12V Dual Battery Isolation Kit with 140A Smart Battery Isolator (VSR Voltage Sensitive Relay) for Auto/Boat/RV

One review could not figure out what the blue light does. It turns on when the batteries are connected as when they are charging together. It turns off when one of the batteries drops to 12.7 volts which is when the batteries disconnect. Another review commented that it’s temperature range of 105 degrees is to low....the 105 degrees is centigrade or well above the boiling point of water. I was concerned about the clear plastic case being too flimsy, but it seems to be plenty solid once screwed into place. I did put strain relief on the two cables entering the device (rubber coated cable clamps screwed into the body) to keep the cables from putting any stress on the lugs in the base of the device. The electronics appear to be hermetically sealed even though the base area with the lugs is not.....does not need to be really. This is a very simple way to install a second battery. It does not allow one to use the second battery to start the engine, but one could always use jumper cables from the second battery to the starter battery. I installed the second battery to run a portable refrigerator during extended desert expeditions with my Tacoma truck. My only comment is the short screws that hold the base down require a smaller drill bit than the 9/64 bit noted in the instructions. The 9/64 bit works well for the long screws that hold the body of the device in place, although I went down a size on those for a better grip. I would recommend this to a friend. It greatly simplifies the installation of a second battery if using the second battery to power accessories.

I am giving this a 5 star rating for now as everything was package well, arrived quickly and in good working order. Iam using product connected to a 100ah battery to run a 3500watt inverter.Install was strategy forward as instructions written well.So far it is doing its job.However I want to use this some more before giving a full review. As of today I would purchase another if needed.I will give an update in 3 months.

This thing works great for charging an auxillary battery in your vehicle. I also have the one they make for UTV's and it works great also. Never had a seconds trouble with either of these.

Easy setup. Hasn't failed me yet. Failure would be running down my primary battery. So, it isolates as it should. Installation was not difficult, even for a woman with only basic knowledge of electricity. The star I deducted is for the price. Must have a considerable mark-up on it.

Needed a new battery and wanted to do a two battery installation so bought this unit. I bought two identical batteries and installed it on an '09 Silverado. Plenty of cable and other parts to do a two battery installation. Took about two hours. I like this unit since the two main lugs did not need to be connected to specific cables. The unit automatically senses which battery is which. This helps with locating the cable openings on the side of the isolator.Only thing I would advise is using little larger drills for the sheet metal screws. Called customer service with one question and was satisfied with timeliness and response. Works perfect and highly recommend this unit over the others.

I received this item on time when promised. The installation couldn't have been easier. Red cable from Positive battery terminal to isolator then Red Cable from Isolator to second battery positive terminal. Ground isolator with black cable to vehicle body or frame. Ground second battery to body or frame and your ready to go. No need to connect alternator to isolator with this product. So far it works perfect!

To put a battery in my cargo trailer to run an inverter,so I can keep the battery charged up.

I was highly dissappointed with this item. I have a 2013 gmc Sierra 1500 that I wanted to install a dual battery system to power my dash cameras and maybe other devices. It worked for about two days. It would constantly drain my starter battery and over charge my auxiliary battery. Thinking I may have wired the terminals incorrectly, I switched them and then it didn't work at all. I don't suggest this product, invest more into something decent.