Lane

Lane

    Soyuz

  • -----
  • Posts: 3591
  • Joined: 19 Nov 2007
  • Loc: Frisco, Texas

Posted 16 May 2009 - 12:52 AM

When I owned my meade LX200 it came with a battery connection that went from the 12v battery to the 18v plug on the mount. There was just this small box in the line that did the conversion and it never heated up that I can recall. I am surprised your mount did not come with one. The 110v power adapter was a option I had to buy separately for my scope.


When new, those models were shipped with an AC supply and the 12-18V inverter you mention was an option.


I probably have it backwards, I ordered everything including the battery at the same time so am really not sure which was included and which was the accessory. But I think I used the AC power supply maybe 2 times, a battery was just much more convenient for me at that time.

Attached Files








Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics