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P80 - Getting home on battery power - House DC current measurements

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abscate
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Post by abscate »

I must have threatened to make this measurement for a decade now - I finally converged on hood up and ammeter in hand during my new career as a model

This thread answers the question - if my alternator dies, how long can I run on a full charged battery??

Idle house load is about 5-6 Amps through the kidney fuse box, confirmed by looking at the alternator resupply through the Positive battery cable

With lights and fan on it goes to 15 amps.

So to 50% battery, you will get 5 -6 hours driving time daytime, at night 2-3 hours dirving time, if you start with a battery at 100% SOC in good condition.

I would half those times for a battery over 3 years old.
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Empty Nester
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850 LPT
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Post by 850 LPT »

:lol: You have too much time on your hands
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Post by scot850 »

Does this work for all P80's? What about the 99- which don't like low voltages?

Neil.
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abscate
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Post by abscate »

You can probably squeak some extra time on a -1998 as it is less electronic. Poorer ignition efficiency and some more draws like IAC valve and such.

Battery at 50% on any electronic car (and transmissions are electronic too) is a good limit point - you are on borrowed time after that.
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Post by volvolugnut »

Your battery mileage may vary.
volvolugnutr
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abscate
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Post by abscate »

I seem to recall one of you guys had a kid in Colorado who had to drive on a battery. Did that experiment mesh with theory above?

Dirk or erikv maybe?
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