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Regis turd ab user
Join Date: Dec 2006
Location: Tacomatose, Wa USA
Posts: 1,489
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Quote:
Mount it in the driver side box. The model is DF75 http://www.batterysales.com/sonnenschein_prevailerger.cfm Last edited by 911s55; 08-17-2008 at 08:26 AM.. |
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08-17-2008, 08:24 AM
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Registered
Join Date: Apr 2001
Location: Linn County, Oregon
Posts: 48,568
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One might work...the factory set up the '73RS lightweights with one battery to save weight. I ran two gel cell Sonnenscheins in my old car. BTW, I kept a "battery tender" hooked to the passenger side battery when not driving. Multimeter testing by myself confirmed that both batteries were charged to the same voltage by charging only one. Nevertheless, I would switch them from side to side from time to time.
Why the dual batteries? Two reasons...to increase the cranking amps, but also a weight distribution thing. I passed on all my records, books, etc. when I sold my car to my Istanbul friend, so don't have numbers to give you as a reference. A search here might help you...there have been many threads on this topic. I was a bit of a purist...but I was also quite happy with the dual sonnenschein gel cells. Soooo much better than the liquid batteries of old...no more worries of spilled acid eating out the battery boxes, battery fumes eating the trunk carpet, etc. Before gel-cells it seemed I was constantly cleaning the batteries & the battery boxes...
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"Now, to put a water-cooled engine in the rear and to have a radiator in the front, that's not very intelligent." -Ferry Porsche (PANO, Oct. '73) (I, Paul D. have loved this quote since 1973. It will remain as long as I post here.) |
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08-17-2008, 08:27 AM
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Student of the obvious
Join Date: May 2000
Location: Phoenix
Posts: 7,714
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I'm going to give it a shot with one battery. My car has no power accessories at all... not even a radio. I'd think my '82 alternator could handle it.
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Lee |
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08-17-2008, 09:38 AM
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Registered
Join Date: May 2002
Location: Portland, Oregon
Posts: 12,667
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Lee,
If you are doing just one battery, and do not mind a bit of simple fabrication, you might want to go with a Optima Red Top Battery (the one at Costco fits just fine). More power and when laid on it's side, fits in the battery box. As a plus, since it is a gel cell, no more worries about acid eating your car. You will need to disconnect the lead from the other (unused) battery and fabricate a hold down. I used a D ring to catch the clip at the back of the battery box and some metal strap plumbers use to hang pipe. The strap wrapped the battery from the rear hold down point (inside the box) to the factory bolt point in front of the battery.
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Harry 1970 VW Sunroof Bus - "The Magic Bus" 1971 Jaguar XKE 2+2 V12 Coupe - {insert name here} 1973.5 911T Targa - "Smokey" 2020 MB E350 4Matic |
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08-17-2008, 01:45 PM
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Student of the obvious
Join Date: May 2000
Location: Phoenix
Posts: 7,714
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The battery I ordered (see previous page) is an AGM battery, similar to the Optima (absorbent glass mat), but different in that it the plates are flat and not wound. Seemed like a good deal for $86 delivered.
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Lee |
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08-17-2008, 03:22 PM
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Registered
Join Date: May 2002
Location: Portland, Oregon
Posts: 12,667
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You are taking a huge cut in battery capacity.
The Red top Optima model 75/25 is rated at CCA=650A, CA=870A. The Miata Battery is rated at: CCA=320 CCA, CA=400A. Hopefully you will have enough oooomph when you need it. Let us know how it works out.
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Harry 1970 VW Sunroof Bus - "The Magic Bus" 1971 Jaguar XKE 2+2 V12 Coupe - {insert name here} 1973.5 911T Targa - "Smokey" 2020 MB E350 4Matic |
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08-17-2008, 08:49 PM
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Moderator
Join Date: Dec 2001
Posts: 9,569
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Lee, search here for posts on how to remove the "extra" battery cable. You do NOT want the free end of the cable to come loose and contact the fuel tank.
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'66 911 #304065 Irischgruen ‘96 993 Carrera 2 Polarsilber '81 R65 Ex-'71 911 PCA C-Stock Club Racer #806 (Sold 5/15/13) Ex-'88 Carrera (Sold 3/29/02) Ex-'91 Carrera 2 Cabriolet (Sold 8/20/04) Ex-'89 944 Turbo S (Sold 8/21/20) |
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08-18-2008, 05:53 AM
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Student of the obvious
Join Date: May 2000
Location: Phoenix
Posts: 7,714
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The battery I ordered is rated at 475 CCA. Since the car has no heat, it's never going to be driven in the severe cold. Wait a minute... this is Phoenix. The closest we get to severe cold is 45 degrees!
Yes, I'm going to remove the cable that runs to the passenger side. There's actually a post on how to do that? Is there something to it beyond, "Remove the cable?" 
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Lee |
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08-18-2008, 06:45 AM
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