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1982 240D M/T White
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196 Posts
Discussion Starter #1
I would like some specific answers on installation.

The Optima 75-35 has the poles (+ and -) reversed and has both standard SAE posts and GM side bolt posts.

The reversed poles will looks ugly once installed and requires longer battery cables.

How long are original M-B cables, positive and negative ?

How long are replacement cables ?

I have thought about screwing in "charging posts" onto the GM side posts (at least for the + pole). Are brass or lead screw ins best ? (These posts allow standard cables to attach).

Should the battery be secured "on it's back" with the top posts pointing out ? Or is any other mounting reasonable (rotate battery 90 degrees with + post out and - post underneath ?)

Any experience and advise would be welcomed.

Best Hopes,

Alan
 

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1959 220S cabriolet, 1983 240D original owner, 1999 E300 turbo diesel, 1988 560SL, 2003 SLK320
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3,513 Posts
Buy the Optima with the reversed terminals. It's called a 35R. That's what generally works best on most Mercedes.

Len
 

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Mercedes 600
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1,171 Posts
I recently bought at Optima 35 for my Porsche. What a difference in weight!
 

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1982 240D M/T White
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196 Posts
Discussion Starter #4
I just installed it this evening. Laid it on it's side with the SAE posts facing out (positive towards engine) and GM "side" terminals facing up.

Battery was 1/8" wider than stock Group 49 battery so the clamps were ground down 1/8" inch to fit (no edge to clamp onto though). Also secured with bungee cord (may be updated).

The clamps stop front-back motion and even side to side motion, but limited up-down motion so I added the bungee cord.

Positive test circle (dime size section of lead or ? exposed on same side as SAE terminal) was covered with orange silicone for insulation.

Terminals bolted on easily !

Plan to add secondary ground wire from GM terminal now on top (add charging post) to engine strut.

A bit odd looking, but very functional !

Optima batteries can be mounted in a variety of ways, including on their side.

Best Hopes,

Alan
 

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'77 6.9, 74 240D, 96 Ram 5.9L Cummins
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2,654 Posts
I like those Optimas. I run them in all my cars although they are smaller but they have plenty of cranking power even when they have been drained considerably.
 
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