I have a 2010 crew and installed a second battery with a isolator switch to connect the two batteries with a toggle. I have all of my aux lights (42" LED light bar and two 35a HID Spot lights) run off of the aux battery. While driving at night with all lights on and both batteries separated by the isolator the Ranger runs fine. However, as soon as I use the toggle to connect the two batteries (for charging purposes of the second battery after being out on the trail for a while), I can definitely feel a power loss. I don't know if it is because the Ranger charging system can't keep up or ???. When I disconnect the batteries, the Ranger's power picks back up.