I’m installing an auxiliary battery in my 2006 LR3. I’ve read conflicting things regarding whether or not this vehicle has a smart alternator or not. A couple of questions …….

1. Does it have a smart alternator and do I need to connect that wire from my DC/DC charger?

2. Do I need to connect the ‘earth ground’ on my inverter??

TIA.

 

It has a smart alternator in the sense that the main ECU regulates its output. Output is based on both engine and exterior temps and maybe some other data. Most use a smart solenoid between them which works fine. If you are using a DC to DC, you should just be able to hook it up to the main battery and it will pull power just fine. Read your manual for the DC to DC to see if it needs a separate ground but you should not need to tap the signal from the ECU to alt.

 

Thanks Dakota! The charger doesn't need a separate ground but it does state that if using a smart alternator then a separate IGN wire I believe needs to be connected to a switched ignition source which ensures that the charger only operates while the engine is running. I have read that these alternators are 'smartish', but wasn't sure if they fall into the complete smart category to require me to need to connect this wire. Still researching whether or not connecting it without a smart alternator is bad...then I may connect it to be on the safe side.

 

Usually they just read voltage and turn on over a certain value, like 13 volts. Because a battery at rest is usually below 13, typically 12.5 to 12.8 is healthy. That is how my smart solenoid works which connects both batteries, one wire from it goes to the "back side" of the 12v supply form the other battery. When the solenoid senses this higher voltage, it waits 30 seconds and connects. When voltage drops, it disconnects. Your DC to DC I would think would work the same. Also if you are using just one aux battery, your DC to DC is probably overkill anyway. The only advantage to one is with larger power banks or very different battery types.

 

Got it… in everything I’ve researched it seemed the safest, easiest way was with a DC-DC charger. At least for my electrically novice self. Ha. So you don’t think that there’s a need to hook up that ignition wire?

thanks