Battery Temperature Sensor

[jelag]

Has anyone tried to change or modify the battery temperature sensor to effect the charging voltage of the truck. . The thermistor under the battery helps adjust the charging voltage. . lower temperature higher charging voltage, higher temperature lower charging voltage.



Or can the dealer adjust this voltage with a scan tool?



Thanks. .



Jim

 

[Bob4x4]

There is no adjusting... ... .....

 

[rbattelle]

Years ago someone sent me some Cummins training materials which included sensor calibrations. The following data was listed under the heading "All Temperature Sensors":



32°F = 5k-7k ohm resistance

77°F = 1700 - 2500 ohm resistance

122°F = 700 - 1000 ohm resistance

167°F = 300 - 450 ohm resistance

212°F = 150 - 220 ohm resistance



You could alter this by installing a resistor between the sensor and the ECM. Use a potentiometer and you could adjust it on the fly.



If I were going to do it, I'd check the accuracy of the table first.



-Ryan

 

[jelag]

Ryan

I found last night a sensor (mopar) on ebay new for $23. I'm going to buy one, and than map a chart like what you just put on the board... than I'm going to find a potentiometer of the right value and solder it into the plug where I remove the thermistor... install it on my truck and play with it...

My only fear is that when the ECM sees the low temperature it will do more than raise the charging voltage and do something like cycle the hot air grid, or cycle the idle RPM trying to deal with a cold engine compartment and battery!!!

Wonder if SAG2 or Bob4X4 knows the answer to this...

 

[Bill Stockard]

Has anyone tried to change or modify the battery temperature sensor to effect the charging voltage of the truck. . The thermistor under the battery helps adjust the charging voltage. . lower temperature higher charging voltage, higher temperature lower charging voltage.



Jim

Why are you wanting to change the battery charge voltage?



Bill

 

[Bill Weber]

As Bill Stockard wanted to know "Why do want to change it?" There are a lot of posts about how long our batteries last. I had 7 1/2 years on mine when I replaced them only because I was driving to Alaska & didn't want to have problems in the middle of No Where. It would seem Dodge has done a good job of making our batteries last - IMHO I wouldn't screw with a good thing.

Bill

 

[rbattelle]

I believe the only thing impacted by the battery temperature sensor is the charging rate. But yours is a 2005, which may be a little different from my 2003.

At least in 2003 the grid heaters were cycled based on the IAT sensor, not the battery sensor.

An easy experiment once you get this thing wired up.

-Ryan

 

[AH64ID]

The temp sensor should only have a role in the charge rate, but like others have said, why?

 

[jelag]

OK guys...

When I was young I was trained to reset the voltage regulator to take care of special needs... I understand generator/regulator, alternator/regulator and starting circuits and can still draw them from heart...

When the truck is cold 35* the charging voltage is about 14. 4 and when the temperature rises to 80* that voltage drops to about 13. 9

Way back when, charging voltage was 14. 2-15. 5 on most cars and trucks...

I currently tow a 30 ft 5er and above average needs at night when we stop for the evening... I've ran 8 gauge wire from the battery, to the plug, to the trailer and back through the ground circuit... I still have 1/2 to 5/8 volt drop from the front batteries to the trailer batteries... I've rechecked the circuit and feel I can't do much better...

If you look at the chart to check the batteries with digital meter (fluke) when the batteries are at rest, mine are only about 70% charged. . If I had space I'd just install another battery...

The converter on the trailer holds the voltage at 12. 8-13. 2 when connected to shore power so when we unplug the trailers and pull away we're still not fully charged. .

In the old days, I'd just open the cover of the regulator and adjust it... I've thought about pulling the alternator and actually changing the field circuit and install a old fashioned regulator... heck if the charging voltage stayed at 14. 4 all day and didn't fall off with the heat. . I'm sure I'd be happy but once the engine heat soaks the engine compartment charging voltage drops to the 13. 9 figure... just not enough. .

I'd like to get this to the point where after 2 or 3 days of being on the road I can keep my better half happy with fully charged batteries and a warm RV at night. .

If you think I'm missing something here. . please share...

BTW I've checked each cell with a cell voltage test... all are within a . 1 volt, well within the standard... a cell voltage test is a better test than a hydrometer test... more accurate... and this cell test verifies I'm not fully charged... I'd rather add distilled water to the truck batteries every few months and have a happy wife... .

 

[AH64ID]

I wonder if you would benefit from a dealer flash. I run about 14. 9 on cold days and 14. 4 on hot days, and about 13. 6 to the camper battery with OEM wiring. After a 2-3 hour tow my batteries on the camper (2 group 24's) are at 100% charge (~12. 7V).

You may also look into a better converter, they can be had for under $200.

 

[Bob4x4]

18-003-06 REV. A flash includes improved Battery charging

 

[jelag]

This truck has not been back to the dealer since it was delivered... at 125K miles would there be a charge for this upgrade... 05 3500 early production... can't remember the month and year from memory

 

[AH64ID]

They probably would.

Do you know anyone with a Smarty? If they tune and de-tune your truck it should add the latest OEM software which should include the improved voltage.

 

[jelag]

I don't know anyone but I'm sure there's someone in Spokane..... but I'd take it to the dealer if the bill would be under $100

 

[kblranch]

You might look at a converter replacement from Progressive Dynamics. Bestconvert.com carries them. Four rates of charging. Direct replacement for the 5er converter.

 

[jelag]

KBL Ranch, the key is... we don't spend a lot of time connected to shore power... that's the key... a few weeks ago we were in the high 20's at night and the heater runs and runs...

 

[Shadrach]

Jim for your RV have you considered multiple 6 volts and a solar panel or two? Shad

 

[kblranch]

jelag same problem camping in my LQ horse trailer so I went and installed an Olympian Wave permanent mount catalytic heater from Camping World. T'd into the gas line going to the stove. Main heater rarely comes on now.

 

[K5IP]

Jim,

You mentioned the old days of adjusting the voltage regulator to over 15. 5 VDC.

If you do end up replacing your sensor (BTS) with a pot, be aware that 15+ VDC will make some of the newer electronics (computer) very unhappy.

If you do make a change, increasing the sensor resistance by placing an external series resistor or pot in the circuit will raise the voltage.

I still think this is a bad idea.

Rog

 

[p-Bar]

The old days as I remember max charge voltage was 13. 8 . I'm sure it's been bumped up'd for all the electrical demand today. Interesting concept Jelag