External Voltage Regulator

[mjonesjr84]

Since before I put an AGM battery in my 2000 TJ, I was only getting about 12.5v of charging after the engine warmed up. With the AGM battery, this is not enough voltages to keep the battery healthy. I tried plugging in a HP Tuners MPVI3 and upping the voltage in the program, but the option was not there for mine. This morning while moving my TJ around in the driveway, I saw 13.5v on the Torque app running on my radio. That is the highest volts I've ever seen on it. It was 31*F this morning. I'm assuming that the battery temp had something to do with the extra voltage. I do have the factory battery temp sensor.

In searching, I found these kits that are an external adjustable voltage regulator. Has anyone installed on or something similar?
https://alternatorparts.com/external-voltage-regulator-high-output-alternator-kit.html

 

[CMBD]

Have not done it on a TJ but googlz looks like it could be a thing maybe.

Could a one wire alternator setup be possible on a TJ?

You would need an internally regulated alternator, but they just do their thing set up like this. Just blip the throttle on startup to excite the field and get 13-14v at idle.

 

[machoheadgames]

Usually people only install the external regulators to solve a bad-PCM problem when the regulator built into it goes bad. That is why the kits exist. You could probably use it to do what you’re wanting, though.

Are you basing your stated charge voltage solely off of reading the OBD? Historically, most vehicles underreport voltage at the OBD. So if that’s all you’re going off of, put an actual meter on the battery to see where it actually is charging. Typical would be about 13.2V when warm. I’d be surprised if it was truly as low as 12.5V, as that isn’t even keeping a stock battery fully charged.

In all reality, no vehicle charges an AGM truly properly. Simply upping the voltage doesn’t really give the AGMs what they want either. They want smarter charging profiles than what a stock vehicle alternator puts out. Even so, most AGMs that are good quality last a while regardless of how the vehicle charges them. My opinion would be to not sweat it that much unless you’re having actual problems. If your charging system is truly only putting out 12.5V, I would expect you would have problems no matter what battery you had installed.

 

[mjonesjr84]

Good info. I do need to stick a volt meter on my battery to see what it is to confirm. I just know when running all day and I put my NOCO AGM charger on the battery it is always showing low charge. I keep the battery plugged in when not driving it since I don't drive it often.