how can I bypass that so my battery charge at 14 all the time when the truck warms up it dropes to 13.2

 

I wouldn't suggest it. It's there to keep the battery from overcharging. It works off the heat buildup in the battery casing. Bypass it and you run a good chance of exploding your battery.

 

I agree. It's there to aid and support an longer lasting and more reilable battery life as well as alternator life.
Charging syste,s do run at 14.4v when running, but that is because there are loads on the system. Batteries are rated at 12v and sit idle at 12.68v


The sensor is likely an open ground so you could try unplugging it to see if it helps. if not, then that means it's a safety design and you would have to run a jumper wire across the terminals(of the plug) I'd have to look at schematics to be completely sure, but there's prob a thermistor and even when it allows full charge, there's still some resistance on the circuit...

If you have battery issues like dim lights and such, you could have a dead cell or two on the battery even though it shows full charge. I would suggest having your system checked or testing it yourself with a meter.
Bettery Testing

 

Even more, you should download the service manual from the links in my signature and read what all exact the batt temp sensor does and how the PCM reads info from it. It does a lot more than help regulate voltage

 

i want to do a dual battery set up so i just want the alt to charge at 14 not 13.3

 

Battery voltage will vary and change depending on several things. Ive got a dual battery setup and have no issues

 

Haaving dual batteries doesnt make the need for the charging voltage to be increased. The only thing that changes, is the time it takes to charge the battery IF you drain them down a bit. I'd reccomend an isolater or else when you drain one, you actually drain both at the same time as one will pull from the other. Use one for your truck, and the other for accessories.
Unless you have a winch or some other device that drains the battery excessively when not running...a 2nd battery isn't needed and won't actually help any.
Guys with stereo's who have additional batteries install upgraded alternators that have the charging capabilities and that is what makes the additional batteries worth having.
Just dont want to see you put $200+labor into your ride for no good purpose. It's your ride though.haha

 

I have the stinger isolator am going to use

 

You should check out this video on my Big 3 upgrade with dual batteries

http://youtu.be/Lz1DNZCzBLc

 

great video am going to do it this weekend ill let you know how it goes