Re: battery temperature sensor

From: jon@dakota-truck.net
Date: Sat Oct 23 2010 - 11:57:26 EDT


ffastje <ffastje@cox.net> wrote:

> On 10/22/2010 8:20 PM, Eric wrote:
>> What exactly is it used for on a 99 Dak?
>>
>> Is it just measuring temperature around the battery, or is it
>> really trying to measure the battery's temperature?

Yes, its trying to measure the battery temperature, though of course
the ambient temperature around the battery will have an effect on it.

>> The reason i'm asking is i'd like to know if putting an optima in
>> there would cause any charging problems.
>>
>>
> Running the optima red top in my 99 3.9 with no problems.
> I thing it regulates the output from the alternator.

That's correct; the battery temperature sensor is one of the inputs
which is used by the PCM to regulate the alternator's current so as to
control the battery's charging rate. (Output is higher at low temps
and is reduced as the battery warms up.)

The battery temperature sensor is also used to determine if certain
OBDII tests should be run, like the O2 sensor heater tests, leak
detection pump, etc. If the battery temp sensor reads below 20
degrees F, these tests are disabled.

The battery temperature sensor is also used as an input to the
transmission control module (on trucks equipped with an electronically
controlled automatic transmission such as the 42/46RE). If the
battery temp sensor reads below 23 degrees F, a shift to overdrive is
not allowed.

I wouldn't anticipate a problem with swapping to an Optima based on
the battery temp sensor. If you are concerned about it and want the
most accurate readings possible, as long as the sensor is touching the
bottom of the battery, the readings should be just as accurate as
stock. However, even if the bottom of the battery has a weird shape
and thus the temp sensor can't touch it, its still in the battery
tray, so I don't think you'd get inaccuracy to the point where it
would cause any problems. If anything, maybe your battery charge rate
would be a little higher than might otherwise be.

-- 
                                          -Jon-

.- Jon Steiger -- jon@dakota-truck.net or jon@jonsteiger.com -. | '96 Kolb Firefly, '96 Suzuki Intruder, Miscellaneous Mopars | `-------------------------------- http://www.jonsteiger.com --'



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