Re: Subject: <All> Negative Battery Cable Switch

[ChrisBourk@xxxxxxx]

Jeff,

The standard automotive battery doesn't seem to have evolved much over time
and one of the worst things you can do is let a battery sit.  As it
discharges, sulfate builds on the plates and no matter what anyone tells you
about the "Amp hour" rating of a battery - it just ain't so once the plates
start to sulfate (which is like immeadiatly)- that's why a 600 amp hour
battery can in fact only have 100 (if that) amp hour available.

FWIW,  I drive my M635 very rarely and had a similar problem.  Here is what I
did:

1) Optima 800U Battery
2) Battery Tender
3) Battery shut off switches (2)

Summer months: Battery tender on whenever the car is in the gararge.
Winter months: Battery swiches open and Battery tender on.

As a side benefit,  after installing the *overkill system*,  the dash gauges
are stable and everything just seems better - heater fan isn't intermitant any
more.  Also,  I think there will be a reduction in electrical component
failure with this system as there should (IMHO) be less heat in the electric
motors, switches etc (do to increased EMF).

<<In a message dated 98-10-31 17:15:39 EST, you write:

 Being a Naval Aviator, I frequently get to spend large amounts of time away
 from home.  During my last cruise, my 88 535i decided that the weekly drives
 and starts that it was getting while I was gone was not enough to keep the
 battery charged up.   As a result my wife wound up stranded when she was
 driving it one weekend.  Well, its time to go to sea again (only 6 weeks
 this time) and I want to take a different approach to the 5er this time.  I
 want to install a switch of some type in line with the negative battery
 cable.  I think this should be a nice mix between preserving the battery
 when the car is not driven for a period of time while still allowing my not
 so mechanically inclined wife the ability to drive the car if need be
 without having to figure out how to attach the battery cable.
 
 Has anyone done this before.  If so, any lessons learned?  Where can I
 get/what kind of switch should I buy.  Can Radio Shack meet my needs?
 
 TIA
 Jeff Wilcox
 88 535i 105K
  >>

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