Dual battery setup
 

Setting my jeep up for dual battery system. I'm aware of the variable voltage alternator/Ecu setup. Has anyone found or know the mod so the alternator charges at a constant rate. I've found other vehicles have a simple mod or wire that needs disconnecting but can't find one on mine. It's a 2016 model. Any help would be great

I believe the dealer may be able to disable it. Never heard of any other way.

What voltage does it drop down to.


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I haven't checked the voltage drop I just know it has the variable voltage setup. there's a kit you can buy but it costs 5x more than the standard kit. Companies are obviously taking advantage and charging a hell of a lot more for the dc-dc isolation kits. I have done it on a navara before. It's just one green wire that needs to be disconnected and the regulator is disengaged providing a constant charge rate to the battery and your auxiliary when the iso switch engages it. Cannot find anything for the jeep!!

The alternator is controlled by a PWM signal from the Powertrain ECU. As it monitors the battery voltage the it would seem possible to use a voltage divider that could be switched in and out as required in the battery sense wire to artificially lower the voltage seen by the PCM and therefore fool it into producing a higher output voltage. As with all these mods.... caution and expertiese is advised otherwise the consequences could be expensive.

From the manual.....

OPERATION
The amount of DC current produced by the generator is controlled by EVR circuitry contained within the PCM. This circuitry is connected in series with the generators second rotor field terminal and its ground.

Voltage is regulated by cycling the ground path to control the strength of the rotor magnetic field. The EVR circuitry monitors system line voltage (B+) and battery temperature (refer to Battery Temperature Sensor for more information). It then determines a target charging voltage. If sensed battery voltage is 0.5 volts or lower than the target voltage, the PCM grounds the field winding until sensed battery voltage is 0.5 volts above target voltage. A circuit in the PCM cycles the ground side of the generator field up to 100 times per second (100Hz), but has the capability to ground the field control wire 100% of the time (full field) to achieve the target voltage. If the charging rate cannot be monitored (limp-in), a duty cycle of 25% is used by the PCM in order to have some generator output. Also refer to Charging System Operation for additional information.

I have the Ctek D250S controlling my under-bonnet dual battery setup and a second one controlling my third battery in the back.

They work fine and can be found for about A$300.